Merge pull request #6 from emeraldpay/feat/normal-request-flow

refactor request flow

build.gradle

@@ -81,7 +81,6 @@ dependencies {
     implementation "io.infinitape:etherjar-hex:$etherjarVersion"
     implementation "io.infinitape:etherjar-rpc-http:$etherjarVersion"
     implementation "io.infinitape:etherjar-rpc-ws:$etherjarVersion"
-    implementation "io.infinitape:etherjar-rpc-emerald:$etherjarVersion"
     implementation "io.infinitape:etherjar-tx:$etherjarVersion"
     implementation 'org.bitcoinj:bitcoinj-core:0.15.8'
 
@@ -125,7 +124,7 @@ compileTestKotlin {
 
 test {
     jvmArgs '-ea'
-    testLogging.showStandardStreams = true
+    testLogging.showStandardStreams = false
     testLogging.exceptionFormat = 'full'
 }
 
@@ -199,4 +198,38 @@ task generateVersion()  {
         ].join("\n")
 
     }
+}
+
+// Show the list of failed tests and output only for them, helpful for CI
+ext.failedTests = []
+tasks.withType(Test) {
+    def stdout = new LinkedList<String>()
+    beforeTest { TestDescriptor td ->
+        stdout.clear()
+    }
+    onOutput { TestDescriptor td, TestOutputEvent toe ->
+        stdout.addAll(toe.getMessage().split('(?m)$'))
+        while (stdout.size() > 100) {
+            stdout.remove()
+        }
+    }
+    afterTest { TestDescriptor descriptor, TestResult result ->
+        if(result.resultType == org.gradle.api.tasks.testing.TestResult.ResultType.FAILURE){
+            failedTests << "${descriptor.className} > ${descriptor.name}"
+            if (!stdout.isEmpty()) {
+                println("-------- ${descriptor.className} > ${descriptor.name} OUTPUT ".padRight(120, "-"))
+                stdout.each { print(it) }
+                println("================".padRight(120, "="))
+            }
+        }
+    }
+}
+gradle.buildFinished {
+    if(!failedTests.empty){
+        println "Failed tests for ${project.name}:"
+        failedTests.each { failedTest ->
+            println failedTest
+        }
+        println ""
+    }
 }

src/main/kotlin/io/emeraldpay/dshackle/cache/BlocksRedisCache.kt

@@ -93,6 +93,7 @@ class BlocksRedisCache(
                 Instant.ofEpochMilli(meta.timestamp),
                 false,
                 value.value.toByteArray(),
+                null,
                 meta.txHashesList.map {
                     TxId(it.toByteArray())
                 }

src/main/kotlin/io/emeraldpay/dshackle/cache/Caches.kt

@@ -22,6 +22,7 @@ import io.emeraldpay.dshackle.data.TxContainer
 import io.emeraldpay.dshackle.data.TxId
 import io.emeraldpay.dshackle.reader.CompoundReader
 import io.emeraldpay.dshackle.reader.Reader
+import io.emeraldpay.dshackle.upstream.ethereum.EthereumFullBlocksReader
 import io.infinitape.etherjar.rpc.json.BlockJson
 import io.infinitape.etherjar.rpc.json.TransactionJson
 import org.slf4j.LoggerFactory
@@ -158,11 +159,11 @@ open class Caches(
     }
 
     fun getFullBlocks(): Reader<BlockId, BlockContainer> {
-        return EthereumBlocksWithTxCache(objectMapper, blocksByHash, txsByHash)
+        return EthereumFullBlocksReader(objectMapper, blocksByHash, txsByHash)
     }
 
     fun getFullBlocksByHeight(): Reader<Long, BlockContainer> {
-        return BlockByHeight(blocksByHeight, EthereumBlocksWithTxCache(objectMapper, blocksByHash, txsByHash))
+        return BlockByHeight(blocksByHeight, EthereumFullBlocksReader(objectMapper, blocksByHash, txsByHash))
     }
 
     enum class Tag {

src/main/kotlin/io/emeraldpay/dshackle/cache/TxRedisCache.kt

@@ -59,7 +59,10 @@ class TxRedisCache(
     fun toProto(value: TxContainer): ByteArray {
         val meta = CachesProto.TxMeta.newBuilder()
                 .setHash(ByteString.copyFrom(value.hash.value))
-                .setHeight(value.height)
+
+        value.height?.let {
+            meta.setHeight(it)
+        }
 
         value.blockId?.value?.let {
             meta.setBlockHash(ByteString.copyFrom(it))

src/main/kotlin/io/emeraldpay/dshackle/config/UpstreamsConfig.kt

@@ -86,19 +86,21 @@ class UpstreamsConfig {
 
     open class UpstreamConnection
 
+    open class RpcConnection : UpstreamConnection() {
+        var rpc: HttpEndpoint? = null
+    }
+
     class GrpcConnection : UpstreamConnection() {
         var host: String? = null
         var port: Int = 0
         var auth: AuthConfig.ClientTlsAuth? = null
     }
 
-    class EthereumConnection : UpstreamConnection() {
-        var rpc: HttpEndpoint? = null
+    class EthereumConnection : RpcConnection() {
         var ws: WsEndpoint? = null
     }
 
-    class BitcoinConnection : UpstreamConnection() {
-        var rpc: HttpEndpoint? = null
+    class BitcoinConnection : RpcConnection() {
     }
 
     class HttpEndpoint(val url: URI) {

src/main/kotlin/io/emeraldpay/dshackle/data/BlockContainer.kt

@@ -20,6 +20,7 @@ import com.fasterxml.jackson.databind.ObjectMapper
 import io.infinitape.etherjar.rpc.json.BlockJson
 import io.infinitape.etherjar.rpc.json.TransactionJson
 import io.infinitape.etherjar.rpc.json.TransactionRefJson
+import org.apache.commons.codec.binary.Hex
 import java.math.BigInteger
 import java.time.Instant
 
@@ -30,12 +31,13 @@ class BlockContainer(
         val timestamp: Instant,
         val full: Boolean,
         json: ByteArray?,
+        val parsed: Any?,
         val transactions: List<TxId> = emptyList()
-) : SourceContainer(json) {
+) : SourceContainer(json, parsed) {
 
     companion object {
         @JvmStatic
-        fun from(block: BlockJson<*>, objectMapper: ObjectMapper): BlockContainer {
+        fun from(block: BlockJson<*>, raw: ByteArray): BlockContainer {
             val hasTransactions = block.transactions?.filterIsInstance<TransactionJson>()?.count() ?: 0 > 0
             return BlockContainer(
                     block.number,
@@ -43,10 +45,26 @@ class BlockContainer(
                     block.totalDifficulty,
                     block.timestamp,
                     hasTransactions,
-                    objectMapper.writeValueAsBytes(block),
+                    raw,
+                    block,
                     block.transactions?.map { TxId.from(it.hash) } ?: emptyList()
             )
         }
+
+        @JvmStatic
+        fun from(block: BlockJson<*>, objectMapper: ObjectMapper): BlockContainer {
+            return from(block, objectMapper.writeValueAsBytes(block))
+        }
+
+        @JvmStatic
+        fun from(raw: ByteArray, objectMapper: ObjectMapper): BlockContainer {
+            val block = objectMapper.readValue(raw, BlockJson::class.java)
+            return from(block, raw)
+        }
+    }
+
+    override fun toString(): String {
+        return "Block $height = $hash"
     }
 
     override fun equals(other: Any?): Boolean {

src/main/kotlin/io/emeraldpay/dshackle/data/BlockId.kt

@@ -25,6 +25,11 @@ class BlockId(
 ) : HashId(value) {
 
     companion object {
+        @JvmStatic
+        fun from(hash: ByteArray): BlockId {
+            return BlockId(hash)
+        }
+
         @JvmStatic
         fun from(hash: BlockHash): BlockId {
             return BlockId(hash.bytes)

src/main/kotlin/io/emeraldpay/dshackle/data/HashId.kt

@@ -40,6 +40,10 @@ open class HashId(
         return String(hex)
     }
 
+    fun toHexWithPrefix(): String {
+        return "0x" + toHex()
+    }
+
     override fun equals(other: Any?): Boolean {
         if (this === other) return true
         if (other !is HashId) return false

src/main/kotlin/io/emeraldpay/dshackle/data/SourceContainer.kt

@@ -16,10 +16,24 @@
  */
 package io.emeraldpay.dshackle.data
 
+import java.lang.ClassCastException
+
 abstract class SourceContainer(
-        val json: ByteArray?
+        val json: ByteArray?,
+        private val parsed: Any?
 ) {
 
+    fun <T> getParsed(clazz: Class<T>): T? {
+        if (parsed == null) {
+            return null
+        }
+        if (clazz.isAssignableFrom(parsed.javaClass)) {
+            return parsed as T
+        }
+        throw ClassCastException("Cannot cast ${parsed.javaClass} to $clazz")
+    }
+
+
     override fun equals(other: Any?): Boolean {
         if (this === other) return true
         if (other !is SourceContainer) return false

src/main/kotlin/io/emeraldpay/dshackle/data/TxContainer.kt

@@ -20,20 +20,26 @@ import com.fasterxml.jackson.databind.ObjectMapper
 import io.infinitape.etherjar.rpc.json.TransactionJson
 
 class TxContainer(
-        val height: Long,
+        val height: Long?,
         val hash: TxId,
         val blockId: BlockId?,
-        json: ByteArray?
-) : SourceContainer(json) {
+        json: ByteArray?,
+        parsed: Any? = null
+) : SourceContainer(json, parsed) {
 
     companion object {
         @JvmStatic
         fun from(tx: TransactionJson, objectMapper: ObjectMapper): TxContainer {
+            return from(tx, objectMapper.writeValueAsBytes(tx))
+        }
+
+        fun from(tx: TransactionJson, raw: ByteArray): TxContainer {
             return TxContainer(
                     tx.blockNumber,
                     TxId.from(tx.hash),
-                    BlockId.from(tx.blockHash),
-                    objectMapper.writeValueAsBytes(tx)
+                    tx.blockHash?.let { BlockId.from(it) },
+                    raw,
+                    tx
             )
         }
     }

src/main/kotlin/io/emeraldpay/dshackle/quorum/AlwaysQuorum.kt

@@ -32,13 +32,17 @@ open class AlwaysQuorum: CallQuorum {
         return resolved
     }
 
-    override fun record(response: ByteArray, upstream: Upstream<*>): Boolean {
+    override fun isFailed(): Boolean {
+        return false
+    }
+
+    override fun record(response: ByteArray, upstream: Upstream): Boolean {
         result = response
         resolved = true
         return true
     }
 
-    override fun record(error: RpcException, upstream: Upstream<*>) {
+    override fun record(error: RpcException, upstream: Upstream) {
     }
 
     override fun getResult(): ByteArray? {

src/main/kotlin/io/emeraldpay/dshackle/quorum/BroadcastQuorum.kt

@@ -16,14 +16,15 @@
  */
 package io.emeraldpay.dshackle.quorum
 
+import com.fasterxml.jackson.databind.ObjectMapper
 import io.emeraldpay.dshackle.upstream.Head
 import io.emeraldpay.dshackle.upstream.Upstream
 import io.infinitape.etherjar.rpc.JacksonRpcConverter
 
 open class BroadcastQuorum(
-        jacksonRpcConverter: JacksonRpcConverter,
+        objectMapper: ObjectMapper,
         val quorum: Int = 3
-): CallQuorum, ValueAwareQuorum<String>(jacksonRpcConverter, String::class.java) {
+) : CallQuorum, ValueAwareQuorum<String>(objectMapper, String::class.java) {
 
     private var result: ByteArray? = null
     private var txid: String? = null
@@ -36,11 +37,15 @@ open class BroadcastQuorum(
         return calls >= quorum
     }
 
+    override fun isFailed(): Boolean {
+        return false
+    }
+
     override fun getResult(): ByteArray? {
         return result
     }
 
-    override fun recordValue(response: ByteArray, responseValue: String?, upstream: Upstream<*>) {
+    override fun recordValue(response: ByteArray, responseValue: String?, upstream: Upstream) {
         calls++
         if (txid == null && responseValue != null) {
             txid = responseValue
@@ -48,7 +53,7 @@ open class BroadcastQuorum(
         }
     }
 
-    override fun recordError(response: ByteArray?, errorMessage: String?, upstream: Upstream<*>) {
+    override fun recordError(response: ByteArray?, errorMessage: String?, upstream: Upstream) {
         // can be "message: known transaction: TXID", "Transaction with the same hash was already imported" or "message: Nonce too low"
         calls++
         if (result == null) {

src/main/kotlin/io/emeraldpay/dshackle/quorum/CallQuorum.kt

@@ -31,8 +31,10 @@ interface CallQuorum {
     fun init(head: Head)
 
     fun isResolved(): Boolean
-    fun record(response: ByteArray, upstream: Upstream<*>): Boolean
-    fun record(error: RpcException, upstream: Upstream<*>)
+    fun isFailed(): Boolean
+
+    fun record(response: ByteArray, upstream: Upstream): Boolean
+    fun record(error: RpcException, upstream: Upstream)
     fun getResult(): ByteArray?
 
     companion object {
@@ -42,8 +44,8 @@ interface CallQuorum {
             }
         }
 
-        fun asReducer(): BiFunction<CallQuorum, Tuple2<ByteArray, Upstream<*>>, CallQuorum> {
-            return BiFunction<CallQuorum, Tuple2<ByteArray, Upstream<*>>, CallQuorum> { a, b ->
+        fun asReducer(): BiFunction<CallQuorum, Tuple2<ByteArray, Upstream>, CallQuorum> {
+            return BiFunction<CallQuorum, Tuple2<ByteArray, Upstream>, CallQuorum> { a, b ->
                 a.record(b.t1, b.t2)
                 return@BiFunction a
             }

src/main/kotlin/io/emeraldpay/dshackle/quorum/NonEmptyQuorum.kt

@@ -16,15 +16,16 @@
  */
 package io.emeraldpay.dshackle.quorum
 
+import com.fasterxml.jackson.databind.ObjectMapper
 import io.emeraldpay.dshackle.upstream.Head
 import io.emeraldpay.dshackle.upstream.Upstream
 import io.infinitape.etherjar.rpc.JacksonRpcConverter
 import io.infinitape.etherjar.rpc.RpcException
 
 open class NonEmptyQuorum(
-        jacksonRpcConverter: JacksonRpcConverter,
+        objectMapper: ObjectMapper,
         val maxTries: Int = 3
-): CallQuorum, ValueAwareQuorum<Any>(jacksonRpcConverter, Any::class.java) {
+) : CallQuorum, ValueAwareQuorum<Any>(objectMapper, Any::class.java) {
 
     private var result: ByteArray? = null
     private var tries: Int = 0
@@ -33,10 +34,14 @@ open class NonEmptyQuorum(
     }
 
     override fun isResolved(): Boolean {
-        return result != null || tries >= maxTries
+        return result != null
     }
 
-    override fun recordValue(response: ByteArray, responseValue: Any?, upstream: Upstream<*>) {
+    override fun isFailed(): Boolean {
+        return tries >= maxTries
+    }
+
+    override fun recordValue(response: ByteArray, responseValue: Any?, upstream: Upstream) {
         tries++
         if (responseValue != null) {
             result = response
@@ -47,10 +52,12 @@ open class NonEmptyQuorum(
         return result
     }
 
-    override fun recordError(response: ByteArray?, errorMessage: String?, upstream: Upstream<*>) {
+    override fun recordError(response: ByteArray?, errorMessage: String?, upstream: Upstream) {
+        tries++
     }
 
-    override fun record(error: RpcException, upstream: Upstream<*>) {
+    override fun record(error: RpcException, upstream: Upstream) {
+        tries++
     }
 
 }

src/main/kotlin/io/emeraldpay/dshackle/quorum/NonceQuorum.kt

@@ -16,6 +16,7 @@
  */
 package io.emeraldpay.dshackle.quorum
 
+import com.fasterxml.jackson.databind.ObjectMapper
 import io.emeraldpay.dshackle.upstream.Head
 import io.emeraldpay.dshackle.upstream.Upstream
 import io.infinitape.etherjar.hex.HexQuantity
@@ -25,9 +26,9 @@ import java.util.concurrent.locks.ReentrantLock
 import kotlin.concurrent.withLock
 
 open class NonceQuorum(
-        jacksonRpcConverter: JacksonRpcConverter,
+        objectMapper: ObjectMapper,
         val tries: Int = 3
-): CallQuorum, ValueAwareQuorum<String>(jacksonRpcConverter, String::class.java) {
+) : CallQuorum, ValueAwareQuorum<String>(objectMapper, String::class.java) {
 
     private val lock = ReentrantLock()
     private var resultValue = 0L
@@ -40,11 +41,15 @@ open class NonceQuorum(
 
     override fun isResolved(): Boolean {
         lock.withLock {
-            return receivedTimes >= tries || errors >= tries
+            return receivedTimes >= tries && !isFailed()
         }
     }
 
-    override fun recordValue(response: ByteArray, responseValue: String?, upstream: Upstream<*>) {
+    override fun isFailed(): Boolean {
+        return errors >= tries
+    }
+
+    override fun recordValue(response: ByteArray, responseValue: String?, upstream: Upstream) {
         val value = responseValue?.let { str ->
             HexQuantity.from(str).value.toLong()
         }
@@ -63,11 +68,7 @@ open class NonceQuorum(
         return result
     }
 
-    override fun recordError(response: ByteArray?, errorMessage: String?, upstream: Upstream<*>) {
-        errors++
-    }
-
-    override fun record(error: RpcException, upstream: Upstream<*>) {
+    override fun recordError(response: ByteArray?, errorMessage: String?, upstream: Upstream) {
         errors++
     }
 

src/main/kotlin/io/emeraldpay/dshackle/quorum/NotLaggingQuorum.kt

@@ -32,7 +32,11 @@ class NotLaggingQuorum(val maxLag: Long = 0): CallQuorum {
         return result.get() != null
     }
 
-    override fun record(response: ByteArray, upstream: Upstream<*>): Boolean {
+    override fun isFailed(): Boolean {
+        return false
+    }
+
+    override fun record(response: ByteArray, upstream: Upstream): Boolean {
         val lagging = upstream.getLag() > maxLag
         if (!lagging) {
             result.set(response)
@@ -41,10 +45,9 @@ class NotLaggingQuorum(val maxLag: Long = 0): CallQuorum {
         return false
     }
 
-    override fun record(error: RpcException, upstream: Upstream<*>) {
+    override fun record(error: RpcException, upstream: Upstream) {
     }
 
-
     override fun getResult(): ByteArray {
         return result.get()
     }

src/main/kotlin/io/emeraldpay/dshackle/quorum/QuorumReaderFactory.kt

@@ -0,0 +1,38 @@
+/**
+ * Copyright (c) 2020 EmeraldPay, Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.emeraldpay.dshackle.quorum
+
+import io.emeraldpay.dshackle.reader.Reader
+import io.emeraldpay.dshackle.upstream.ApiSource
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+
+// creates instance of a Quorum based reader
+interface QuorumReaderFactory {
+
+    companion object {
+        fun default(): QuorumReaderFactory {
+            return Default()
+        }
+    }
+
+    fun create(apis: ApiSource, quorum: CallQuorum): Reader<JsonRpcRequest, QuorumRpcReader.Result>
+
+    class Default : QuorumReaderFactory {
+        override fun create(apis: ApiSource, quorum: CallQuorum): Reader<JsonRpcRequest, QuorumRpcReader.Result> {
+            return QuorumRpcReader(apis, quorum)
+        }
+    }
+}

src/main/kotlin/io/emeraldpay/dshackle/quorum/QuorumRpcReader.kt

@@ -0,0 +1,105 @@
+/**
+ * Copyright (c) 2020 EmeraldPay, Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.emeraldpay.dshackle.quorum
+
+import io.emeraldpay.dshackle.reader.Reader
+import io.emeraldpay.dshackle.upstream.ApiSource
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
+import io.infinitape.etherjar.rpc.RpcException
+import org.slf4j.LoggerFactory
+import reactor.core.publisher.Flux
+import reactor.core.publisher.Mono
+import reactor.util.function.Tuples
+
+/**
+ * Makes request with applying Quorum
+ */
+class QuorumRpcReader(
+        private val apis: ApiSource,
+        private val quorum: CallQuorum
+) : Reader<JsonRpcRequest, QuorumRpcReader.Result> {
+
+    companion object {
+        private val log = LoggerFactory.getLogger(QuorumRpcReader::class.java)
+    }
+
+    override fun read(key: JsonRpcRequest): Mono<QuorumRpcReader.Result> {
+        apis.request(1)
+
+        // uses a mix of retry strategy and managed Publisher for calls.
+        // retry is used when an error happened
+        // but if no error received, we check quorum and if not enough data received we request more
+        // eventually source of upstreams is Completed (or something Errored) and if finalizes the result
+
+        val retrySpec = reactor.util.retry.Retry.from { signal ->
+            signal.takeUntil {
+                it.totalRetries() >= 3 || quorum.isResolved() || quorum.isFailed()
+            }.doOnNext {
+                // need one more API source if retried
+                apis.request(1)
+            }
+        }
+
+        return Flux.from(apis)
+                .flatMap { api ->
+                    api.getApi().read(key)
+                            .flatMap(JsonRpcResponse::requireResult)
+                            // on error notify quorum, it may use error message or other details
+                            .doOnError { err ->
+                                if (err is RpcException) {
+                                    quorum.record(err, api)
+                                }
+                            }
+                            .map { Tuples.of(it, api) }
+                }
+                .retryWhen(retrySpec)
+                // record all correct responses until quorum reached
+                .reduce(quorum, { res, a ->
+                    if (res.record(a.t1, a.t2)) {
+                        apis.resolve()
+                    } else {
+                        apis.request(1)
+                    }
+                    res
+                })
+                // if last call resulted in error it's still possible that request was resolved correctly. i.e. for BroadcastQuorum
+                .onErrorResume { err ->
+                    if (quorum.isResolved()) {
+                        Mono.just(quorum)
+                    } else {
+                        Mono.error(err)
+                    }
+                }
+                .doOnNext {
+                    if (!it.isResolved()) {
+                        log.debug("No quorum for ${key.method} as ${quorum}")
+                    }
+                }
+                // return nothing if not resolved
+                .filter { it.isResolved() }
+                .map {
+                    // TODO find actual quorum number
+                    QuorumRpcReader.Result(it.getResult()!!, 1)
+                }
+    }
+
+
+    class Result(
+            val value: ByteArray,
+            val quorum: Int
+    )
+}

src/main/kotlin/io/emeraldpay/dshackle/quorum/ValueAwareQuorum.kt

@@ -16,23 +16,24 @@
  */
 package io.emeraldpay.dshackle.quorum
 
+import com.fasterxml.jackson.databind.ObjectMapper
 import io.emeraldpay.dshackle.upstream.Upstream
 import io.infinitape.etherjar.rpc.JacksonRpcConverter
 import io.infinitape.etherjar.rpc.RpcException
 import org.slf4j.LoggerFactory
 
 abstract class ValueAwareQuorum<T>(
-        val jacksonRpcConverter: JacksonRpcConverter,
+        val objectMapper: ObjectMapper,
         val clazz: Class<T>
 ): CallQuorum {
 
     private val log = LoggerFactory.getLogger(ValueAwareQuorum::class.java)
 
     fun extractValue(response: ByteArray, clazz: Class<T>): T? {
-        return jacksonRpcConverter.fromJson(response.inputStream(), clazz)
+        return objectMapper.readValue(response.inputStream(), clazz)
     }
 
-    override fun record(response: ByteArray, upstream: Upstream<*>): Boolean {
+    override fun record(response: ByteArray, upstream: Upstream): Boolean {
         try {
             val value = extractValue(response, clazz)
             recordValue(response, value, upstream)
@@ -44,12 +45,12 @@ abstract class ValueAwareQuorum<T>(
         return isResolved();
     }
 
-    override fun record(error: RpcException, upstream: Upstream<*>) {
+    override fun record(error: RpcException, upstream: Upstream) {
         recordError(null, error.rpcMessage, upstream)
     }
 
-    abstract fun recordValue(response: ByteArray, responseValue: T?, upstream: Upstream<*>)
+    abstract fun recordValue(response: ByteArray, responseValue: T?, upstream: Upstream)
 
-    abstract fun recordError(response: ByteArray?, errorMessage: String?, upstream: Upstream<*>)
+    abstract fun recordError(response: ByteArray?, errorMessage: String?, upstream: Upstream)
 
 }

src/main/kotlin/io/emeraldpay/dshackle/reader/Reader.kt

@@ -18,7 +18,7 @@ package io.emeraldpay.dshackle.reader
 
 import reactor.core.publisher.Mono
 
-interface Reader<K, D> {
+interface Reader<in K, D> {
 
     fun read(key: K): Mono<D>
 

src/main/kotlin/io/emeraldpay/dshackle/rpc/Describe.kt

@@ -29,15 +29,15 @@ import reactor.core.publisher.Mono
 
 @Service
 class Describe(
-        @Autowired private val upstreams: Upstreams,
+        @Autowired private val multistreamHolder: MultistreamHolder,
         @Autowired private val subscribeStatus: SubscribeStatus
 ) {
 
     fun describe(requestMono: Mono<BlockchainOuterClass.DescribeRequest>): Mono<BlockchainOuterClass.DescribeResponse> {
         return requestMono.map { _ ->
             val resp = BlockchainOuterClass.DescribeResponse.newBuilder()
-            upstreams.getAvailable().forEach { chain ->
-                upstreams.getUpstream(chain)?.let { chainUpstreams ->
+            multistreamHolder.getAvailable().forEach { chain ->
+                multistreamHolder.getUpstream(chain)?.let { chainUpstreams ->
                     val status = subscribeStatus.chainStatus(chain, chainUpstreams.getAll())
                     val targets = chainUpstreams.getMethods().getSupportedMethods()
                     val chainDescription = BlockchainOuterClass.DescribeChain.newBuilder()

src/main/kotlin/io/emeraldpay/dshackle/rpc/NativeCall.kt

@@ -24,8 +24,14 @@ import io.emeraldpay.dshackle.SilentException
 import io.emeraldpay.dshackle.upstream.*
 import io.emeraldpay.dshackle.quorum.AlwaysQuorum
 import io.emeraldpay.dshackle.quorum.CallQuorum
+import io.emeraldpay.dshackle.quorum.QuorumReaderFactory
+import io.emeraldpay.dshackle.quorum.QuorumRpcReader
+import io.emeraldpay.dshackle.upstream.ethereum.EthereumMultistream
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import io.emeraldpay.grpc.Chain
 import io.infinitape.etherjar.rpc.RpcException
+import io.infinitape.etherjar.rpc.RpcResponseError
 import org.apache.commons.lang3.StringUtils
 import org.slf4j.LoggerFactory
 import org.springframework.beans.factory.annotation.Autowired
@@ -36,21 +42,23 @@ import java.lang.Exception
 
 @Service
 open class NativeCall(
-        @Autowired private val upstreams: Upstreams,
+        @Autowired private val multistreamHolder: MultistreamHolder,
         @Autowired private val objectMapper: ObjectMapper
 ) {
 
     private val log = LoggerFactory.getLogger(NativeCall::class.java)
 
+    var quorumReaderFactory: QuorumReaderFactory = QuorumReaderFactory.default()
+
     open fun nativeCall(requestMono: Mono<BlockchainOuterClass.NativeCallRequest>): Flux<BlockchainOuterClass.NativeCallReplyItem> {
         return requestMono.flatMapMany(this::prepareCall)
                 .map(this::setupCallParams)
                 .parallel()
-            .flatMap(this::fetch)
-            .sequential()
-            .map(this::buildResponse)
-            .doOnError { e -> log.warn("Error during native call: ${e.message}") }
-            .onErrorResume(this::processException)
+                .flatMap(this::fetch)
+                .sequential()
+                .map(this::buildResponse)
+                .doOnError { e -> log.warn("Error during native call: ${e.message}") }
+                .onErrorResume(this::processException)
     }
 
     fun setupCallParams(it: CallContext<RawCallDetails>): CallContext<ParsedCallDetails> {
@@ -87,17 +95,17 @@ open class NativeCall(
             return Flux.error(CallFailure(0, SilentException.UnsupportedBlockchain(request.chain.number)))
         }
 
-        if (!upstreams.isAvailable(chain)) {
+        if (!multistreamHolder.isAvailable(chain)) {
             return Flux.error(CallFailure(0, SilentException.UnsupportedBlockchain(request.chain.number)))
         }
 
-        val upstream = upstreams.getUpstream(chain)
+        val upstream = multistreamHolder.getUpstream(chain)
                 ?: return Flux.error(CallFailure(0, SilentException.UnsupportedBlockchain(chain)))
 
         return prepareCall(request, upstream)
     }
 
-    fun prepareCall(request: BlockchainOuterClass.NativeCallRequest, upstream: AggregatedUpstream<*>): Flux<CallContext<RawCallDetails>> {
+    fun prepareCall(request: BlockchainOuterClass.NativeCallRequest, upstream: Multistream): Flux<CallContext<RawCallDetails>> {
         return request.itemsList.toFlux().map {
             val method = it.method
             val params = it.payload.toStringUtf8()
@@ -115,75 +123,29 @@ open class NativeCall(
     }
 
     fun fetch(ctx: CallContext<ParsedCallDetails>): Mono<CallContext<ByteArray>> {
-        return fetchFromCache(ctx)
-                .onErrorResume { t ->
-                    log.warn("Failed to read from cache", t);
-                    Mono.empty()
-                }
-                .switchIfEmpty(
+        return ctx.upstream.getRoutedApi(ctx.matcher)
+                .flatMap { api ->
+                    api.read(JsonRpcRequest(ctx.payload.method, ctx.payload.params))
+                            .flatMap(JsonRpcResponse::requireResult)
+                            .map {
+                                ctx.withPayload(it)
+                            }
+                }.switchIfEmpty(
                         Mono.just(ctx).flatMap(this::executeOnRemote)
                 )
-    }
-
-    fun fetchFromCache(ctx: CallContext<ParsedCallDetails>): Mono<CallContext<ByteArray>> {
-        val cachingApi = ctx.upstream.cache
-        return cachingApi.execute(ctx.id, ctx.payload.method, ctx.payload.params).map { ctx.withPayload(it) }
+                .onErrorMap {
+                    CallFailure(ctx.id, it)
+                }
     }
 
     fun executeOnRemote(ctx: CallContext<ParsedCallDetails>): Mono<CallContext<ByteArray>> {
-        val apis = ctx.getApis()
-        apis.request(1)
-        var failures = 0
-        return Flux.from(apis)
-                .flatMap { api ->
-                    val upstream = ctx.upstream
-                    api.execute(ctx.id, ctx.payload.method, ctx.payload.params)
-                            // on error notify quorum, it may use error message or other details
-                            .doOnError { err ->
-                                if (err is RpcException) {
-                                    ctx.callQuorum.record(err, upstream)
-                                }
-                            }
-                            .map { Tuples.of(it, upstream) }
-                }
-                .retry {
-                    failures++
-                    if (ctx.callQuorum.isResolved()) {
-                        false
-                    } else if (failures < 3) {
-                        apis.request(1)
-                        true
-                    } else {
-                        false
-                    }
-                }
-                // record all correct responses until quorum reached
-                .reduce(ctx.callQuorum, {res, a ->
-                    if (res.record(a.t1, a.t2)) {
-                        apis.resolve()
-                    } else {
-                        apis.request(1)
-                    }
-                    res
-                })
-                // if last call resulted in error it's still possible that request was resolved correctly. i.e. for BroadcastQuorum
-                .onErrorResume { err ->
-                    if (ctx.callQuorum.isResolved()) {
-                        Mono.just(ctx.callQuorum)
-                    } else {
-                        Mono.error(err)
-                    }
-                }
-                .doOnNext {
-                    if (!it.isResolved()) {
-                        log.debug("No quorum for ${ctx.payload.method} as ${ctx.callQuorum}")
-                    }
-                }
-                .filter { it.isResolved() }
+        if (!ctx.upstream.getMethods().isAllowed(ctx.payload.method)) {
+            return Mono.error(RpcException(RpcResponseError.CODE_METHOD_NOT_EXIST, "Unsupported method"))
+        }
+        val reader = quorumReaderFactory.create(ctx.getApis(), ctx.callQuorum)
+        return reader.read(JsonRpcRequest(ctx.payload.method, ctx.payload.params))
                 .map {
-                    val result  = it.getResult()
-                            ?: throw CallFailure(ctx.id, Exception("No response from upstream for ${ctx.payload.method}"))
-                    ctx.withPayload(result)
+                    ctx.withPayload(it.value)
                 }
                 .onErrorMap {
                     log.error("Failed to make a call", it)
@@ -204,7 +166,7 @@ open class NativeCall(
     }
 
     open class CallContext<T>(val id: Int,
-                              val upstream: AggregatedUpstream<*>,
+                              val upstream: Multistream,
                               val matcher: Selector.Matcher,
                               val callQuorum: CallQuorum,
                               val payload: T) {
@@ -212,8 +174,8 @@ open class NativeCall(
             return CallContext(id, upstream, matcher, callQuorum, payload)
         }
 
-        fun getApis(): ApiSource<*> {
-            return upstream.getApis(matcher)
+        fun getApis(): ApiSource {
+            return upstream.getApiSource(matcher)
         }
     }
 

src/main/kotlin/io/emeraldpay/dshackle/rpc/StreamHead.kt

@@ -21,10 +21,8 @@ import io.emeraldpay.api.proto.BlockchainOuterClass
 import io.emeraldpay.api.proto.Common
 import io.emeraldpay.dshackle.BlockchainType
 import io.emeraldpay.dshackle.data.BlockContainer
-import io.emeraldpay.dshackle.upstream.Upstreams
+import io.emeraldpay.dshackle.upstream.MultistreamHolder
 import io.emeraldpay.grpc.Chain
-import io.infinitape.etherjar.rpc.json.BlockJson
-import io.infinitape.etherjar.rpc.json.TransactionRefJson
 import org.slf4j.LoggerFactory
 import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.stereotype.Service
@@ -33,7 +31,7 @@ import reactor.core.publisher.Mono
 
 @Service
 class StreamHead(
-        @Autowired private val upstreams: Upstreams
+        @Autowired private val multistreamHolder: MultistreamHolder
 ) {
 
     private val log = LoggerFactory.getLogger(StreamHead::class.java)
@@ -42,7 +40,7 @@ class StreamHead(
         return requestMono.map { request ->
             Chain.byId(request.type.number)
         }.flatMapMany { chain ->
-            val up = upstreams.getUpstream(chain)
+            val up = multistreamHolder.getUpstream(chain)
                     ?: return@flatMapMany Flux.error<BlockchainOuterClass.ChainHead>(Exception("Unavailable chain: $chain"))
             up.getHead()
                     .getFlux()
@@ -64,7 +62,7 @@ class StreamHead(
         return BlockchainOuterClass.ChainHead.newBuilder()
                 .setChainValue(chain.id)
                 .setHeight(block.height)
-                .setTimestamp(block.timestamp!!.toEpochMilli())
+                .setTimestamp(block.timestamp.toEpochMilli())
                 .setWeight(ByteString.copyFrom(block.difficulty.toByteArray()))
                 .setBlockId(block.hash.toHex())
                 .build()

src/main/kotlin/io/emeraldpay/dshackle/rpc/SubscribeStatus.kt

@@ -27,13 +27,13 @@ import reactor.core.publisher.Mono
 
 @Service
 class SubscribeStatus(
-        @Autowired private val upstreams: Upstreams
+        @Autowired private val multistreamHolder: MultistreamHolder
 ) {
 
     fun subscribeStatus(requestMono: Mono<BlockchainOuterClass.StatusRequest>): Flux<BlockchainOuterClass.ChainStatus> {
         return requestMono.flatMapMany {
-            val ups = upstreams.getAvailable().mapNotNull { chain ->
-                val chainUpstream = upstreams.getUpstream(chain)
+            val ups = multistreamHolder.getAvailable().mapNotNull { chain ->
+                val chainUpstream = multistreamHolder.getUpstream(chain)
                 chainUpstream?.observeStatus()?.map { avail ->
                     ChainSubscription(chain, chainUpstream, avail)
                 }
@@ -46,7 +46,7 @@ class SubscribeStatus(
         }
     }
 
-    fun chainStatus(chain: Chain, ups: List<Upstream<*>>): BlockchainOuterClass.ChainStatus {
+    fun chainStatus(chain: Chain, ups: List<Upstream>): BlockchainOuterClass.ChainStatus {
         val available = ups.map { u ->
             u.getStatus()
         }.min() ?: UpstreamAvailability.UNAVAILABLE
@@ -60,6 +60,6 @@ class SubscribeStatus(
                 .build()
     }
 
-    class ChainSubscription(val chain: Chain, val up: AggregatedUpstream<*>, val avail: UpstreamAvailability)
+    class ChainSubscription(val chain: Chain, val up: Multistream, val avail: UpstreamAvailability)
 
 }

src/main/kotlin/io/emeraldpay/dshackle/rpc/TrackBitcoinAddress.kt

@@ -19,9 +19,8 @@ import io.emeraldpay.api.proto.BlockchainOuterClass
 import io.emeraldpay.api.proto.Common
 import io.emeraldpay.dshackle.BlockchainType
 import io.emeraldpay.dshackle.SilentException
-import io.emeraldpay.dshackle.upstream.Selector
-import io.emeraldpay.dshackle.upstream.Upstreams
-import io.emeraldpay.dshackle.upstream.bitcoin.DirectBitcoinApi
+import io.emeraldpay.dshackle.upstream.MultistreamHolder
+import io.emeraldpay.dshackle.upstream.bitcoin.BitcoinMultistream
 import io.emeraldpay.grpc.Chain
 import org.slf4j.LoggerFactory
 import org.springframework.beans.factory.annotation.Autowired
@@ -35,7 +34,7 @@ import kotlin.collections.HashMap
 
 @Service
 class TrackBitcoinAddress(
-        @Autowired private val upstreams: Upstreams
+        @Autowired private val multistreamHolder: MultistreamHolder
 ) : TrackAddress {
 
     companion object {
@@ -43,7 +42,7 @@ class TrackBitcoinAddress(
     }
 
     override fun isSupported(chain: Chain): Boolean {
-        return BlockchainType.fromBlockchain(chain) == BlockchainType.BITCOIN && upstreams.isAvailable(chain)
+        return BlockchainType.fromBlockchain(chain) == BlockchainType.BITCOIN && multistreamHolder.isAvailable(chain)
     }
 
     fun allAddresses(request: BlockchainOuterClass.BalanceRequest): List<String>? {
@@ -63,8 +62,8 @@ class TrackBitcoinAddress(
         }
     }
 
-    fun requestBalances(chain: Chain, api: DirectBitcoinApi, addresses: List<String>): Flux<AddressBalance> {
-        return api.executeAndResult(0, "listunspent", emptyList(), List::class.java)
+    fun requestBalances(chain: Chain, api: BitcoinMultistream, addresses: List<String>): Flux<AddressBalance> {
+        return api.getReader().listUnspent()
                 .flatMapMany { unspents ->
                     val result = getTotal(chain, addresses, unspents)
                     Flux.fromIterable(result)
@@ -73,17 +72,14 @@ class TrackBitcoinAddress(
 
     override fun getBalance(request: BlockchainOuterClass.BalanceRequest): Flux<BlockchainOuterClass.AddressBalance> {
         val chain = Chain.byId(request.asset.chainValue)
-        val upstream = upstreams.getUpstream(chain)?.castApi(DirectBitcoinApi::class.java)
+        val upstream = multistreamHolder.getUpstream(chain)?.cast(BitcoinMultistream::class.java)
                 ?: return Flux.error(SilentException.UnsupportedBlockchain(request.asset.chainValue))
         val addresses = allAddresses(request) ?: return Flux.error(SilentException("Unsupported address"))
         if (addresses.isEmpty()) {
             return Flux.empty()
         }
-        val result = upstream.getApi(Selector.empty).flatMapMany { api ->
-            requestBalances(chain, api, addresses)
-                    .map(this@TrackBitcoinAddress::buildResponse)
-        }
-        return result
+        return requestBalances(chain, upstream, addresses)
+                .map(this@TrackBitcoinAddress::buildResponse)
     }
 
     fun getTotal(chain: Chain, addresses: List<String>, unspents: List<*>): List<AddressBalance> {
@@ -122,20 +118,16 @@ class TrackBitcoinAddress(
 
     override fun subscribe(request: BlockchainOuterClass.BalanceRequest): Flux<BlockchainOuterClass.AddressBalance> {
         val chain = Chain.byId(request.asset.chainValue)
-        val upstream = upstreams.getUpstream(chain)?.castApi(DirectBitcoinApi::class.java)
+        val upstream = multistreamHolder.getUpstream(chain)?.cast(BitcoinMultistream::class.java)
                 ?: return Flux.error(SilentException.UnsupportedBlockchain(request.asset.chainValue))
         val addresses = allAddresses(request) ?: return Flux.error(SilentException("Unsupported address"))
         if (addresses.isEmpty()) {
             return Flux.empty()
         }
-        val initial = upstream.getApi(Selector.empty).flatMapMany { api ->
-            requestBalances(chain, api, addresses)
-        }
+        val initial = requestBalances(chain, upstream, addresses)
         val following = upstream.getHead().getFlux()
                 .flatMap { block ->
-                    upstream.getApi(Selector.empty).flatMapMany { api ->
-                        requestBalances(chain, api, addresses)
-                    }
+                    requestBalances(chain, upstream, addresses)
                 }
         val last = HashMap<Address, BigInteger>()
         val result = Flux.merge(initial, following)

src/main/kotlin/io/emeraldpay/dshackle/rpc/TrackBitcoinTx.kt

@@ -20,10 +20,8 @@ import io.emeraldpay.api.proto.BlockchainOuterClass
 import io.emeraldpay.api.proto.Common
 import io.emeraldpay.dshackle.BlockchainType
 import io.emeraldpay.dshackle.SilentException
-import io.emeraldpay.dshackle.upstream.Selector
-import io.emeraldpay.dshackle.upstream.Upstreams
-import io.emeraldpay.dshackle.upstream.bitcoin.DirectBitcoinApi
-import io.emeraldpay.dshackle.upstream.bitcoin.BitcoinUpstream
+import io.emeraldpay.dshackle.upstream.MultistreamHolder
+import io.emeraldpay.dshackle.upstream.bitcoin.BitcoinMultistream
 import io.emeraldpay.dshackle.upstream.bitcoin.ExtractBlock
 import io.emeraldpay.grpc.Chain
 import org.slf4j.LoggerFactory
@@ -39,7 +37,7 @@ import kotlin.math.min
 
 @Service
 class TrackBitcoinTx(
-        @Autowired private val upstreams: Upstreams
+        @Autowired private val multistreamHolder: MultistreamHolder
 ) : TrackTx {
 
     companion object {
@@ -47,36 +45,35 @@ class TrackBitcoinTx(
     }
 
     override fun isSupported(chain: Chain): Boolean {
-        return BlockchainType.fromBlockchain(chain) == BlockchainType.BITCOIN && upstreams.isAvailable(chain)
+        return BlockchainType.fromBlockchain(chain) == BlockchainType.BITCOIN && multistreamHolder.isAvailable(chain)
     }
 
     override fun subscribe(request: BlockchainOuterClass.TxStatusRequest): Flux<BlockchainOuterClass.TxStatus> {
         val chain = Chain.byId(request.chainValue)
-        val upstream = upstreams.getUpstream(chain)?.cast(BitcoinUpstream::class.java, DirectBitcoinApi::class.java)
+        val upstream = multistreamHolder.getUpstream(chain)?.cast(BitcoinMultistream::class.java)
                 ?: return Flux.error(SilentException.UnsupportedBlockchain(chain))
         val txid = request.txId
         val confirmations = max(min(1, request.confirmationLimit), 12)
-        return upstream.getApi(Selector.empty).flatMapMany { api ->
-            subscribe(chain, api, upstream, txid)
-        }.takeUntil { tx ->
-            tx.confirmations >= confirmations
-        }.map(this::asProto)
+        return subscribe(chain, upstream, txid)
+                .takeUntil { tx ->
+                    tx.confirmations >= confirmations
+                }.map(this::asProto)
     }
 
-    fun subscribe(chain: Chain, api: DirectBitcoinApi, upstream: BitcoinUpstream, txid: String): Flux<TxStatus> {
-        return loadExisting(api, txid)
+    fun subscribe(chain: Chain, upstream: BitcoinMultistream, txid: String): Flux<TxStatus> {
+        return loadExisting(upstream, txid)
                 .flatMapMany { status ->
                     if (status.mined) {
                         //Head almost always knows the current height, so it can continue with calculating confirmations
                         //without publishing an empty TxStatus first
-                        continueWithMined(api, upstream, status)
+                        continueWithMined(upstream, status)
                     } else {
                         loadMempool(upstream, txid)
                                 .flatMapMany { tx ->
                                     val next = if (tx.found) {
                                         untilMined(upstream, tx)
                                     } else {
-                                        untilFound(chain, api, upstream, txid)
+                                        untilFound(chain, upstream, txid)
                                     }
                                     //fist provide the current status, then updates
                                     Flux.concat(Mono.just(tx), next)
@@ -85,8 +82,8 @@ class TrackBitcoinTx(
                 }
     }
 
-    fun continueWithMined(api: DirectBitcoinApi, upstream: BitcoinUpstream, status: TxStatus): Flux<TxStatus> {
-        return api.getBlock(status.blockHash!!)
+    fun continueWithMined(upstream: BitcoinMultistream, status: TxStatus): Flux<TxStatus> {
+        return upstream.getReader().getBlock(status.blockHash!!)
                 .map { block ->
                     TxStatus(status.txid, true, ExtractBlock.getHeight(block), true, status.blockHash, ExtractBlock.getTime(block), ExtractBlock.getDifficulty(block))
                 }.flatMapMany { tx ->
@@ -94,41 +91,40 @@ class TrackBitcoinTx(
                 }
     }
 
-    fun untilFound(chain: Chain, api: DirectBitcoinApi, upstream: BitcoinUpstream, txid: String): Flux<TxStatus> {
+    fun untilFound(chain: Chain, upstream: BitcoinMultistream, txid: String): Flux<TxStatus> {
         return Flux.interval(Duration.ofSeconds(1))
                 .take(Duration.ofMinutes(10))
                 .flatMap { loadMempool(upstream, txid) }
                 .skipUntil { it.found }
-                .flatMap { subscribe(chain, api, upstream, txid) }
+                .flatMap { subscribe(chain, upstream, txid) }
                 .doOnError { t ->
                     log.error("Failed to wait until found", t)
                 }
     }
 
-    fun untilMined(upstream: BitcoinUpstream, tx: TxStatus): Mono<TxStatus> {
+    fun untilMined(upstream: BitcoinMultistream, tx: TxStatus): Mono<TxStatus> {
         return upstream.getHead().getFlux().flatMap {
-            upstream.getApi(Selector.empty).flatMap { api ->
-                loadExisting(api, tx.txid)
-            }.filter { it.mined }
+            loadExisting(upstream, tx.txid)
+                    .filter { it.mined }
         }.single()
     }
 
-    fun withConfirmations(upstream: BitcoinUpstream, tx: TxStatus): Flux<TxStatus> {
+    fun withConfirmations(upstream: BitcoinMultistream, tx: TxStatus): Flux<TxStatus> {
         return upstream.getHead().getFlux().map {
             tx.withHead(it.height)
         }
     }
 
-    fun loadExisting(api: DirectBitcoinApi, txid: String): Mono<TxStatus> {
-        val mined = api.getTx(txid)
+    fun loadExisting(api: BitcoinMultistream, txid: String): Mono<TxStatus> {
+        val mined = api.getReader().getTx(txid)
         return mined.map {
             val block = it["blockhash"] as String?
             TxStatus(txid, found = true, mined = block != null, blockHash = block, height = ExtractBlock.getHeight(it))
         }
     }
 
-    fun loadMempool(upstream: BitcoinUpstream, txid: String): Mono<TxStatus> {
-        val mempool = upstream.getData().getMempool().get()
+    fun loadMempool(upstream: BitcoinMultistream, txid: String): Mono<TxStatus> {
+        val mempool = upstream.getReader().getMempool().get()
         return mempool.map {
             if (it.contains(txid)) {
                 TxStatus(txid, found = true, mined = false)

src/main/kotlin/io/emeraldpay/dshackle/rpc/TrackEthereumAddress.kt

@@ -21,9 +21,8 @@ import io.emeraldpay.api.proto.Common
 import io.emeraldpay.dshackle.BlockchainType
 import io.emeraldpay.dshackle.Defaults
 import io.emeraldpay.dshackle.SilentException
-import io.emeraldpay.dshackle.upstream.Upstreams
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumApi
-import io.emeraldpay.dshackle.upstream.ethereum.AggregatedEthereumUpstreams
+import io.emeraldpay.dshackle.upstream.MultistreamHolder
+import io.emeraldpay.dshackle.upstream.ethereum.EthereumMultistream
 import io.emeraldpay.grpc.Chain
 import io.infinitape.etherjar.domain.Address
 import io.infinitape.etherjar.domain.Wei
@@ -35,13 +34,13 @@ import reactor.core.publisher.Mono
 
 @Service
 class TrackEthereumAddress(
-        @Autowired private val upstreams: Upstreams
+        @Autowired private val multistreamHolder: MultistreamHolder
 ) : TrackAddress {
 
     private val log = LoggerFactory.getLogger(TrackEthereumAddress::class.java)
 
     override fun isSupported(chain: Chain): Boolean {
-        return BlockchainType.fromBlockchain(chain) == BlockchainType.ETHEREUM && upstreams.isAvailable(chain)
+        return BlockchainType.fromBlockchain(chain) == BlockchainType.ETHEREUM && multistreamHolder.isAvailable(chain)
     }
 
     override fun getBalance(request: BlockchainOuterClass.BalanceRequest): Flux<BlockchainOuterClass.AddressBalance> {
@@ -52,7 +51,7 @@ class TrackEthereumAddress(
 
     override fun subscribe(request: BlockchainOuterClass.BalanceRequest): Flux<BlockchainOuterClass.AddressBalance> {
         val chain = Chain.byId(request.asset.chainValue)
-        val head = upstreams.getUpstream(chain)?.getHead()?.getFlux() ?: Flux.empty()
+        val head = multistreamHolder.getUpstream(chain)?.getHead()?.getFlux() ?: Flux.empty()
         val balances = initAddress(request)
                 .flatMap { tracked ->
                     val current = getBalance(tracked)
@@ -87,14 +86,14 @@ class TrackEthereumAddress(
         }
     }
 
-    fun getUpstream(chain: Chain): AggregatedEthereumUpstreams {
-        return upstreams.getUpstream(chain)?.cast(AggregatedEthereumUpstreams::class.java, EthereumApi::class.java)
+    fun getUpstream(chain: Chain): EthereumMultistream {
+        return multistreamHolder.getUpstream(chain)?.cast(EthereumMultistream::class.java)
                 ?: throw SilentException.UnsupportedBlockchain(chain)
     }
 
     private fun initAddress(request: BlockchainOuterClass.BalanceRequest): Flux<TrackedAddress> {
         val chain = Chain.byId(request.asset.chainValue)
-        if (!upstreams.isAvailable(chain)) {
+        if (!multistreamHolder.isAvailable(chain)) {
             return Flux.error(SilentException.UnsupportedBlockchain(request.asset.chainValue))
         }
         if (request.asset.code?.toLowerCase() != "ether") {

src/main/kotlin/io/emeraldpay/dshackle/rpc/TrackEthereumTx.kt

@@ -23,10 +23,8 @@ import io.emeraldpay.dshackle.BlockchainType
 import io.emeraldpay.dshackle.SilentException
 import io.emeraldpay.dshackle.data.BlockContainer
 import io.emeraldpay.dshackle.data.TxId
-import io.emeraldpay.dshackle.upstream.Upstream
-import io.emeraldpay.dshackle.upstream.Upstreams
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumApi
-import io.emeraldpay.dshackle.upstream.ethereum.AggregatedEthereumUpstreams
+import io.emeraldpay.dshackle.upstream.MultistreamHolder
+import io.emeraldpay.dshackle.upstream.ethereum.EthereumMultistream
 import io.emeraldpay.grpc.Chain
 import io.infinitape.etherjar.domain.BlockHash
 import io.infinitape.etherjar.domain.TransactionId
@@ -50,7 +48,7 @@ import kotlin.math.min
 
 @Service
 class TrackEthereumTx(
-        @Autowired private val upstreams: Upstreams
+        @Autowired private val multistreamHolder: MultistreamHolder
 ) : TrackTx {
 
     companion object {
@@ -65,7 +63,7 @@ class TrackEthereumTx(
     private val log = LoggerFactory.getLogger(TrackEthereumTx::class.java)
 
     override fun isSupported(chain: Chain): Boolean {
-        return BlockchainType.fromBlockchain(chain) == BlockchainType.ETHEREUM && upstreams.isAvailable(chain)
+        return BlockchainType.fromBlockchain(chain) == BlockchainType.ETHEREUM && multistreamHolder.isAvailable(chain)
     }
 
     override fun subscribe(request: BlockchainOuterClass.TxStatusRequest): Flux<BlockchainOuterClass.TxStatus> {
@@ -85,12 +83,12 @@ class TrackEthereumTx(
     }
 
 
-    fun getUpstream(chain: Chain): AggregatedEthereumUpstreams {
-        return upstreams.getUpstream(chain)?.cast(AggregatedEthereumUpstreams::class.java, EthereumApi::class.java)
+    fun getUpstream(chain: Chain): EthereumMultistream {
+        return multistreamHolder.getUpstream(chain)?.cast(EthereumMultistream::class.java)
                 ?: throw SilentException.UnsupportedBlockchain(chain)
     }
 
-    fun subscribe(base: TxDetails, up: AggregatedEthereumUpstreams): Flux<TxDetails> {
+    fun subscribe(base: TxDetails, up: EthereumMultistream): Flux<TxDetails> {
         var latestTx = base
 
         val untilFound = Mono.just(latestTx)
@@ -215,7 +213,7 @@ class TrackEthereumTx(
                 }
     }
 
-    fun updateFromBlock(upstream: AggregatedEthereumUpstreams, tx: TxDetails, blockTx: TransactionJson): Mono<TxDetails> {
+    fun updateFromBlock(upstream: EthereumMultistream, tx: TxDetails, blockTx: TransactionJson): Mono<TxDetails> {
         return if (blockTx.blockNumber != null && blockTx.blockHash != null && blockTx.blockHash != ZERO_BLOCK) {
             val updated = tx.withStatus(
                     blockHash = blockTx.blockHash,

src/main/kotlin/io/emeraldpay/dshackle/startup/ConfiguredUpstreams.kt

@@ -19,19 +19,20 @@ package io.emeraldpay.dshackle.startup
 import com.fasterxml.jackson.databind.ObjectMapper
 import io.emeraldpay.dshackle.BlockchainType
 import io.emeraldpay.dshackle.FileResolver
+import io.emeraldpay.dshackle.cache.CachesFactory
 import io.emeraldpay.dshackle.config.UpstreamsConfig
-import io.emeraldpay.dshackle.upstream.CurrentUpstreams
-import io.emeraldpay.dshackle.upstream.bitcoin.DirectBitcoinApi
-import io.emeraldpay.dshackle.upstream.bitcoin.BitcoinRpcClient
+import io.emeraldpay.dshackle.reader.Reader
+import io.emeraldpay.dshackle.upstream.CurrentMultistreamHolder
 import io.emeraldpay.dshackle.upstream.bitcoin.BitcoinUpstream
 import io.emeraldpay.dshackle.upstream.calls.CallMethods
 import io.emeraldpay.dshackle.upstream.calls.ManagedCallMethods
-import io.emeraldpay.dshackle.upstream.ethereum.DirectEthereumApi
 import io.emeraldpay.dshackle.upstream.ethereum.EthereumUpstream
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumWs
+import io.emeraldpay.dshackle.upstream.ethereum.EthereumWsFactory
 import io.emeraldpay.dshackle.upstream.grpc.GrpcUpstreams
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcHttpClient
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import io.emeraldpay.grpc.Chain
-import io.infinitape.etherjar.rpc.http.ReactorHttpRpcClient
 import org.slf4j.LoggerFactory
 import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.stereotype.Repository
@@ -44,9 +45,10 @@ import kotlin.collections.HashMap
 @Repository
 open class ConfiguredUpstreams(
         @Autowired private val objectMapper: ObjectMapper,
-        @Autowired private val currentUpstreams: CurrentUpstreams,
+        @Autowired private val currentUpstreams: CurrentMultistreamHolder,
         @Autowired private val fileResolver: FileResolver,
-        @Autowired private val config: UpstreamsConfig
+        @Autowired private val config: UpstreamsConfig,
+        @Autowired private val cachesFactory: CachesFactory
 ) {
 
     private val log = LoggerFactory.getLogger(ConfiguredUpstreams::class.java)
@@ -134,80 +136,61 @@ open class ConfiguredUpstreams(
                                      options: UpstreamsConfig.Options) {
 
         val conn = config.connection!!
-        var rpcApi: DirectBitcoinApi? = null
+        val directApi: Reader<JsonRpcRequest, JsonRpcResponse>? = buildHttpClient(config)
+        if (directApi == null) {
+            log.warn("Upstream doesn't have API configuration")
+            return
+        }
+
         val methods = buildMethods(config, chain)
-        conn.rpc?.let { endpoint ->
-            val rpcClient = BitcoinRpcClient(endpoint.url.toString(), endpoint.basicAuth!!)
-            rpcApi = DirectBitcoinApi(rpcClient, objectMapper, methods)
-        }
-        rpcApi?.let { api ->
-            val upstream = BitcoinUpstream(config.id
-                    ?: "bitcoin-${seq.getAndIncrement()}", chain, api,
-                    options, QuorumForLabels.QuorumItem(1, config.labels),
-                    objectMapper, methods)
-
-            upstream.start()
-            currentUpstreams.update(UpstreamChange(chain, upstream, UpstreamChange.ChangeType.ADDED))
-        }
+        val upstream = BitcoinUpstream(config.id
+                ?: "bitcoin-${seq.getAndIncrement()}", chain, directApi,
+                options, QuorumForLabels.QuorumItem(1, config.labels),
+                objectMapper, methods)
 
+        upstream.start()
+        currentUpstreams.update(UpstreamChange(chain, upstream, UpstreamChange.ChangeType.ADDED))
     }
 
     private fun buildEthereumUpstream(config: UpstreamsConfig.Upstream<UpstreamsConfig.EthereumConnection>,
                                       chain: Chain,
                                       options: UpstreamsConfig.Options) {
         val conn = config.connection!!
-        var rpcApi: DirectEthereumApi? = null
+        val directApi: Reader<JsonRpcRequest, JsonRpcResponse>? = buildHttpClient(config)
+        if (directApi == null) {
+            log.warn("Upstream doesn't have API configuration")
+            return
+        }
+
         val urls = ArrayList<URI>()
         val methods = buildMethods(config, chain)
         conn.rpc?.let { endpoint ->
-            val rpcClient = ReactorHttpRpcClient.newBuilder()
-                    .connectTo(endpoint.url)
-                    .alwaysSeparate()
-            conn.rpc?.basicAuth?.let { auth ->
-                rpcClient.basicAuth(auth.username, auth.password)
-            }
-            conn.rpc?.tls?.let { tls ->
-                tls.ca?.let { ca ->
-                    fileResolver.resolve(ca).inputStream().use { cert -> rpcClient.trustedCertificate(cert) }
-                }
-            }
-            rpcApi = DirectEthereumApi(
-                    rpcClient.build(),
-                    null,
-                    objectMapper,
-                    methods
-            ).apply {
-                timeout = options.timeout
-            }
-
             urls.add(endpoint.url)
         }
-        if (rpcApi != null) {
-            val wsApi: EthereumWs? = conn.ws?.let { endpoint ->
-                val wsApi = EthereumWs(
-                        endpoint.url,
-                        endpoint.origin ?: URI("http://localhost"),
-                        rpcApi!!,
-                        objectMapper
-                )
-                endpoint.basicAuth?.let { auth ->
-                    wsApi.basicAuth = auth
-                }
-                wsApi.connect()
-                urls.add(endpoint.url)
-                wsApi
-            }
 
-            log.info("Using ${chain.chainName} upstream, at ${urls.joinToString()}")
-            val ethereumUpstream = EthereumUpstream(
-                    config.id!!,
-                    chain, rpcApi!!, wsApi, options,
-                    QuorumForLabels.QuorumItem(1, config.labels),
-                    methods,
-                    objectMapper)
-            ethereumUpstream.start()
-            currentUpstreams.update(UpstreamChange(chain, ethereumUpstream, UpstreamChange.ChangeType.ADDED))
+        val wsFactoryApi: EthereumWsFactory? = conn.ws?.let { endpoint ->
+            val wsApi = EthereumWsFactory(
+                    endpoint.url,
+                    endpoint.origin ?: URI("http://localhost"),
+                    objectMapper
+            )
+            endpoint.basicAuth?.let { auth ->
+                wsApi.basicAuth = auth
+            }
+            urls.add(endpoint.url)
+            wsApi
         }
+
+        log.info("Using ${chain.chainName} upstream, at ${urls.joinToString()}")
+        val ethereumUpstream = EthereumUpstream(
+                config.id!!,
+                chain, directApi, wsFactoryApi, options,
+                QuorumForLabels.QuorumItem(1, config.labels),
+                methods,
+                objectMapper
+        )
+        ethereumUpstream.start()
+        currentUpstreams.update(UpstreamChange(chain, ethereumUpstream, UpstreamChange.ChangeType.ADDED))
     }
 
     private fun buildGrpcUpstream(config: UpstreamsConfig.Upstream<UpstreamsConfig.GrpcConnection>, options: UpstreamsConfig.Options) {
@@ -230,5 +213,22 @@ open class ConfiguredUpstreams(
                 .subscribe(currentUpstreams::update)
     }
 
-
+    private fun buildHttpClient(config: UpstreamsConfig.Upstream<out UpstreamsConfig.RpcConnection>): JsonRpcHttpClient? {
+        val conn = config.connection!!
+        val urls = ArrayList<URI>()
+        return conn.rpc?.let { endpoint ->
+            val tls = conn.rpc?.tls?.let { tls ->
+                tls.ca?.let { ca ->
+                    fileResolver.resolve(ca).readBytes()
+                }
+            }
+            urls.add(endpoint.url)
+            JsonRpcHttpClient(
+                    endpoint.url.toString(),
+                    objectMapper,
+                    conn.rpc?.basicAuth,
+                    tls
+            )
+        }
+    }
 }

src/main/kotlin/io/emeraldpay/dshackle/startup/UpstreamChange.kt

@@ -32,7 +32,7 @@ class UpstreamChange(
         /**
          * Corresponding upstream
          */
-        val upstream: Upstream<*>,
+        val upstream: Upstream,
         /**
          * Type of the change
          */

src/main/kotlin/io/emeraldpay/dshackle/upstream/AbstractHead.kt

@@ -31,15 +31,24 @@ abstract class AbstractHead : Head {
 
     private val head = AtomicReference<BlockContainer>(null)
     private val stream: TopicProcessor<BlockContainer> = TopicProcessor.create()
+    private val beforeBlockHandlers = ArrayList<Runnable>()
 
     fun follow(source: Flux<BlockContainer>): Disposable {
-        return source.distinctUntilChanged {
-            it.hash
-        }.filter { block ->
-            val curr = head.get()
-            curr == null || curr.difficulty < block.difficulty
-        }
+        return source
+                .distinctUntilChanged {
+                    it.hash
+                }.filter { block ->
+                    val curr = head.get()
+                    curr == null || curr.difficulty < block.difficulty
+                }
+                .doFinally {
+                    // close internal stream if upstream is finished, otherwise it gets stuck
+                    // but technically is should never happen during normal work, only when the Head
+                    // is stopping
+                    stream.onComplete()
+                }
                 .subscribe { block ->
+                    notifyBeforeBlock()
                     val prev = head.getAndUpdate { curr ->
                         if (curr == null || curr.difficulty < block.difficulty) {
                             block
@@ -54,6 +63,20 @@ abstract class AbstractHead : Head {
                 }
     }
 
+    fun notifyBeforeBlock() {
+        beforeBlockHandlers.forEach { handler ->
+            try {
+                handler.run()
+            } catch (t: Throwable) {
+                log.warn("Before Block handler error", t)
+            }
+        }
+    }
+
+    override fun onBeforeBlock(handler: Runnable) {
+        beforeBlockHandlers.add(handler)
+    }
+
     override fun getFlux(): Flux<BlockContainer> {
         return Flux.merge(
                 Mono.justOrEmpty(head.get()),

src/main/kotlin/io/emeraldpay/dshackle/upstream/AggregatedUpstream.kt

@@ -1,122 +0,0 @@
-/**
- * Copyright (c) 2020 EmeraldPay, Inc
- * Copyright (c) 2019 ETCDEV GmbH
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream
-
-import com.fasterxml.jackson.databind.ObjectMapper
-import io.emeraldpay.dshackle.cache.*
-import io.emeraldpay.dshackle.config.UpstreamsConfig
-import io.emeraldpay.dshackle.upstream.calls.AggregatedCallMethods
-import io.emeraldpay.dshackle.upstream.calls.CallMethods
-import org.springframework.context.Lifecycle
-import reactor.core.Disposable
-import reactor.core.publisher.Flux
-import java.time.Duration
-import java.time.Instant
-import java.util.concurrent.atomic.AtomicReference
-import java.util.concurrent.locks.ReentrantLock
-import java.util.function.Predicate
-import kotlin.concurrent.withLock
-
-/**
- * Aggregation of multiple upstreams responding to a single blockchain
- */
-abstract class AggregatedUpstream<U : UpstreamApi>(
-        private val objectMapper: ObjectMapper,
-        val caches: Caches
-) : Upstream<U>, Lifecycle {
-
-    private var cacheSubscription: Disposable? = null
-    var cache: CachingEthereumApi = CachingEthereumApi.empty(objectMapper)
-    private val reconfigLock = ReentrantLock()
-    private var callMethods: CallMethods? = null
-
-    abstract fun getAll(): List<Upstream<U>>
-    abstract fun addUpstream(upstream: Upstream<U>)
-    abstract fun getApis(matcher: Selector.Matcher): ApiSource<U>
-
-    fun onUpstreamsUpdated() {
-        reconfigLock.withLock {
-            getAll().map { it.getMethods() }.let {
-                callMethods = AggregatedCallMethods(it)
-            }
-        }
-    }
-
-    override fun observeStatus(): Flux<UpstreamAvailability> {
-        val upstreamsFluxes = getAll().map { up -> up.observeStatus().map { UpstreamStatus(up, it) } }
-        return Flux.merge(upstreamsFluxes)
-                .filter(FilterBestAvailability())
-                .map { it.status }
-    }
-
-    override fun isAvailable(): Boolean {
-        return getAll().any { it.isAvailable() }
-    }
-
-    override fun getStatus(): UpstreamAvailability {
-        val upstreams = getAll()
-        return if (upstreams.isEmpty()) UpstreamAvailability.UNAVAILABLE
-        else upstreams.map { it.getStatus() }.min()!!
-    }
-
-    override fun getOptions(): UpstreamsConfig.Options {
-        return UpstreamsConfig.Options()
-    }
-
-    override fun getMethods(): CallMethods {
-        return callMethods ?: throw IllegalStateException("Methods are not initialized yet")
-    }
-
-    override fun start() {
-    }
-
-    override fun stop() {
-        cacheSubscription?.dispose()
-        cacheSubscription = null
-    }
-
-    fun onHeadUpdated(head: Head) {
-        reconfigLock.withLock {
-            cacheSubscription?.dispose()
-            cacheSubscription = head.getFlux().subscribe {
-                caches.cache(Caches.Tag.LATEST, it)
-            }
-            cache = CachingEthereumApi(objectMapper, caches, head)
-        }
-    }
-
-    // --------------------------------------------------------------------------------------------------------
-
-    class UpstreamStatus(val upstream: Upstream<UpstreamApi>, val status: UpstreamAvailability, val ts: Instant = Instant.now())
-
-    class FilterBestAvailability() : Predicate<UpstreamStatus> {
-        private val lastRef = AtomicReference<UpstreamStatus>()
-
-        override fun test(t: UpstreamStatus): Boolean {
-            val last = lastRef.get()
-            val changed = last == null
-                    || t.status > last.status
-                    || (last.upstream == t.upstream && t.status != last.status)
-                    || last.ts.isBefore(Instant.now() - Duration.ofSeconds(60))
-            if (changed) {
-                lastRef.set(t)
-            }
-            return changed
-        }
-    }
-
-}

src/main/kotlin/io/emeraldpay/dshackle/upstream/ApiSource.kt

@@ -16,10 +16,12 @@
  */
 package io.emeraldpay.dshackle.upstream
 
-import io.emeraldpay.dshackle.upstream.ethereum.DirectEthereumApi
+import io.emeraldpay.dshackle.reader.Reader
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import org.reactivestreams.Publisher
 
-interface ApiSource<U : UpstreamApi> : Publisher<U> {
+interface ApiSource : Publisher<Upstream> {
 
     fun resolve()
     fun request(tries: Int)

src/main/kotlin/io/emeraldpay/dshackle/upstream/CachingEthereumApi.kt

@@ -1,145 +0,0 @@
-/**
- * Copyright (c) 2020 EmeraldPay, Inc
- * Copyright (c) 2019 ETCDEV GmbH
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream
-
-import com.fasterxml.jackson.databind.ObjectMapper
-import io.emeraldpay.dshackle.cache.Caches
-import io.emeraldpay.dshackle.data.*
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumApi
-import io.infinitape.etherjar.hex.HexQuantity
-import org.slf4j.LoggerFactory
-import reactor.core.publisher.Mono
-import java.math.BigInteger
-import java.util.function.Function
-
-open class CachingEthereumApi(
-        private val objectMapper: ObjectMapper,
-        private val caches: Caches,
-        private val head: Head
-): EthereumApi(objectMapper) {
-
-    companion object {
-        private val log = LoggerFactory.getLogger(CachingEthereumApi::class.java)
-
-        /**
-         * Create caching API with empty memory-only cache
-         */
-        @JvmStatic
-        fun empty(objectMapper: ObjectMapper): CachingEthereumApi {
-            return CachingEthereumApi(objectMapper, Caches.default(objectMapper), EmptyHead())
-        }
-    }
-
-    private val rawJsonBuilder = RawJsonBuilder()
-
-    private val cacheBlocks = caches.getBlocksByHash()
-    private val cacheBlocksByHeight = caches.getBlocksByHeight()
-    private val cacheTx = caches.getTxByHash()
-    private val cacheFullBlocks = caches.getFullBlocks()
-    private val cacheFullBlocksByHeight = caches.getFullBlocksByHeight()
-
-    fun readBlockByHash(id: Int, method: String, params: List<Any>): Mono<ByteArray> {
-        return if (params.size == 2) {
-            val includeTransactions = params[1].toString().toBoolean()
-            val cache = if (includeTransactions) {
-                cacheFullBlocks
-            } else {
-                cacheBlocks
-            }
-            Mono.just(params[0])
-                    .map { BlockId.from(it as String) }
-                    .flatMap(cache::read)
-                    .transform(converter(id))
-                    .transform(finalizer())
-        }
-        else Mono.empty()
-    }
-
-    fun readBlockByNumber(id: Int, method: String, params: List<Any>): Mono<ByteArray> {
-        return if (params.size == 2) {
-            val includeTransactions = params[1].toString().toBoolean()
-            val cache = if (includeTransactions) {
-                cacheFullBlocksByHeight
-            } else {
-                cacheBlocksByHeight
-            }
-            Mono.just(params[0])
-                    .map { HexQuantity.from(it as String) }
-                    .filter { it.value < BigInteger.valueOf(Long.MAX_VALUE) }
-                    .map { it.value.toLong() }
-                    .flatMap(cache::read)
-                    .transform(converter(id))
-                    .transform(finalizer())
-        }
-        else Mono.empty()
-    }
-
-    override fun execute(id: Int, method: String, params: List<Any>): Mono<ByteArray> {
-        return when (method) {
-            "eth_blockNumber" ->
-                head.getFlux().next()
-                        .map { HexQuantity.from(it.height).toHex() }
-                        .map { objectMapper.writeValueAsBytes(it) }
-                        .map(bytesToJson(id))
-            "eth_getBlockByHash" -> readBlockByHash(id, method, params)
-            "eth_getBlockByNumber" -> readBlockByNumber(id, method, params)
-            "eth_getTransactionByHash" ->
-                if (params.size == 1)
-                    Mono.just(params[0])
-                            .map { TxId.from(it as String) }
-                            .flatMap(cacheTx::read)
-                            .transform(converter(id))
-                            .transform(finalizer())
-                else Mono.empty()
-            else ->
-                Mono.empty()
-        }
-    }
-
-    /**
-     * Convert to JSON RPC response
-     */
-    fun converter(id: Int): Function<in Mono<out SourceContainer>, out Mono<ByteArray>> {
-        return Function { mono ->
-            mono.map(containerToJson(id))
-        }
-    }
-
-    /**
-     * Handle errors and other stuff
-     */
-    fun finalizer(): Function<Mono<ByteArray>, Mono<ByteArray>> {
-        return Function { mono ->
-            mono.onErrorResume { t ->
-                log.warn("Error during read from cache", t)
-                Mono.empty()
-            }
-        }
-    }
-
-    fun bytesToJson(id: Int): Function<ByteArray, ByteArray> {
-        return Function { data ->
-            rawJsonBuilder.write(id, data)
-        }
-    }
-
-    fun containerToJson(id: Int): Function<SourceContainer, ByteArray> {
-        return Function { data ->
-            rawJsonBuilder.write(id, data.json!!)
-        }
-    }
-}

src/main/kotlin/io/emeraldpay/dshackle/upstream/ChainUpstreams.kt

@@ -1,135 +0,0 @@
-/**
- * Copyright (c) 2020 EmeraldPay, Inc
- * Copyright (c) 2019 ETCDEV GmbH
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream
-
-import com.fasterxml.jackson.databind.ObjectMapper
-import io.emeraldpay.dshackle.cache.Caches
-import io.emeraldpay.grpc.Chain
-import org.slf4j.LoggerFactory
-import org.springframework.context.Lifecycle
-import reactor.core.Disposable
-import reactor.core.publisher.Mono
-import java.lang.IllegalStateException
-import java.time.Duration
-
-/**
- * General interface to upstream(s) to a single chain
- */
-abstract class ChainUpstreams<U : UpstreamApi>(
-        val chain: Chain,
-        private val upstreams: MutableList<Upstream<U>>,
-        caches: Caches,
-        objectMapper: ObjectMapper
-) : AggregatedUpstream<U>(objectMapper, caches), Lifecycle {
-
-    private val log = LoggerFactory.getLogger(ChainUpstreams::class.java)
-    private var seq = 0
-    protected var lagObserver: HeadLagObserver<U>? = null
-    private var subscription: Disposable? = null
-
-    open fun init() {
-        onUpstreamsUpdated()
-    }
-
-    abstract fun updateHead(): Head
-    abstract fun setHead(head: Head)
-
-    override fun getId(): String {
-        return "!all:${chain.chainCode}"
-    }
-
-    override fun isRunning(): Boolean {
-        return subscription != null
-    }
-
-    override fun start() {
-        super.start()
-        subscription = observeStatus()
-                .distinctUntilChanged()
-                .subscribe { printStatus() }
-    }
-
-    override fun stop() {
-        super.stop()
-        subscription?.dispose()
-        subscription = null
-        getHead().let {
-            if (it is Lifecycle) {
-                it.stop()
-            }
-        }
-        lagObserver?.stop()
-    }
-
-    override fun getAll(): List<Upstream<U>> {
-        return upstreams
-    }
-
-    override fun addUpstream(upstream: Upstream<U>) {
-        upstreams.add(upstream)
-        setHead(updateHead())
-        onUpstreamsUpdated()
-    }
-
-    fun removeUpstream(id: String) {
-        if (upstreams.removeIf { it.getId() == id }) {
-            setHead(updateHead())
-            onUpstreamsUpdated()
-        }
-    }
-
-    override fun getApis(matcher: Selector.Matcher): ApiSource<U> {
-        val i = seq++
-        if (seq >= Int.MAX_VALUE / 2) {
-            seq = 0
-        }
-        return FilteredApis(upstreams, matcher, i)
-    }
-
-    override fun getApi(matcher: Selector.Matcher): Mono<U> {
-        val apis = getApis(matcher)
-        apis.request(1)
-        return Mono.from(apis)
-                .switchIfEmpty(Mono.error<U>(Exception("No API available")))
-    }
-
-    override fun setLag(lag: Long) {
-    }
-
-    override fun getLag(): Long {
-        return 0
-    }
-
-    fun printStatus() {
-        var height: Long? = null
-        try {
-            height = getHead().getFlux().next().block(Duration.ofSeconds(1))?.height
-        } catch (e: IllegalStateException) {
-            //timout
-        } catch (e: Exception) {
-            log.warn("Head processing error: ${e.javaClass} ${e.message}")
-        }
-        val statuses = upstreams.map { it.getStatus() }
-                .groupBy { it }
-                .map { "${it.key.name}/${it.value.size}" }
-                .joinToString(",")
-        val lag = upstreams.map { it.getLag() }
-                .joinToString(", ")
-
-        log.info("State of ${chain.chainCode}: height=${height ?: '?'}, status=$statuses, lag=[$lag]")
-    }
-}

src/main/kotlin/io/emeraldpay/dshackle/upstream/CurrentMultistreamHolder.kt

@@ -21,14 +21,12 @@ import io.emeraldpay.dshackle.BlockchainType
 import io.emeraldpay.dshackle.cache.CachesEnabled
 import io.emeraldpay.dshackle.cache.CachesFactory
 import io.emeraldpay.dshackle.startup.UpstreamChange
-import io.emeraldpay.dshackle.upstream.bitcoin.DirectBitcoinApi
-import io.emeraldpay.dshackle.upstream.bitcoin.BitcoinChainUpstreams
+import io.emeraldpay.dshackle.upstream.bitcoin.BitcoinMultistream
 import io.emeraldpay.dshackle.upstream.bitcoin.BitcoinUpstream
-import io.emeraldpay.dshackle.upstream.bitcoin.DefaultBitcoinMethods
+import io.emeraldpay.dshackle.upstream.calls.DefaultBitcoinMethods
 import io.emeraldpay.dshackle.upstream.calls.CallMethods
 import io.emeraldpay.dshackle.upstream.calls.DefaultEthereumMethods
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumApi
-import io.emeraldpay.dshackle.upstream.ethereum.AggregatedEthereumUpstreams
+import io.emeraldpay.dshackle.upstream.ethereum.EthereumMultistream
 import io.emeraldpay.dshackle.upstream.ethereum.EthereumUpstream
 import io.emeraldpay.grpc.Chain
 import org.slf4j.LoggerFactory
@@ -44,14 +42,14 @@ import java.util.concurrent.locks.ReentrantLock
 import kotlin.concurrent.withLock
 
 @Repository
-class CurrentUpstreams(
+class CurrentMultistreamHolder(
         @Autowired private val objectMapper: ObjectMapper,
         @Autowired private val cachesFactory: CachesFactory
-): Upstreams {
+) : MultistreamHolder {
 
-    private val log = LoggerFactory.getLogger(CurrentUpstreams::class.java)
+    private val log = LoggerFactory.getLogger(CurrentMultistreamHolder::class.java)
 
-    private val chainMapping = ConcurrentHashMap<Chain, ChainUpstreams<*>>()
+    private val chainMapping = ConcurrentHashMap<Chain, Multistream>()
     private val chainsBus = TopicProcessor.create<Chain>()
     private val callTargets = HashMap<Chain, CallMethods>()
     private val updateLock = ReentrantLock()
@@ -61,20 +59,18 @@ class CurrentUpstreams(
             val chain = change.chain
             when (BlockchainType.fromBlockchain(chain)) {
                 BlockchainType.ETHEREUM -> {
-                    val up = change.upstream
-                            .cast(EthereumUpstream::class.java, EthereumApi::class.java) as Upstream<EthereumApi>
-                    val current = chainMapping[chain] as ChainUpstreams<EthereumApi>?
+                    val up = change.upstream.cast(EthereumUpstream::class.java)
+                    val current = chainMapping[chain] as Multistream?
                     val factory = Callable {
-                        AggregatedEthereumUpstreams(chain, ArrayList(), cachesFactory.getCaches(chain), objectMapper) as ChainUpstreams<EthereumApi>
+                        EthereumMultistream(chain, ArrayList(), cachesFactory.getCaches(chain), objectMapper) as Multistream
                     }
                     processUpdate(change, up, current, factory)
                 }
                 BlockchainType.BITCOIN -> {
-                    val up = change.upstream
-                            .cast(BitcoinUpstream::class.java, DirectBitcoinApi::class.java)
-                    val current = chainMapping[chain] as ChainUpstreams<DirectBitcoinApi>?
+                    val up = change.upstream.cast(BitcoinUpstream::class.java)
+                    val current = chainMapping[chain] as Multistream?
                     val factory = Callable {
-                        BitcoinChainUpstreams(chain, ArrayList(), cachesFactory.getCaches(chain), objectMapper) as ChainUpstreams<DirectBitcoinApi>
+                        BitcoinMultistream(chain, ArrayList(), cachesFactory.getCaches(chain), objectMapper) as Multistream
                     }
                     processUpdate(change, up, current, factory)
                 }
@@ -85,7 +81,7 @@ class CurrentUpstreams(
         }
     }
 
-    fun <A : UpstreamApi> processUpdate(change: UpstreamChange, up: Upstream<A>, current: ChainUpstreams<A>?, factory: Callable<ChainUpstreams<A>>) {
+    fun processUpdate(change: UpstreamChange, up: Upstream, current: Multistream?, factory: Callable<Multistream>) {
         val chain = change.chain
         if (change.type == UpstreamChange.ChangeType.REMOVED) {
             current?.removeUpstream(up.getId())
@@ -113,7 +109,7 @@ class CurrentUpstreams(
         }
     }
 
-    override fun getUpstream(chain: Chain): AggregatedUpstream<*>? {
+    override fun getUpstream(chain: Chain): Multistream? {
         return chainMapping[chain]
     }
 

src/main/kotlin/io/emeraldpay/dshackle/upstream/DefaultUpstream.kt

@@ -22,13 +22,13 @@ import reactor.core.publisher.Flux
 import reactor.core.publisher.TopicProcessor
 import java.util.concurrent.atomic.AtomicReference
 
-abstract class DefaultUpstream<U : UpstreamApi>(
+abstract class DefaultUpstream(
         private val id: String,
         defaultLag: Long,
         defaultAvail: UpstreamAvailability,
         private val options: UpstreamsConfig.Options,
         private val targets: CallMethods?
-) : Upstream<U> {
+) : Upstream {
 
     constructor(id: String, options: UpstreamsConfig.Options, targets: CallMethods?) : this(id, Long.MAX_VALUE, UpstreamAvailability.UNAVAILABLE, options, targets)
 

src/main/kotlin/io/emeraldpay/dshackle/upstream/EmptyHead.kt

@@ -25,4 +25,7 @@ class EmptyHead : Head {
     override fun getFlux(): Flux<BlockContainer> {
         return Flux.empty()
     }
+
+    override fun onBeforeBlock(handler: Runnable) {
+    }
 }

src/main/kotlin/io/emeraldpay/dshackle/upstream/FilteredApis.kt

@@ -16,6 +16,9 @@
  */
 package io.emeraldpay.dshackle.upstream
 
+import io.emeraldpay.dshackle.reader.Reader
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import org.reactivestreams.Subscriber
 import reactor.core.publisher.EmitterProcessor
 import reactor.core.publisher.Flux
@@ -26,28 +29,28 @@ import kotlin.math.pow
 import kotlin.math.roundToLong
 import kotlin.random.Random
 
-class FilteredApis<U : UpstreamApi>(
-        allUpstreams: List<Upstream<U>>,
+class FilteredApis(
+        allUpstreams: List<Upstream>,
         private val matcher: Selector.Matcher,
         pos: Int,
         private val repeatLimit: Long,
         jitter: Int
-) : ApiSource<U> {
+) : ApiSource {
 
     companion object {
         private const val DEFAULT_DELAY_STEP = 100
         private const val MAX_WAIT_MILLIS = 5000L
     }
 
-    constructor(allUpstreams: List<Upstream<U>>,
+    constructor(allUpstreams: List<Upstream>,
                 matcher: Selector.Matcher,
                 pos: Int) : this(allUpstreams, matcher, pos, 10, 7)
 
-    constructor(allUpstreams: List<Upstream<U>>,
+    constructor(allUpstreams: List<Upstream>,
                 matcher: Selector.Matcher) : this(allUpstreams, matcher, 0, 10, 10)
 
     private val delay: Int
-    private val upstreams: List<Upstream<UpstreamApi>>
+    private val upstreams: List<Upstream>
 
     private val control = EmitterProcessor.create<Boolean>(32, false)
 
@@ -75,18 +78,18 @@ class FilteredApis<U : UpstreamApi>(
         return Duration.ofMillis(time)
     }
 
-    override fun subscribe(subscriber: Subscriber<in U>) {
+    override fun subscribe(subscriber: Subscriber<in Upstream>) {
         val first = Flux.fromIterable(upstreams)
         val retries = (1 until repeatLimit).map { r ->
             Flux.fromIterable(upstreams).delaySubscription(waitDuration(r))
         }.let { Flux.concat(it) }
 
         Flux.concat(first, retries)
-                .filter(Upstream<UpstreamApi>::isAvailable)
+                .filter(Upstream::isAvailable)
                 .filter(matcher::matches)
-                .flatMap { it.getApi(matcher) }
-                .zipWith(control).map { it.t1 }
-                .subscribe(subscriber as Subscriber<in UpstreamApi>)
+                .zipWith(control)
+                .map { it.t1 }
+                .subscribe(subscriber)
     }
 
     override fun resolve() {

src/main/kotlin/io/emeraldpay/dshackle/upstream/Head.kt

@@ -20,6 +20,20 @@ import io.emeraldpay.dshackle.data.BlockContainer
 import reactor.core.publisher.Flux
 import reactor.core.publisher.Mono
 
+/**
+ * Subscription to listen to updates to the head of a blockchain.
+ */
 interface Head {
+
+    /**
+     * @return stream of all new blocks, starts from the current block (i.e., first item should be available immediately).
+     */
     fun getFlux(): Flux<BlockContainer>
+
+    /**
+     * Add handler that is going to be called each time _before_ a new block is submitted to stream of new blocks.
+     * Supposed to be used for cleanup/preparation before actual block data will come, to avoid race condition.
+     * @see getFlux
+     */
+    fun onBeforeBlock(handler: Runnable)
 }

src/main/kotlin/io/emeraldpay/dshackle/upstream/HeadLagObserver.kt

@@ -28,9 +28,9 @@ import reactor.util.function.Tuples
  * Observer group of upstreams and defined a distance in blocks (lag) between a leader (best height/difficulty) and
  * other upstreams.
  */
-abstract class HeadLagObserver<A : UpstreamApi>(
+abstract class HeadLagObserver(
         private val master: Head,
-        private val followers: Collection<Upstream<A>>
+        private val followers: Collection<Upstream>
 ) : Lifecycle {
 
     private val log = LoggerFactory.getLogger(HeadLagObserver::class.java)
@@ -58,7 +58,7 @@ abstract class HeadLagObserver<A : UpstreamApi>(
                 }
     }
 
-    fun probeFollowers(top: BlockContainer): Flux<Tuple2<Long, Upstream<A>>> {
+    fun probeFollowers(top: BlockContainer): Flux<Tuple2<Long, Upstream>> {
         return Flux.fromIterable(followers)
                 .parallel(followers.size)
                 .flatMap { mapLagging(top, it, getCurrentBlocks(it)) }
@@ -66,9 +66,9 @@ abstract class HeadLagObserver<A : UpstreamApi>(
                 .onErrorContinue { t, _ -> log.warn("Failed to update lagging distance", t) }
     }
 
-    abstract fun getCurrentBlocks(up: Upstream<A>): Flux<BlockContainer>
+    abstract fun getCurrentBlocks(up: Upstream): Flux<BlockContainer>
 
-    fun mapLagging(top: BlockContainer, up: Upstream<A>, blocks: Flux<BlockContainer>): Flux<Tuple2<Long, Upstream<A>>> {
+    fun mapLagging(top: BlockContainer, up: Upstream, blocks: Flux<BlockContainer>): Flux<Tuple2<Long, Upstream>> {
         return blocks
                 .map { extractDistance(top, it) }
                 .takeUntil { lag -> lag <= 0L }

src/main/kotlin/io/emeraldpay/dshackle/upstream/Multistream.kt

@@ -0,0 +1,235 @@
+/**
+ * Copyright (c) 2020 EmeraldPay, Inc
+ * Copyright (c) 2019 ETCDEV GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.emeraldpay.dshackle.upstream
+
+import io.emeraldpay.dshackle.cache.*
+import io.emeraldpay.dshackle.config.UpstreamsConfig
+import io.emeraldpay.dshackle.reader.Reader
+import io.emeraldpay.dshackle.upstream.calls.AggregatedCallMethods
+import io.emeraldpay.dshackle.upstream.calls.CallMethods
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
+import io.emeraldpay.grpc.Chain
+import org.slf4j.LoggerFactory
+import org.springframework.context.Lifecycle
+import reactor.core.Disposable
+import reactor.core.publisher.Flux
+import reactor.core.publisher.Mono
+import java.time.Duration
+import java.time.Instant
+import java.util.concurrent.atomic.AtomicReference
+import java.util.concurrent.locks.ReentrantLock
+import java.util.function.Predicate
+import kotlin.concurrent.withLock
+
+/**
+ * Aggregation of multiple upstreams responding to a single blockchain
+ */
+abstract class Multistream(
+        val chain: Chain,
+        private val upstreams: MutableList<Upstream>,
+        val caches: Caches
+) : Upstream, Lifecycle {
+
+    companion object {
+        private val log = LoggerFactory.getLogger(Multistream::class.java)
+    }
+
+    private var cacheSubscription: Disposable? = null
+    private val reconfigLock = ReentrantLock()
+    private var callMethods: CallMethods? = null
+    private var seq = 0
+    protected var lagObserver: HeadLagObserver? = null
+    private var subscription: Disposable? = null
+
+    open fun init() {
+        onUpstreamsUpdated()
+    }
+
+    /**
+     * Get list of all underlying upstreams
+     */
+    fun getAll(): List<Upstream> {
+        return upstreams
+    }
+
+    /**
+     * Add an upstream
+     */
+    fun addUpstream(upstream: Upstream) {
+        upstreams.add(upstream)
+        setHead(updateHead())
+        onUpstreamsUpdated()
+    }
+
+    fun removeUpstream(id: String) {
+        if (upstreams.removeIf { it.getId() == id }) {
+            setHead(updateHead())
+            onUpstreamsUpdated()
+        }
+    }
+
+    /**
+     * Get a source for direct APIs
+     */
+    fun getApiSource(matcher: Selector.Matcher): ApiSource {
+        val i = seq++
+        if (seq >= Int.MAX_VALUE / 2) {
+            seq = 0
+        }
+        return FilteredApis(upstreams, matcher, i)
+    }
+
+    /**
+     * Finds an API that executed directly on a remote.
+     */
+    fun getDirectApi(matcher: Selector.Matcher): Mono<Reader<JsonRpcRequest, JsonRpcResponse>> {
+        val apis = getApiSource(matcher)
+        apis.request(1)
+        return Mono.from(apis)
+                .map(Upstream::getApi)
+                .switchIfEmpty(Mono.error(Exception("No API available for $chain")))
+    }
+
+    /**
+     * Finds an API that leverages caches and other optimizations/transformations of the request.
+     */
+    abstract fun getRoutedApi(matcher: Selector.Matcher): Mono<Reader<JsonRpcRequest, JsonRpcResponse>>
+
+    override fun getApi(): Reader<JsonRpcRequest, JsonRpcResponse> {
+        throw NotImplementedError("Immediate direct API is not implemented for Aggregated Upstream")
+    }
+
+    fun onUpstreamsUpdated() {
+        reconfigLock.withLock {
+            getAll().map { it.getMethods() }.let {
+                callMethods = AggregatedCallMethods(it)
+            }
+        }
+    }
+
+    override fun observeStatus(): Flux<UpstreamAvailability> {
+        val upstreamsFluxes = getAll().map { up -> up.observeStatus().map { UpstreamStatus(up, it) } }
+        return Flux.merge(upstreamsFluxes)
+                .filter(FilterBestAvailability())
+                .map { it.status }
+    }
+
+    override fun isAvailable(): Boolean {
+        return getAll().any { it.isAvailable() }
+    }
+
+    override fun getStatus(): UpstreamAvailability {
+        val upstreams = getAll()
+        return if (upstreams.isEmpty()) UpstreamAvailability.UNAVAILABLE
+        else upstreams.map { it.getStatus() }.min()!!
+    }
+
+    override fun getOptions(): UpstreamsConfig.Options {
+        return UpstreamsConfig.Options()
+    }
+
+    override fun getMethods(): CallMethods {
+        return callMethods ?: throw IllegalStateException("Methods are not initialized yet")
+    }
+
+    override fun start() {
+        subscription = observeStatus()
+                .distinctUntilChanged()
+                .subscribe { printStatus() }
+    }
+
+    override fun stop() {
+        cacheSubscription?.dispose()
+        cacheSubscription = null
+        subscription?.dispose()
+        subscription = null
+        getHead().let {
+            if (it is Lifecycle) {
+                it.stop()
+            }
+        }
+        lagObserver?.stop()
+    }
+
+    fun onHeadUpdated(head: Head) {
+        reconfigLock.withLock {
+            cacheSubscription?.dispose()
+            cacheSubscription = head.getFlux().subscribe {
+                caches.cache(Caches.Tag.LATEST, it)
+            }
+        }
+    }
+
+    abstract fun updateHead(): Head
+    abstract fun setHead(head: Head)
+
+    override fun getId(): String {
+        return "!all:${chain.chainCode}"
+    }
+
+    override fun isRunning(): Boolean {
+        return subscription != null
+    }
+
+    override fun setLag(lag: Long) {
+    }
+
+    override fun getLag(): Long {
+        return 0
+    }
+
+    fun printStatus() {
+        var height: Long? = null
+        try {
+            height = getHead().getFlux().next().block(Duration.ofSeconds(1))?.height
+        } catch (e: java.lang.IllegalStateException) {
+            //timout
+        } catch (e: Exception) {
+            log.warn("Head processing error: ${e.javaClass} ${e.message}")
+        }
+        val statuses = upstreams.map { it.getStatus() }
+                .groupBy { it }
+                .map { "${it.key.name}/${it.value.size}" }
+                .joinToString(",")
+        val lag = upstreams.map { it.getLag() }
+                .joinToString(", ")
+
+        log.info("State of ${chain.chainCode}: height=${height ?: '?'}, status=$statuses, lag=[$lag]")
+    }
+
+    // --------------------------------------------------------------------------------------------------------
+
+    class UpstreamStatus(val upstream: Upstream, val status: UpstreamAvailability, val ts: Instant = Instant.now())
+
+    class FilterBestAvailability() : Predicate<UpstreamStatus> {
+        private val lastRef = AtomicReference<UpstreamStatus>()
+
+        override fun test(t: UpstreamStatus): Boolean {
+            val last = lastRef.get()
+            val changed = last == null
+                    || t.status > last.status
+                    || (last.upstream == t.upstream && t.status != last.status)
+                    || last.ts.isBefore(Instant.now() - Duration.ofSeconds(60))
+            if (changed) {
+                lastRef.set(t)
+            }
+            return changed
+        }
+    }
+
+}

src/main/kotlin/io/emeraldpay/dshackle/upstream/MultistreamHolder.kt

@@ -20,8 +20,11 @@ import io.emeraldpay.dshackle.upstream.calls.CallMethods
 import io.emeraldpay.grpc.Chain
 import reactor.core.publisher.Flux
 
-interface Upstreams {
-    fun getUpstream(chain: Chain): AggregatedUpstream<*>?
+/**
+ * Holds Multistreams configured for a chain.
+ */
+interface MultistreamHolder {
+    fun getUpstream(chain: Chain): Multistream?
     fun getAvailable(): List<Chain>
     fun observeChains(): Flux<Chain>
     fun getDefaultMethods(chain: Chain): CallMethods

src/main/kotlin/io/emeraldpay/dshackle/upstream/Selector.kt

@@ -96,13 +96,13 @@ class Selector {
     }
 
     interface Matcher {
-        fun matches(up: Upstream<UpstreamApi>): Boolean
+        fun matches(up: Upstream): Boolean
     }
 
     class MultiMatcher(
             private val matchers: Collection<Matcher>
     ): Matcher {
-        override fun matches(up: Upstream<UpstreamApi>): Boolean {
+        override fun matches(up: Upstream): Boolean {
             return matchers.all { it.matches(up) }
         }
 
@@ -114,13 +114,13 @@ class Selector {
     class MethodMatcher(
             val method: String
     ): Matcher {
-        override fun matches(up: Upstream<UpstreamApi>): Boolean {
+        override fun matches(up: Upstream): Boolean {
             return up.getMethods().isAllowed(method)
         }
     }
 
     abstract class LabelSelectorMatcher: Matcher {
-        override fun matches(up: Upstream<UpstreamApi>): Boolean {
+        override fun matches(up: Upstream): Boolean {
             return up.getLabels().any(this::matches)
         }
 
@@ -129,7 +129,7 @@ class Selector {
     }
 
     class EmptyMatcher: Matcher {
-        override fun matches(up: Upstream<UpstreamApi>): Boolean {
+        override fun matches(up: Upstream): Boolean {
             return true
         }
     }
@@ -144,7 +144,7 @@ class Selector {
             return null
         }
 
-        override fun matches(up: Upstream<UpstreamApi>): Boolean {
+        override fun matches(up: Upstream): Boolean {
             return true
         }
     }

src/main/kotlin/io/emeraldpay/dshackle/upstream/Upstream.kt

@@ -17,16 +17,19 @@
 package io.emeraldpay.dshackle.upstream
 
 import io.emeraldpay.dshackle.config.UpstreamsConfig
+import io.emeraldpay.dshackle.reader.Reader
 import io.emeraldpay.dshackle.upstream.calls.CallMethods
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import reactor.core.publisher.Flux
 import reactor.core.publisher.Mono
 
-interface Upstream<out A : UpstreamApi> {
+interface Upstream {
     fun isAvailable(): Boolean
     fun getStatus(): UpstreamAvailability
     fun observeStatus(): Flux<UpstreamAvailability>
     fun getHead(): Head
-    fun getApi(matcher: Selector.Matcher): Mono<out A>
+    fun getApi(): Reader<JsonRpcRequest, JsonRpcResponse>
     fun getOptions(): UpstreamsConfig.Options
     fun setLag(lag: Long)
     fun getLag(): Long
@@ -34,6 +37,5 @@ interface Upstream<out A : UpstreamApi> {
     fun getMethods(): CallMethods
     fun getId(): String
 
-    fun <TA : UpstreamApi> castApi(apiType: Class<TA>): Upstream<TA>
-    fun <T : Upstream<TA>, TA : UpstreamApi> cast(selfType: Class<T>, apiType: Class<TA>): T
+    fun <T : Upstream> cast(selfType: Class<T>): T
 }

src/main/kotlin/io/emeraldpay/dshackle/upstream/bitcoin/BitcoinMultistream.kt

@@ -18,24 +18,29 @@ package io.emeraldpay.dshackle.upstream.bitcoin
 import com.fasterxml.jackson.databind.ObjectMapper
 import io.emeraldpay.dshackle.cache.Caches
 import io.emeraldpay.dshackle.config.UpstreamsConfig
+import io.emeraldpay.dshackle.reader.EmptyReader
+import io.emeraldpay.dshackle.reader.Reader
 import io.emeraldpay.dshackle.upstream.*
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumApi
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import io.emeraldpay.grpc.Chain
 import org.slf4j.LoggerFactory
 import org.springframework.context.Lifecycle
+import reactor.core.publisher.Mono
 
-class BitcoinChainUpstreams(
+open class BitcoinMultistream(
         chain: Chain,
         val upstreams: MutableList<BitcoinUpstream>,
         caches: Caches,
-        objectMapper: ObjectMapper
-) : ChainUpstreams<DirectBitcoinApi>(chain, upstreams as MutableList<Upstream<DirectBitcoinApi>>, caches, objectMapper) {
+        private val objectMapper: ObjectMapper
+) : Multistream(chain, upstreams as MutableList<Upstream>, caches), Lifecycle {
 
     companion object {
-        private val log = LoggerFactory.getLogger(BitcoinChainUpstreams::class.java)
+        private val log = LoggerFactory.getLogger(BitcoinMultistream::class.java)
     }
 
     private var head: Head? = null
+    private var reader = BitcoinReader(this, EmptyHead(), objectMapper)
 
     override fun init() {
         if (upstreams.size > 0) {
@@ -68,8 +73,18 @@ class BitcoinChainUpstreams(
         return head
     }
 
+    override fun getRoutedApi(matcher: Selector.Matcher): Mono<Reader<JsonRpcRequest, JsonRpcResponse>> {
+        //TODO
+        return Mono.just(EmptyReader())
+    }
+
+    open fun getReader(): BitcoinReader {
+        return reader
+    }
+
     override fun setHead(head: Head) {
         this.head = head
+        reader = BitcoinReader(this, head, objectMapper)
     }
 
     override fun getHead(): Head {
@@ -80,18 +95,24 @@ class BitcoinChainUpstreams(
         return upstreams.flatMap { it.getLabels() }
     }
 
-    override fun <A : UpstreamApi> castApi(apiType: Class<A>): Upstream<A> {
-        if (!apiType.isAssignableFrom(DirectBitcoinApi::class.java)) {
-            throw ClassCastException("Cannot cast ${EthereumApi::class.java} to $apiType")
-        }
-        return this as Upstream<A>
-    }
-
-    override fun <T : Upstream<TA>, TA : UpstreamApi> cast(selfType: Class<T>, apiType: Class<TA>): T {
+    override fun <T : Upstream> cast(selfType: Class<T>): T {
         if (!selfType.isAssignableFrom(this.javaClass)) {
             throw ClassCastException("Cannot cast ${this.javaClass} to $selfType")
         }
-        return castApi(apiType) as T
+        return this as T
     }
 
+    override fun isRunning(): Boolean {
+        return super.isRunning() || reader.isRunning
+    }
+
+    override fun start() {
+        super.start()
+        reader.start()
+    }
+
+    override fun stop() {
+        super.stop()
+        reader.stop()
+    }
 }

src/main/kotlin/io/emeraldpay/dshackle/upstream/bitcoin/BitcoinReader.kt

@@ -15,25 +15,44 @@
  */
 package io.emeraldpay.dshackle.upstream.bitcoin
 
+import com.fasterxml.jackson.databind.ObjectMapper
 import io.emeraldpay.dshackle.upstream.Head
+import io.emeraldpay.dshackle.upstream.Selector
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import org.slf4j.LoggerFactory
 import org.springframework.context.Lifecycle
+import reactor.core.publisher.Mono
+import reactor.kotlin.core.publisher.cast
 
 open class BitcoinReader(
-        api: DirectBitcoinApi,
-        head: Head
+        private val upstreams: BitcoinMultistream,
+        head: Head,
+        private val objectMapper: ObjectMapper
 ) : Lifecycle {
 
     companion object {
         private val log = LoggerFactory.getLogger(BitcoinReader::class.java)
     }
 
-    private val mempool = CachingMempoolData(api, head)
+    private val mempool = CachingMempoolData(upstreams, head, objectMapper)
 
     open fun getMempool(): CachingMempoolData {
         return mempool
     }
 
+    open fun getBlock(hash: String): Mono<Map<String, Any>> {
+        return castedRead(JsonRpcRequest("getblock", listOf(hash)), Map::class.java).cast()
+    }
+
+    open fun getTx(txid: String): Mono<Map<String, Any>> {
+        return castedRead(JsonRpcRequest("getrawtransaction", listOf(txid, true)), Map::class.java).cast()
+    }
+
+    open fun listUnspent(): Mono<List<String>> {
+        return castedRead(JsonRpcRequest("listunspent", emptyList()), List::class.java).cast()
+    }
+
     override fun isRunning(): Boolean {
         return mempool.isRunning
     }
@@ -45,4 +64,14 @@ open class BitcoinReader(
     override fun stop() {
         mempool.stop()
     }
+
+    fun <T> castedRead(req: JsonRpcRequest, clazz: Class<T>): Mono<T> {
+        return upstreams.getDirectApi(Selector.empty).flatMap { api ->
+            api.read(req)
+                    .flatMap(JsonRpcResponse::requireResult)
+                    .map {
+                        objectMapper.readValue(it, clazz) as T
+                    }
+        }
+    }
 }

src/main/kotlin/io/emeraldpay/dshackle/upstream/bitcoin/BitcoinRpcHead.kt

@@ -16,8 +16,11 @@
 package io.emeraldpay.dshackle.upstream.bitcoin
 
 import io.emeraldpay.dshackle.Defaults
+import io.emeraldpay.dshackle.reader.Reader
 import io.emeraldpay.dshackle.upstream.AbstractHead
 import io.emeraldpay.dshackle.upstream.Head
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import org.slf4j.LoggerFactory
 import org.springframework.context.Lifecycle
 import org.springframework.scheduling.concurrent.CustomizableThreadFactory
@@ -29,7 +32,7 @@ import java.time.Duration
 import java.util.concurrent.Executors
 
 class BitcoinRpcHead(
-        private val api: DirectBitcoinApi,
+        private val api: Reader<JsonRpcRequest, JsonRpcResponse>,
         private val extractBlock: ExtractBlock,
         private val interval: Duration = Duration.ofSeconds(15)
 ) : Head, AbstractHead(), Lifecycle {
@@ -53,12 +56,14 @@ class BitcoinRpcHead(
         val base = Flux.interval(interval)
                 .publishOn(scheduler)
                 .flatMap {
-                    api.executeAndResult(0, "getbestblockhash", emptyList(), String::class.java)
+                    api.read(JsonRpcRequest("getbestblockhash", emptyList()))
+                            .flatMap(JsonRpcResponse::requireStringResult)
                             .timeout(Defaults.timeout, Mono.error(Exception("Best block hash is not received")))
                 }
                 .distinctUntilChanged()
                 .flatMap { hash ->
-                    api.execute(0, "getblock", listOf(hash))
+                    api.read(JsonRpcRequest("getblock", listOf(hash)))
+                            .flatMap(JsonRpcResponse::requireResult)
                             .map(extractBlock::extract)
                             .timeout(Defaults.timeout, Mono.error(Exception("Block data is not received")))
                 }

src/main/kotlin/io/emeraldpay/dshackle/upstream/bitcoin/BitcoinUpstream.kt

@@ -17,9 +17,12 @@ package io.emeraldpay.dshackle.upstream.bitcoin
 
 import com.fasterxml.jackson.databind.ObjectMapper
 import io.emeraldpay.dshackle.config.UpstreamsConfig
+import io.emeraldpay.dshackle.reader.Reader
 import io.emeraldpay.dshackle.startup.QuorumForLabels
 import io.emeraldpay.dshackle.upstream.*
 import io.emeraldpay.dshackle.upstream.calls.CallMethods
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import io.emeraldpay.grpc.Chain
 import org.slf4j.LoggerFactory
 import org.springframework.context.Lifecycle
@@ -29,12 +32,12 @@ import reactor.core.publisher.Mono
 open class BitcoinUpstream(
         id: String,
         val chain: Chain,
-        private val api: DirectBitcoinApi,
+        private val directApi: Reader<JsonRpcRequest, JsonRpcResponse>,
         options: UpstreamsConfig.Options,
         val node: QuorumForLabels.QuorumItem,
         private val objectMapper: ObjectMapper,
         callMethods: CallMethods
-) : DefaultUpstream<DirectBitcoinApi>(id, options, callMethods), Lifecycle {
+) : DefaultUpstream(id, options, callMethods), Lifecycle {
 
     companion object {
         private val log = LoggerFactory.getLogger(BitcoinUpstream::class.java)
@@ -42,43 +45,31 @@ open class BitcoinUpstream(
 
     private val head: Head = createHead()
     private var validatorSubscription: Disposable? = null
-    private val data = BitcoinReader(api, head)
 
     private fun createHead(): Head {
         return BitcoinRpcHead(
-                api,
+                directApi,
                 ExtractBlock(objectMapper)
         )
     }
 
-    open fun getData(): BitcoinReader {
-        return data
-    }
-
     override fun getHead(): Head {
         return head
     }
 
-    override fun getApi(matcher: Selector.Matcher): Mono<out DirectBitcoinApi> {
-        return Mono.just(api)
+    override fun getApi(): Reader<JsonRpcRequest, JsonRpcResponse> {
+        return directApi
     }
 
     override fun getLabels(): Collection<UpstreamsConfig.Labels> {
         return listOf(UpstreamsConfig.Labels())
     }
 
-    override fun <T : Upstream<TA>, TA : UpstreamApi> cast(selfType: Class<T>, apiType: Class<TA>): T {
+    override fun <T : Upstream> cast(selfType: Class<T>): T {
         if (!selfType.isAssignableFrom(this.javaClass)) {
             throw ClassCastException("Cannot cast ${this.javaClass} to $selfType")
         }
-        return castApi(apiType) as T
-    }
-
-    override fun <A : UpstreamApi> castApi(apiType: Class<A>): Upstream<A> {
-        if (!apiType.isAssignableFrom(DirectBitcoinApi::class.java)) {
-            throw ClassCastException("Cannot cast ${DirectBitcoinApi::class.java} to $apiType")
-        }
-        return this as Upstream<A>
+        return this as T
     }
 
     override fun isRunning(): Boolean {
@@ -86,7 +77,7 @@ open class BitcoinUpstream(
         if (head is Lifecycle) {
             runningAny = runningAny || head.isRunning
         }
-        runningAny = runningAny || data.isRunning
+        runningAny = runningAny
         return runningAny
     }
 
@@ -97,7 +88,6 @@ open class BitcoinUpstream(
                 head.start()
             }
         }
-        data.start()
 
         validatorSubscription?.dispose()
 
@@ -105,7 +95,7 @@ open class BitcoinUpstream(
             this.setLag(0)
             this.setStatus(UpstreamAvailability.OK)
         } else {
-            val validator = BitcoinUpstreamValidator(api, getOptions())
+            val validator = BitcoinUpstreamValidator(directApi, getOptions())
             validatorSubscription = validator.start()
                     .subscribe(this::setStatus)
         }
@@ -115,9 +105,7 @@ open class BitcoinUpstream(
         if (head is Lifecycle) {
             head.stop()
         }
-        data.stop()
         validatorSubscription?.dispose()
     }
 
-
 }

src/main/kotlin/io/emeraldpay/dshackle/upstream/bitcoin/BitcoinUpstreamValidator.kt

@@ -16,7 +16,10 @@
 package io.emeraldpay.dshackle.upstream.bitcoin
 
 import io.emeraldpay.dshackle.config.UpstreamsConfig
+import io.emeraldpay.dshackle.reader.Reader
 import io.emeraldpay.dshackle.upstream.UpstreamAvailability
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import org.slf4j.LoggerFactory
 import org.springframework.scheduling.concurrent.CustomizableThreadFactory
 import reactor.core.publisher.Flux
@@ -26,7 +29,7 @@ import java.time.Duration
 import java.util.concurrent.Executors
 
 class BitcoinUpstreamValidator(
-        private val api: DirectBitcoinApi,
+        private val api: Reader<JsonRpcRequest, JsonRpcResponse>,
         private val options: UpstreamsConfig.Options
 ) {
 
@@ -36,7 +39,9 @@ class BitcoinUpstreamValidator(
     }
 
     fun validate(): Mono<UpstreamAvailability> {
-        return api.executeAndResult(0, "getconnectioncount", emptyList(), Int::class.java)
+        return api.read(JsonRpcRequest("getconnectioncount", emptyList()))
+                .flatMap(JsonRpcResponse::requireResult)
+                .map { Integer.parseInt(String(it)) }
                 .map { count ->
                     val minPeers = options.minPeers ?: 1
                     if (count < minPeers) {

src/main/kotlin/io/emeraldpay/dshackle/upstream/bitcoin/CachingMempoolData.kt

@@ -15,7 +15,11 @@
  */
 package io.emeraldpay.dshackle.upstream.bitcoin
 
+import com.fasterxml.jackson.databind.ObjectMapper
 import io.emeraldpay.dshackle.upstream.Head
+import io.emeraldpay.dshackle.upstream.Selector
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import org.slf4j.LoggerFactory
 import org.springframework.context.Lifecycle
 import reactor.core.Disposable
@@ -26,8 +30,9 @@ import java.util.concurrent.atomic.AtomicReference
 import java.util.concurrent.locks.ReentrantLock
 
 open class CachingMempoolData(
-        private val api: DirectBitcoinApi,
-        private val head: Head
+        private val upstreams: BitcoinMultistream,
+        private val head: Head,
+        private val objectMapper: ObjectMapper
 ) : Lifecycle {
 
     companion object {
@@ -56,7 +61,11 @@ open class CachingMempoolData(
     }
 
     fun fetchFromUpstream(): Mono<List<String>> {
-        return api.executeAndResult(0, "getrawmempool", emptyList(), List::class.java) as Mono<List<String>>
+        return upstreams.getDirectApi(Selector.empty).flatMap { api ->
+            api.read(JsonRpcRequest("getrawmempool", emptyList()))
+                    .flatMap(JsonRpcResponse::requireResult)
+                    .map { objectMapper.readValue(it, List::class.java) as List<String> }
+        }
     }
 
     class Container(val since: Instant, val value: List<String>) {

src/main/kotlin/io/emeraldpay/dshackle/upstream/bitcoin/DirectBitcoinApi.kt

@@ -1,122 +0,0 @@
-/**
- * Copyright (c) 2020 EmeraldPay, Inc
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream.bitcoin
-
-import com.fasterxml.jackson.databind.JavaType
-import com.fasterxml.jackson.databind.ObjectMapper
-import io.emeraldpay.dshackle.upstream.UpstreamApi
-import io.emeraldpay.dshackle.upstream.calls.CallMethods
-import io.grpc.Status
-import io.grpc.StatusRuntimeException
-import io.infinitape.etherjar.rpc.RpcException
-import io.infinitape.etherjar.rpc.RpcResponseError
-import io.infinitape.etherjar.rpc.json.FullResponseJson
-import io.infinitape.etherjar.rpc.json.RequestJson
-import io.infinitape.etherjar.rpc.json.ResponseJson
-import org.slf4j.LoggerFactory
-import reactor.core.publisher.Mono
-
-open class DirectBitcoinApi(
-        val bitcoinRpcClient: BitcoinRpcClient,
-        val objectMapper: ObjectMapper,
-        val targets: CallMethods
-) : UpstreamApi {
-
-    companion object {
-        private val log = LoggerFactory.getLogger(DirectBitcoinApi::class.java)
-    }
-
-    open override fun execute(id: Int, method: String, params: List<Any>): Mono<ByteArray> {
-        //TODO it's almost the same code as for DirectEthereumApi; refactor
-        val result: Mono<out Any> = when {
-            targets.isHardcoded(method) -> Mono.just(method).map { targets.executeHardcoded(it) }
-            targets.isAllowed(method) -> executeAndResult(id, method, params, Object::class.java)
-            else -> Mono.error(RpcException(-32601, "Method not allowed or not found"))
-        }
-        return processResult(id, method, result)
-    }
-
-    public fun processResult(id: Int, method: String, result: Mono<out Any>): Mono<ByteArray> {
-        //TODO it's the same code as for DirectEthereumApi; refactor
-        return result
-                .doOnError { t ->
-                    log.warn("Upstream error: [${t.message}] for $method")
-                }
-                .map {
-                    val resp = ResponseJson<Any, Int>()
-                    resp.id = id
-                    resp.result = it
-                    resp
-                }
-                .switchIfEmpty(
-                        Mono.fromCallable {
-                            val resp = ResponseJson<Any, Int>()
-                            resp.id = id
-                            resp.result = null
-                            resp
-                        }
-                )
-                .map {
-                    objectMapper.writer().writeValueAsBytes(it)
-                }
-                .onErrorResume(StatusRuntimeException::class.java) { t ->
-                    if (t.status.code == Status.Code.CANCELLED) {
-                        Mono.empty<ByteArray>()
-                    } else {
-                        Mono.error(RpcException(RpcResponseError.CODE_UPSTREAM_CONNECTION_ERROR, "gRPC error ${t.status}"))
-                    }
-                }
-                .onErrorMap { t ->
-                    if (RpcException::class.java.isAssignableFrom(t.javaClass)) {
-                        t
-                    } else {
-                        log.warn("Convert to RPC error. Exception ${t.javaClass}:${t.message}", t)
-                        RpcException(-32020, "Error reading from upstream", null, t)
-                    }
-                }
-                .onErrorResume(RpcException::class.java) { t ->
-                    val resp = ResponseJson<Any, Int>()
-                    resp.id = id
-                    resp.error = t.error
-                    Mono.just(objectMapper.writer().writeValueAsBytes(resp))
-                }
-    }
-
-    open fun <T> executeAndResult(id: Int, method: String, params: List<Any>, resultType: Class<T>): Mono<T> {
-        val rpc = RequestJson<Int>(method, params, id)
-        return Mono.just(rpc)
-                .map(objectMapper::writeValueAsBytes)
-                .flatMap(bitcoinRpcClient::execute)
-                .flatMap { json ->
-                    val type: JavaType = objectMapper.typeFactory.constructParametricType(FullResponseJson::class.java, resultType, Int::class.java)
-                    val resp = objectMapper.readerFor(type).readValue<FullResponseJson<T, Int>>(json)
-                    if (resp.hasError()) {
-                        Mono.error(resp.error.asException())
-                    } else {
-                        Mono.just(resp.result)
-                    }
-                }
-    }
-
-    open fun getBlock(hash: String): Mono<Map<String, Any>> {
-        return executeAndResult(0, "getblock", listOf(hash), Map::class.java) as Mono<Map<String, Any>>
-    }
-
-    open fun getTx(txid: String): Mono<Map<String, Any>> {
-        return executeAndResult(0, "getrawtransaction", listOf(txid, true), Map::class.java) as Mono<Map<String, Any>>
-    }
-
-}

src/main/kotlin/io/emeraldpay/dshackle/upstream/bitcoin/ExtractBlock.kt

@@ -63,6 +63,7 @@ class ExtractBlock(
                 getTime(data) ?: throw IllegalArgumentException("Block JSON has no time"),
                 false,
                 json,
+                data,
                 transactions
         )
     }

src/main/kotlin/io/emeraldpay/dshackle/upstream/calls/AggregatedCallMethods.kt

@@ -40,7 +40,7 @@ class AggregatedCallMethods(
      */
     override fun getQuorumFor(method: String): CallQuorum {
         return delegates.find {
-            it.isAllowed(method)
+            it.isAllowed(method) || it.isHardcoded(method)
         }?.getQuorumFor(method) ?: throw IllegalStateException("No quorum for $method")
     }
 
@@ -62,15 +62,15 @@ class AggregatedCallMethods(
      * @return true if there is at least one delegate that allows the method and it's hardcoded on that delegate
      */
     override fun isHardcoded(method: String): Boolean {
-        return delegates.any { it.isAllowed(method) && it.isHardcoded(method) }
+        return delegates.any { it.isHardcoded(method) }
     }
 
     /**
      * Executed the method on the first delegate that supports it as a hardcoded method
      */
-    override fun executeHardcoded(method: String): Any {
+    override fun executeHardcoded(method: String): ByteArray {
         return delegates.find {
-            it.isAllowed(method) && it.isHardcoded(method)
+            it.isHardcoded(method)
         }?.executeHardcoded(method) ?: throw IllegalStateException("No hardcoded for $method")
     }
 }

src/main/kotlin/io/emeraldpay/dshackle/upstream/calls/CallMethods.kt

@@ -46,5 +46,5 @@ interface CallMethods {
     /**
      * Read [supposed to be predefined] method from this config
      */
-    fun executeHardcoded(method: String): Any
+    fun executeHardcoded(method: String): ByteArray
 }

src/main/kotlin/io/emeraldpay/dshackle/upstream/calls/DefaultBitcoinMethods.kt

@@ -13,12 +13,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package io.emeraldpay.dshackle.upstream.bitcoin
+package io.emeraldpay.dshackle.upstream.calls
 
 import com.fasterxml.jackson.databind.ObjectMapper
 import io.emeraldpay.dshackle.quorum.*
-import io.emeraldpay.dshackle.upstream.calls.CallMethods
-import io.infinitape.etherjar.rpc.JacksonRpcConverter
 import io.infinitape.etherjar.rpc.RpcException
 import java.util.*
 
@@ -26,9 +24,6 @@ class DefaultBitcoinMethods(
         private val objectMapper: ObjectMapper
 ) : CallMethods {
 
-    //TODO maybe Ethereum RPC parser should not be really used for Bitcoin
-    private val jacksonRpcConverter = JacksonRpcConverter(objectMapper)
-
     private val anyResponseMethods = listOf(
             "getblock",
             "gettransaction", "getrawtransaction", "gettxout",
@@ -55,7 +50,7 @@ class DefaultBitcoinMethods(
             Collections.binarySearch(hardcodedMethods, method) >= 0 -> AlwaysQuorum()
             Collections.binarySearch(anyResponseMethods, method) >= 0 -> NotLaggingQuorum(2)
             Collections.binarySearch(headVerifiedMethods, method) >= 0 -> NotLaggingQuorum(0)
-            Collections.binarySearch(broadcastMethods, method) >= 0 -> BroadcastQuorum(jacksonRpcConverter)
+            Collections.binarySearch(broadcastMethods, method) >= 0 -> BroadcastQuorum(objectMapper)
             else -> AlwaysQuorum()
         }
     }
@@ -72,13 +67,10 @@ class DefaultBitcoinMethods(
         return Collections.binarySearch(hardcodedMethods, method) >= 0;
     }
 
-    override fun executeHardcoded(method: String): Any {
+    override fun executeHardcoded(method: String): ByteArray {
         return when (method) {
-            "getconnectioncount" -> 42
-            "getnetworkinfo" -> mapOf(
-                    "version" to 700000,
-                    "subversion" to "/EmeraldDshackle:v0.7/"
-            )
+            "getconnectioncount" -> "42".toByteArray()
+            "getnetworkinfo" -> "{\"version\": 700000, \"subversion\": \"/EmeraldDshackle:v0.7/\"}".toByteArray()
             else -> throw RpcException(-32601, "Method not found")
         }
     }

src/main/kotlin/io/emeraldpay/dshackle/upstream/calls/DefaultEthereumMethods.kt

@@ -32,8 +32,6 @@ class DefaultEthereumMethods(
         private val chain: Chain
 ) : CallMethods {
 
-    private val jacksonRpcConverter = JacksonRpcConverter(objectMapper)
-
     private val anyResponseMethods = listOf(
             "eth_gasPrice",
             "eth_call",
@@ -90,9 +88,9 @@ class DefaultEthereumMethods(
             headVerifiedMethods.contains(method) -> NotLaggingQuorum(1)
             specialMethods.contains(method) -> {
                 when (method) {
-                    "eth_getTransactionCount" -> NonceQuorum(jacksonRpcConverter)
+                    "eth_getTransactionCount" -> NonceQuorum(objectMapper)
                     "eth_getBalance" -> NotLaggingQuorum(1)
-                    "eth_sendRawTransaction" -> BroadcastQuorum(jacksonRpcConverter)
+                    "eth_sendRawTransaction" -> BroadcastQuorum(objectMapper)
                     else -> AlwaysQuorum()
                 }
             }
@@ -108,50 +106,55 @@ class DefaultEthereumMethods(
         return hardcodedMethods.contains(method)
     }
 
-    override fun executeHardcoded(method: String): Any {
-        if ("net_version" == method) {
-            if (Chain.ETHEREUM == chain) {
-                return "1"
+    override fun executeHardcoded(method: String): ByteArray {
+        val json = when (method) {
+            "net_version" -> {
+                when {
+                    Chain.ETHEREUM == chain -> {
+                        "1"
+                    }
+                    Chain.ETHEREUM_CLASSIC == chain -> {
+                        "1"
+                    }
+                    Chain.TESTNET_MORDEN == chain -> {
+                        "2"
+                    }
+                    Chain.TESTNET_KOVAN == chain -> {
+                        "42"
+                    }
+                    else -> throw RpcException(-32602, "Invalid chain")
+                }
             }
-            if (Chain.ETHEREUM_CLASSIC == chain) {
-                return "1"
+            "net_peerCount" -> {
+                "\"0x2a\""
             }
-            if (Chain.TESTNET_MORDEN == chain) {
-                return "2"
+            "net_listening" -> {
+                "true"
             }
-            if (Chain.TESTNET_KOVAN == chain) {
-                return "42"
+            "web3_clientVersion" -> {
+                "\"EmeraldDshackle/v0.2\""
             }
-            throw RpcException(-32602, "Invalid chain")
+            "eth_protocolVersion" -> {
+                "\"0x3f\""
+            }
+            "eth_syncing" -> {
+                "false"
+            }
+            "eth_coinbase" -> {
+                "\"0x0000000000000000000000000000000000000000\""
+            }
+            "eth_mining" -> {
+                "false"
+            }
+            "eth_hashrate" -> {
+                "\"0x0\""
+            }
+            "eth_accounts" -> {
+                "[]"
+            }
+            else -> throw RpcException(-32601, "Method not found")
         }
-        if ("net_peerCount" == method) {
-            return "0x2a"
-        }
-        if ("net_listening" == method) {
-            return true
-        }
-        if ("web3_clientVersion" == method) {
-            return "EmeraldDshackle/v0.2"
-        }
-        if ("eth_protocolVersion" == method) {
-            return "0x3f"
-        }
-        if ("eth_syncing" == method) {
-            return false
-        }
-        if ("eth_coinbase" == method) {
-            return "0x0000000000000000000000000000000000000000"
-        }
-        if ("eth_mining" == method) {
-            return "false"
-        }
-        if ("eth_hashrate" == method) {
-            return "0x0"
-        }
-        if ("eth_accounts" == method) {
-            return Collections.emptyList<String>()
-        }
-        throw RpcException(-32601, "Method not found")
+        return json.toByteArray()
     }
 
     override fun getSupportedMethods(): Set<String> {

src/main/kotlin/io/emeraldpay/dshackle/upstream/calls/DirectCallMethods.kt

@@ -44,7 +44,7 @@ open class DirectCallMethods(private val methods: Set<String>) : CallMethods {
         return false
     }
 
-    override fun executeHardcoded(method: String): Any {
-        return "unsupported"
+    override fun executeHardcoded(method: String): ByteArray {
+        return "unsupported".toByteArray()
     }
 }

src/main/kotlin/io/emeraldpay/dshackle/upstream/calls/ManagedCallMethods.kt

@@ -55,7 +55,7 @@ class ManagedCallMethods(
         return delegate.isHardcoded(method)
     }
 
-    override fun executeHardcoded(method: String): Any {
+    override fun executeHardcoded(method: String): ByteArray {
         return delegate.executeHardcoded(method)
     }
 }

src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/DirectEthereumApi.kt

@@ -1,177 +0,0 @@
-/**
- * Copyright (c) 2020 EmeraldPay, Inc
- * Copyright (c) 2019 ETCDEV GmbH
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream.ethereum
-
-import com.fasterxml.jackson.databind.ObjectMapper
-import io.emeraldpay.dshackle.Defaults
-import io.emeraldpay.dshackle.cache.Caches
-import io.emeraldpay.dshackle.upstream.calls.CallMethods
-import io.grpc.Status
-import io.grpc.StatusRuntimeException
-import io.infinitape.etherjar.domain.BlockHash
-import io.infinitape.etherjar.domain.TransactionId
-import io.infinitape.etherjar.hex.HexQuantity
-import io.infinitape.etherjar.rpc.*
-import io.infinitape.etherjar.rpc.json.ResponseJson
-import org.slf4j.LoggerFactory
-import reactor.core.publisher.Mono
-import java.math.BigInteger
-
-open class DirectEthereumApi(
-        val rpcClient: ReactorRpcClient,
-        var caches: Caches?,
-        private val objectMapper: ObjectMapper,
-        val targets: CallMethods
-): EthereumApi(objectMapper) {
-
-    var timeout = Defaults.timeout
-    private val log = LoggerFactory.getLogger(EthereumApi::class.java)
-
-    override fun execute(id: Int, method: String, params: List<Any>): Mono<ByteArray> {
-        val result: Mono<out Any> = when {
-            targets.isHardcoded(method) -> Mono.just(method).map { targets.executeHardcoded(it) }
-            targets.isAllowed(method)   -> callUpstream(method, params)
-            else -> Mono.error(RpcException(-32601, "Method not allowed or not found"))
-        }
-        return processResult(id, method, result)
-    }
-
-    public fun processResult(id: Int, method: String, result: Mono<out Any>): Mono<ByteArray> {
-        return result
-                .doOnError { t ->
-                    log.warn("Upstream error: [${t.message}] for $method")
-                }
-                .map {
-                    val resp = ResponseJson<Any, Int>()
-                    resp.id = id
-                    resp.result = it
-                    resp
-                }
-                .switchIfEmpty(
-                        Mono.fromCallable {
-                            val resp = ResponseJson<Any, Int>()
-                            resp.id = id
-                            resp.result = null
-                            resp
-                        }
-                )
-                .map {
-                    objectMapper.writer().writeValueAsBytes(it)
-                }
-                .onErrorResume(StatusRuntimeException::class.java) { t ->
-                    if (t.status.code == Status.Code.CANCELLED) {
-                        Mono.empty<ByteArray>()
-                    } else {
-                        Mono.error(RpcException(RpcResponseError.CODE_UPSTREAM_CONNECTION_ERROR, "gRPC error ${t.status}"))
-                    }
-                }
-                .onErrorMap { t ->
-                    if (RpcException::class.java.isAssignableFrom(t.javaClass)) {
-                        t
-                    } else {
-                        log.warn("Convert to RPC error. Exception ${t.javaClass}:${t.message}", t)
-                        RpcException(-32020, "Error reading from upstream", null, t)
-                    }
-                }
-                .onErrorResume(RpcException::class.java) { t ->
-                    val resp = ResponseJson<Any, Int>()
-                    resp.id = id
-                    resp.error = t.error
-                    Mono.just(objectMapper.writer().writeValueAsBytes(resp))
-                }
-    }
-
-    /**
-     * Actual request to the remote endpoint
-     */
-    private fun callUpstream(method: String, params: List<Any>): Mono<out Any> {
-        return rpcClient.execute(callMapping(method, params))
-                .timeout(timeout, Mono.error(RpcException(-32603, "Upstream timeout")))
-                .doOnNext { value ->
-                    try {
-                        caches?.cacheRequested(value)
-                    } catch (e: Throwable) {
-                        //ignore all caching errors, client shouldn't have problems because of them
-                        log.warn("Uncaught caching exception", e)
-                    }
-                }
-    }
-
-    /**
-     * Prepare RpcCall with data types specific for that particular requests. In general it may return a call that just
-     * parses JSON into Map. But the purpose of further processing and caching for some of the requests we want
-     * to have actual data types.
-     */
-    fun callMapping(method: String, params: List<Any>): RpcCall<out Any, out Any> {
-        return when {
-            method == "eth_getTransactionByHash" -> {
-                if (params.size != 1) {
-                    throw RpcException(RpcResponseError.CODE_INVALID_METHOD_PARAMS, "Must provide 1 parameter")
-                }
-                val hash: TransactionId
-                try {
-                    hash = TransactionId.from(params[0].toString())
-                } catch (e: IllegalArgumentException) {
-                    throw RpcException(RpcResponseError.CODE_INVALID_METHOD_PARAMS, "[0] must be transaction id")
-                }
-                Commands.eth().getTransaction(hash)
-            }
-            method == "eth_getBlockByHash" -> {
-                if (params.size != 2) {
-                    throw RpcException(RpcResponseError.CODE_INVALID_METHOD_PARAMS, "Must provide 2 parameters")
-                }
-                val hash: BlockHash
-                try {
-                    hash = BlockHash.from(params[0].toString())
-                } catch (e: IllegalArgumentException) {
-                    throw RpcException(RpcResponseError.CODE_INVALID_METHOD_PARAMS, "[0] must be block hash")
-                }
-                val withTx = params[1].toString().toBoolean()
-                if (withTx) {
-                    Commands.eth().getBlockWithTransactions(hash)
-                } else {
-                    Commands.eth().getBlock(hash)
-                }
-            }
-            method == "eth_getBlockByNumber" -> {
-                if (params.size != 2) {
-                    throw RpcException(RpcResponseError.CODE_INVALID_METHOD_PARAMS, "Must provide 2 parameters")
-                }
-                val number: Long
-                try {
-                    val quantity = HexQuantity.from(params[0].toString()) ?: throw IllegalArgumentException()
-                    number = quantity.value.let {
-                        if (it < BigInteger.valueOf(Long.MAX_VALUE) && it >= BigInteger.ZERO) {
-                            it.toLong()
-                        } else {
-                            throw IllegalArgumentException()
-                        }
-                    }
-                } catch (e: IllegalArgumentException) {
-                    throw RpcException(RpcResponseError.CODE_INVALID_METHOD_PARAMS, "[0] must be block number")
-                }
-                val withTx = params[1].toString().toBoolean()
-                if (withTx) {
-                    Commands.eth().getBlockWithTransactions(number)
-                } else {
-                    Commands.eth().getBlock(number)
-                }
-            }
-            else -> RpcCall.create(method, Any::class.java, params)
-        }
-    }
-}

src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumApi.kt

@@ -1,65 +0,0 @@
-/**
- * Copyright (c) 2020 EmeraldPay, Inc
- * Copyright (c) 2019 ETCDEV GmbH
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream.ethereum
-
-import com.fasterxml.jackson.databind.ObjectMapper
-import io.emeraldpay.dshackle.reader.Reader
-import io.emeraldpay.dshackle.upstream.Upstream
-import io.emeraldpay.dshackle.upstream.UpstreamApi
-import io.infinitape.etherjar.rpc.*
-import io.infinitape.etherjar.rpc.json.BlockJson
-import io.infinitape.etherjar.rpc.json.TransactionRefJson
-import org.slf4j.LoggerFactory
-import reactor.core.publisher.Mono
-import java.io.InputStream
-
-abstract class EthereumApi(
-        objectMapper: ObjectMapper
-) : UpstreamApi {
-
-    companion object {
-        private val log = LoggerFactory.getLogger(EthereumApi::class.java)
-    }
-
-    private val jacksonRpcConverter = JacksonRpcConverter(objectMapper)
-    var upstream: Upstream<EthereumApi>? = null
-
-    fun <JS, RS> reader(): Reader<RpcCall<JS, RS>, RS> {
-        return object : Reader<RpcCall<JS, RS>, RS> {
-            override fun read(key: RpcCall<JS, RS>): Mono<RS> {
-                return this@EthereumApi.executeAndConvert(key)
-            }
-        }
-    }
-
-    fun <JS, RS> execute(rpcCall: RpcCall<JS, RS>): Mono<ByteArray> {
-        return execute(0, rpcCall.method, rpcCall.params as List<Any>)
-    }
-
-    fun <JS, RS> executeAndConvert(rpcCall: RpcCall<JS, RS>): Mono<RS> {
-        val convertToJS = java.util.function.Function<ByteArray, Mono<JS>> { resp ->
-            val inputStream: InputStream = resp.inputStream()
-            val jsonValue: JS? = jacksonRpcConverter.fromJson(inputStream, rpcCall.jsonType, Int::class.java)
-            if (jsonValue == null) Mono.empty<JS>()
-            else Mono.just(jsonValue)
-        }
-        return execute(rpcCall)
-                .flatMap(convertToJS)
-                .map(rpcCall.converter::apply)
-                .doOnError { err -> log.debug("Failed to read from upstream", err) }
-    }
-}

src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumFullBlocksReader.kt

@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package io.emeraldpay.dshackle.cache
+package io.emeraldpay.dshackle.upstream.ethereum
 
 import com.fasterxml.jackson.databind.ObjectMapper
 import io.emeraldpay.dshackle.data.BlockContainer
@@ -30,20 +30,20 @@ import reactor.core.publisher.Flux
 import reactor.core.publisher.Mono
 
 /**
- * Reads blocks with full transactions details. Based on data contained in cashes for blocks
- * and transactions, i.e. two separate caches that must be provided.
+ * Reads blocks with full transactions details. Based on data contained in readers for blocks
+ * and transactions, i.e. two separate readers that must be provided.
  *
  * If source block, with just transaction hashes is not available, it returns empty
  * If any of the expected block transactions is not available it returns empty
  */
-class EthereumBlocksWithTxCache(
+class EthereumFullBlocksReader(
         private val objectMapper: ObjectMapper,
         private val blocks: Reader<BlockId, BlockContainer>,
         private val txes: Reader<TxId, TxContainer>
 ) : Reader<BlockId, BlockContainer> {
 
     companion object {
-        private val log = LoggerFactory.getLogger(EthereumBlocksWithTxCache::class.java)
+        private val log = LoggerFactory.getLogger(EthereumFullBlocksReader::class.java)
     }
 
     override fun read(key: BlockId): Mono<BlockContainer> {

src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumHeadLagObserver.kt

@@ -26,14 +26,14 @@ import java.time.Duration
 
 class EthereumHeadLagObserver(
         master: Head,
-        followers: Collection<Upstream<EthereumApi>>
-) : HeadLagObserver<EthereumApi>(master, followers) {
+        followers: Collection<Upstream>
+) : HeadLagObserver(master, followers) {
 
     companion object {
         private val log = LoggerFactory.getLogger(EthereumHeadLagObserver::class.java)
     }
 
-    override fun getCurrentBlocks(up: Upstream<EthereumApi>): Flux<BlockContainer> {
+    override fun getCurrentBlocks(up: Upstream): Flux<BlockContainer> {
         val head = up.getHead()
         return head.getFlux().take(Duration.ofSeconds(1))
     }

src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumMultistream.kt

@@ -19,20 +19,24 @@ package io.emeraldpay.dshackle.upstream.ethereum
 import com.fasterxml.jackson.databind.ObjectMapper
 import io.emeraldpay.dshackle.cache.Caches
 import io.emeraldpay.dshackle.config.UpstreamsConfig
+import io.emeraldpay.dshackle.reader.Reader
 import io.emeraldpay.dshackle.upstream.*
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import io.emeraldpay.grpc.Chain
 import org.slf4j.LoggerFactory
 import org.springframework.context.Lifecycle
+import reactor.core.publisher.Mono
 
-open class AggregatedEthereumUpstreams(
+open class EthereumMultistream(
         chain: Chain,
         val upstreams: MutableList<EthereumUpstream>,
         caches: Caches,
-        objectMapper: ObjectMapper
-) : ChainUpstreams<EthereumApi>(chain, upstreams as MutableList<Upstream<EthereumApi>>, caches, objectMapper) {
+        private val objectMapper: ObjectMapper
+) : Multistream(chain, upstreams as MutableList<Upstream>, caches) {
 
     companion object {
-        private val log = LoggerFactory.getLogger(AggregatedEthereumUpstreams::class.java)
+        private val log = LoggerFactory.getLogger(EthereumMultistream::class.java)
     }
 
     private var head: Head? = null
@@ -92,7 +96,7 @@ open class AggregatedEthereumUpstreams(
             val newHead = MergedHead(upstreams.map { it.getHead() }).apply {
                 this.start()
             }
-            val lagObserver = EthereumHeadLagObserver(newHead, upstreams as Collection<Upstream<EthereumApi>>).apply {
+            val lagObserver = EthereumHeadLagObserver(newHead, upstreams as Collection<Upstream>).apply {
                 this.start()
             }
             this.lagObserver = lagObserver
@@ -107,18 +111,15 @@ open class AggregatedEthereumUpstreams(
     }
 
     @SuppressWarnings("unchecked")
-    override fun <T : Upstream<TA>, TA : UpstreamApi> cast(selfType: Class<T>, apiType: Class<TA>): T {
+    override fun <T : Upstream> cast(selfType: Class<T>): T {
         if (!selfType.isAssignableFrom(this.javaClass)) {
             throw ClassCastException("Cannot cast ${this.javaClass} to $selfType")
         }
-        return castApi(apiType) as T
+        return this as T
     }
 
-    override fun <A : UpstreamApi> castApi(apiType: Class<A>): Upstream<A> {
-        if (!apiType.isAssignableFrom(EthereumApi::class.java)) {
-            throw ClassCastException("Cannot cast ${EthereumApi::class.java} to $apiType")
-        }
-        return this as Upstream<A>
+    override fun getRoutedApi(matcher: Selector.Matcher): Mono<Reader<JsonRpcRequest, JsonRpcResponse>> {
+        return Mono.just(NativeCallRouter(objectMapper, reader, getMethods()))
     }
 
 }

src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumReader.kt

@@ -18,24 +18,21 @@ package io.emeraldpay.dshackle.upstream.ethereum
 import com.fasterxml.jackson.databind.ObjectMapper
 import io.emeraldpay.dshackle.Defaults
 import io.emeraldpay.dshackle.cache.Caches
-import io.emeraldpay.dshackle.cache.CachesEnabled
 import io.emeraldpay.dshackle.cache.CurrentBlockCache
-import io.emeraldpay.dshackle.data.BlockContainer
-import io.emeraldpay.dshackle.data.BlockId
-import io.emeraldpay.dshackle.data.TxContainer
-import io.emeraldpay.dshackle.data.TxId
+import io.emeraldpay.dshackle.data.*
 import io.emeraldpay.dshackle.reader.*
-import io.emeraldpay.dshackle.upstream.Head
+import io.emeraldpay.dshackle.upstream.Multistream
 import io.emeraldpay.dshackle.upstream.Selector
-import io.emeraldpay.dshackle.upstream.Upstream
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import io.infinitape.etherjar.domain.Address
 import io.infinitape.etherjar.domain.BlockHash
 import io.infinitape.etherjar.domain.TransactionId
 import io.infinitape.etherjar.domain.Wei
-import io.infinitape.etherjar.rpc.Commands
-import io.infinitape.etherjar.rpc.RpcCall
+import io.infinitape.etherjar.hex.HexQuantity
+import io.infinitape.etherjar.rpc.RpcException
+import io.infinitape.etherjar.rpc.RpcResponseError
 import io.infinitape.etherjar.rpc.json.BlockJson
-import io.infinitape.etherjar.rpc.json.BlockTag
 import io.infinitape.etherjar.rpc.json.TransactionJson
 import io.infinitape.etherjar.rpc.json.TransactionRefJson
 import org.slf4j.LoggerFactory
@@ -48,7 +45,7 @@ import java.util.concurrent.TimeoutException
 import java.util.function.Function
 
 open class EthereumReader(
-        private val up: Upstream<EthereumApi>,
+        private val up: Multistream,
         private val caches: Caches,
         private val objectMapper: ObjectMapper
 ) : Lifecycle {
@@ -57,51 +54,109 @@ open class EthereumReader(
         private val log = LoggerFactory.getLogger(EthereumReader::class.java)
     }
 
-    private var headListener: Disposable? = null
     private val balanceCache = CurrentBlockCache<Address, Wei>()
 
-    private val extractBlock = Function<BlockContainer, BlockJson<TransactionRefJson>> { block ->
-        objectMapper
-                .readValue(block.json, BlockJson::class.java)
-                .withoutTransactionDetails()
+    val extractBlock = Function<BlockContainer, BlockJson<TransactionRefJson>> { block ->
+        val existing = block.getParsed(BlockJson::class.java)
+        if (existing != null) {
+            existing.withoutTransactionDetails()
+        } else {
+            objectMapper
+                    .readValue(block.json, BlockJson::class.java)
+                    .withoutTransactionDetails()
+        }
     }
 
-    private val extractTx = Function<TxContainer, TransactionJson> { tx ->
-        objectMapper
-                .readValue(tx.json, TransactionJson::class.java)
+    val extractTx = Function<TxContainer, TransactionJson> { tx ->
+        tx.getParsed(TransactionJson::class.java) ?: objectMapper.readValue(tx.json, TransactionJson::class.java)
     }
 
-    private val blocksDirect: Reader<BlockHash, BlockJson<TransactionRefJson>>
-    private val txDirect: Reader<TransactionId, TransactionJson>
+    val asRaw = Function<SourceContainer, ByteArray> { tx ->
+        tx.json ?: ByteArray(0)
+    }
+
+    val jsonToRaw = Function<Any, ByteArray> { json ->
+        objectMapper.writeValueAsBytes(json)
+    }
+
+    val blockAsContainer = Function<BlockJson<*>, BlockContainer> { block ->
+        BlockContainer.from(block.withoutTransactionDetails(), objectMapper)
+    }
+    val txAsContainer = Function<TransactionJson, TxContainer> { tx ->
+        TxContainer.from(tx, objectMapper)
+    }
+
+    private val blocksDirect: Reader<BlockHash, BlockContainer>
+    private val blocksByHeightDirect: Reader<Long, BlockContainer>
+    private val txDirect: Reader<TransactionId, TxContainer>
     private val balanceDirect: Reader<Address, Wei>
 
     private val idToBlockHash = Function<BlockId, BlockHash> { id -> BlockHash.from(id.value) }
     private val blockHashToId = Function<BlockHash, BlockId> { hash -> BlockId.from(hash) }
 
     private val txHashToId = Function<TransactionId, TxId> { hash -> TxId.from(hash) }
+    private val idToTxHash = Function<TxId, TransactionId> { id -> TransactionId.from(id.value) }
+
+    private val directResponseBytes = Function<JsonRpcResponse, ByteArray> { resp ->
+        if (resp.error != null) {
+            throw resp.error.asException()
+        } else {
+            resp.getResult()
+        }
+    }
 
     init {
-        blocksDirect = object : Reader<BlockHash, BlockJson<TransactionRefJson>> {
-            override fun read(key: BlockHash): Mono<BlockJson<TransactionRefJson>> {
-                return up.getApi(Selector.empty).flatMap { api ->
-                    api.executeAndConvert(Commands.eth().getBlock(key))
+        blocksDirect = object : Reader<BlockHash, BlockContainer> {
+            override fun read(key: BlockHash): Mono<BlockContainer> {
+                return up.getDirectApi(Selector.empty).flatMap { api ->
+                    val request = JsonRpcRequest("eth_getBlockByHash", listOf(key.toHex(), false))
+                    api.read(request)
                             .timeout(Defaults.timeoutInternal, Mono.error(TimeoutException("Block not read $key")))
+                            .map(directResponseBytes)
                             .retryWhen(Retry.backoff(3, Duration.ofSeconds(1)))
+                            .map { blockbytes ->
+                                val block = objectMapper.readValue(blockbytes, BlockJson::class.java) as BlockJson<TransactionRefJson>
+                                BlockContainer.from(block, blockbytes)
+                            }
                             .doOnNext { block ->
-                                caches.cache(Caches.Tag.REQUESTED, BlockContainer.from(block, objectMapper))
+                                caches.cache(Caches.Tag.REQUESTED, block)
                             }
                 }
             }
         }
-        txDirect = object : Reader<TransactionId, TransactionJson> {
-            override fun read(key: TransactionId): Mono<TransactionJson> {
-                return up.getApi(Selector.empty).flatMap { api ->
-                    api.executeAndConvert(Commands.eth().getTransaction(key))
-                            .timeout(Defaults.timeoutInternal, Mono.error(TimeoutException("Tx not read $key")))
+        blocksByHeightDirect = object : Reader<Long, BlockContainer> {
+            override fun read(key: Long): Mono<BlockContainer> {
+                return up.getDirectApi(Selector.empty).flatMap { api ->
+                    val request = JsonRpcRequest("eth_getBlockByNumber", listOf(HexQuantity.from(key).toHex(), false))
+                    api.read(request)
+                            .timeout(Defaults.timeoutInternal, Mono.error(TimeoutException("Block not read $key")))
+                            .map(directResponseBytes)
                             .retryWhen(Retry.backoff(3, Duration.ofSeconds(1)))
+                            .map { blockbytes ->
+                                val block = objectMapper.readValue(blockbytes, BlockJson::class.java) as BlockJson<TransactionRefJson>
+                                BlockContainer.from(block, blockbytes)
+                            }
+                            .doOnNext { block ->
+                                caches.cache(Caches.Tag.REQUESTED, block)
+                            }
+                }
+            }
+        }
+        txDirect = object : Reader<TransactionId, TxContainer> {
+            override fun read(key: TransactionId): Mono<TxContainer> {
+                return up.getDirectApi(Selector.empty).flatMap { api ->
+                    val request = JsonRpcRequest("eth_getTransactionByHash", listOf(key.toHex()))
+                    api.read(request)
+                            .timeout(Defaults.timeoutInternal, Mono.error(TimeoutException("Tx not read $key")))
+                            .map(directResponseBytes)
+                            .retryWhen(Retry.backoff(3, Duration.ofSeconds(1)))
+                            .map { txbytes ->
+                                val tx = objectMapper.readValue(txbytes, TransactionJson::class.java)
+                                TxContainer.from(tx, txbytes)
+                            }
                             .doOnNext { tx ->
-                                if (tx.blockNumber != null && tx.blockHash != null) {
-                                    caches.cache(Caches.Tag.REQUESTED, TxContainer.from(tx, objectMapper))
+                                if (tx.blockId != null) {
+                                    caches.cache(Caches.Tag.REQUESTED, tx)
                                 }
                             }
                 }
@@ -109,9 +164,19 @@ open class EthereumReader(
         }
         balanceDirect = object : Reader<Address, Wei> {
             override fun read(key: Address): Mono<Wei> {
-                return up.getApi(Selector.empty).flatMap { api ->
-                    api.executeAndConvert(Commands.eth().getBalance(key, BlockTag.LATEST))
+                return up.getDirectApi(Selector.empty).flatMap { api ->
+                    val request = JsonRpcRequest("eth_getBalance", listOf(key.toHex(), "latest"))
+                    api.read(request)
                             .timeout(Defaults.timeoutInternal, Mono.error(TimeoutException("Balance not read $key")))
+                            .map(directResponseBytes)
+                            .map {
+                                val str = String(it)
+                                if (str.startsWith("\"") && str.endsWith("\"")) {
+                                    Wei.from(str.substring(1, str.length - 1))
+                                } else {
+                                    throw RpcException(RpcResponseError.CODE_UPSTREAM_INVALID_RESPONSE, "Not Wei value")
+                                }
+                            }
                             .retryWhen(Retry.backoff(3, Duration.ofSeconds(1)))
                             .doOnNext { value ->
                                 balanceCache.put(key, value)
@@ -121,30 +186,61 @@ open class EthereumReader(
         }
     }
 
-    fun blocksById(): Reader<BlockId, BlockJson<TransactionRefJson>> {
-        return CompoundReader(
-                TransformingReader(caches.getBlocksByHash(), extractBlock),
-                RekeyingReader(idToBlockHash, blocksDirect)
+    fun blocksByHash(): Reader<BlockHash, BlockJson<TransactionRefJson>> {
+        return TransformingReader(
+                CompoundReader(
+                        RekeyingReader(blockHashToId, caches.getBlocksByHash()),
+                        blocksDirect
+                ),
+                extractBlock
         )
     }
 
-    fun blocksByHash(): Reader<BlockHash, BlockJson<TransactionRefJson>> {
-        return CompoundReader(
-                RekeyingReader(
-                        blockHashToId,
-                        TransformingReader(caches.getBlocksByHash(), extractBlock)
+    fun blocksById(): Reader<BlockId, BlockJson<TransactionRefJson>> {
+        return TransformingReader(
+                CompoundReader(
+                        caches.getBlocksByHash(),
+                        RekeyingReader(idToBlockHash, blocksDirect)
                 ),
-                blocksDirect
+                extractBlock
+        )
+    }
+
+    fun blocksByHashAsCont(): Reader<BlockHash, BlockContainer> {
+        return TransformingReader(
+                blocksByHash(),
+                blockAsContainer
+        )
+    }
+
+    fun blocksByIdAsCont(): Reader<BlockId, BlockContainer> {
+        return TransformingReader(
+                blocksById(),
+                blockAsContainer
+        )
+    }
+
+    fun blocksByHeightAsCont(): Reader<Long, BlockContainer> {
+        return CompoundReader(
+                caches.getBlocksByHeight(),
+                blocksByHeightDirect
         )
     }
 
     fun txByHash(): Reader<TransactionId, TransactionJson> {
-        return CompoundReader(
-                RekeyingReader(
-                        txHashToId,
-                        TransformingReader(caches.getTxByHash(), extractTx)
+        return TransformingReader(
+                CompoundReader(
+                        RekeyingReader(txHashToId, caches.getTxByHash()),
+                        txDirect
                 ),
-                txDirect
+                extractTx
+        )
+    }
+
+    fun txByHashAsCont(): Reader<TxId, TxContainer> {
+        return CompoundReader(
+                caches.getTxByHash(),
+                RekeyingReader(idToTxHash, txDirect)
         )
     }
 
@@ -155,18 +251,17 @@ open class EthereumReader(
     }
 
     override fun isRunning(): Boolean {
-        return this.headListener != null
+        //TODO should be always running?
+        return up.isRunning
     }
 
     override fun start() {
-        this.headListener = up.getHead().getFlux().subscribe {
+        val evictCaches: Runnable = Runnable {
             balanceCache.evict()
         }
+        up.getHead().onBeforeBlock(evictCaches)
     }
 
     override fun stop() {
-        val headListener = this.headListener
-        this.headListener = null
-        headListener?.dispose()
     }
 }

src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumRpcHead.kt

@@ -19,6 +19,10 @@ package io.emeraldpay.dshackle.upstream.ethereum
 import com.fasterxml.jackson.databind.ObjectMapper
 import io.emeraldpay.dshackle.Defaults
 import io.emeraldpay.dshackle.data.BlockContainer
+import io.emeraldpay.dshackle.reader.Reader
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
+import io.infinitape.etherjar.hex.HexQuantity
 import io.infinitape.etherjar.rpc.Commands
 import org.slf4j.LoggerFactory
 import org.springframework.context.Lifecycle
@@ -31,7 +35,7 @@ import java.time.Duration
 import java.util.concurrent.Executors
 
 class EthereumRpcHead(
-        private val api: DirectEthereumApi,
+        private val api: Reader<in JsonRpcRequest, out JsonRpcResponse>,
         private val objectMapper: ObjectMapper,
         private val interval: Duration = Duration.ofSeconds(10)
 ): DefaultEthereumHead(), Lifecycle {
@@ -48,21 +52,27 @@ class EthereumRpcHead(
         val base = Flux.interval(interval)
                 .publishOn(scheduler)
                 .flatMap {
-                    api.rpcClient
-                            .execute(Commands.eth().blockNumber)
+                    api.read(JsonRpcRequest("eth_blockNumber", emptyList()))
                             .subscribeOn(scheduler)
                             .timeout(Defaults.timeout, Mono.error(Exception("Block number not received")))
+                            .flatMap {
+                                if (it.error != null) {
+                                    Mono.error(it.error.asException())
+                                } else {
+                                    val value = it.getResultAsProcessedString()
+                                    Mono.just(HexQuantity.from(value))
+                                }
+                            }
                 }
                 .flatMap {
                     //fetching by Block Height here, critical to use same upstream,
                     //different upstreams may have different blocks on the same height
-                    api.rpcClient
-                            .execute(Commands.eth().getBlock(it))
+                    api.read(JsonRpcRequest("eth_getBlockByNumber", listOf(it.toHex(), false)))
                             .subscribeOn(scheduler)
                             .timeout(Defaults.timeout, Mono.error(Exception("Block data not received")))
                 }
                 .map {
-                    BlockContainer.from(it, objectMapper)
+                    BlockContainer.from(it.getResult(), objectMapper)
                 }
                 .onErrorContinue { err, _ ->
                     log.debug("RPC error ${err.message}")

src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumUpstream.kt

@@ -20,10 +20,13 @@ import com.fasterxml.jackson.databind.ObjectMapper
 import io.emeraldpay.dshackle.cache.Caches
 import io.emeraldpay.dshackle.cache.CachesEnabled
 import io.emeraldpay.dshackle.config.UpstreamsConfig
+import io.emeraldpay.dshackle.reader.Reader
 import io.emeraldpay.dshackle.startup.QuorumForLabels
 import io.emeraldpay.dshackle.upstream.*
 import io.emeraldpay.dshackle.upstream.calls.CallMethods
 import io.emeraldpay.dshackle.upstream.calls.DirectCallMethods
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import io.emeraldpay.grpc.Chain
 import org.slf4j.LoggerFactory
 import org.springframework.context.Lifecycle
@@ -34,15 +37,15 @@ import java.time.Duration
 open class EthereumUpstream(
         id: String,
         val chain: Chain,
-        private val api: DirectEthereumApi,
-        private val ethereumWs: EthereumWs? = null,
+        private val directReader: Reader<JsonRpcRequest, JsonRpcResponse>,
+        private val ethereumWsFactory: EthereumWsFactory? = null,
         options: UpstreamsConfig.Options,
         val node: QuorumForLabels.QuorumItem,
         targets: CallMethods,
         private val objectMapper: ObjectMapper
-) : DefaultUpstream<EthereumApi>(id, options, targets), Upstream<EthereumApi>, CachesEnabled, Lifecycle {
+) : DefaultUpstream(id, options, targets), Upstream, CachesEnabled, Lifecycle {
 
-    constructor(id: String, chain: Chain, api: DirectEthereumApi, objectMapper: ObjectMapper) : this(id, chain, api, null,
+    constructor(id: String, chain: Chain, api: Reader<JsonRpcRequest, JsonRpcResponse>, objectMapper: ObjectMapper) : this(id, chain, api, null,
             UpstreamsConfig.Options.getDefaults(), QuorumForLabels.QuorumItem(1, UpstreamsConfig.Labels()),
             DirectCallMethods(), objectMapper)
 
@@ -52,12 +55,7 @@ open class EthereumUpstream(
     private val head: Head = this.createHead()
     private var validatorSubscription: Disposable? = null
 
-    init {
-        api.upstream = this
-    }
-
     override fun setCaches(caches: Caches) {
-        api.caches = caches;
         if (head is CachesEnabled) {
             head.setCaches(caches)
         }
@@ -70,7 +68,7 @@ open class EthereumUpstream(
             this.setLag(0)
             this.setStatus(UpstreamAvailability.OK)
         } else {
-            val validator = EthereumUpstreamValidator(this, getOptions())
+            val validator = EthereumUpstreamValidator(this, getOptions(), objectMapper)
             validatorSubscription = validator.start()
                     .subscribe(this::setStatus)
         }
@@ -89,21 +87,24 @@ open class EthereumUpstream(
     }
 
     open fun createHead(): Head {
-        return if (ethereumWs != null) {
-            val ws = EthereumWsHead(ethereumWs).apply {
-                this.start()
+        return if (ethereumWsFactory != null) {
+            val ws = ethereumWsFactory.create(this).apply {
+                connect()
             }
-            // receive bew blocks through Websockets, but periodically verify with RPC
-            val rpc = EthereumRpcHead(api, objectMapper, Duration.ofSeconds(30)).apply {
-                this.start()
+            val wsHead = EthereumWsHead(ws).apply {
+                start()
             }
-            MergedHead(listOf(rpc, ws)).apply {
-                this.start()
+            // receive bew blocks through WebSockets, but also periodically verify with RPC in case if WS failed
+            val rpcHead = EthereumRpcHead(getApi(), objectMapper, Duration.ofSeconds(60)).apply {
+                start()
+            }
+            MergedHead(listOf(rpcHead, wsHead)).apply {
+                start()
             }
         } else {
             log.warn("Setting up upstream ${this.getId()} with RPC-only access, less effective than WS+RPC")
-            EthereumRpcHead(api, objectMapper).apply {
-                this.start()
+            EthereumRpcHead(getApi(), objectMapper).apply {
+                start()
             }
         }
     }
@@ -112,8 +113,8 @@ open class EthereumUpstream(
         return head
     }
 
-    override fun getApi(matcher: Selector.Matcher): Mono<DirectEthereumApi> {
-        return Mono.just(api)
+    override fun getApi(): Reader<JsonRpcRequest, JsonRpcResponse> {
+        return directReader
     }
 
     override fun getLabels(): Collection<UpstreamsConfig.Labels> {
@@ -121,18 +122,11 @@ open class EthereumUpstream(
     }
 
     @Suppress("unchecked")
-    override fun <T : Upstream<TA>, TA : UpstreamApi> cast(selfType: Class<T>, apiType: Class<TA>): T {
+    override fun <T : Upstream> cast(selfType: Class<T>): T {
         if (!selfType.isAssignableFrom(this.javaClass)) {
             throw ClassCastException("Cannot cast ${this.javaClass} to $selfType")
         }
-        return castApi(apiType) as T
-    }
-
-    override fun <A : UpstreamApi> castApi(apiType: Class<A>): Upstream<A> {
-        if (!apiType.isAssignableFrom(EthereumApi::class.java)) {
-            throw ClassCastException("Cannot cast ${EthereumApi::class.java} to $apiType")
-        }
-        return this as Upstream<A>
+        return this as T
     }
 
 }

src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumUpstreamValidator.kt

@@ -16,11 +16,13 @@
  */
 package io.emeraldpay.dshackle.upstream.ethereum
 
+import com.fasterxml.jackson.databind.ObjectMapper
 import io.emeraldpay.dshackle.Defaults
 import io.emeraldpay.dshackle.config.UpstreamsConfig
-import io.emeraldpay.dshackle.upstream.Selector
 import io.emeraldpay.dshackle.upstream.UpstreamAvailability
-import io.infinitape.etherjar.rpc.*
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
+import io.infinitape.etherjar.rpc.json.SyncingJson
 import org.slf4j.LoggerFactory
 import org.springframework.scheduling.concurrent.CustomizableThreadFactory
 import reactor.core.publisher.Flux
@@ -30,8 +32,9 @@ import java.time.Duration
 import java.util.concurrent.Executors
 
 class EthereumUpstreamValidator(
-        private val ethereumUpstream: EthereumUpstream,
-        private val options: UpstreamsConfig.Options
+        private val upstream: EthereumUpstream,
+        private val options: UpstreamsConfig.Options,
+        private val objectMapper: ObjectMapper
 ) {
     companion object {
         private val log = LoggerFactory.getLogger(EthereumUpstreamValidator::class.java)
@@ -39,30 +42,32 @@ class EthereumUpstreamValidator(
     }
 
     fun validate(): Mono<UpstreamAvailability> {
-        return ethereumUpstream
-                .getApi(Selector.empty)
-                .flatMapMany { api ->
-                    api.rpcClient
-                            .execute(Commands.eth().syncing())
-                            .timeout(Defaults.timeoutInternal, Mono.error(Exception("Validation timeout for Syncing")))
-                            .flatMap { value ->
-                                if (value.isSyncing) {
-                                    Mono.just(UpstreamAvailability.SYNCING)
-                                } else {
-                                    api.rpcClient.execute(Commands.net().peerCount())
-                                            .timeout(Defaults.timeoutInternal, Mono.error(Exception("Validation timeout for Peers")))
-                                            .map { count ->
-                                                val minPeers = options.minPeers ?: 1
-                                                if (count < minPeers) {
-                                                    UpstreamAvailability.IMMATURE
-                                                } else {
-                                                    UpstreamAvailability.OK
-                                                }
-                                            }
+        return upstream
+                .getApi()
+                .read(JsonRpcRequest("eth_syncing", listOf()))
+                .flatMap(JsonRpcResponse::requireResult)
+                .map { objectMapper.readValue(it, SyncingJson::class.java) }
+                .timeout(Defaults.timeoutInternal, Mono.error(Exception("Validation timeout for Syncing")))
+                .flatMap { value ->
+                    if (value.isSyncing) {
+                        Mono.just(UpstreamAvailability.SYNCING)
+                    } else {
+                        upstream
+                                .getApi()
+                                .read(JsonRpcRequest("net_peerCount", listOf()))
+                                .flatMap(JsonRpcResponse::requireStringResult)
+                                .map(Integer::decode)
+                                .timeout(Defaults.timeoutInternal, Mono.error(Exception("Validation timeout for Peers")))
+                                .map { count ->
+                                    val minPeers = options.minPeers ?: 1
+                                    if (count < minPeers) {
+                                        UpstreamAvailability.IMMATURE
+                                    } else {
+                                        UpstreamAvailability.OK
+                                    }
                                 }
-                            }
+                    }
                 }
-                .single()
                 .onErrorReturn(UpstreamAvailability.UNAVAILABLE)
     }
 

src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumWs.kt

@@ -1,108 +0,0 @@
-/**
- * Copyright (c) 2020 EmeraldPay, Inc
- * Copyright (c) 2019 ETCDEV GmbH
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream.ethereum
-
-import com.fasterxml.jackson.databind.ObjectMapper
-import io.emeraldpay.dshackle.Defaults
-import io.emeraldpay.dshackle.cache.Caches
-import io.emeraldpay.dshackle.cache.CachesEnabled
-import io.emeraldpay.dshackle.config.AuthConfig
-import io.emeraldpay.dshackle.data.BlockContainer
-import io.emeraldpay.dshackle.data.BlockId
-import io.emeraldpay.dshackle.reader.EmptyReader
-import io.emeraldpay.dshackle.reader.Reader
-import io.infinitape.etherjar.rpc.Commands
-import io.infinitape.etherjar.rpc.json.BlockJson
-import io.infinitape.etherjar.rpc.json.TransactionRefJson
-import io.infinitape.etherjar.rpc.ws.WebsocketClient
-import org.slf4j.LoggerFactory
-import reactor.core.publisher.Flux
-import reactor.core.publisher.Mono
-import reactor.core.publisher.TopicProcessor
-import reactor.retry.Repeat
-import java.net.URI
-import java.time.Duration
-
-class EthereumWs(
-        private val uri: URI,
-        private val origin: URI,
-        private val api: EthereumApi,
-        private val objectMapper: ObjectMapper
-): CachesEnabled {
-
-    private val log = LoggerFactory.getLogger(EthereumWs::class.java)
-    private val topic = TopicProcessor
-            .builder<BlockContainer>()
-            .name("new-blocks")
-            .build()
-    var basicAuth: AuthConfig.ClientBasicAuth? = null
-
-    private var blockCache: Reader<BlockId, BlockContainer> = EmptyReader()
-
-    fun connect() {
-        log.info("Connecting to WebSocket: $uri")
-        val clientBuilder = WebsocketClient.newBuilder()
-                .connectTo(uri)
-                .origin(origin)
-        basicAuth?.let { auth ->
-            clientBuilder.basicAuth(auth.username, auth.password)
-        }
-        val client = clientBuilder.build()
-        try {
-            client.connect()
-            client.onNewBlock(this::onNewBlock)
-        } catch (e: Exception) {
-            log.error("Failed to connect to websocket at $uri. Error: ${e.message}")
-        }
-    }
-
-    fun onNewBlock(block: BlockJson<TransactionRefJson>) {
-        // WS returns incomplete blocks
-        if (block.difficulty == null || block.transactions == null) {
-            Mono.just(block.hash).flatMap { hash ->
-                val hash = BlockId.from(hash)
-                // first check in cache, if empty then check api
-                blockCache.read(hash)
-                        .switchIfEmpty(request(hash))
-            }.repeatWhenEmpty { n ->
-                Repeat.times<Any>(10)
-                        .exponentialBackoff(Duration.ofMillis(50), Duration.ofMillis(250))
-                        .apply(n)
-            }
-                    .timeout(Defaults.timeout, Mono.empty())
-                    .subscribe(topic::onNext)
-
-        } else {
-            topic.onNext(BlockContainer.from(block, objectMapper))
-        }
-    }
-
-    fun request(hash: BlockId): Mono<BlockContainer> {
-        return api
-                .executeAndConvert(Commands.eth().getBlock(io.infinitape.etherjar.domain.BlockHash(hash.value)))
-                .map { BlockContainer.from(it, objectMapper) }
-    }
-
-    fun getFlux(): Flux<BlockContainer> {
-        return Flux.from(this.topic)
-                .onBackpressureLatest()
-    }
-
-    override fun setCaches(caches: Caches) {
-        blockCache = caches.getBlocksByHash()
-    }
-}

src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumWsFactory.kt

@@ -0,0 +1,122 @@
+/**
+ * Copyright (c) 2020 EmeraldPay, Inc
+ * Copyright (c) 2019 ETCDEV GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.emeraldpay.dshackle.upstream.ethereum
+
+import com.fasterxml.jackson.databind.ObjectMapper
+import io.emeraldpay.dshackle.Defaults
+import io.emeraldpay.dshackle.SilentException
+import io.emeraldpay.dshackle.config.AuthConfig
+import io.emeraldpay.dshackle.data.BlockContainer
+import io.emeraldpay.dshackle.data.BlockId
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
+import io.infinitape.etherjar.rpc.json.BlockJson
+import io.infinitape.etherjar.rpc.json.TransactionRefJson
+import io.infinitape.etherjar.rpc.ws.WebsocketClient
+import org.slf4j.LoggerFactory
+import reactor.core.publisher.Flux
+import reactor.core.publisher.Mono
+import reactor.core.publisher.TopicProcessor
+import reactor.retry.Repeat
+import java.net.URI
+import java.time.Duration
+
+class EthereumWsFactory(
+        private val uri: URI,
+        private val origin: URI,
+        private val objectMapper: ObjectMapper
+) {
+
+    var basicAuth: AuthConfig.ClientBasicAuth? = null
+
+    fun create(upstream: EthereumUpstream): EthereumWs {
+        return EthereumWs(uri, origin, upstream, objectMapper, basicAuth)
+    }
+
+    class EthereumWs(
+            private val uri: URI,
+            private val origin: URI,
+            private val upstream: EthereumUpstream,
+            private val objectMapper: ObjectMapper,
+            private val basicAuth: AuthConfig.ClientBasicAuth?
+    ) {
+
+        companion object {
+            private val log = LoggerFactory.getLogger(EthereumWs::class.java)
+        }
+
+        private val topic = TopicProcessor
+                .builder<BlockContainer>()
+                .name("new-blocks")
+                .build()
+
+        fun connect() {
+            log.info("Connecting to WebSocket: $uri")
+            val clientBuilder = WebsocketClient.newBuilder()
+                    .connectTo(uri)
+                    .origin(origin)
+            basicAuth?.let { auth ->
+                clientBuilder.basicAuth(auth.username, auth.password)
+            }
+            val client = clientBuilder.build()
+            try {
+                client.connect()
+                client.onNewBlock(this::onNewBlock)
+            } catch (e: Exception) {
+                log.error("Failed to connect to websocket at $uri. Error: ${e.message}")
+            }
+        }
+
+        fun onNewBlock(block: BlockJson<TransactionRefJson>) {
+            // WS returns incomplete blocks
+            if (block.difficulty == null || block.transactions == null) {
+                Mono.just(block.hash)
+                        .flatMap { hash ->
+                            upstream.getApi()
+                                    .read(JsonRpcRequest("eth_getBlockByHash", listOf(hash.toHex(), false)))
+                                    .flatMap { resp ->
+                                        if (resp.isNull()) {
+                                            Mono.error(SilentException("Received null for block $hash"))
+                                        } else {
+                                            Mono.just(resp)
+                                        }
+                                    }
+                                    .flatMap(JsonRpcResponse::requireResult)
+                                    .map { BlockContainer.from(it, objectMapper) }
+                        }.repeatWhenEmpty { n ->
+                            Repeat.times<Any>(5)
+                                    .exponentialBackoff(Duration.ofMillis(50), Duration.ofMillis(500))
+                                    .apply(n)
+                        }
+                        .timeout(Defaults.timeout, Mono.empty())
+                        .onErrorResume { Mono.empty() }
+                        .subscribe(topic::onNext)
+
+            } else {
+                topic.onNext(BlockContainer.from(block, objectMapper))
+            }
+        }
+
+        fun getFlux(): Flux<BlockContainer> {
+            return Flux.from(this.topic)
+                    .onBackpressureLatest()
+        }
+    }
+
+
+
+}

src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumWsHead.kt

@@ -16,15 +16,13 @@
  */
 package io.emeraldpay.dshackle.upstream.ethereum
 
-import io.emeraldpay.dshackle.cache.Caches
-import io.emeraldpay.dshackle.cache.CachesEnabled
 import org.slf4j.LoggerFactory
 import org.springframework.context.Lifecycle
 import reactor.core.Disposable
 
 class EthereumWsHead(
-        private val ws: EthereumWs
-): DefaultEthereumHead(), Lifecycle, CachesEnabled {
+        private val ws: EthereumWsFactory.EthereumWs
+) : DefaultEthereumHead(), Lifecycle {
 
     private val log = LoggerFactory.getLogger(EthereumWsHead::class.java)
 
@@ -43,8 +41,4 @@ class EthereumWsHead(
         subscription = null
     }
 
-    override fun setCaches(caches: Caches) {
-        ws.setCaches(caches)
-    }
-
 }

src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/NativeCallRouter.kt

@@ -0,0 +1,129 @@
+/**
+ * Copyright (c) 2020 EmeraldPay, Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.emeraldpay.dshackle.upstream.ethereum
+
+import com.fasterxml.jackson.databind.ObjectMapper
+import io.emeraldpay.dshackle.data.BlockId
+import io.emeraldpay.dshackle.data.TxId
+import io.emeraldpay.dshackle.reader.Reader
+import io.emeraldpay.dshackle.upstream.calls.CallMethods
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
+import io.infinitape.etherjar.hex.HexQuantity
+import io.infinitape.etherjar.rpc.RpcException
+import io.infinitape.etherjar.rpc.RpcResponseError
+import org.slf4j.LoggerFactory
+import reactor.core.publisher.Mono
+import java.math.BigInteger
+
+class NativeCallRouter(
+        private val objectMapper: ObjectMapper,
+        private val reader: EthereumReader,
+        private val methods: CallMethods
+) : Reader<JsonRpcRequest, JsonRpcResponse> {
+
+    companion object {
+        private val log = LoggerFactory.getLogger(NativeCallRouter::class.java)
+    }
+
+    private val fullBlocksReader = EthereumFullBlocksReader(
+            objectMapper,
+            reader.blocksByIdAsCont(),
+            reader.txByHashAsCont()
+    )
+
+    override fun read(key: JsonRpcRequest): Mono<JsonRpcResponse> {
+        if (methods.isHardcoded(key.method)) {
+            return Mono.just(methods.executeHardcoded(key.method))
+                    .map { JsonRpcResponse(it, null) }
+        }
+        if (!methods.isAllowed(key.method)) {
+            return Mono.error(RpcException(RpcResponseError.CODE_METHOD_NOT_EXIST, "Unsupported method"))
+        }
+        val common = commonRequests(key)
+        if (common != null) {
+            return common.map { JsonRpcResponse(it, null) }
+        }
+        return Mono.empty()
+    }
+
+    /**
+     * Prepare RpcCall with data types specific for that particular requests. In general it may return a call that just
+     * parses JSON into Map. But the purpose of further processing and caching for some of the requests we want
+     * to have actual data types.
+     */
+    fun commonRequests(key: JsonRpcRequest): Mono<ByteArray>? {
+        val method = key.method
+        val params = key.params
+        return when {
+            method == "eth_getTransactionByHash" -> {
+                if (params.size != 1) {
+                    throw RpcException(RpcResponseError.CODE_INVALID_METHOD_PARAMS, "Must provide 1 parameter")
+                }
+                val hash: TxId
+                try {
+                    hash = TxId.from(params[0].toString())
+                } catch (e: IllegalArgumentException) {
+                    throw RpcException(RpcResponseError.CODE_INVALID_METHOD_PARAMS, "[0] must be transaction id")
+                }
+                reader.txByHashAsCont().read(hash).map { it.json!! }
+            }
+            method == "eth_getBlockByHash" -> {
+                if (params.size != 2) {
+                    throw RpcException(RpcResponseError.CODE_INVALID_METHOD_PARAMS, "Must provide 2 parameters")
+                }
+                val hash: BlockId
+                try {
+                    hash = BlockId.from(params[0].toString())
+                } catch (e: IllegalArgumentException) {
+                    throw RpcException(RpcResponseError.CODE_INVALID_METHOD_PARAMS, "[0] must be block hash")
+                }
+                val withTx = params[1].toString().toBoolean()
+                if (withTx) {
+                    fullBlocksReader.read(hash).map { it.json!! }
+                } else {
+                    reader.blocksByIdAsCont().read(hash).map { it.json!! }
+                }
+            }
+            method == "eth_getBlockByNumber" -> {
+                if (params.size != 2) {
+                    throw RpcException(RpcResponseError.CODE_INVALID_METHOD_PARAMS, "Must provide 2 parameters")
+                }
+                val number: Long
+                try {
+                    val quantity = HexQuantity.from(params[0].toString()) ?: throw IllegalArgumentException()
+                    number = quantity.value.let {
+                        if (it < BigInteger.valueOf(Long.MAX_VALUE) && it >= BigInteger.ZERO) {
+                            it.toLong()
+                        } else {
+                            throw IllegalArgumentException()
+                        }
+                    }
+                } catch (e: IllegalArgumentException) {
+                    throw RpcException(RpcResponseError.CODE_INVALID_METHOD_PARAMS, "[0] must be block number")
+                }
+                val withTx = params[1].toString().toBoolean()
+                if (withTx) {
+                    log.warn("Block by number is not implemented")
+                    null
+                } else {
+                    reader.blocksByHeightAsCont().read(number).map { it.json!! }
+                }
+            }
+            else -> null
+        }
+    }
+}

src/main/kotlin/io/emeraldpay/dshackle/upstream/grpc/EthereumGrpcUpstream.kt

@@ -22,22 +22,21 @@ import io.emeraldpay.api.proto.BlockchainOuterClass
 import io.emeraldpay.api.proto.Common
 import io.emeraldpay.api.proto.ReactorBlockchainGrpc
 import io.emeraldpay.dshackle.Defaults
-import io.emeraldpay.dshackle.cache.Caches
-import io.emeraldpay.dshackle.cache.CachesEnabled
 import io.emeraldpay.dshackle.config.UpstreamsConfig
 import io.emeraldpay.dshackle.data.BlockContainer
 import io.emeraldpay.dshackle.data.BlockId
+import io.emeraldpay.dshackle.reader.Reader
 import io.emeraldpay.dshackle.startup.QuorumForLabels
 import io.emeraldpay.dshackle.upstream.*
 import io.emeraldpay.dshackle.upstream.calls.CallMethods
 import io.emeraldpay.dshackle.upstream.calls.DirectCallMethods
-import io.emeraldpay.dshackle.upstream.ethereum.DefaultEthereumHead
-import io.emeraldpay.dshackle.upstream.ethereum.DirectEthereumApi
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumApi
+import io.emeraldpay.dshackle.upstream.ethereum.*
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcGrpcClient
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import io.emeraldpay.grpc.Chain
 import io.infinitape.etherjar.domain.BlockHash
 import io.infinitape.etherjar.rpc.*
-import io.infinitape.etherjar.rpc.emerald.ReactorEmeraldClient
 import org.slf4j.LoggerFactory
 import org.springframework.context.Lifecycle
 import reactor.core.Disposable
@@ -58,16 +57,15 @@ open class EthereumGrpcUpstream(
         private val chain: Chain,
         private val blockchainStub: ReactorBlockchainGrpc.ReactorBlockchainStub,
         private val objectMapper: ObjectMapper,
-        private val rpcClient: ReactorEmeraldClient
-) : DefaultUpstream<EthereumApi>(
+        private val client: JsonRpcGrpcClient
+) : DefaultUpstream(
         "$parentId/${chain.chainCode}",
         UpstreamsConfig.Options.getDefaults(),
         null
-), CachesEnabled, Lifecycle {
+), Lifecycle {
 
     private var allLabels: Collection<UpstreamsConfig.Labels> = ArrayList<UpstreamsConfig.Labels>()
     private val log = LoggerFactory.getLogger(EthereumGrpcUpstream::class.java)
-    private var caches: Caches? = null
 
     private val nodes = AtomicReference<QuorumForLabels>(QuorumForLabels())
     private val head = DefaultEthereumHead()
@@ -76,16 +74,7 @@ open class EthereumGrpcUpstream(
 
     var timeout = Defaults.timeout
 
-    open fun createApi(matcher: Selector.Matcher): DirectEthereumApi {
-        val targets = this.getMethods()
-        val client = Selector.extractLabels(matcher)?.let { selector ->
-            rpcClient.copyWithSelector(selector.asProto())
-        } ?: rpcClient
-        return DirectEthereumApi(client, caches, objectMapper, targets).let {
-            it.upstream = this
-            it
-        }
-    }
+    private val defaultReader: Reader<JsonRpcRequest, JsonRpcResponse> = client.forSelector(Selector.empty)
 
     override fun start() {
         if (this.isRunning) return
@@ -123,6 +112,7 @@ open class EthereumGrpcUpstream(
                     BigInteger(1, value.weight.toByteArray()),
                     Instant.ofEpochMilli(value.timestamp),
                     false,
+                    null,
                     null
             )
             block
@@ -132,9 +122,11 @@ open class EthereumGrpcUpstream(
             val curr = head.getCurrent()
             curr == null || curr.difficulty < block.difficulty
         }.flatMap {
-            getApi(Selector.EmptyMatcher())
-                    .flatMap { api -> api.executeAndConvert(Commands.eth().getBlock(BlockHash(it.hash.value))) }
-                    .map { BlockContainer.from(it, objectMapper) }
+            defaultReader.read(JsonRpcRequest("eth_getBlockByHash", listOf(it.hash.toHexWithPrefix(), false)))
+                    .flatMap(JsonRpcResponse::requireResult)
+                    .map {
+                        BlockContainer.from(it, objectMapper)
+                    }
                     .timeout(timeout, Mono.error(TimeoutException("Timeout from upstream")))
                     .doOnError { t ->
                         setStatus(UpstreamAvailability.UNAVAILABLE)
@@ -208,26 +200,16 @@ open class EthereumGrpcUpstream(
         return head
     }
 
-    override fun getApi(matcher: Selector.Matcher): Mono<DirectEthereumApi> {
-        return Mono.just(createApi(matcher))
-    }
-
-    override fun setCaches(caches: Caches) {
-        this.caches = caches
+    override fun getApi(): Reader<JsonRpcRequest, JsonRpcResponse> {
+        return defaultReader
     }
 
     @SuppressWarnings("unchecked")
-    override fun <T : Upstream<TA>, TA : UpstreamApi> cast(selfType: Class<T>, apiType: Class<TA>): T {
+    override fun <T : Upstream> cast(selfType: Class<T>): T {
         if (!selfType.isAssignableFrom(this.javaClass)) {
             throw ClassCastException("Cannot cast ${this.javaClass} to $selfType")
         }
-        return castApi(apiType) as T
+        return this as T
     }
 
-    override fun <A : UpstreamApi> castApi(apiType: Class<A>): Upstream<A> {
-        if (!apiType.isAssignableFrom(EthereumApi::class.java)) {
-            throw ClassCastException("Cannot cast ${EthereumApi::class.java} to $apiType")
-        }
-        return this as Upstream<A>
-    }
 }

src/main/kotlin/io/emeraldpay/dshackle/upstream/grpc/GrpcUpstreams.kt

@@ -25,10 +25,10 @@ import io.emeraldpay.dshackle.FileResolver
 import io.emeraldpay.dshackle.config.AuthConfig
 import io.emeraldpay.dshackle.upstream.UpstreamAvailability
 import io.emeraldpay.dshackle.startup.UpstreamChange
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcGrpcClient
 import io.emeraldpay.grpc.Chain
 import io.grpc.ManagedChannelBuilder
 import io.grpc.netty.NettyChannelBuilder
-import io.infinitape.etherjar.rpc.emerald.ReactorEmeraldClient
 import io.netty.handler.ssl.*
 import org.apache.commons.lang3.StringUtils
 import org.apache.commons.lang3.exception.ExceptionUtils
@@ -57,7 +57,6 @@ class GrpcUpstreams(
     private var client: ReactorBlockchainGrpc.ReactorBlockchainStub? = null
     private val known = HashMap<Chain, EthereumGrpcUpstream>()
     private val lock = ReentrantLock()
-    private var grpcTransport: ReactorEmeraldClient? = null
 
     fun start(): Flux<UpstreamChange> {
         val channel: ManagedChannelBuilder<*> = if (auth != null && StringUtils.isNotEmpty(auth.ca)) {
@@ -74,10 +73,6 @@ class GrpcUpstreams(
 
         val client = ReactorBlockchainGrpc.newReactorStub(channel.build())
         this.client = client
-        this.grpcTransport = ReactorEmeraldClient.newBuilder()
-                .connectUsing(client.channel)
-                .objectMapper(objectMapper)
-                .build()
 
         val statusSubscription = AtomicReference<Disposable>()
 
@@ -162,7 +157,8 @@ class GrpcUpstreams(
         lock.withLock {
             val current = known[chain]
             return if (current == null) {
-                val created = EthereumGrpcUpstream(id, chain, client!!, objectMapper, grpcTransport!!.copyForChain(chain))
+                val rpcClient = JsonRpcGrpcClient(client!!, chain, objectMapper)
+                val created = EthereumGrpcUpstream(id, chain, client!!, objectMapper, rpcClient)
                 created.timeout = this.timeout
                 known[chain] = created
                 created.start()

src/main/kotlin/io/emeraldpay/dshackle/upstream/rpcclient/JsonRpcGrpcClient.kt

@@ -0,0 +1,86 @@
+/**
+ * Copyright (c) 2020 EmeraldPay, Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.emeraldpay.dshackle.upstream.rpcclient
+
+import com.fasterxml.jackson.databind.ObjectMapper
+import com.google.protobuf.ByteString
+import io.emeraldpay.api.proto.BlockchainOuterClass
+import io.emeraldpay.api.proto.ReactorBlockchainGrpc
+import io.emeraldpay.dshackle.reader.Reader
+import io.emeraldpay.dshackle.upstream.Selector
+import io.emeraldpay.grpc.Chain
+import io.grpc.Channel
+import io.infinitape.etherjar.rpc.RpcException
+import io.infinitape.etherjar.rpc.RpcResponseError
+import org.slf4j.LoggerFactory
+import reactor.core.publisher.Mono
+
+class JsonRpcGrpcClient(
+        private val stub: ReactorBlockchainGrpc.ReactorBlockchainStub,
+        private val chain: Chain,
+        private val objectMapper: ObjectMapper
+) {
+
+    companion object {
+        private val log = LoggerFactory.getLogger(JsonRpcGrpcClient::class.java)
+    }
+
+    fun forSelector(matcher: Selector.Matcher): Reader<JsonRpcRequest, JsonRpcResponse> {
+        return Executor(stub, chain, matcher, objectMapper)
+    }
+
+    class Executor(
+            private val stub: ReactorBlockchainGrpc.ReactorBlockchainStub,
+            private val chain: Chain,
+            private val matcher: Selector.Matcher,
+            private val objectMapper: ObjectMapper
+    ) : Reader<JsonRpcRequest, JsonRpcResponse> {
+
+        private val parser = JsonRpcParser()
+
+        override fun read(key: JsonRpcRequest): Mono<JsonRpcResponse> {
+            val req = BlockchainOuterClass.NativeCallRequest.newBuilder()
+                    .setChainValue(chain.id)
+
+            if (matcher != Selector.empty) {
+                Selector.extractLabels(matcher)?.asProto().let {
+                    req.setSelector(it)
+                }
+            }
+
+            BlockchainOuterClass.NativeCallItem.newBuilder()
+                    .setId(1)
+                    .setMethod(key.method)
+                    .setPayload(ByteString.copyFrom(objectMapper.writeValueAsBytes(key.params)))
+                    .build().let {
+                        req.addItems(it)
+                    }
+
+            return stub.nativeCall(req.build())
+                    .single()
+                    .flatMap { resp ->
+                        if (resp.succeed) {
+                            val bytes = resp.payload.toByteArray()
+                            Mono.just(JsonRpcResponse(bytes, null))
+                        } else {
+                            Mono.error(RpcException(RpcResponseError.CODE_UPSTREAM_CONNECTION_ERROR, resp.errorMessage))
+                        }
+                    }
+        }
+
+    }
+
+}

src/main/kotlin/io/emeraldpay/dshackle/upstream/rpcclient/JsonRpcHttpClient.kt

@@ -13,27 +13,41 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package io.emeraldpay.dshackle.upstream.bitcoin
+package io.emeraldpay.dshackle.upstream.rpcclient
 
+import com.fasterxml.jackson.databind.ObjectMapper
 import io.emeraldpay.dshackle.config.AuthConfig
+import io.emeraldpay.dshackle.reader.Reader
 import io.netty.buffer.Unpooled
 import io.netty.handler.codec.http.HttpHeaderNames
 import io.netty.handler.codec.http.HttpHeaders
+import io.netty.handler.ssl.SslContextBuilder
 import org.slf4j.LoggerFactory
 import reactor.core.publisher.Mono
 import reactor.netty.http.client.HttpClient
+import reactor.netty.tcp.SslProvider
+import java.io.ByteArrayInputStream
+import java.security.KeyStore
+import java.security.cert.CertificateFactory
+import java.security.cert.X509Certificate
 import java.util.*
 import java.util.function.Consumer
 
-open class BitcoinRpcClient(
+/**
+ * JSON RPC client
+ */
+class JsonRpcHttpClient(
         private val target: String,
-        basicAuth: AuthConfig.ClientBasicAuth?
-) {
+        private val objectMapper: ObjectMapper,
+        basicAuth: AuthConfig.ClientBasicAuth? = null,
+        tlsCAAuth: ByteArray? = null
+) : Reader<JsonRpcRequest, JsonRpcResponse> {
 
     companion object {
-        private val log = LoggerFactory.getLogger(BitcoinRpcClient::class.java)
+        private val log = LoggerFactory.getLogger(JsonRpcHttpClient::class.java)
     }
 
+    private val parser = JsonRpcParser()
     private val httpClient: HttpClient
 
     init {
@@ -43,14 +57,27 @@ open class BitcoinRpcClient(
             h.add(HttpHeaderNames.CONTENT_TYPE, "application/json")
         }
 
-        basicAuth?.let { basicAuth ->
-            val authString: String = basicAuth.username + ":" + basicAuth.password
+        basicAuth?.let { auth ->
+            val authString: String = auth.username + ":" + auth.password
             val authBase64 = Base64.getEncoder().encodeToString(authString.toByteArray())
-            val auth = "Basic $authBase64"
-            val headers = Consumer { h: HttpHeaders -> h.add(HttpHeaderNames.AUTHORIZATION, auth) }
+            val encodedAuth = "Basic $authBase64"
+            val headers = Consumer { h: HttpHeaders -> h.add(HttpHeaderNames.AUTHORIZATION, encodedAuth) }
             build = build.headers(headers)
         }
 
+        tlsCAAuth?.let { auth ->
+            val cf = CertificateFactory.getInstance("X.509")
+            val cert = cf.generateCertificate(ByteArrayInputStream(auth)) as X509Certificate
+            val ks = KeyStore.getInstance(KeyStore.getDefaultType())
+            ks.load(null, "".toCharArray())
+            ks.setCertificateEntry("server", cert)
+            val sslContext = SslContextBuilder.forClient().trustManager(cert).build()
+
+            build.secure { spec ->
+                spec.sslContext(sslContext)
+            }
+        }
+
         this.httpClient = build
     }
 
@@ -65,5 +92,10 @@ open class BitcoinRpcClient(
                 .asByteArray()
     }
 
-
+    override fun read(key: JsonRpcRequest): Mono<JsonRpcResponse> {
+        return Mono.just(key)
+                .map { it.toJson(objectMapper) }
+                .flatMap(this@JsonRpcHttpClient::execute)
+                .map(parser::parse)
+    }
 }

src/main/kotlin/io/emeraldpay/dshackle/upstream/rpcclient/JsonRpcParser.kt

@@ -0,0 +1,98 @@
+/**
+ * Copyright (c) 2020 EmeraldPay, Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.emeraldpay.dshackle.upstream.rpcclient
+
+import com.fasterxml.jackson.core.JsonFactory
+import com.fasterxml.jackson.core.JsonParser
+import com.fasterxml.jackson.core.JsonToken
+import io.infinitape.etherjar.rpc.RpcResponseError
+import org.slf4j.LoggerFactory
+
+class JsonRpcParser() {
+
+    companion object {
+        private val log = LoggerFactory.getLogger(JsonRpcParser::class.java)
+    }
+
+    private val jsonFactory = JsonFactory()
+
+    fun parse(json: ByteArray): JsonRpcResponse {
+        val parser: JsonParser = jsonFactory.createParser(json)
+        parser.nextToken()
+        if (parser.currentToken != JsonToken.START_OBJECT) {
+            return JsonRpcResponse(null, JsonRpcResponse.ResponseError(RpcResponseError.CODE_UPSTREAM_INVALID_RESPONSE, "Invalid JSON"))
+        }
+        var nullResponse: JsonRpcResponse? = null
+        while (parser.nextToken() != JsonToken.END_OBJECT) {
+            val field = parser.currentName
+            if (field == "jsonrpc" || field == "id") {
+                if (!parser.nextToken().isScalarValue) {
+                    return JsonRpcResponse(null, JsonRpcResponse.ResponseError(RpcResponseError.CODE_UPSTREAM_INVALID_RESPONSE, "Invalid JSON (id/type)"))
+                }
+                // just skip the field
+            } else if (field == "result") {
+                val value = parser.nextToken()
+                val start = parser.tokenLocation
+                if (value.isScalarValue) {
+                    val text = parser.text
+                    if (value == JsonToken.VALUE_STRING) {
+                        return JsonRpcResponse(("\"" + text + "\"").toByteArray(), null)
+                    } else if (value == JsonToken.VALUE_NULL) {
+                        //if null we should check if error is present
+                        nullResponse = JsonRpcResponse(text.toByteArray(), null)
+                    } else {
+                        return JsonRpcResponse(text.toByteArray(), null)
+                    }
+                } else if (value == JsonToken.START_OBJECT || value == JsonToken.START_ARRAY) {
+                    parser.skipChildren()
+                    val end = parser.currentLocation.byteOffset.toInt()
+                    val copy = ByteArray((end - start.byteOffset).toInt())
+                    System.arraycopy(json, start.byteOffset.toInt(), copy, 0, copy.size)
+                    return JsonRpcResponse(copy, null)
+                }
+            } else if (field == "error") {
+                val err = readError(parser)
+                if (err != null) {
+                    return JsonRpcResponse(null, err)
+                }
+            }
+        }
+        if (nullResponse != null) {
+            return nullResponse
+        }
+        return JsonRpcResponse(null, JsonRpcResponse.ResponseError(RpcResponseError.CODE_UPSTREAM_INVALID_RESPONSE, "Invalid JSON structure"))
+    }
+
+    fun readError(parser: JsonParser): JsonRpcResponse.ResponseError? {
+        var code = 0
+        var message = ""
+
+        while (parser.nextToken() != JsonToken.END_OBJECT) {
+            if (parser.currentToken() == JsonToken.VALUE_NULL) {
+                // error is just null
+                return null
+            }
+            val field = parser.currentName()
+            if (field == "code" && parser.currentToken == JsonToken.VALUE_NUMBER_INT) {
+                code = parser.intValue
+            } else if (field == "message" && parser.currentToken == JsonToken.VALUE_STRING) {
+                message = parser.valueAsString
+            }
+        }
+
+        return JsonRpcResponse.ResponseError(code, message)
+    }
+}

src/main/kotlin/io/emeraldpay/dshackle/upstream/rpcclient/JsonRpcRequest.kt

@@ -0,0 +1,52 @@
+/**
+ * Copyright (c) 2020 EmeraldPay, Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.emeraldpay.dshackle.upstream.rpcclient
+
+import com.fasterxml.jackson.databind.ObjectMapper
+
+class JsonRpcRequest(
+        val method: String,
+        val params: List<Any>
+) {
+
+    fun toJson(objectMapper: ObjectMapper): ByteArray {
+        val json = mapOf(
+                "jsonrpc" to "2.0",
+                "id" to 1,
+                "method" to method,
+                "params" to params
+        )
+        return objectMapper.writeValueAsBytes(json)
+    }
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other !is JsonRpcRequest) return false
+
+        if (method != other.method) return false
+        if (params != other.params) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        var result = method.hashCode()
+        result = 31 * result + params.hashCode()
+        return result
+    }
+
+
+}

src/main/kotlin/io/emeraldpay/dshackle/upstream/rpcclient/JsonRpcResponse.kt

@@ -0,0 +1,136 @@
+/**
+ * Copyright (c) 2020 EmeraldPay, Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.emeraldpay.dshackle.upstream.rpcclient
+
+import com.fasterxml.jackson.core.JsonGenerator
+import com.fasterxml.jackson.databind.JsonSerializer
+import com.fasterxml.jackson.databind.SerializerProvider
+import io.infinitape.etherjar.rpc.RpcException
+import reactor.core.publisher.Mono
+
+class JsonRpcResponse(
+        private val result: ByteArray?,
+        val error: ResponseError?
+) {
+
+    companion object {
+        private val NULL_VALUE = "null".toByteArray()
+
+        @JvmStatic
+        fun ok(value: ByteArray): JsonRpcResponse {
+            return JsonRpcResponse(value, null)
+        }
+
+        @JvmStatic
+        fun ok(value: String): JsonRpcResponse {
+            return JsonRpcResponse(value.toByteArray(), null)
+        }
+
+        @JvmStatic
+        fun error(code: Int, msg: String): JsonRpcResponse {
+            return JsonRpcResponse(null, ResponseError(code, msg))
+        }
+    }
+
+    fun hasResult(): Boolean {
+        return result != null
+    }
+
+    fun hasError(): Boolean {
+        return error != null
+    }
+
+    fun isNull(): Boolean {
+        return result != null && NULL_VALUE.contentEquals(result)
+    }
+
+    fun getResult(): ByteArray {
+        return result ?: ByteArray(0)
+    }
+
+    fun getResultAsRawString(): String {
+        return String(getResult())
+    }
+
+    fun getResultAsProcessedString(): String {
+        val str = getResultAsRawString()
+        if (str.startsWith("\"") && str.endsWith("\"")) {
+            return str.substring(1, str.length - 1)
+        }
+        throw IllegalStateException("Not as JS string")
+    }
+
+    fun requireResult(): Mono<ByteArray> {
+        return if (error != null) {
+            Mono.error(error.asException())
+        } else {
+            Mono.just(getResult())
+        }
+    }
+
+    fun requireStringResult(): Mono<String> {
+        return if (error != null) {
+            Mono.error(error.asException())
+        } else {
+            Mono.just(getResultAsProcessedString())
+        }
+    }
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other !is JsonRpcResponse) return false
+
+        if (result != null) {
+            if (other.result == null) return false
+            if (!result.contentEquals(other.result)) return false
+        } else if (other.result != null) return false
+        if (error != other.error) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        var result1 = result?.contentHashCode() ?: 0
+        result1 = 31 * result1 + (error?.hashCode() ?: 0)
+        return result1
+    }
+
+    class ResponseError(val code: Int, val message: String) {
+        fun asException(): RpcException {
+            return RpcException(code, message)
+        }
+    }
+
+    class ResponseJsonSerializer : JsonSerializer<JsonRpcResponse>() {
+        override fun serialize(value: JsonRpcResponse, gen: JsonGenerator, serializers: SerializerProvider) {
+            gen.writeStartObject()
+            gen.writeStringField("jsonrpc", "2.0")
+            gen.writeNumberField("id", 0)
+            if (value.error != null) {
+                gen.writeObjectFieldStart("error")
+                gen.writeNumberField("code", value.error.code)
+                gen.writeStringField("message", value.error.message)
+                gen.writeEndObject()
+            } else {
+                if (value.result == null) {
+                    throw IllegalStateException("No result set")
+                }
+                gen.writeRawUTF8String(value.result, 0, value.result.size)
+            }
+            gen.writeEndObject()
+        }
+    }
+}

src/test/groovy/io/emeraldpay/dshackle/cache/BlocksRedisCacheSpec.groovy

@@ -63,6 +63,7 @@ class BlocksRedisCacheSpec extends Specification {
                 Instant.ofEpochSecond(10501050),
                 false,
                 "test".bytes,
+                null,
                 [TxId.from(hash2), TxId.from(hash1)]
         )
 

src/test/groovy/io/emeraldpay/dshackle/cache/TxRedisCacheSpec.groovy

@@ -63,7 +63,8 @@ class TxRedisCacheSpec extends Specification {
                 2000,
                 TxId.from(hash1),
                 BlockId.from(hash2),
-                "test".bytes
+                "test".bytes,
+                null
         )
         when:
         def enc = cache.toProto(cont)

src/test/groovy/io/emeraldpay/dshackle/quorum/BroadcastQuorumSpec.groovy

@@ -20,16 +20,16 @@ import io.emeraldpay.dshackle.test.TestingCommons
 import io.emeraldpay.dshackle.upstream.Head
 import io.emeraldpay.dshackle.upstream.Upstream
 import io.emeraldpay.dshackle.quorum.BroadcastQuorum
+import io.infinitape.etherjar.rpc.RpcException
 import spock.lang.Specification
 
 class BroadcastQuorumSpec extends Specification {
 
-    def rpcConverted = TestingCommons.rpcConverter()
     def objectMapper = TestingCommons.objectMapper()
 
     def "Resolved with first after 3 tries"() {
         setup:
-        def q = Spy(new BroadcastQuorum(rpcConverted, 3))
+        def q = Spy(new BroadcastQuorum(objectMapper, 3))
         def upstream1 = Stub(Upstream)
         def upstream2 = Stub(Upstream)
         def upstream3 = Stub(Upstream)
@@ -40,28 +40,28 @@ class BroadcastQuorumSpec extends Specification {
         !q.isResolved()
 
         when:
-        q.record(objectMapper.writeValueAsBytes([result: "0xeaa972c0d8d1ecd3e34fbbef6d34e06670e745c788bdba31c4234a1762f0378c"]), upstream1)
+        q.record('"0xeaa972c0d8d1ecd3e34fbbef6d34e06670e745c788bdba31c4234a1762f0378c"'.bytes, upstream1)
         then:
         !q.isResolved()
         1 * q.recordValue(_, "0xeaa972c0d8d1ecd3e34fbbef6d34e06670e745c788bdba31c4234a1762f0378c", _)
 
         when:
-        q.record(objectMapper.writeValueAsBytes([result: "0xeaa972c0d8d1ecd3e34fbbef6d34e06670e745c788bdba31c4234a1762f0378c"]), upstream2)
+        q.record('"0xeaa972c0d8d1ecd3e34fbbef6d34e06670e745c788bdba31c4234a1762f0378c"'.bytes, upstream2)
         then:
         !q.isResolved()
         1 * q.recordValue(_, "0xeaa972c0d8d1ecd3e34fbbef6d34e06670e745c788bdba31c4234a1762f0378c", _)
 
         when:
-        q.record(objectMapper.writeValueAsBytes([error: [message: "Nonce too low"]]), upstream3)
+        q.record(new RpcException(1, "Nonce too low"), upstream3)
         then:
         1 * q.recordError(_, _, _)
         q.isResolved()
-        objectMapper.readValue(q.result, Map) == [result: "0xeaa972c0d8d1ecd3e34fbbef6d34e06670e745c788bdba31c4234a1762f0378c"]
+        objectMapper.readValue(q.result, Object) == "0xeaa972c0d8d1ecd3e34fbbef6d34e06670e745c788bdba31c4234a1762f0378c"
     }
 
     def "Remembers first response"() {
         setup:
-        def q = Spy(new BroadcastQuorum(rpcConverted, 3))
+        def q = Spy(new BroadcastQuorum(objectMapper, 3))
         def upstream1 = Stub(Upstream)
         def upstream2 = Stub(Upstream)
         def upstream3 = Stub(Upstream)
@@ -72,22 +72,22 @@ class BroadcastQuorumSpec extends Specification {
         !q.isResolved()
 
         when:
-        q.record(objectMapper.writeValueAsBytes([error: [message: "Internal error"]]), upstream1)
+        q.record(new RpcException(1, "Internal error"), upstream1)
         then:
         !q.isResolved()
         1 * q.recordError(_, _, _)
 
         when:
-        q.record(objectMapper.writeValueAsBytes([result: "0xeaa972c0d8d1ecd3e34fbbef6d34e06670e745c788bdba31c4234a1762f0378c"]), upstream2)
+        q.record('"0xeaa972c0d8d1ecd3e34fbbef6d34e06670e745c788bdba31c4234a1762f0378c"'.bytes, upstream2)
         then:
         !q.isResolved()
         1 * q.recordValue(_, "0xeaa972c0d8d1ecd3e34fbbef6d34e06670e745c788bdba31c4234a1762f0378c", _)
 
         when:
-        q.record(objectMapper.writeValueAsBytes([error: [message: "Nonce too low"]]), upstream3)
+        q.record(new RpcException(1, "Nonce too low"), upstream3)
         then:
         1 * q.recordError(_, _, _)
         q.isResolved()
-        objectMapper.readValue(q.result, Map) == [result: "0xeaa972c0d8d1ecd3e34fbbef6d34e06670e745c788bdba31c4234a1762f0378c"]
+        objectMapper.readValue(q.result, Object) == "0xeaa972c0d8d1ecd3e34fbbef6d34e06670e745c788bdba31c4234a1762f0378c"
     }
 }

src/test/groovy/io/emeraldpay/dshackle/quorum/NonEmptyQuorumSpec.groovy

@@ -0,0 +1,133 @@
+/**
+ * Copyright (c) 2020 EmeraldPay, Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.emeraldpay.dshackle.quorum
+
+import io.emeraldpay.dshackle.test.TestingCommons
+import io.emeraldpay.dshackle.upstream.Head
+import io.emeraldpay.dshackle.upstream.Upstream
+import io.infinitape.etherjar.rpc.RpcException
+import spock.lang.Specification
+
+class NonEmptyQuorumSpec extends Specification {
+
+    def "Fail if too many errors"() {
+        setup:
+        def q = Spy(new NonEmptyQuorum(TestingCommons.objectMapper(), 3))
+        def upstream1 = Stub(Upstream)
+        def upstream2 = Stub(Upstream)
+        def upstream3 = Stub(Upstream)
+
+        when:
+        q.init(Stub(Head))
+        then:
+        !q.isResolved()
+        !q.isFailed()
+
+        when:
+        q.record(new RpcException(1, "Internal"), upstream1)
+        then:
+        !q.isResolved()
+        !q.isFailed()
+
+        when:
+        q.record(new RpcException(1, "Internal"), upstream2)
+        then:
+        !q.isResolved()
+        !q.isFailed()
+
+        when:
+        q.record(new RpcException(1, "Internal"), upstream3)
+        then:
+        q.isFailed()
+        !q.isResolved()
+    }
+
+    def "Fail first if not error"() {
+        setup:
+        def q = Spy(new NonEmptyQuorum(TestingCommons.objectMapper(), 3))
+        def upstream1 = Stub(Upstream)
+        def upstream2 = Stub(Upstream)
+        def upstream3 = Stub(Upstream)
+
+        when:
+        q.init(Stub(Head))
+        then:
+        !q.isResolved()
+        !q.isFailed()
+
+        when:
+        q.record('"0x11"'.bytes, upstream1)
+        then:
+        q.isResolved()
+        !q.isFailed()
+    }
+
+    def "Fail second if first is error"() {
+        setup:
+        def q = Spy(new NonEmptyQuorum(TestingCommons.objectMapper(), 3))
+        def upstream1 = Stub(Upstream)
+        def upstream2 = Stub(Upstream)
+        def upstream3 = Stub(Upstream)
+
+        when:
+        q.init(Stub(Head))
+        then:
+        !q.isResolved()
+        !q.isFailed()
+
+        when:
+        q.record(new RpcException(1, "Internal"), upstream1)
+        then:
+        !q.isFailed()
+        !q.isResolved()
+
+
+        when:
+        q.record('"0x11"'.bytes, upstream2)
+        then:
+        q.isResolved()
+        !q.isFailed()
+    }
+
+    def "Fail second if first is null"() {
+        setup:
+        def q = Spy(new NonEmptyQuorum(TestingCommons.objectMapper(), 3))
+        def upstream1 = Stub(Upstream)
+        def upstream2 = Stub(Upstream)
+        def upstream3 = Stub(Upstream)
+
+        when:
+        q.init(Stub(Head))
+        then:
+        !q.isResolved()
+        !q.isFailed()
+
+        when:
+        q.record('null'.bytes, upstream2)
+        then:
+        !q.isFailed()
+        !q.isResolved()
+
+
+        when:
+        q.record('"0x11"'.bytes, upstream2)
+        then:
+        q.isResolved()
+        !q.isFailed()
+    }
+
+
+}

src/test/groovy/io/emeraldpay/dshackle/quorum/NonceQuorumSpec.groovy

@@ -20,16 +20,16 @@ import io.emeraldpay.dshackle.test.TestingCommons
 import io.emeraldpay.dshackle.upstream.Head
 import io.emeraldpay.dshackle.upstream.Upstream
 import io.emeraldpay.dshackle.quorum.NonceQuorum
+import io.infinitape.etherjar.rpc.RpcException
 import spock.lang.Specification
 
 class NonceQuorumSpec extends Specification {
 
-    def rpcConverted = TestingCommons.rpcConverter()
     def objectMapper = TestingCommons.objectMapper()
 
     def "Gets max value"() {
         setup:
-        def q = Spy(new NonceQuorum(rpcConverted, 3))
+        def q = Spy(new NonceQuorum(objectMapper, 3))
         def upstream1 = Stub(Upstream)
         def upstream2 = Stub(Upstream)
         def upstream3 = Stub(Upstream)
@@ -40,28 +40,28 @@ class NonceQuorumSpec extends Specification {
         !q.isResolved()
 
         when:
-        q.record(objectMapper.writeValueAsBytes([result: "0x10"]), upstream1)
+        q.record('"0x10"'.bytes, upstream1)
         then:
         !q.isResolved()
         1 * q.recordValue(_, "0x10", _)
 
         when:
-        q.record(objectMapper.writeValueAsBytes([result: "0x11"]), upstream2)
+        q.record('"0x11"'.bytes, upstream2)
         then:
         !q.isResolved()
         1 * q.recordValue(_, "0x11", _)
 
         when:
-        q.record(objectMapper.writeValueAsBytes([result: "0x10"]), upstream3)
+        q.record('"0x10"'.bytes, upstream3)
         then:
         1 * q.recordValue(_, "0x10", _)
         q.isResolved()
-        objectMapper.readValue(q.result, Map) == [result: "0x11"]
+        objectMapper.readValue(q.result, Object) == "0x11"
     }
 
     def "Ignores errors"() {
         setup:
-        def q = Spy(new NonceQuorum(rpcConverted, 3))
+        def q = Spy(new NonceQuorum(objectMapper, 3))
         def upstream1 = Stub(Upstream)
         def upstream2 = Stub(Upstream)
         def upstream3 = Stub(Upstream)
@@ -72,28 +72,60 @@ class NonceQuorumSpec extends Specification {
         !q.isResolved()
 
         when:
-        q.record(objectMapper.writeValueAsBytes([error: [error: "Internal"]]), upstream1)
+        q.record(new RpcException(1, "Internal"), upstream1)
         then:
         !q.isResolved()
         1 * q.recordError(_, _, _)
 
         when:
-        q.record(objectMapper.writeValueAsBytes([result: "0x11"]), upstream2)
+        q.record('"0x11"'.bytes, upstream2)
         then:
         !q.isResolved()
         1 * q.recordValue(_, "0x11", _)
 
         when:
-        q.record(objectMapper.writeValueAsBytes([result: "0x10"]), upstream3)
+        q.record('"0x10"'.bytes, upstream3)
         then:
         1 * q.recordValue(_, "0x10", _)
         !q.isResolved()
 
         when:
-        q.record(objectMapper.writeValueAsBytes([result: "0x11"]), upstream1)
+        q.record('"0x11"'.bytes, upstream1)
         then:
         1 * q.recordValue(_, "0x11", _)
         q.isResolved()
-        objectMapper.readValue(q.result, Map) == [result: "0x11"]
+        objectMapper.readValue(q.result, Object) == "0x11"
+    }
+
+    def "Fail if too many errors"() {
+        setup:
+        def q = Spy(new NonceQuorum(objectMapper, 3))
+        def upstream1 = Stub(Upstream)
+        def upstream2 = Stub(Upstream)
+        def upstream3 = Stub(Upstream)
+
+        when:
+        q.init(Stub(Head))
+        then:
+        !q.isResolved()
+        !q.isFailed()
+
+        when:
+        q.record(new RpcException(1, "Internal"), upstream1)
+        then:
+        !q.isResolved()
+        !q.isFailed()
+
+        when:
+        q.record(new RpcException(1, "Internal"), upstream2)
+        then:
+        !q.isResolved()
+        !q.isFailed()
+
+        when:
+        q.record(new RpcException(1, "Internal"), upstream3)
+        then:
+        q.isFailed()
+        !q.isResolved()
     }
 }

src/test/groovy/io/emeraldpay/dshackle/quorum/QuorumRpcReaderSpec.groovy

@@ -0,0 +1,206 @@
+/**
+ * Copyright (c) 2020 EmeraldPay, Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.emeraldpay.dshackle.quorum
+
+import io.emeraldpay.dshackle.reader.Reader
+import io.emeraldpay.dshackle.test.TestingCommons
+import io.emeraldpay.dshackle.upstream.FilteredApis
+import io.emeraldpay.dshackle.upstream.Selector
+import io.emeraldpay.dshackle.upstream.Upstream
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
+import reactor.core.publisher.Mono
+import reactor.test.StepVerifier
+import spock.lang.Specification
+
+import java.time.Duration
+
+class QuorumRpcReaderSpec extends Specification {
+
+    def "always-quorum - get the result if ok"() {
+        setup:
+        def up = Mock(Upstream) {
+            _ * isAvailable() >> true
+            1 * getApi() >> Mock(Reader) {
+                1 * read(new JsonRpcRequest("eth_test", [])) >> Mono.just(JsonRpcResponse.ok("1"))
+            }
+        }
+        def apis = new FilteredApis(
+                [up], Selector.empty
+        )
+        def reader = new QuorumRpcReader(apis, new AlwaysQuorum())
+
+        when:
+        def act = reader.read(new JsonRpcRequest("eth_test", []))
+                .map {
+                    new String(it.value)
+                }
+
+        then:
+        StepVerifier.create(act)
+                .expectNext("1")
+                .expectComplete()
+                .verify(Duration.ofSeconds(1))
+    }
+
+    def "always-quorum - retry upstream error"() {
+        setup:
+        def up = Mock(Upstream) {
+            _ * isAvailable() >> true
+            _ * getApi() >> Mock(Reader) {
+                2 * read(new JsonRpcRequest("eth_test", [])) >>> [
+                        Mono.just(JsonRpcResponse.error(1, "test")),
+                        Mono.just(JsonRpcResponse.ok("1"))
+                ]
+            }
+        }
+        def apis = new FilteredApis(
+                [up], Selector.empty
+        )
+        def reader = new QuorumRpcReader(apis, new AlwaysQuorum())
+
+        when:
+        def act = reader.read(new JsonRpcRequest("eth_test", []))
+                .map {
+                    new String(it.value)
+                }
+
+        then:
+        StepVerifier.create(act)
+                .expectNext("1")
+                .expectComplete()
+                .verify(Duration.ofSeconds(1))
+    }
+
+    def "non-empty-quorum - get the second result if first is null"() {
+        setup:
+        def up = Mock(Upstream) {
+            _ * isAvailable() >> true
+            _ * getApi() >> Mock(Reader) {
+                2 * read(new JsonRpcRequest("eth_test", [])) >>> [
+                        Mono.just(JsonRpcResponse.ok("null")),
+                        Mono.just(JsonRpcResponse.ok("1"))
+                ]
+            }
+        }
+        def apis = new FilteredApis(
+                [up], Selector.empty
+        )
+        def reader = new QuorumRpcReader(apis, new NonEmptyQuorum(TestingCommons.objectMapper(), 3))
+
+        when:
+        def act = reader.read(new JsonRpcRequest("eth_test", []))
+                .map {
+                    new String(it.value)
+                }
+
+        then:
+        StepVerifier.create(act)
+                .expectNext("1")
+                .expectComplete()
+                .verify(Duration.ofSeconds(1))
+    }
+
+
+    def "non-empty-quorum - get the second result if first is error"() {
+        setup:
+        def up = Mock(Upstream) {
+            _ * isAvailable() >> true
+            _ * getApi() >> Mock(Reader) {
+                2 * read(new JsonRpcRequest("eth_test", [])) >>> [
+                        Mono.just(JsonRpcResponse.error(1, "test")),
+                        Mono.just(JsonRpcResponse.ok("1"))
+                ]
+            }
+        }
+        def apis = new FilteredApis(
+                [up], Selector.empty
+        )
+        def reader = new QuorumRpcReader(apis, new NonEmptyQuorum(TestingCommons.objectMapper(), 3))
+
+        when:
+        def act = reader.read(new JsonRpcRequest("eth_test", []))
+                .map {
+                    new String(it.value)
+                }
+
+        then:
+        StepVerifier.create(act)
+                .expectNext("1")
+                .expectComplete()
+                .verify(Duration.ofSeconds(1))
+    }
+
+    def "non-empty-quorum - get the third result if first two are not ok"() {
+        setup:
+        def up = Mock(Upstream) {
+            _ * isAvailable() >> true
+            _ * getApi() >> Mock(Reader) {
+                3 * read(new JsonRpcRequest("eth_test", [])) >>> [
+                        Mono.just(JsonRpcResponse.ok("null")),
+                        Mono.just(JsonRpcResponse.error(1, "test")),
+                        Mono.just(JsonRpcResponse.ok("1"))
+                ]
+            }
+        }
+        def apis = new FilteredApis(
+                [up], Selector.empty
+        )
+        def reader = new QuorumRpcReader(apis, new NonEmptyQuorum(TestingCommons.objectMapper(), 3))
+
+        when:
+        def act = reader.read(new JsonRpcRequest("eth_test", []))
+                .map {
+                    new String(it.value)
+                }
+
+        then:
+        StepVerifier.create(act)
+                .expectNext("1")
+                .expectComplete()
+                .verify(Duration.ofSeconds(1))
+    }
+
+    def "non-empty-quorum - no result if all failed"() {
+        setup:
+        def up = Mock(Upstream) {
+            _ * isAvailable() >> true
+            _ * getApi() >> Mock(Reader) {
+                3 * read(new JsonRpcRequest("eth_test", [])) >>> [
+                        Mono.just(JsonRpcResponse.ok("null")),
+                        Mono.just(JsonRpcResponse.error(1, "test")),
+                        Mono.just(JsonRpcResponse.ok("null"))
+                ]
+            }
+        }
+        def apis = new FilteredApis(
+                [up], Selector.empty
+        )
+        def reader = new QuorumRpcReader(apis, new NonEmptyQuorum(TestingCommons.objectMapper(), 3))
+
+        when:
+        def act = reader.read(new JsonRpcRequest("eth_test", []))
+                .map {
+                    new String(it.value)
+                }
+
+        then:
+        StepVerifier.create(act)
+                .expectComplete()
+                .verify(Duration.ofSeconds(1))
+    }
+
+}

src/test/groovy/io/emeraldpay/dshackle/quorum/ValueAwareQuorumSpec.groovy

@@ -0,0 +1,98 @@
+/**
+ * Copyright (c) 2020 EmeraldPay, Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.emeraldpay.dshackle.quorum
+
+import io.emeraldpay.dshackle.test.TestingCommons
+import io.emeraldpay.dshackle.upstream.Head
+import io.emeraldpay.dshackle.upstream.Upstream
+import org.jetbrains.annotations.NotNull
+import org.jetbrains.annotations.Nullable
+import spock.lang.Specification
+
+class ValueAwareQuorumSpec extends Specification {
+
+    def "Extract null"() {
+        setup:
+        def quorum = new ValueAwareQuorumImpl()
+        when:
+        def act = quorum.extractValue("null".bytes, Object)
+        then:
+        act == null
+    }
+
+    def "Extract string"() {
+        setup:
+        def quorum = new ValueAwareQuorumImpl()
+        when:
+        def act = quorum.extractValue("\"foo\"".bytes, Object)
+        then:
+        act == "foo"
+    }
+
+    def "Extract number"() {
+        setup:
+        def quorum = new ValueAwareQuorumImpl()
+        when:
+        def act = quorum.extractValue("100".bytes, Object)
+        then:
+        act == 100
+    }
+
+    def "Extract map"() {
+        setup:
+        def quorum = new ValueAwareQuorumImpl()
+        when:
+        def act = quorum.extractValue("{\"foo\": 1}".bytes, Object)
+        then:
+        act == [foo: 1]
+    }
+
+    class ValueAwareQuorumImpl extends ValueAwareQuorum {
+        ValueAwareQuorumImpl() {
+            super(TestingCommons.objectMapper(), Object)
+        }
+
+        @Override
+        void recordValue(@NotNull byte[] response, @Nullable Object responseValue, @NotNull Upstream upstream) {
+
+        }
+
+        @Override
+        void recordError(@Nullable byte[] response, @Nullable String errorMessage, @NotNull Upstream upstream) {
+
+        }
+
+        @Override
+        void init(@NotNull Head head) {
+
+        }
+
+        @Override
+        boolean isResolved() {
+            return false
+        }
+
+        @Override
+        byte[] getResult() {
+            return new byte[0]
+        }
+
+        @Override
+        boolean isFailed() {
+            return false
+        }
+    }
+}

src/test/groovy/io/emeraldpay/dshackle/rpc/NativeCallSpec.groovy

@@ -19,21 +19,25 @@ package io.emeraldpay.dshackle.rpc
 
 import io.emeraldpay.api.proto.BlockchainOuterClass
 import io.emeraldpay.dshackle.quorum.BroadcastQuorum
+import io.emeraldpay.dshackle.quorum.QuorumReaderFactory
+import io.emeraldpay.dshackle.quorum.QuorumRpcReader
+import io.emeraldpay.dshackle.reader.Reader
 import io.emeraldpay.dshackle.test.TestingCommons
 import io.emeraldpay.dshackle.quorum.AlwaysQuorum
-import io.emeraldpay.dshackle.upstream.CachingEthereumApi
-import io.emeraldpay.dshackle.upstream.ethereum.DirectEthereumApi
 import io.emeraldpay.dshackle.quorum.NonEmptyQuorum
+import io.emeraldpay.dshackle.upstream.Multistream
 import io.emeraldpay.dshackle.upstream.Selector
-import io.emeraldpay.dshackle.upstream.Upstream
-import io.emeraldpay.dshackle.upstream.Upstreams
+import io.emeraldpay.dshackle.upstream.MultistreamHolder
+import io.emeraldpay.dshackle.upstream.ethereum.NativeCallRouter
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import io.emeraldpay.grpc.Chain
 import io.infinitape.etherjar.rpc.ReactorRpcClient
 import io.infinitape.etherjar.rpc.RpcException
 import io.infinitape.etherjar.rpc.RpcResponseError
-import io.infinitape.etherjar.rpc.RpcResponseException
 import reactor.core.publisher.Mono
 import reactor.test.StepVerifier
+import spock.lang.Ignore
 import spock.lang.Specification
 
 import java.time.Duration
@@ -43,140 +47,99 @@ class NativeCallSpec extends Specification {
 
     def objectMapper = TestingCommons.objectMapper()
 
+    def "Tries router first"() {
+        def routedApi = Mock(Reader) {
+            1 * read(new JsonRpcRequest("eth_test", [])) >> Mono.just(new JsonRpcResponse("1".bytes, null))
+        }
+        def upstream = Mock(Multistream) {
+            1 * getRoutedApi(_) >> Mono.just(routedApi)
+        }
+        def upstreams = Stub(MultistreamHolder)
+
+        def nativeCall = new NativeCall(upstreams, TestingCommons.objectMapper())
+        def ctx = new NativeCall.CallContext<NativeCall.ParsedCallDetails>(
+                1, upstream, Selector.empty, new AlwaysQuorum(),
+                new NativeCall.ParsedCallDetails("eth_test", [])
+        )
+
+        when:
+        def act = nativeCall.fetch(ctx).block(Duration.ofSeconds(1))
+        then:
+        act.payload == "1".bytes
+    }
+
+    def "Return error if router denied the requests"() {
+        def routedApi = Mock(Reader) {
+            1 * read(new JsonRpcRequest("eth_test", [])) >> Mono.error(new RpcException(RpcResponseError.CODE_METHOD_NOT_EXIST, "Test message"))
+        }
+        def upstream = Mock(Multistream) {
+            1 * getRoutedApi(_) >> Mono.just(routedApi)
+        }
+        def upstreams = Stub(MultistreamHolder)
+
+        def nativeCall = new NativeCall(upstreams, TestingCommons.objectMapper())
+        def ctx = new NativeCall.CallContext<NativeCall.ParsedCallDetails>(
+                15, upstream, Selector.empty, new AlwaysQuorum(),
+                new NativeCall.ParsedCallDetails("eth_test", [])
+        )
+
+        when:
+        def act = nativeCall.fetch(ctx) //.block(Duration.ofSeconds(1))
+        then:
+        StepVerifier.create(act)
+                .expectErrorMatches { t ->
+                    t instanceof NativeCall.CallFailure &&
+                            t.id == 15 &&
+                            t.reason instanceof RpcException &&
+                            t.reason.rpcMessage == "Test message"
+                }
+                .verify(Duration.ofSeconds(1))
+    }
+
     def "Quorum is applied"() {
         setup:
-        def quorum = Spy(new AlwaysQuorum())
-        def upstreams = Stub(Upstreams)
-        ReactorRpcClient rpcClient = Stub(ReactorRpcClient)
-        def apiMock = TestingCommons.api(rpcClient)
-        apiMock.upstream = Stub(Upstream)
+        def quorum = new AlwaysQuorum()
 
-        apiMock.answer("eth_test", [], "foo")
-
-        def nativeCall = new NativeCall(upstreams, TestingCommons.objectMapper())
-        def call = new NativeCall.CallContext(1, TestingCommons.aggregatedUpstream(apiMock),
-                Selector.empty, quorum,
+        def nativeCall = new NativeCall(Stub(MultistreamHolder), TestingCommons.objectMapper())
+        nativeCall.quorumReaderFactory = Mock(QuorumReaderFactory) {
+            1 * create(_, _) >> Mock(Reader) {
+                1 * read(_) >> Mono.just(new QuorumRpcReader.Result("\"foo\"".bytes, 1))
+            }
+        }
+        def call = new NativeCall.CallContext(1, TestingCommons.aggregatedUpstream(TestingCommons.api()), Selector.empty, quorum,
                 new NativeCall.ParsedCallDetails("eth_test", []))
 
         when:
-        def resp = nativeCall.executeOnRemote(call).block(Duration.ofSeconds(2))
-        def act = objectMapper.readValue(resp.payload, Map)
+        def resp = nativeCall.executeOnRemote(call).block(Duration.ofSeconds(1))
+        def act = objectMapper.readValue(resp.payload, Object)
         then:
-        act == [jsonrpc:"2.0", id:1, result: "foo"]
-        1 * quorum.record(_, _)
-        1 * quorum.getResult()
-    }
-
-    def "Quorum may return not first received value"() {
-        setup:
-        def quorum = Spy(new NonEmptyQuorum(TestingCommons.rpcConverter(), 3))
-
-        def upstreams = Stub(Upstreams)
-        ReactorRpcClient rpcClient = Stub(ReactorRpcClient)
-        def apiMock = TestingCommons.api(rpcClient)
-        apiMock.upstream = Stub(Upstream)
-
-        apiMock.answerOnce("eth_test", [], null)
-        apiMock.answerOnce("eth_test", [], "bar")
-        apiMock.answerOnce("eth_test", [], null)
-
-        def nativeCall = new NativeCall(upstreams, TestingCommons.objectMapper())
-        def call = new NativeCall.CallContext(1, TestingCommons.aggregatedUpstream(apiMock),
-                Selector.empty, quorum,
-                new NativeCall.ParsedCallDetails("eth_test", []))
-
-
-        when:
-        def resp = nativeCall.executeOnRemote(call).block(Duration.ofSeconds(2))
-        def act = objectMapper.readValue(resp.payload, Map)
-        then:
-        act == [jsonrpc:"2.0", id:1, result: "bar"]
-        2 * quorum.record(_, _)
-        1 * quorum.getResult()
-    }
-
-    def "Have pause between repeats"() {
-        setup:
-        def quorum = Spy(new NonEmptyQuorum(TestingCommons.rpcConverter(), 3))
-
-        def upstreams = Stub(Upstreams)
-        ReactorRpcClient rpcClient = Stub(ReactorRpcClient)
-        def apiMock = TestingCommons.api(rpcClient)
-        apiMock.upstream = Stub(Upstream)
-
-        apiMock.answerOnce("eth_test", [], null)
-        apiMock.answerOnce("eth_test", [], "bar")
-
-        def nativeCall = new NativeCall(upstreams, TestingCommons.objectMapper())
-        def call = new NativeCall.CallContext(1, TestingCommons.aggregatedUpstream(apiMock),
-                Selector.empty, quorum,
-                new NativeCall.ParsedCallDetails("eth_test", []))
-
-
-        when:
-        def t1 = System.currentTimeMillis()
-        def resp = nativeCall.executeOnRemote(call).block(Duration.ofSeconds(2))
-        def delta = System.currentTimeMillis() - t1
-        then:
-        delta > 95 // should be 100, but sometimes gives less ???
-        new String(resp.payload) == '{"jsonrpc":"2.0","id":1,"result":"bar"}'
-    }
-
-    def "One call has no pause"() {
-        setup:
-        def quorum = Spy(new NonEmptyQuorum(TestingCommons.rpcConverter(), 3))
-
-        def upstreams = Stub(Upstreams)
-        ReactorRpcClient rpcClient = Stub(ReactorRpcClient)
-        def apiMock = TestingCommons.api(rpcClient)
-        apiMock.upstream = Stub(Upstream)
-
-        apiMock.answerOnce("eth_test", [], "bar")
-
-        def nativeCall = new NativeCall(upstreams, TestingCommons.objectMapper())
-        def call = new NativeCall.CallContext(1, TestingCommons.aggregatedUpstream(apiMock),
-                Selector.empty, quorum,
-                new NativeCall.ParsedCallDetails("eth_test", []))
-
-
-        when:
-        def t1 = System.currentTimeMillis()
-        nativeCall.executeOnRemote(call).block(Duration.ofSeconds(2))
-        def delta = System.currentTimeMillis() - t1
-        then:
-        delta < 50
+        act == "foo"
     }
 
     def "Returns error if no quorum"() {
         setup:
-        def quorum = Spy(new NonEmptyQuorum(TestingCommons.rpcConverter(), 3))
+        def quorum = new AlwaysQuorum()
 
-        def upstreams = Stub(Upstreams)
-        ReactorRpcClient rpcClient = Stub(ReactorRpcClient)
-        def apiMock = TestingCommons.api(rpcClient)
-        apiMock.upstream = Stub(Upstream)
-
-        apiMock.answer("eth_test", [], null, 3)
-        apiMock.answerOnce("eth_test", [], "foo")
-
-        def nativeCall = new NativeCall(upstreams, TestingCommons.objectMapper())
-        def call = new NativeCall.CallContext(1, TestingCommons.aggregatedUpstream(apiMock), Selector.empty, quorum,
+        def nativeCall = new NativeCall(Stub(MultistreamHolder), TestingCommons.objectMapper())
+        nativeCall.quorumReaderFactory = Mock(QuorumReaderFactory) {
+            1 * create(_, _) >> Mock(Reader) {
+                1 * read(_) >> Mono.empty()
+            }
+        }
+        def call = new NativeCall.CallContext(1, TestingCommons.aggregatedUpstream(TestingCommons.api()), Selector.empty, quorum,
                 new NativeCall.ParsedCallDetails("eth_test", []))
 
-        3 * quorum.record(_, _)
-        1 * quorum.getResult()
-
         when:
         def resp = nativeCall.executeOnRemote(call)
         then:
         StepVerifier.create(resp)
-            .expectErrorMatches({t -> t instanceof NativeCall.CallFailure && t.id == 1})
-            .verify(Duration.ofSeconds(1))
+                .expectErrorMatches({ t -> t instanceof NativeCall.CallFailure && t.id == 1 })
+                .verify(Duration.ofSeconds(1))
     }
 
     def "Packs call exception into response with id"() {
         setup:
-        def upstreams = Stub(Upstreams)
+        def upstreams = Stub(MultistreamHolder)
         def nativeCall = new NativeCall(upstreams, TestingCommons.objectMapper())
         when:
         def resp = nativeCall.processException(new NativeCall.CallFailure(5, new IllegalArgumentException("test test")))
@@ -193,7 +156,7 @@ class NativeCallSpec extends Specification {
 
     def "Packs unknown exception into response"() {
         setup:
-        def upstreams = Stub(Upstreams)
+        def upstreams = Stub(MultistreamHolder)
         def nativeCall = new NativeCall(upstreams, TestingCommons.objectMapper())
         when:
         def resp = nativeCall.processException(new IllegalArgumentException("test test"))
@@ -209,13 +172,13 @@ class NativeCallSpec extends Specification {
 
     def "Builds normal response"() {
         setup:
-        def upstreams = Stub(Upstreams)
+        def upstreams = Stub(MultistreamHolder)
         def nativeCall = new NativeCall(upstreams, TestingCommons.objectMapper())
         def json = [jsonrpc:"2.0", id:1, result: "foo"]
 
         when:
         def resp = nativeCall.buildResponse(
-                new NativeCall.CallContext<byte[]>(1561, TestingCommons.aggregatedUpstream(Stub(DirectEthereumApi)), Selector.empty, new AlwaysQuorum(), objectMapper.writeValueAsBytes(json))
+                new NativeCall.CallContext<byte[]>(1561, TestingCommons.aggregatedUpstream(TestingCommons.api()), Selector.empty, new AlwaysQuorum(), objectMapper.writeValueAsBytes(json))
         )
         then:
         resp.id == 1561
@@ -225,7 +188,7 @@ class NativeCallSpec extends Specification {
 
     def "Returns error for invalid chain"() {
         setup:
-        def upstreams = Stub(Upstreams)
+        def upstreams = Stub(MultistreamHolder)
         def nativeCall = new NativeCall(upstreams, TestingCommons.objectMapper())
 
         def req = BlockchainOuterClass.NativeCallRequest.newBuilder()
@@ -248,7 +211,7 @@ class NativeCallSpec extends Specification {
 
     def "Returns error for unsupported chain"() {
         setup:
-        def upstreams =  Mock(Upstreams)
+        def upstreams = Mock(MultistreamHolder)
         def nativeCall = new NativeCall(upstreams, TestingCommons.objectMapper())
 
         def req = BlockchainOuterClass.NativeCallRequest.newBuilder()
@@ -270,14 +233,14 @@ class NativeCallSpec extends Specification {
                 .verify(Duration.ofSeconds(1))
     }
 
+    @Ignore
+    //TODO
     def "Calls cache before remote"() {
         setup:
-        def upstreams = Stub(Upstreams)
+        def upstreams = Stub(MultistreamHolder)
         def nativeCall = new NativeCall(upstreams, TestingCommons.objectMapper())
-        def api = Mock(DirectEthereumApi)
+        def api = TestingCommons.api()
         def upstream = TestingCommons.aggregatedUpstream(api)
-        def cacheMock = Mock(CachingEthereumApi)
-        upstream.cache = cacheMock
 
         def ctx = new NativeCall.CallContext<NativeCall.ParsedCallDetails>(10,
                 upstream,
@@ -289,13 +252,13 @@ class NativeCallSpec extends Specification {
         1 * cacheMock.execute(10, "eth_test", []) >> Mono.empty()
     }
 
+    @Ignore
+    //TODO
     def "Uses cached value"() {
         setup:
-        def upstreams = Stub(Upstreams)
+        def upstreams = Stub(MultistreamHolder)
         def nativeCall = new NativeCall(upstreams, TestingCommons.objectMapper())
-        def upstream = TestingCommons.aggregatedUpstream(Stub(DirectEthereumApi))
-        def cacheMock = Mock(CachingEthereumApi)
-        upstream.cache = cacheMock
+        def upstream = TestingCommons.aggregatedUpstream(TestingCommons.api())
 
         def ctx = new NativeCall.CallContext<NativeCall.ParsedCallDetails>(10,
                 upstream,
@@ -307,63 +270,4 @@ class NativeCallSpec extends Specification {
         1 * cacheMock.execute(10, "eth_test", []) >> Mono.just('{"result": "foo"}'.bytes)
         new String(act.block().payload) == '{"result": "foo"}'
     }
-
-    def "Retries on error"() {
-        setup:
-        def quorum = Spy(new AlwaysQuorum())
-
-        def upstreams = Stub(Upstreams)
-        ReactorRpcClient rpcClient = Stub(ReactorRpcClient)
-        def apiMock = TestingCommons.api(rpcClient)
-        apiMock.upstream = Stub(Upstream)
-
-        apiMock.answer("eth_test", [], null, 1, new TimeoutException("test 1"))
-        apiMock.answer("eth_test", [], null, 1, new TimeoutException("test 2"))
-        apiMock.answerOnce("eth_test", [], "bar")
-
-        def nativeCall = new NativeCall(upstreams, TestingCommons.objectMapper())
-        def call = new NativeCall.CallContext(1, TestingCommons.aggregatedUpstream(apiMock),
-                Selector.empty, quorum,
-                new NativeCall.ParsedCallDetails("eth_test", []))
-
-
-        when:
-        def resp = nativeCall.executeOnRemote(call).block(Duration.ofSeconds(2))
-        def act = objectMapper.readValue(resp.payload, Map)
-        then:
-        act == [jsonrpc:"2.0", id:1, result: "bar"]
-        1 * quorum.record(_, _)
-        1 * quorum.getResult()
-    }
-
-    def "Send raw retries 3 times"() {
-        setup:
-        def quorum = Spy(new BroadcastQuorum(TestingCommons.rpcConverter(), 3))
-
-        def upstreams = Stub(Upstreams)
-        ReactorRpcClient rpcClient = Stub(ReactorRpcClient)
-        def apiMock = TestingCommons.api(rpcClient)
-        apiMock.upstream = Stub(Upstream)
-
-        apiMock.answer("eth_sendRawTransaction", ["0x1234"],
-                "0x4b66b555df9faed6f0711f2104d183736c8e2dc7434626dd2622e243f041d41b", 1)
-        apiMock.answer("eth_sendRawTransaction", ["0x1234"], null, 10,
-                new RpcException(RpcResponseError.CODE_INVALID_REQUEST, "Transaction with the same hash was already imported"))
-//        apiMock.answer("eth_sendRawTransaction", ["0x1234"],
-//                new RpcResponseError(RpcResponseError.CODE_INVALID_REQUEST, "Transaction with the same hash was already imported"), 10)
-
-        def nativeCall = new NativeCall(upstreams, TestingCommons.objectMapper())
-        def call = new NativeCall.CallContext(1, TestingCommons.aggregatedUpstream(apiMock),
-                Selector.empty, quorum,
-                new NativeCall.ParsedCallDetails("eth_sendRawTransaction", ["0x1234"]))
-
-
-        when:
-        def resp = nativeCall.executeOnRemote(call).block(Duration.ofSeconds(2))
-        def act = objectMapper.readValue(resp.payload, Map)
-        then:
-        act == [jsonrpc:"2.0", id:1, result: "0x4b66b555df9faed6f0711f2104d183736c8e2dc7434626dd2622e243f041d41b"]
-        1 * quorum.record(_ as byte[], _)
-        2 * quorum.record(_ as RpcException, _)
-    }
 }

src/test/groovy/io/emeraldpay/dshackle/rpc/StreamHeadSpec.groovy

@@ -23,13 +23,10 @@ import io.emeraldpay.api.proto.Common
 import io.emeraldpay.dshackle.data.BlockContainer
 import io.emeraldpay.dshackle.test.EthereumUpstreamMock
 import io.emeraldpay.dshackle.test.TestingCommons
-import io.emeraldpay.dshackle.test.UpstreamsMock
-import io.emeraldpay.dshackle.upstream.ethereum.DirectEthereumApi
-import io.emeraldpay.dshackle.upstream.Upstream
+import io.emeraldpay.dshackle.test.MultistreamHolderMock
 import io.emeraldpay.dshackle.upstream.ethereum.EthereumUpstream
 import io.emeraldpay.grpc.Chain
 import io.infinitape.etherjar.domain.BlockHash
-import io.infinitape.etherjar.domain.TransactionId
 import io.infinitape.etherjar.rpc.json.BlockJson
 import io.infinitape.etherjar.rpc.json.TransactionRefJson
 import reactor.core.publisher.Mono
@@ -45,7 +42,7 @@ class StreamHeadSpec extends Specification {
 
     def "Errors on unavailable chain"() {
         setup:
-        def upstreams = new UpstreamsMock(Chain.ETHEREUM, Stub(EthereumUpstream))
+        def upstreams = new MultistreamHolderMock(Chain.ETHEREUM, Stub(EthereumUpstream))
         def streamHead = new StreamHead(upstreams)
         when:
         def flux = streamHead.add(
@@ -80,8 +77,8 @@ class StreamHeadSpec extends Specification {
                 .build()
         }
 
-        def upstream = new EthereumUpstreamMock(Chain.ETHEREUM, Stub(DirectEthereumApi.class))
-        def upstreams = new UpstreamsMock(Chain.ETHEREUM, upstream)
+        def upstream = new EthereumUpstreamMock(Chain.ETHEREUM, TestingCommons.api())
+        def upstreams = new MultistreamHolderMock(Chain.ETHEREUM, upstream)
         def streamHead = new StreamHead(upstreams)
         when:
         def flux = streamHead.add(

src/test/groovy/io/emeraldpay/dshackle/rpc/TrackBitcoinAddressSpec.groovy

@@ -20,11 +20,11 @@ import io.emeraldpay.api.proto.Common
 import io.emeraldpay.dshackle.data.BlockContainer
 import io.emeraldpay.dshackle.data.BlockId
 import io.emeraldpay.dshackle.test.TestingCommons
-import io.emeraldpay.dshackle.upstream.AggregatedUpstream
+import io.emeraldpay.dshackle.test.MultistreamHolderMock
 import io.emeraldpay.dshackle.upstream.Head
-import io.emeraldpay.dshackle.upstream.Upstream
-import io.emeraldpay.dshackle.upstream.Upstreams
-import io.emeraldpay.dshackle.upstream.bitcoin.DirectBitcoinApi
+import io.emeraldpay.dshackle.upstream.MultistreamHolder
+import io.emeraldpay.dshackle.upstream.bitcoin.BitcoinMultistream
+import io.emeraldpay.dshackle.upstream.bitcoin.BitcoinReader
 import io.emeraldpay.grpc.Chain
 import reactor.core.publisher.Flux
 import reactor.core.publisher.Mono
@@ -43,7 +43,7 @@ class TrackBitcoinAddressSpec extends Specification {
         setup:
         def json = this.class.getClassLoader().getResourceAsStream("bitcoin/unspent-one-addr.json")
         def unspents = TestingCommons.objectMapper().readValue(json, List)
-        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(Upstreams))
+        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(MultistreamHolder))
         when:
         def total = track.getTotal(Chain.BITCOIN, ["1K7xkspJg7DDKNwzXgoRSDCUxiFsRegsSK"], unspents)
 
@@ -58,7 +58,7 @@ class TrackBitcoinAddressSpec extends Specification {
         setup:
         def json = this.class.getClassLoader().getResourceAsStream("bitcoin/unspent-two-addr.json")
         def unspents = TestingCommons.objectMapper().readValue(json, List)
-        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(Upstreams))
+        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(MultistreamHolder))
         when:
         def total = track.getTotal(Chain.BITCOIN, ["1K7xkspJg7DDKNwzXgoRSDCUxiFsRegsSK"], unspents)
 
@@ -73,7 +73,7 @@ class TrackBitcoinAddressSpec extends Specification {
         setup:
         def json = this.class.getClassLoader().getResourceAsStream("bitcoin/unspent-two-addr.json")
         def unspents = TestingCommons.objectMapper().readValue(json, List)
-        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(Upstreams))
+        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(MultistreamHolder))
         when:
         def total = track.getTotal(Chain.BITCOIN, ["1K7xkspJg7DDKNwzXgoRSDCUxiFsRegsSK", "35hK24tcLEWcgNA4JxpvbkNkoAcDGqQPsP"], unspents).sort { it.address.address }
 
@@ -93,7 +93,7 @@ class TrackBitcoinAddressSpec extends Specification {
 
     def "Zero for empty unspents"() {
         setup:
-        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(Upstreams))
+        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(MultistreamHolder))
         when:
         def total = track.getTotal(Chain.BITCOIN, ["1K7xkspJg7DDKNwzXgoRSDCUxiFsRegsSK"], [])
 
@@ -108,7 +108,7 @@ class TrackBitcoinAddressSpec extends Specification {
         setup:
         def json = this.class.getClassLoader().getResourceAsStream("bitcoin/unspent-two-addr.json")
         def unspents = TestingCommons.objectMapper().readValue(json, List)
-        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(Upstreams))
+        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(MultistreamHolder))
         when:
         def total = track.getTotal(Chain.BITCOIN, ["16rCmCmbuWDhPjWTrpQGaU3EPdZF7MTdUk", "1K7xkspJg7DDKNwzXgoRSDCUxiFsRegsSK"], unspents).sort { it.address.address }
 
@@ -126,7 +126,7 @@ class TrackBitcoinAddressSpec extends Specification {
 
     def "One address for single provided"() {
         setup:
-        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(Upstreams))
+        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(MultistreamHolder))
         def req = BlockchainOuterClass.BalanceRequest.newBuilder()
                 .setAddress(
                         Common.AnyAddress.newBuilder()
@@ -144,7 +144,7 @@ class TrackBitcoinAddressSpec extends Specification {
 
     def "Sorted addresses for multiple provided"() {
         setup:
-        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(Upstreams))
+        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(MultistreamHolder))
         def req = BlockchainOuterClass.BalanceRequest.newBuilder()
                 .setAddress(
                         Common.AnyAddress.newBuilder()
@@ -165,7 +165,7 @@ class TrackBitcoinAddressSpec extends Specification {
 
     def "Null for no address provided"() {
         setup:
-        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(Upstreams))
+        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(MultistreamHolder))
         def req = BlockchainOuterClass.BalanceRequest.newBuilder()
                 .build()
         when:
@@ -176,7 +176,7 @@ class TrackBitcoinAddressSpec extends Specification {
 
     def "Build proto for common balance"() {
         setup:
-        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(Upstreams))
+        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(MultistreamHolder))
         def balance = new TrackBitcoinAddress.AddressBalance(Chain.BITCOIN, "1K7xkspJg7DDKNwzXgoRSDCUxiFsRegsSK", BigInteger.valueOf(123456))
         when:
         def act = track.buildResponse(balance)
@@ -189,7 +189,7 @@ class TrackBitcoinAddressSpec extends Specification {
 
     def "Build proto for zero balance"() {
         setup:
-        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(Upstreams))
+        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(MultistreamHolder))
         def balance = new TrackBitcoinAddress.AddressBalance(Chain.BITCOIN, "1K7xkspJg7DDKNwzXgoRSDCUxiFsRegsSK", BigInteger.ZERO)
         when:
         def act = track.buildResponse(balance)
@@ -202,7 +202,7 @@ class TrackBitcoinAddressSpec extends Specification {
 
     def "Build proto for all bitcoins"() {
         setup:
-        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(Upstreams))
+        TrackBitcoinAddress track = new TrackBitcoinAddress(Stub(MultistreamHolder))
         def balance = new TrackBitcoinAddress.AddressBalance(Chain.BITCOIN, "1K7xkspJg7DDKNwzXgoRSDCUxiFsRegsSK", BigInteger.valueOf(21_000_000).multiply(BigInteger.TEN.pow(8)))
         when:
         def act = track.buildResponse(balance)
@@ -216,24 +216,24 @@ class TrackBitcoinAddressSpec extends Specification {
     def "Get update for a balance"() {
         setup:
 
-        DirectBitcoinApi api = Mock(DirectBitcoinApi) {
-            2 * executeAndResult(0, "listunspent", [], List) >>> [
-                    Mono.just([]), Mono.just([[address: "1K7xkspJg7DDKNwzXgoRSDCUxiFsRegsSK", amount: 0.0123]])
-            ]
-        }
         def blocks = TopicProcessor.create()
         Head head = Mock(Head) {
             1 * getFlux() >> Flux.from(blocks)
         }
-        Upstream upstream
-        upstream = Mock(AggregatedUpstream) {
-            _ * getApi(_) >> Mono.just(api)
+        def upstream = null
+        upstream = Mock(BitcoinMultistream) {
+            _ * getReader() >> Mock(BitcoinReader) {
+                2 * listUnspent() >>> [
+                        Mono.just([]),
+                        Mono.just([[address: "1K7xkspJg7DDKNwzXgoRSDCUxiFsRegsSK", amount: 0.0123]])
+                ]
+            }
             _ * getHead() >> head
-            _ * castApi(_) >> { return upstream }
-        }
-        Upstreams upstreams = Mock(Upstreams) {
-            _ * getUpstream(Chain.BITCOIN) >> upstream
+            _ * cast(_) >> {
+                upstream
+            }
         }
+        MultistreamHolder upstreams = new MultistreamHolderMock(Chain.BITCOIN, upstream)
         TrackBitcoinAddress track = new TrackBitcoinAddress(upstreams)
 
         when:
@@ -253,7 +253,7 @@ class TrackBitcoinAddressSpec extends Specification {
         StepVerifier.create(resp)
                 .expectNext("0")
                 .then {
-                    blocks.onNext(new BlockContainer(1L, BlockId.from(hash1), BigInteger.ONE, Instant.now(), false, null, []))
+                    blocks.onNext(new BlockContainer(1L, BlockId.from(hash1), BigInteger.ONE, Instant.now(), false, null, null, []))
                 }
                 .expectNext("1230000")
                 .then {

src/test/groovy/io/emeraldpay/dshackle/rpc/TrackBitcoinTxSpec.groovy

@@ -18,11 +18,9 @@ package io.emeraldpay.dshackle.rpc
 import io.emeraldpay.dshackle.data.BlockContainer
 import io.emeraldpay.dshackle.data.BlockId
 import io.emeraldpay.dshackle.upstream.Head
-import io.emeraldpay.dshackle.upstream.Upstream
-import io.emeraldpay.dshackle.upstream.Upstreams
+import io.emeraldpay.dshackle.upstream.MultistreamHolder
+import io.emeraldpay.dshackle.upstream.bitcoin.BitcoinMultistream
 import io.emeraldpay.dshackle.upstream.bitcoin.BitcoinReader
-import io.emeraldpay.dshackle.upstream.bitcoin.DirectBitcoinApi
-import io.emeraldpay.dshackle.upstream.bitcoin.BitcoinUpstream
 import io.emeraldpay.dshackle.upstream.bitcoin.CachingMempoolData
 import io.emeraldpay.grpc.Chain
 import reactor.core.publisher.Flux
@@ -37,7 +35,7 @@ class TrackBitcoinTxSpec extends Specification {
 
     def "loadMempool() returns not found when not found"() {
         setup:
-        TrackBitcoinTx track = new TrackBitcoinTx(Stub(Upstreams))
+        TrackBitcoinTx track = new TrackBitcoinTx(Stub(MultistreamHolder))
 
         CachingMempoolData mempoolAccess = Mock(CachingMempoolData) {
             1 * get() >> Mono.just([
@@ -45,8 +43,8 @@ class TrackBitcoinTxSpec extends Specification {
                     "d296c6d47335a7f283574b06f1d6303b30ac75631e081ab128346a549ad93350"
             ])
         }
-        BitcoinUpstream upstream = Mock(BitcoinUpstream) {
-            _ * getData() >> Mock(BitcoinReader) {
+        BitcoinMultistream upstream = Mock(BitcoinMultistream) {
+            _ * getReader() >> Mock(BitcoinReader) {
                 _ * getMempool() >> mempoolAccess
             }
         }
@@ -64,15 +62,15 @@ class TrackBitcoinTxSpec extends Specification {
 
     def "loadMempool() returns ok when found"() {
         setup:
-        TrackBitcoinTx track = new TrackBitcoinTx(Stub(Upstreams))
+        TrackBitcoinTx track = new TrackBitcoinTx(Stub(MultistreamHolder))
         CachingMempoolData mempoolAccess = Mock(CachingMempoolData) {
             1 * get() >> Mono.just([
                     "69cd44d7c641db82e69824523c7ac0c5c1e5628f025474529cf5ffe64527efc9",
                     "d296c6d47335a7f283574b06f1d6303b30ac75631e081ab128346a549ad93350"
             ])
         }
-        BitcoinUpstream upstream = Mock(BitcoinUpstream) {
-            _ * getData() >> Mock(BitcoinReader) {
+        BitcoinMultistream upstream = Mock(BitcoinMultistream) {
+            _ * getReader() >> Mock(BitcoinReader) {
                 _ * getMempool() >> mempoolAccess
             }
         }
@@ -90,15 +88,17 @@ class TrackBitcoinTxSpec extends Specification {
 
     def "loadExiting() returns not found if not mined"() {
         setup:
-        TrackBitcoinTx track = new TrackBitcoinTx(Stub(Upstreams))
+        TrackBitcoinTx track = new TrackBitcoinTx(Stub(MultistreamHolder))
         def txid = "69cd44d7c641db82e69824523c7ac0c5c1e5628f025474529cf5ffe64527efc9"
-        DirectBitcoinApi api = Mock(DirectBitcoinApi) {
-            1 * getTx(txid) >> Mono.just([
-                    txid: txid
-            ])
+        BitcoinMultistream upstream = Mock(BitcoinMultistream) {
+            _ * getReader() >> Mock(BitcoinReader) {
+                1 * getTx(txid) >> Mono.just([
+                        txid: txid
+                ])
+            }
         }
         when:
-        def act = track.loadExisting(api, txid)
+        def act = track.loadExisting(upstream, txid)
 
         then:
         StepVerifier.create(act)
@@ -111,17 +111,19 @@ class TrackBitcoinTxSpec extends Specification {
 
     def "loadExiting() returns block if mined"() {
         setup:
-        TrackBitcoinTx track = new TrackBitcoinTx(Stub(Upstreams))
+        TrackBitcoinTx track = new TrackBitcoinTx(Stub(MultistreamHolder))
         def txid = "69cd44d7c641db82e69824523c7ac0c5c1e5628f025474529cf5ffe64527efc9"
-        DirectBitcoinApi api = Mock(DirectBitcoinApi) {
-            1 * getTx(txid) >> Mono.just([
-                    txid     : txid,
-                    blockhash: "0000000000000000000895d1b9d3898700e1deecc3b0e69f439aa77875e6042f",
-                    height   : 100
-            ])
+        BitcoinMultistream upstream = Mock(BitcoinMultistream) {
+            _ * getReader() >> Mock(BitcoinReader) {
+                1 * getTx(txid) >> Mono.just([
+                        txid     : txid,
+                        blockhash: "0000000000000000000895d1b9d3898700e1deecc3b0e69f439aa77875e6042f",
+                        height   : 100
+                ])
+            }
         }
         when:
-        def act = track.loadExisting(api, txid)
+        def act = track.loadExisting(upstream, txid)
 
         then:
         StepVerifier.create(act)
@@ -136,16 +138,16 @@ class TrackBitcoinTxSpec extends Specification {
 
     def "Goes with confirmations"() {
         setup:
-        TrackBitcoinTx track = new TrackBitcoinTx(Stub(Upstreams))
+        TrackBitcoinTx track = new TrackBitcoinTx(Stub(MultistreamHolder))
         def txid = "69cd44d7c641db82e69824523c7ac0c5c1e5628f025474529cf5ffe64527efc9"
         // start with the current block
         def next = Flux.fromIterable([10, 12, 13, 14, 15]).map { h ->
-            new BlockContainer(h.longValue(), BlockId.from("0000000000000000000895d1b9d3898700e1deecc3b0e69f439aa77875e6042f"), BigInteger.ONE, Instant.now(), false, null, [])
+            new BlockContainer(h.longValue(), BlockId.from("0000000000000000000895d1b9d3898700e1deecc3b0e69f439aa77875e6042f"), BigInteger.ONE, Instant.now(), false, null, null, [])
         }
         Head head = Mock(Head) {
             1 * getFlux() >> next
         }
-        Upstream upstream = Mock(BitcoinUpstream) {
+        BitcoinMultistream upstream = Mock(BitcoinMultistream) {
             1 * getHead() >> head
         }
         def status = new TrackBitcoinTx.TxStatus(
@@ -167,16 +169,16 @@ class TrackBitcoinTxSpec extends Specification {
 
     def "Wait until mined"() {
         setup:
-        TrackBitcoinTx track = new TrackBitcoinTx(Stub(Upstreams))
+        TrackBitcoinTx track = new TrackBitcoinTx(Stub(MultistreamHolder))
         def txid = "69cd44d7c641db82e69824523c7ac0c5c1e5628f025474529cf5ffe64527efc9"
         // start with the current block
         def next = Flux.fromIterable([10, 12, 13]).map { h ->
-            new BlockContainer(h.longValue(), BlockId.from("0000000000000000000895d1b9d3898700e1deecc3b0e69f439aa77875e6042f"), BigInteger.ONE, Instant.now(), false, null, [])
+            new BlockContainer(h.longValue(), BlockId.from("0000000000000000000895d1b9d3898700e1deecc3b0e69f439aa77875e6042f"), BigInteger.ONE, Instant.now(), false, null, null, [])
         }
         Head head = Mock(Head) {
             1 * getFlux() >> next
         }
-        DirectBitcoinApi api = Mock(DirectBitcoinApi) {
+        BitcoinReader api = Mock(BitcoinReader) {
             3 * getTx(txid) >>> [
                     Mono.just([
                             txid: txid
@@ -191,9 +193,9 @@ class TrackBitcoinTxSpec extends Specification {
                     ])
             ]
         }
-        Upstream upstream = Mock(BitcoinUpstream) {
+        BitcoinMultistream upstream = Mock(BitcoinMultistream) {
             1 * getHead() >> head
-            _ * getApi(_) >> Mono.just(api)
+            _ * getReader() >> api
         }
         def status = new TrackBitcoinTx.TxStatus(
                 txid, false, null, false, null, null, null, 0
@@ -210,13 +212,9 @@ class TrackBitcoinTxSpec extends Specification {
 
     def "Check mempool until found"() {
         setup:
-        TrackBitcoinTx track = new TrackBitcoinTx(Stub(Upstreams))
+        TrackBitcoinTx track = new TrackBitcoinTx(Stub(MultistreamHolder))
         def txid = "69cd44d7c641db82e69824523c7ac0c5c1e5628f025474529cf5ffe64527efc9"
-        DirectBitcoinApi api = Mock(DirectBitcoinApi) {
-            1 * getTx(txid) >> Mono.just([
-                    txid: txid
-            ])
-        }
+
         Head head = Mock(Head) {
             _ * getFlux() >> Flux.empty()
         }
@@ -228,17 +226,20 @@ class TrackBitcoinTxSpec extends Specification {
                     Mono.just(["4523c7ac0c5c1e5628f025474529c69cd44d7c641db82e6982f5ffe64527efc9", txid]) //second call when started over
             ]
         }
-        BitcoinUpstream upstream = Mock(BitcoinUpstream) {
-            _ * getApi(_) >> Mono.just(api)
+        BitcoinReader api = Mock(BitcoinReader) {
+            1 * getTx(txid) >> Mono.just([
+                    txid: txid
+            ])
+            _ * getMempool() >> mempoolAccess
+        }
+        BitcoinMultistream upstream = Mock(BitcoinMultistream) {
             _ * getHead() >> head
-            _ * getData() >> Mock(BitcoinReader) {
-                _ * getMempool() >> mempoolAccess
-            }
+            _ * getReader() >> api
         }
 
         when:
         def steps = StepVerifier.withVirtualTime {
-            track.untilFound(Chain.BITCOIN, api, upstream, txid).take(1)
+            track.untilFound(Chain.BITCOIN, upstream, txid).take(1)
         }
 
         then:
@@ -252,9 +253,9 @@ class TrackBitcoinTxSpec extends Specification {
 
     def "Subscribe to an existing tx"() {
         setup:
-        TrackBitcoinTx track = new TrackBitcoinTx(Stub(Upstreams))
+        TrackBitcoinTx track = new TrackBitcoinTx(Stub(MultistreamHolder))
         def txid = "69cd44d7c641db82e69824523c7ac0c5c1e5628f025474529cf5ffe64527efc9"
-        DirectBitcoinApi api = Mock(DirectBitcoinApi) {
+        BitcoinReader api = Mock(BitcoinReader) {
             _ * getTx(txid) >> Mono.just([
                     txid     : txid,
                     blockhash: "0000000000000000000895d1b9d3898700e1deecc3b0e69f439aa77875e6042f",
@@ -267,18 +268,18 @@ class TrackBitcoinTxSpec extends Specification {
             ])
         }
         def next = Flux.fromIterable([10, 11, 12]).map { h ->
-            new BlockContainer(h.longValue(), BlockId.from("0000000000000000000895d1b9d3898700e1deecc3b0e69f439aa77875e6042f"), BigInteger.ONE, Instant.now(), false, null, [])
+            new BlockContainer(h.longValue(), BlockId.from("0000000000000000000895d1b9d3898700e1deecc3b0e69f439aa77875e6042f"), BigInteger.ONE, Instant.now(), false, null, null, [])
         }
         Head head = Mock(Head) {
             _ * getFlux() >> next
         }
-        BitcoinUpstream upstream = Mock(BitcoinUpstream) {
-            _ * getApi(_) >> Mono.just(api)
+        BitcoinMultistream upstream = Mock(BitcoinMultistream) {
+            _ * getReader() >> api
             _ * getHead() >> head
         }
 
         when:
-        def act = track.subscribe(Chain.BITCOIN, api, upstream, txid)
+        def act = track.subscribe(Chain.BITCOIN, upstream, txid)
 
         then:
         StepVerifier.create(act)

src/test/groovy/io/emeraldpay/dshackle/rpc/TrackEthereumAddressSpec.groovy

@@ -19,21 +19,12 @@ package io.emeraldpay.dshackle.rpc
 import io.emeraldpay.api.proto.BlockchainOuterClass
 import io.emeraldpay.api.proto.Common
 import io.emeraldpay.dshackle.data.BlockContainer
-import io.emeraldpay.dshackle.reader.Reader
 import io.emeraldpay.dshackle.test.TestingCommons
-import io.emeraldpay.dshackle.test.UpstreamsMock
-import io.emeraldpay.dshackle.upstream.Upstreams
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumReader
+import io.emeraldpay.dshackle.test.MultistreamHolderMock
+import io.emeraldpay.dshackle.upstream.MultistreamHolder
 import io.emeraldpay.grpc.Chain
-import io.infinitape.etherjar.domain.Address
 import io.infinitape.etherjar.domain.BlockHash
-import io.infinitape.etherjar.rpc.ReactorRpcClient
-import io.infinitape.etherjar.rpc.RpcCall
 import io.infinitape.etherjar.rpc.json.BlockJson
-import reactor.core.publisher.Flux
-import reactor.core.publisher.Mono
-import reactor.core.publisher.TopicProcessor
-import reactor.core.scheduler.Schedulers
 import reactor.test.StepVerifier
 import spock.lang.Specification
 
@@ -64,9 +55,9 @@ class TrackEthereumAddressSpec extends Specification {
             .setBalance("1234567890")
             .build()
 
-        def apiMock = TestingCommons.api(Stub(ReactorRpcClient))
+        def apiMock = TestingCommons.api()
         def upstreamMock = TestingCommons.upstream(apiMock)
-        Upstreams upstreams = new UpstreamsMock(Chain.ETHEREUM, upstreamMock)
+        MultistreamHolder upstreams = new MultistreamHolderMock(Chain.ETHEREUM, upstreamMock)
         TrackEthereumAddress trackAddress = new TrackEthereumAddress(upstreams)
 
         apiMock.answer("eth_getBalance", ["0xe2c8fa8120d813cd0b5e6add120295bf20cfa09f", "latest"], "0x499602D2")
@@ -104,9 +95,9 @@ class TrackEthereumAddressSpec extends Specification {
             return it
         }
 
-        def apiMock = TestingCommons.api(Stub(ReactorRpcClient))
+        def apiMock = TestingCommons.api()
         def upstreamMock = TestingCommons.upstream(apiMock)
-        Upstreams upstreams = new UpstreamsMock(Chain.ETHEREUM, upstreamMock)
+        MultistreamHolder upstreams = new MultistreamHolderMock(Chain.ETHEREUM, upstreamMock)
         TrackEthereumAddress trackAddress = new TrackEthereumAddress(upstreams)
 
         apiMock.answerOnce("eth_getBalance", ["0xe2c8fa8120d813cd0b5e6add120295bf20cfa09f", "latest"], "0x499602D2")
@@ -121,6 +112,6 @@ class TrackEthereumAddressSpec extends Specification {
                 }
                 .expectNext(exp2).as("Second block")
                 .thenCancel()
-                .verify(Duration.ofSeconds(1))
+                .verify(Duration.ofSeconds(2))
     }
 }

src/test/groovy/io/emeraldpay/dshackle/rpc/TrackEthereumTxSpec.groovy

@@ -23,15 +23,13 @@ import io.emeraldpay.dshackle.data.BlockContainer
 import io.emeraldpay.dshackle.data.BlockId
 import io.emeraldpay.dshackle.data.TxId
 import io.emeraldpay.dshackle.test.TestingCommons
-import io.emeraldpay.dshackle.test.UpstreamsMock
+import io.emeraldpay.dshackle.test.MultistreamHolderMock
 import io.emeraldpay.dshackle.upstream.Head
-import io.emeraldpay.dshackle.upstream.Upstreams
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumApi
-import io.emeraldpay.dshackle.upstream.ethereum.AggregatedEthereumUpstreams
+import io.emeraldpay.dshackle.upstream.MultistreamHolder
+import io.emeraldpay.dshackle.upstream.ethereum.EthereumMultistream
 import io.emeraldpay.grpc.Chain
 import io.infinitape.etherjar.domain.BlockHash
 import io.infinitape.etherjar.domain.TransactionId
-import io.infinitape.etherjar.rpc.ReactorRpcClient
 import io.infinitape.etherjar.rpc.json.BlockJson
 import io.infinitape.etherjar.rpc.json.TransactionJson
 import io.infinitape.etherjar.rpc.json.TransactionRefJson
@@ -98,9 +96,9 @@ class TrackEthereumTxSpec extends Specification {
                         .setTimestamp(blockJson.timestamp.toEpochMilli())
             ).build()
 
-        def apiMock = TestingCommons.api(Stub(ReactorRpcClient))
+        def apiMock = TestingCommons.api()
         def upstreamMock = TestingCommons.upstream(apiMock)
-        Upstreams upstreams = new UpstreamsMock(Chain.ETHEREUM, upstreamMock)
+        MultistreamHolder upstreams = new MultistreamHolderMock(Chain.ETHEREUM, upstreamMock)
         TrackEthereumTx trackTx = new TrackEthereumTx(upstreams)
 
         apiMock.answer("eth_getTransactionByHash", [txId], txJson)
@@ -118,10 +116,10 @@ class TrackEthereumTxSpec extends Specification {
 
     def "Wait for unknown transaction"() {
         setup:
-        def apiMock = TestingCommons.api(Stub(ReactorRpcClient))
+        def apiMock = TestingCommons.api()
         def upstreamMock = TestingCommons.upstream(apiMock)
-        Upstreams upstreams = new UpstreamsMock(Chain.ETHEREUM, upstreamMock)
-        ((AggregatedEthereumUpstreams) upstreams.getUpstream(Chain.ETHEREUM)).head = Mock(Head) {
+        MultistreamHolder upstreams = new MultistreamHolderMock(Chain.ETHEREUM, upstreamMock)
+        ((EthereumMultistream) upstreams.getUpstream(Chain.ETHEREUM)).head = Mock(Head) {
             _ * getFlux() >> Flux.empty()
         }
         TrackEthereumTx trackTx = new TrackEthereumTx(upstreams)
@@ -133,7 +131,7 @@ class TrackEthereumTxSpec extends Specification {
         when:
         def tx = new TrackEthereumTx.TxDetails(Chain.ETHEREUM, Instant.now(), TransactionId.from(txId), 6)
         def act = StepVerifier.withVirtualTime(
-                { trackTx.subscribe(tx, upstreams.getUpstream(Chain.ETHEREUM).castApi(EthereumApi.class)) },
+                { trackTx.subscribe(tx, upstreams.getUpstream(Chain.ETHEREUM).cast(EthereumMultistream)) },
                 { scheduler },
                 5)
 
@@ -168,9 +166,9 @@ class TrackEthereumTxSpec extends Specification {
             it
         }
 
-        def apiMock = TestingCommons.api(Stub(ReactorRpcClient))
+        def apiMock = TestingCommons.api()
         def upstreamMock = TestingCommons.upstream(apiMock)
-        Upstreams upstreams = new UpstreamsMock(Chain.ETHEREUM, upstreamMock)
+        MultistreamHolder upstreams = new MultistreamHolderMock(Chain.ETHEREUM, upstreamMock)
         TrackEthereumTx trackTx = new TrackEthereumTx(upstreams)
         def scheduler = VirtualTimeScheduler.create(true)
         trackTx.scheduler = scheduler
@@ -193,14 +191,14 @@ class TrackEthereumTxSpec extends Specification {
 
     def "New block makes tx mined"() {
         setup:
-        def apiMock = TestingCommons.api(Stub(ReactorRpcClient))
+        def apiMock = TestingCommons.api()
         def upstreamMock = TestingCommons.upstream(apiMock)
-        Upstreams upstreams = new UpstreamsMock(Chain.ETHEREUM, upstreamMock)
+        MultistreamHolder upstreams = new MultistreamHolderMock(Chain.ETHEREUM, upstreamMock)
         TrackEthereumTx trackTx = new TrackEthereumTx(upstreams)
 
         def tx = new TrackEthereumTx.TxDetails(Chain.ETHEREUM, Instant.now(), TransactionId.from(txId), 6)
         def block = new BlockContainer(
-                100, BlockId.from(txId), BigInteger.ONE, Instant.now(), false, "".bytes,
+                100, BlockId.from(txId), BigInteger.ONE, Instant.now(), false, "".bytes, null,
                 [TxId.from(txId)]
         )
 
@@ -215,14 +213,14 @@ class TrackEthereumTxSpec extends Specification {
 
     def "New block without current tx requires a call"() {
         setup:
-        def apiMock = TestingCommons.api(Stub(ReactorRpcClient))
+        def apiMock = TestingCommons.api()
         def upstreamMock = TestingCommons.upstream(apiMock)
-        Upstreams upstreams = new UpstreamsMock(Chain.ETHEREUM, upstreamMock)
+        MultistreamHolder upstreams = new MultistreamHolderMock(Chain.ETHEREUM, upstreamMock)
         TrackEthereumTx trackTx = new TrackEthereumTx(upstreams)
 
         def tx = new TrackEthereumTx.TxDetails(Chain.ETHEREUM, Instant.now(), TransactionId.from(txId), 6)
         def block = new BlockContainer(
-                100, BlockId.from(txId), BigInteger.ONE, Instant.now(), false, "".bytes,
+                100, BlockId.from(txId), BigInteger.ONE, Instant.now(), false, "".bytes, null,
                 [TxId.from("0xa0e65cbc1b52a8ca60562112c6060552d882f16f34a9dba2ccdc05c0a6a27c22")]
         )
         apiMock.answer("eth_getTransactionByHash", [txId], null)
@@ -288,9 +286,9 @@ class TrackEthereumTxSpec extends Specification {
                 )
 
 
-        def apiMock = TestingCommons.api(Stub(ReactorRpcClient))
+        def apiMock = TestingCommons.api()
         def upstreamMock = TestingCommons.upstream(apiMock)
-        Upstreams upstreams = new UpstreamsMock(Chain.ETHEREUM, upstreamMock)
+        MultistreamHolder upstreams = new MultistreamHolderMock(Chain.ETHEREUM, upstreamMock)
         TrackEthereumTx trackTx = new TrackEthereumTx(upstreams)
 
         apiMock.answerOnce("eth_getTransactionByHash", [txId], null)

src/test/groovy/io/emeraldpay/dshackle/test/EthereumApiMock.groovy

@@ -19,11 +19,10 @@ package io.emeraldpay.dshackle.test
 import com.fasterxml.jackson.databind.ObjectMapper
 import com.google.protobuf.ByteString
 import io.emeraldpay.api.proto.BlockchainOuterClass
-import io.emeraldpay.dshackle.upstream.calls.DirectCallMethods
-import io.emeraldpay.dshackle.upstream.ethereum.DirectEthereumApi
-import io.emeraldpay.grpc.Chain
+import io.emeraldpay.dshackle.reader.Reader
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import io.grpc.stub.StreamObserver
-import io.infinitape.etherjar.rpc.ReactorRpcClient
 import io.infinitape.etherjar.rpc.RpcResponseError
 import io.infinitape.etherjar.rpc.json.ResponseJson
 import org.jetbrains.annotations.NotNull
@@ -31,16 +30,18 @@ import org.slf4j.Logger
 import org.slf4j.LoggerFactory
 import reactor.core.publisher.Mono
 
+import java.time.Duration
 import java.util.concurrent.Callable
 
-class EthereumApiMock extends DirectEthereumApi {
+class EthereumApiMock implements Reader<JsonRpcRequest, JsonRpcResponse> {
 
     private static final Logger log = LoggerFactory.getLogger(this)
     List<PredefinedResponse> predefined = []
     private ObjectMapper objectMapper
 
-    EthereumApiMock(@NotNull ReactorRpcClient rpcClient, @NotNull ObjectMapper objectMapper, @NotNull Chain chain) {
-        super(rpcClient, null, objectMapper, new DirectCallMethods())
+    String id = "default"
+
+    EthereumApiMock(@NotNull ObjectMapper objectMapper) {
         this.objectMapper = objectMapper
     }
 
@@ -55,10 +56,11 @@ class EthereumApiMock extends DirectEthereumApi {
     }
 
     @Override
-    Mono<byte[]> execute(int id, @NotNull String method, @NotNull List<?> params) {
-        Callable<byte[]> call = {
-            def predefined = predefined.find { it.isSame(id, method, params) }
-            ResponseJson json = new ResponseJson<Object, Integer>(id: id)
+    Mono<JsonRpcResponse> read(JsonRpcRequest request) {
+        Callable<JsonRpcResponse> call = {
+            def predefined = predefined.find { it.isSame(request.method, request.params) }
+            byte[] result = null
+            JsonRpcResponse.ResponseError error = null
             if (predefined != null) {
                 if (predefined.exception != null) {
                     predefined.onCalled()
@@ -66,32 +68,37 @@ class EthereumApiMock extends DirectEthereumApi {
                     throw predefined.exception
                 }
                 if (predefined.result instanceof RpcResponseError) {
-                    json.error = predefined.result
+                    ((RpcResponseError) predefined.result).with { err ->
+                        error = new JsonRpcResponse.ResponseError(err.code, err.message)
+                    }
                 } else {
-                    json.result = predefined.result
+//                    ResponseJson json = new ResponseJson<Object, Integer>(id: 1, result: predefined.result)
+                    result = objectMapper.writeValueAsBytes(predefined.result)
                 }
                 predefined.onCalled()
                 predefined.print()
             } else {
-                log.error("Method ${method} with ${params} is not mocked")
-                json.error = new RpcResponseError(-32601, "Method ${method} with ${params} is not mocked")
+                log.error("Method ${request.method} with ${request.params} is not mocked")
+                error = new JsonRpcResponse.ResponseError(-32601, "Method ${request.method} with ${request.params} is not mocked")
             }
-            byte[] result = objectMapper.writeValueAsBytes(json)
-            return result
-        } as Callable<byte[]>
+            return new JsonRpcResponse(result, error)
+        } as Callable<JsonRpcResponse>
         return Mono.fromCallable(call)
     }
 
     def nativeCall(BlockchainOuterClass.NativeCallRequest request, StreamObserver<BlockchainOuterClass.NativeCallReplyItem> responseObserver) {
         request.itemsList.forEach { req ->
-            def resp = execute(req.id, req.method, objectMapper.readerFor(List).readValue(req.payload.toByteArray()))
-            resp.subscribe {
-                def proto = BlockchainOuterClass.NativeCallReplyItem.newBuilder()
-                        .setId(req.id)
-                        .setSucceed(true)
-                        .setPayload(ByteString.copyFrom(resp.block()))
-                responseObserver.onNext(proto.build())
+            JsonRpcResponse resp = read(new JsonRpcRequest(req.method, objectMapper.readerFor(List).readValue(req.payload.toByteArray())))
+                    .block(Duration.ofSeconds(5))
+            def proto = BlockchainOuterClass.NativeCallReplyItem.newBuilder()
+                    .setId(req.id)
+                    .setSucceed(resp.hasResult())
+                    .setPayload(ByteString.copyFrom(resp.getResult()))
+
+            resp.error?.with { err ->
+                proto.setErrorMessage(err.message)
             }
+            responseObserver.onNext(proto.build())
         }
         responseObserver.onCompleted()
     }
@@ -103,7 +110,7 @@ class EthereumApiMock extends DirectEthereumApi {
         Integer limit
         Throwable exception
 
-        boolean isSame(int id, String method, List<?> params) {
+        boolean isSame(String method, List<?> params) {
             if (limit != null) {
                 if (limit <= 0) {
                     return false

src/test/groovy/io/emeraldpay/dshackle/test/EthereumApiStub.groovy

@@ -16,28 +16,20 @@
  */
 package io.emeraldpay.dshackle.test
 
-import com.fasterxml.jackson.databind.ObjectMapper
-import io.emeraldpay.dshackle.upstream.calls.DirectCallMethods
-import io.emeraldpay.dshackle.upstream.ethereum.DirectEthereumApi
-import io.infinitape.etherjar.rpc.ReactorBatch
-import io.infinitape.etherjar.rpc.ReactorRpcClient
-import io.infinitape.etherjar.rpc.RpcCall
-import io.infinitape.etherjar.rpc.RpcCallResponse
-import reactor.core.publisher.Flux
+import io.emeraldpay.dshackle.reader.Reader
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import reactor.core.publisher.Mono
 
-class EthereumApiStub extends DirectEthereumApi {
+class EthereumApiStub implements Reader<JsonRpcRequest, JsonRpcResponse> {
 
     private String id
-    private static ObjectMapper objectMapper = TestingCommons.objectMapper()
-    private static ReactorRpcClient rpcClient = new RpcClientMock();
 
     EthereumApiStub(Integer id) {
         this(id.toString())
     }
 
     EthereumApiStub(String id) {
-        super(rpcClient, null, objectMapper, new DirectCallMethods())
         this.id = id
     }
 
@@ -46,16 +38,9 @@ class EthereumApiStub extends DirectEthereumApi {
         return "API Stub $id"
     }
 
-    static class RpcClientMock implements ReactorRpcClient {
-
-        @Override
-        Flux<RpcCallResponse> execute(ReactorBatch batch) {
-            return Flux.error(new Exception("Not implemented in mock"))
-        }
-
-        @Override
-        def <JS, RES> Mono<RES> execute(RpcCall<JS, RES> call) {
-            return Mono.error(new Exception("Not implemented in mock"))
-        }
+    @Override
+    Mono<JsonRpcResponse> read(JsonRpcRequest key) {
+        return Mono.error(new Exception("Not implemented in mock"))
     }
+
 }

src/test/groovy/io/emeraldpay/dshackle/test/EthereumHeadMock.groovy

@@ -18,6 +18,7 @@ package io.emeraldpay.dshackle.test
 
 import io.emeraldpay.dshackle.data.BlockContainer
 import io.emeraldpay.dshackle.upstream.Head
+import org.jetbrains.annotations.NotNull
 import org.reactivestreams.Publisher
 import reactor.core.publisher.Flux
 import reactor.core.publisher.Mono
@@ -28,9 +29,14 @@ class EthereumHeadMock implements Head {
     private TopicProcessor<BlockContainer> bus = TopicProcessor.create()
     private Publisher<BlockContainer> predefined = null
     private BlockContainer latest
+    private List<Runnable> handlers = []
 
     void nextBlock(BlockContainer block) {
+        handlers.forEach {
+            it.run()
+        }
         assert block != null
+        println("New block: ${block.height} / ${block.hash}")
         latest = block
         bus.onNext(block)
     }
@@ -51,4 +57,9 @@ class EthereumHeadMock implements Head {
             return Flux.concat(Mono.justOrEmpty(latest), bus).distinctUntilChanged()
         }
     }
+
+    @Override
+    void onBeforeBlock(@NotNull Runnable handler) {
+        handlers.add(handler)
+    }
 }

src/test/groovy/io/emeraldpay/dshackle/test/EthereumUpstreamMock.groovy

@@ -16,18 +16,22 @@
  */
 package io.emeraldpay.dshackle.test
 
+
 import io.emeraldpay.dshackle.config.UpstreamsConfig
 import io.emeraldpay.dshackle.data.BlockContainer
 import io.emeraldpay.dshackle.upstream.Head
+import io.emeraldpay.dshackle.upstream.calls.AggregatedCallMethods
 import io.emeraldpay.dshackle.upstream.calls.CallMethods
 import io.emeraldpay.dshackle.startup.QuorumForLabels
+import io.emeraldpay.dshackle.upstream.calls.DefaultBitcoinMethods
 import io.emeraldpay.dshackle.upstream.calls.DefaultEthereumMethods
-import io.emeraldpay.dshackle.upstream.ethereum.DirectEthereumApi
+import io.emeraldpay.dshackle.upstream.calls.DirectCallMethods
 import io.emeraldpay.dshackle.upstream.ethereum.EthereumUpstream
 import io.emeraldpay.dshackle.upstream.UpstreamAvailability
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
+import io.emeraldpay.dshackle.reader.Reader
 import io.emeraldpay.grpc.Chain
-import io.infinitape.etherjar.domain.TransactionId
-import io.infinitape.etherjar.rpc.json.BlockJson
 import org.jetbrains.annotations.NotNull
 import org.reactivestreams.Publisher
 
@@ -35,24 +39,33 @@ class EthereumUpstreamMock extends EthereumUpstream {
 
     EthereumHeadMock ethereumHeadMock = new EthereumHeadMock()
 
-    EthereumUpstreamMock(@NotNull Chain chain, @NotNull DirectEthereumApi api) {
-        this(chain, api, new DefaultEthereumMethods(TestingCommons.objectMapper(), chain))
+    static CallMethods allMethods() {
+        new AggregatedCallMethods([
+                new DefaultEthereumMethods(TestingCommons.objectMapper(), Chain.ETHEREUM),
+                new DefaultBitcoinMethods(TestingCommons.objectMapper()),
+                new DirectCallMethods(["eth_test"])
+        ])
     }
 
-    EthereumUpstreamMock(@NotNull String id, @NotNull Chain chain, @NotNull DirectEthereumApi api) {
-        this(id, chain, api, new DefaultEthereumMethods(TestingCommons.objectMapper(), chain))
+    EthereumUpstreamMock(@NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api) {
+        this(chain, api, allMethods())
     }
 
-    EthereumUpstreamMock(@NotNull Chain chain, @NotNull DirectEthereumApi api, CallMethods methods) {
+    EthereumUpstreamMock(@NotNull String id, @NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api) {
+        this(id, chain, api, allMethods())
+    }
+
+    EthereumUpstreamMock(@NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api, CallMethods methods) {
         this("test", chain, api, methods)
     }
 
-    EthereumUpstreamMock(@NotNull String id, @NotNull Chain chain, @NotNull DirectEthereumApi api, CallMethods methods) {
+    EthereumUpstreamMock(@NotNull String id, @NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api, CallMethods methods) {
         super(id, chain, api, null,
                 UpstreamsConfig.Options.getDefaults(), new QuorumForLabels.QuorumItem(1, new UpstreamsConfig.Labels()),
                 methods, TestingCommons.objectMapper())
         setLag(0)
         setStatus(UpstreamAvailability.OK)
+        start()
     }
 
     void nextBlock(BlockContainer block) {

src/test/groovy/io/emeraldpay/dshackle/test/MultistreamHolderMock.groovy

@@ -16,48 +16,60 @@
  */
 package io.emeraldpay.dshackle.test
 
-import com.fasterxml.jackson.databind.ObjectMapper
+
+import io.emeraldpay.dshackle.BlockchainType
 import io.emeraldpay.dshackle.cache.Caches
-import io.emeraldpay.dshackle.upstream.AggregatedUpstream
+import io.emeraldpay.dshackle.upstream.Multistream
+import io.emeraldpay.dshackle.upstream.bitcoin.BitcoinMultistream
+import io.emeraldpay.dshackle.upstream.bitcoin.BitcoinUpstream
 import io.emeraldpay.dshackle.upstream.calls.DefaultEthereumMethods
 import io.emeraldpay.dshackle.upstream.Upstream
-import io.emeraldpay.dshackle.upstream.Upstreams
-import io.emeraldpay.dshackle.upstream.ethereum.AggregatedEthereumUpstreams
+import io.emeraldpay.dshackle.upstream.MultistreamHolder
+import io.emeraldpay.dshackle.upstream.ethereum.EthereumMultistream
 import io.emeraldpay.dshackle.upstream.ethereum.EthereumReader
 import io.emeraldpay.dshackle.upstream.ethereum.EthereumUpstream
 import io.emeraldpay.grpc.Chain
 import org.jetbrains.annotations.NotNull
 import reactor.core.publisher.Flux
 
-class UpstreamsMock implements Upstreams {
+class MultistreamHolderMock implements MultistreamHolder {
 
     private Map<Chain, DefaultEthereumMethods> target = [:]
-    private Map<Chain, AggregatedEthereumUpstreamsMock> upstreams = [:]
+    private Map<Chain, Multistream> upstreams = [:]
 
-    UpstreamsMock(Chain chain, Upstream up) {
+    MultistreamHolderMock(Chain chain, Upstream up) {
         addUpstream(chain, up)
     }
-    UpstreamsMock(Chain chain1, Upstream up1, Chain chain2, Upstream up2) {
-        addUpstream(chain1, up1)
-        addUpstream(chain2, up2)
-    }
 
-    AggregatedUpstream addUpstream(@NotNull Chain chain, @NotNull EthereumUpstream up) {
+    Multistream addUpstream(@NotNull Chain chain, @NotNull Upstream up) {
         if (!upstreams.containsKey(chain)) {
-            upstreams[chain] = new AggregatedEthereumUpstreamsMock(chain, [up], Caches.default(TestingCommons.objectMapper()), TestingCommons.objectMapper())
-            upstreams[chain].start()
+            if (BlockchainType.fromBlockchain(chain) == BlockchainType.ETHEREUM) {
+                if (up instanceof EthereumMultistream) {
+                    upstreams[chain] = up
+                } else if (up instanceof EthereumUpstream) {
+                    upstreams[chain] = new EthereumMultistreamMock(chain, [up as EthereumUpstream], Caches.default(TestingCommons.objectMapper()))
+                } else {
+                    throw new IllegalArgumentException("Unsupported upstream type ${up.class}")
+                }
+                upstreams[chain].start()
+            } else if (BlockchainType.fromBlockchain(chain) == BlockchainType.BITCOIN) {
+                if (up instanceof BitcoinMultistream) {
+                    upstreams[chain] = up
+                } else if (up instanceof BitcoinUpstream) {
+                    upstreams[chain] = new BitcoinMultistream(chain, [up as BitcoinUpstream], Caches.default(TestingCommons.objectMapper()), TestingCommons.objectMapper())
+                } else {
+                    throw new IllegalArgumentException("Unsupported upstream type ${up.class}")
+                }
+                upstreams[chain].start()
+            }
         } else {
             upstreams[chain].addUpstream(up)
         }
         return upstreams[chain]
     }
 
-    void setReader(@NotNull Chain chain, EthereumReader reader) {
-        upstreams[chain].customReader = reader
-    }
-
     @Override
-    AggregatedUpstream getUpstream(@NotNull Chain chain) {
+    Multistream getUpstream(@NotNull Chain chain) {
         return upstreams[chain]
     }
 
@@ -85,12 +97,12 @@ class UpstreamsMock implements Upstreams {
         return upstreams.containsKey(chain)
     }
 
-    static class AggregatedEthereumUpstreamsMock extends AggregatedEthereumUpstreams {
+    static class EthereumMultistreamMock extends EthereumMultistream {
 
         EthereumReader customReader = null
 
-        AggregatedEthereumUpstreamsMock(@NotNull Chain chain, @NotNull List<EthereumUpstream> upstreams, @NotNull Caches caches, @NotNull ObjectMapper objectMapper) {
-            super(chain, upstreams, caches, objectMapper)
+        EthereumMultistreamMock(@NotNull Chain chain, @NotNull List<EthereumUpstream> upstreams, @NotNull Caches caches) {
+            super(chain, upstreams, caches, TestingCommons.objectMapper())
         }
 
         @Override

src/test/groovy/io/emeraldpay/dshackle/test/ReaderMock.groovy

@@ -1,6 +1,5 @@
 /**
  * Copyright (c) 2020 EmeraldPay, Inc
- * Copyright (c) 2020 ETCDEV GmbH
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,20 +13,25 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package io.emeraldpay.dshackle.upstream
+package io.emeraldpay.dshackle.test
 
+import io.emeraldpay.dshackle.reader.Reader
 import reactor.core.publisher.Mono
 
-/**
- * A general interface to make a request to an Upstream API
- */
-interface UpstreamApi {
+class ReaderMock<K, D> implements Reader<K, D> {
 
-    /**
-     * @param id an internal uniq id, if multiple requests are made in batch
-     * @param method JSON RPC method name
-     * @param params JSON RPC parameters, must be serializable into a JSON array
-     */
-    fun execute(id: Int, method: String, params: List<Any>): Mono<ByteArray>
+    private Map<K, D> mapping = new HashMap<K, D>()
 
-}
+    ReaderMock() {
+    }
+
+    ReaderMock with(K key, D data) {
+        mapping[key] = data
+        return this
+    }
+
+    @Override
+    Mono<D> read(K key) {
+        return Mono.justOrEmpty(mapping.get(key))
+    }
+}

src/test/groovy/io/emeraldpay/dshackle/test/TestingCommons.groovy

@@ -24,14 +24,15 @@ import io.emeraldpay.dshackle.FileResolver
 import io.emeraldpay.dshackle.cache.Caches
 import io.emeraldpay.dshackle.cache.CachesFactory
 import io.emeraldpay.dshackle.config.CacheConfig
-import io.emeraldpay.dshackle.upstream.AggregatedUpstream
+import io.emeraldpay.dshackle.reader.Reader
+import io.emeraldpay.dshackle.upstream.Multistream
 import io.emeraldpay.dshackle.upstream.calls.DirectCallMethods
-import io.emeraldpay.dshackle.upstream.ethereum.DirectEthereumApi
-import io.emeraldpay.dshackle.upstream.ethereum.AggregatedEthereumUpstreams
+import io.emeraldpay.dshackle.upstream.ethereum.EthereumMultistream
 import io.emeraldpay.dshackle.upstream.ethereum.EthereumUpstream
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import io.emeraldpay.grpc.Chain
 import io.infinitape.etherjar.rpc.JacksonRpcConverter
-import io.infinitape.etherjar.rpc.ReactorRpcClient
 
 import java.text.SimpleDateFormat
 
@@ -50,32 +51,34 @@ class TestingCommons {
         return objectMapper
     }
 
-    static EthereumApiMock api(ReactorRpcClient rpcClient) {
-        return new EthereumApiMock(rpcClient, objectMapper(), Chain.ETHEREUM)
+    static EthereumApiMock api() {
+        return new EthereumApiMock(objectMapper())
     }
 
     static JacksonRpcConverter rpcConverter() {
         return new JacksonRpcConverter(objectMapper())
     }
 
-    static EthereumUpstreamMock upstream(DirectEthereumApi api) {
+    static EthereumUpstreamMock upstream(Reader<JsonRpcRequest, JsonRpcResponse> api) {
         return new EthereumUpstreamMock(Chain.ETHEREUM, api)
     }
 
-    static EthereumUpstreamMock upstream(DirectEthereumApi api, String method) {
+    static EthereumUpstreamMock upstream(Reader<JsonRpcRequest, JsonRpcResponse> api, String method) {
         return upstream(api, [method])
     }
 
-    static EthereumUpstreamMock upstream(DirectEthereumApi api, List<String> methods) {
+    static EthereumUpstreamMock upstream(Reader<JsonRpcRequest, JsonRpcResponse> api, List<String> methods) {
         return new EthereumUpstreamMock(Chain.ETHEREUM, api, new DirectCallMethods(methods))
     }
 
-    static AggregatedUpstream aggregatedUpstream(DirectEthereumApi api) {
+    static Multistream aggregatedUpstream(Reader<JsonRpcRequest, JsonRpcResponse> api) {
         return aggregatedUpstream(upstream(api))
     }
 
-    static AggregatedUpstream aggregatedUpstream(EthereumUpstream up) {
-        return new AggregatedEthereumUpstreams(Chain.ETHEREUM, [up], Caches.default(objectMapper()), objectMapper())
+    static Multistream aggregatedUpstream(EthereumUpstream up) {
+        return new EthereumMultistream(Chain.ETHEREUM, [up], Caches.default(objectMapper()), objectMapper()).tap {
+            start()
+        }
     }
 
     static CachesFactory emptyCaches() {

src/test/groovy/io/emeraldpay/dshackle/upstream/AbstractHeadSpec.groovy

@@ -0,0 +1,117 @@
+/**
+ * Copyright (c) 2020 EmeraldPay, Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.emeraldpay.dshackle.upstream
+
+import io.emeraldpay.dshackle.data.BlockContainer
+import io.emeraldpay.dshackle.data.BlockId
+import reactor.core.publisher.Flux
+import reactor.core.publisher.TopicProcessor
+import reactor.test.StepVerifier
+import spock.lang.Specification
+
+import java.time.Duration
+import java.time.Instant
+
+class AbstractHeadSpec extends Specification {
+
+    def blocks = [1L, 2, 3, 4].collect { i ->
+        byte[] hash = new byte[32]
+        hash[0] = i as byte
+        new BlockContainer(i, BlockId.from(hash), BigInteger.valueOf(i), Instant.now(), false, null, null, [])
+    }
+
+    def "Calls beforeBlock on each block"() {
+        setup:
+        TopicProcessor<BlockContainer> source = TopicProcessor.create()
+        def head = new TestHead()
+        def called = false
+        when:
+        head.follow(Flux.from(source))
+        head.onBeforeBlock {
+            called = true
+        }
+        def act = head.flux
+        source.onNext(blocks[0])
+        then:
+        StepVerifier.create(act)
+                .expectNext(blocks[0])
+                .then {
+                    assert called
+                    called = false
+                    source.onNext(blocks[1])
+                }
+                .expectNext(blocks[1])
+                .then {
+                    assert called
+                    source.onComplete()
+                }
+                .expectComplete()
+                .verify(Duration.ofSeconds(1))
+    }
+
+    def "Follows source"() {
+        setup:
+        TopicProcessor<BlockContainer> source = TopicProcessor.create()
+        def head = new TestHead()
+        when:
+        head.follow(Flux.from(source))
+        def act = head.flux
+        source.onNext(blocks[0])
+        then:
+        StepVerifier.create(act)
+                .expectNext(blocks[0])
+                .then { source.onNext(blocks[1]) }
+                .expectNext(blocks[1])
+                .then { source.onNext(blocks[2]) }
+                .expectNext(blocks[2])
+                .then { source.onNext(blocks[3]) }
+                .expectNext(blocks[3])
+                .then { source.onComplete() }
+                .expectComplete()
+                .verify(Duration.ofSeconds(1))
+    }
+
+    def "Ignores block will less difficulty"() {
+        setup:
+        TopicProcessor<BlockContainer> source = TopicProcessor.create()
+        def head = new TestHead()
+        def wrongblock = new BlockContainer(
+                blocks[1].height, BlockId.from(blocks[1].hash.value.clone().tap { it[1] = 0xff as byte }),
+                blocks[1].difficulty - 1,
+                Instant.now(),
+                false, null, null, []
+        )
+        when:
+        head.follow(Flux.from(source))
+        def act = head.flux
+        source.onNext(blocks[0])
+        then:
+        StepVerifier.create(act)
+                .expectNext(blocks[0])
+                .then { source.onNext(blocks[1]) }
+                .expectNext(blocks[1])
+                .then { source.onNext(wrongblock) }
+                .then { source.onNext(blocks[3]) }
+                .expectNext(blocks[3])
+                .then { source.onComplete() }
+                .expectComplete()
+                .verify(Duration.ofSeconds(1))
+    }
+
+    class TestHead extends AbstractHead {
+
+    }
+}