Add support for JSON-RPC array payload. (#335)

This PR introduces solution for #333 - it adds support for array JSON-RPC payload.

unmarshalMessage tries to unmarshal JSON paylod into *jsonrpcMessage object, and in case of failure, analyzes error and, if it's unmarshalling array error, tries to unmarshal it as an array.

geth/rpc/call_raw.go

@@ -3,6 +3,7 @@ package rpc
 import (
 	"context"
 	"encoding/json"
+	"errors"
 
 	gethrpc "github.com/ethereum/go-ethereum/rpc"
 	"github.com/status-im/status-go/geth/log"
@@ -96,7 +97,6 @@ func methodAndParamsFromBody(body string) (string, []interface{}, json.RawMessag
 	if msg.Params != nil {
 		err = json.Unmarshal(msg.Params, &params)
 		if err != nil {
-			log.Error("unmarshal params", "error", err)
 			return "", nil, nil, err
 		}
 	}
@@ -104,12 +104,44 @@ func methodAndParamsFromBody(body string) (string, []interface{}, json.RawMessag
 	return msg.Method, params, msg.ID, nil
 }
 
+// unmarshalMessage tries to unmarshal JSON-RPC message.
+// somehow JSON-RPC input from web3.js can be in two forms:
+//
+// object:  {"jsonrpc":"2.0", …}
+// array:   [{"jsonrpc":"2.0", …}]
+//
+// unmarhsalMessage tries first option and in case of error,
+// tries to unmarshal it as an array.
+//
+// TODO(divan): fix the source of this error and cleanup.
 func unmarshalMessage(body string) (*jsonrpcMessage, error) {
 	var msg jsonrpcMessage
 	err := json.Unmarshal([]byte(body), &msg)
+	// check for array case
+	if e, ok := err.(*json.UnmarshalTypeError); ok {
+		if e.Value == "array" {
+			return unmarshalMessageArray(body)
+		}
+	}
 	return &msg, err
 }
 
+func unmarshalMessageArray(body string) (*jsonrpcMessage, error) {
+	var msgs []*jsonrpcMessage
+	err := json.Unmarshal([]byte(body), &msgs)
+	if err != nil {
+		return nil, err
+	}
+
+	// return first element
+	if len(msgs) == 0 {
+		return nil, errors.New("empty array")
+	} else if len(msgs) > 1 {
+		log.Warn("JSON-RPC payload has more then 1 objects", "len", len(msgs), "body", body)
+	}
+	return msgs[0], nil
+}
+
 func newSuccessResponse(result json.RawMessage, id json.RawMessage) string {
 	if id == nil {
 		id = defaultMsgID

geth/rpc/call_raw_test.go

@@ -50,11 +50,12 @@ func TestUnmarshalMessage(t *testing.T) {
 
 func TestMethodAndParamsFromBody(t *testing.T) {
 	cases := []struct {
-		name   string
-		body   string
-		params []interface{}
-		method string
-		id     json.RawMessage
+		name       string
+		body       string
+		params     []interface{}
+		method     string
+		id         json.RawMessage
+		shouldFail bool
 	}{
 		{
 			"params_array",
@@ -67,30 +68,60 @@ func TestMethodAndParamsFromBody(t *testing.T) {
 			},
 			"subtract",
 			json.RawMessage(`42`),
+			false,
 		},
 		{
 			"params_empty_array",
 			`{"jsonrpc": "2.0", "method": "test", "params": []}`,
 			[]interface{}{},
 			"test",
-			json.RawMessage(nil),
+			nil,
+			false,
 		},
 		{
 			"params_none",
 			`{"jsonrpc": "2.0", "method": "test"}`,
 			[]interface{}{},
 			"test",
-			json.RawMessage(nil),
+			nil,
+			false,
+		},
+		{
+			"getFilterMessage",
+			`{"jsonrpc":"2.0","id":44,"method":"shh_getFilterMessages","params":["3de6a8867aeb75be74d68478b853b4b0e063704d30f8231c45d0fcbd97af207e"]}`,
+			[]interface{}{string("3de6a8867aeb75be74d68478b853b4b0e063704d30f8231c45d0fcbd97af207e")},
+			"shh_getFilterMessages",
+			json.RawMessage(`44`),
+			false,
+		},
+		{
+			"getFilterMessage_array",
+			`[{"jsonrpc":"2.0","id":44,"method":"shh_getFilterMessages","params":["3de6a8867aeb75be74d68478b853b4b0e063704d30f8231c45d0fcbd97af207e"]}]`,
+			[]interface{}{string("3de6a8867aeb75be74d68478b853b4b0e063704d30f8231c45d0fcbd97af207e")},
+			"shh_getFilterMessages",
+			json.RawMessage(`44`),
+			false,
+		},
+		{
+			"empty_array",
+			`[]`,
+			[]interface{}{},
+			"",
+			nil,
+			true,
 		},
 	}
 
 	for _, test := range cases {
 		t.Run(test.name, func(t *testing.T) {
 			method, params, id, err := methodAndParamsFromBody(test.body)
+			if test.shouldFail {
+				require.Error(t, err)
+			}
 			require.NoError(t, err)
 			require.Equal(t, test.method, method)
 			require.Equal(t, test.params, params)
-			require.Equal(t, test.id, id)
+			require.EqualValues(t, test.id, id)
 		})
 	}
 }

geth/rpc/client_test.go

@@ -6,7 +6,6 @@ import (
 	"net/http/httptest"
 	"testing"
 
-	"github.com/status-im/status-go/geth/log"
 	"github.com/status-im/status-go/geth/node"
 	"github.com/status-im/status-go/geth/params"
 	"github.com/status-im/status-go/geth/rpc"
@@ -183,7 +182,6 @@ func (s *RPCTestSuite) TestCallRPC() {
 				"id": 1
 			}`,
 			func(resultJSON string) {
-				log.Info("eth_sendTransaction")
 				progress <- struct{}{}
 			},
 		},