implemented the start of JSON-RPC

pkg/network/rpc.go

@@ -0,0 +1,129 @@
+package network
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+)
+
+const (
+	rpcPortMainNet = 20332
+	rpcPortTestNet = 10332
+	rpcVersion     = "2.0"
+
+	// error response messages
+	methodNotFound = "Method not found"
+	parseError     = "Parse error"
+)
+
+// Each NEO node has a set of optional APIs for accessing blockchain
+// data and making things easier for development of blockchain apps.
+// APIs are provided via JSON-RPC , comm at bottom layer is with http/https protocol.
+
+// listenHTTP creates an ingress bridge from the outside world to the passed
+// server, by installing handlers for all the necessary RPCs to the passed mux.
+func listenHTTP(s *Server, port int) {
+	api := &API{s}
+	p := fmt.Sprintf(":%d", port)
+	s.logger.Printf("serving RPC on %d", port)
+	s.logger.Printf("%s", http.ListenAndServe(p, api))
+}
+
+// API serves JSON-RPC.
+type API struct {
+	s *Server
+}
+
+func (s *API) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	// Official nodes respond a parse error if the method is not POST.
+	// Instead of returning a decent response for this, let's do the same.
+	if r.Method != "POST" {
+		writeError(w, 0, 0, parseError)
+	}
+
+	var req Request
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		writeError(w, 0, 0, parseError)
+		return
+	}
+	defer r.Body.Close()
+
+	if req.Version != rpcVersion {
+		writeJSON(w, http.StatusBadRequest, nil)
+		return
+	}
+
+	switch req.Method {
+	case "getconnectioncount":
+		if err := s.getConnectionCount(w, &req); err != nil {
+			writeError(w, 0, 0, parseError)
+			return
+		}
+	case "getblockcount":
+	case "getbestblockhash":
+	default:
+		writeError(w, 0, 0, methodNotFound)
+	}
+}
+
+// This is an Example on how we could handle incomming RPC requests.
+func (s *API) getConnectionCount(w http.ResponseWriter, req *Request) error {
+	count := s.s.peerCount()
+
+	resp := ConnectionCountResponse{
+		Version: rpcVersion,
+		Result:  count,
+		ID:      1,
+	}
+
+	return writeJSON(w, http.StatusOK, resp)
+}
+
+// writeError returns a JSON error with given parameters. All error HTTP
+// status codes are 200. According to the official API.
+func writeError(w http.ResponseWriter, id, code int, msg string) error {
+	resp := RequestError{
+		Version: rpcVersion,
+		ID:      id,
+		Error: Error{
+			Code:    code,
+			Message: msg,
+		},
+	}
+
+	return writeJSON(w, http.StatusOK, resp)
+}
+
+func writeJSON(w http.ResponseWriter, status int, v interface{}) error {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	return json.NewEncoder(w).Encode(v)
+}
+
+// Request is an object received through JSON-RPC from the client.
+type Request struct {
+	Version string   `json:"jsonrpc"`
+	Method  string   `json:"method"`
+	Params  []string `json:"params"`
+	ID      int      `json:"id"`
+}
+
+// ConnectionCountResponse ..
+type ConnectionCountResponse struct {
+	Version string `json:"jsonrpc"`
+	Result  int    `json:"result"`
+	ID      int    `json:"id"`
+}
+
+// RequestError ..
+type RequestError struct {
+	Version string `json:"jsonrpc"`
+	ID      int    `json:"id"`
+	Error   Error  `json:"error"`
+}
+
+// Error holds information about an RCP error.
+type Error struct {
+	Code    int    `json:"code"`
+	Message string `json:"message"`
+}