[Minor] Ignore extra json rpc params (#1261)

Signed-off-by: Adrian Sutton <adrian.sutton@consensys.net>

ethereum/jsonrpc/src/main/java/tech/pegasys/pantheon/ethereum/jsonrpc/internal/JsonRpcRequest.java

@@ -19,12 +19,14 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonGetter;
 import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonSetter;
 import com.google.common.base.Objects;
 
+@JsonIgnoreProperties(ignoreUnknown = true)
 public class JsonRpcRequest {
 
   private JsonRpcRequestId id;

ethereum/jsonrpc/src/test/java/tech/pegasys/pantheon/ethereum/jsonrpc/JsonRpcHttpServiceTest.java

@@ -202,6 +202,28 @@ public class JsonRpcHttpServiceTest {
     }
   }
 
+  @Test
+  public void handleUnknownRequestFields() throws Exception {
+    final String id = "123";
+    // Create a request with an extra "beta" param
+    final RequestBody body =
+        RequestBody.create(
+            JSON,
+            "{\"jsonrpc\":\"2.0\",\"id\":"
+                + Json.encode(id)
+                + ",\"method\":\"net_version\", \"beta\":true}");
+
+    try (final Response resp = client.newCall(buildPostRequest(body)).execute()) {
+      assertThat(resp.code()).isEqualTo(200);
+      // Check general format of result
+      final JsonObject json = new JsonObject(resp.body().string());
+      testHelper.assertValidJsonRpcResult(json, id);
+      // Check result
+      final String result = json.getString("result");
+      assertThat(result).isEqualTo(String.valueOf(CHAIN_ID));
+    }
+  }
+
   @Test
   public void getSocketAddressWhenActive() {
     final InetSocketAddress socketAddress = service.socketAddress();