[ETCM-110] Add eth_chainId RPC method (#683)

Author: kapke

.gitignore

@@ -5,6 +5,7 @@ project/plugins/project/
 .ensime
 .ensime_cache/
 .bloop
+out/
 
 # IDE folders
 .idea/
@@ -20,4 +21,4 @@ metals.sbt
 .evm-runner_history
 
 # Nix
-result
+result

insomnia_workspace.json

@@ -1,7 +1,7 @@
 {
   "_type": "export",
   "__export_format": 4,
-  "__export_date": "2020-09-16T09:48:00.794Z",
+  "__export_date": "2020-09-21T12:39:47.334Z",
   "__export_source": "insomnia.desktop.app:v2020.3.3",
   "resources": [
     {
@@ -198,6 +198,50 @@
       "parentId": "wrk_097d43914a4d4aea8b6f73f647921182",
       "_type": "request_group"
     },
+    {
+      "_id": "req_0ff71c4f648c4d3782612e9c53179321",
+      "authentication": {},
+      "body": {
+        "mimeType": "application/json",
+        "text": "{\n\t\"jsonrpc\": \"2.0\",\n  \"method\": \"eth_chainId\", \n\t\"params\": [],\n  \"id\": 1\n}"
+      },
+      "created": 1600691926224,
+      "description": "",
+      "headers": [
+        {
+          "id": "pair_c33a6ada19dd4aa8b75527639519f427",
+          "name": "Content-Type",
+          "value": "application/json"
+        }
+      ],
+      "isPrivate": false,
+      "metaSortKey": -1600691926224,
+      "method": "POST",
+      "modified": 1600691932451,
+      "name": "eth_chainId",
+      "parameters": [],
+      "parentId": "fld_a06eb77e183c4727800eb7dc43ceabe1",
+      "settingDisableRenderRequestBody": false,
+      "settingEncodeUrl": true,
+      "settingFollowRedirects": "global",
+      "settingRebuildPath": true,
+      "settingSendCookies": true,
+      "settingStoreCookies": true,
+      "url": "{{node_url}}",
+      "_type": "request"
+    },
+    {
+      "_id": "fld_a06eb77e183c4727800eb7dc43ceabe1",
+      "created": 1552939140291,
+      "description": "",
+      "environment": {},
+      "environmentPropertyOrder": null,
+      "metaSortKey": -1552939140292,
+      "modified": 1599825661277,
+      "name": "Eth",
+      "parentId": "wrk_097d43914a4d4aea8b6f73f647921182",
+      "_type": "request_group"
+    },
     {
       "_id": "req_b60c1a4f9d604d868910f967c6a070d7",
       "authentication": {},
@@ -235,18 +279,6 @@
       "url": "{{ node_url }}",
       "_type": "request"
     },
-    {
-      "_id": "fld_a06eb77e183c4727800eb7dc43ceabe1",
-      "created": 1552939140291,
-      "description": "",
-      "environment": {},
-      "environmentPropertyOrder": null,
-      "metaSortKey": -1552939140292,
-      "modified": 1599825661277,
-      "name": "Eth",
-      "parentId": "wrk_097d43914a4d4aea8b6f73f647921182",
-      "_type": "request_group"
-    },
     {
       "_id": "req_97fa82439e3e46bfb8ee26400af6215d",
       "authentication": {},
@@ -797,4 +829,4 @@
       "_type": "environment"
     }
   ]
-}
+}

src/main/scala/io/iohk/ethereum/jsonrpc/DebugJsonMethodsImplicits.scala

@@ -1,15 +1,14 @@
 package io.iohk.ethereum.jsonrpc
 
-import io.iohk.ethereum.jsonrpc.DebugService.{ ListPeersInfoRequest, ListPeersInfoResponse }
-import org.json4s.JsonAST.{ JArray, JString, JValue }
+import io.iohk.ethereum.jsonrpc.DebugService.{ListPeersInfoRequest, ListPeersInfoResponse}
+import io.iohk.ethereum.jsonrpc.JsonRpcController.{Codec, JsonEncoder}
+import io.iohk.ethereum.jsonrpc.JsonRpcController.JsonDecoder.NoParamsDecoder
+import org.json4s.JsonAST.{JArray, JString, JValue}
 
 object DebugJsonMethodsImplicits extends JsonMethodsImplicits {
 
   implicit val debug_listPeersInfo: Codec[ListPeersInfoRequest, ListPeersInfoResponse] =
-    new Codec[ListPeersInfoRequest, ListPeersInfoResponse] {
-      def decodeJson(params: Option[JArray]): Either[JsonRpcError, ListPeersInfoRequest] =
-        Right(ListPeersInfoRequest())
-
+    new NoParamsDecoder(ListPeersInfoRequest()) with JsonEncoder[ListPeersInfoResponse] {
       def encodeJson(t: ListPeersInfoResponse): JValue =
         JArray(t.peers.map(a => JString(a.toString)))
     }