problem: no response on invalid request to proxy

rel: #43

src/test/groovy/io/emeraldpay/dshackle/proxy/ProxyServerSpec.groovy

@@ -22,7 +22,10 @@ import io.emeraldpay.dshackle.TlsSetup
 import io.emeraldpay.dshackle.config.ProxyConfig
 import io.emeraldpay.dshackle.rpc.NativeCall
 import io.emeraldpay.dshackle.test.TestingCommons
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
+import io.infinitape.etherjar.rpc.RpcException
 import reactor.core.publisher.Flux
+import reactor.core.publisher.Mono
 import reactor.test.StepVerifier
 import spock.lang.Specification
 
@@ -65,4 +68,24 @@ class ProxyServerSpec extends Specification {
                 .expectComplete()
                 .verify(Duration.ofSeconds(1))
     }
+
+    def "Return error on invalid request"() {
+        setup:
+        ReadRpcJson read = Mock(ReadRpcJson) {
+            1 * apply(_) >> { throw new RpcException(-32123, "test", new JsonRpcResponse.IntId(4)) }
+        }
+        def server = new ProxyServer(
+                Stub(ProxyConfig),
+                read,
+                Stub(WriteRpcJson), Stub(NativeCall), Stub(TlsSetup)
+        )
+        when:
+        def act = server.processRequest(Common.ChainRef.CHAIN_ETHEREUM, Mono.just("".bytes))
+                .map { new String(it.array()) }
+        then:
+        StepVerifier.create(act)
+                .expectNext('{"jsonrpc":"2.0","id":4,"error":{"code":-32123,"message":"test"}}')
+                .expectComplete()
+                .verify(Duration.ofSeconds(1))
+    }
 }

src/test/groovy/io/emeraldpay/dshackle/proxy/ReadRpcJsonSpec.groovy

@@ -17,6 +17,7 @@
 package io.emeraldpay.dshackle.proxy
 
 import io.emeraldpay.dshackle.test.TestingCommons
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import io.infinitape.etherjar.rpc.RpcException
 import spock.lang.Specification
 
@@ -174,4 +175,53 @@ class ReadRpcJsonSpec extends Specification {
             payload.toStringUtf8() == '[143,false]'
         }
     }
+
+    def "Error if id is not set"() {
+        when:
+        reader.apply('{"jsonrpc":"2.0", "method":"net_peerCount", "params":[]}'.bytes)
+        then:
+        def t = thrown(RpcException)
+        t.code == -32600
+        t.rpcMessage.toLowerCase() == "id is not set"
+    }
+
+    def "Error if jsonrpc is not set"() {
+        when:
+        reader.apply('{"id":2, "method":"net_peerCount", "params":[]}'.bytes)
+        then:
+        def t = thrown(RpcException)
+        t.code == -32600
+        t.rpcMessage.toLowerCase() == "jsonrpc version is not set"
+        t.details == new JsonRpcResponse.IntId(2)
+    }
+
+    def "Error if jsonrpc version is invalid"() {
+        when:
+        reader.apply('{"id":2, "jsonrpc":"3.0", "method":"net_peerCount", "params":[]}'.bytes)
+        then:
+        def t = thrown(RpcException)
+        t.code == -32600
+        t.rpcMessage.toLowerCase() == "unsupported json rpc version: 3.0"
+        t.details == new JsonRpcResponse.IntId(2)
+    }
+
+    def "Error if method is not set"() {
+        when:
+        reader.apply('{"id":2,  "jsonrpc":"2.0", "params":[]}'.bytes)
+        then:
+        def t = thrown(RpcException)
+        t.code == -32600
+        t.rpcMessage.toLowerCase() == "method is not set"
+        t.details == new JsonRpcResponse.IntId(2)
+    }
+
+    def "Error if params is not array"() {
+        when:
+        reader.apply('{"id":2, "jsonrpc":"2.0", "method":"test", "params":123}'.bytes)
+        then:
+        def t = thrown(RpcException)
+        t.code == -32600
+        t.rpcMessage.toLowerCase() == "params must be an array"
+        t.details == new JsonRpcResponse.IntId(2)
+    }
 }