Add handling for standard bitcoind-style RPC.

With the exception of the createencryptedwallet extension (which is
required to make a wallet), all websocket-specific handlers are now
only available from a websocket connection, and standard RPC requests
are handled with a normal HTTP request and reply.

As an added bonus, listening on IPv6 now works.

cmd.go

@@ -316,14 +316,15 @@ func main() {
 	go DirtyAccountSyncer()
 
 	go func() {
-		// Start HTTP server to listen and send messages to frontend and btcd
-		// backend.  Try reconnection if connection failed.
-		for {
-			if err := FrontendListenAndServe(); err != nil {
-				log.Info("Unable to start frontend HTTP server: %v", err)
+		s, err := newServer()
+		if err != nil {
+			log.Errorf("Unable to create HTTP server: %v", err)
 			os.Exit(1)
 		}
-		}
+
+		// Start HTTP server to listen and send messages to frontend and btcd
+		// backend.  Try reconnection if connection failed.
+		s.Start()
 	}()
 
 	// Begin generating new IDs for JSON calls.

cmdmgr.go

@@ -37,7 +37,7 @@ var (
 
 type cmdHandler func(chan []byte, btcjson.Cmd)
 
-var handlers = map[string]cmdHandler{
+var rpcHandlers = map[string]cmdHandler{
 	// Standard bitcoind methods
 	"getaddressesbyaccount": GetAddressesByAccount,
 	"getbalance":            GetBalance,
@@ -49,8 +49,12 @@ var handlers = map[string]cmdHandler{
 	"walletlock":            WalletLock,
 	"walletpassphrase":      WalletPassphrase,
 
-	// btcwallet extensions
+	// Extensions not exclusive to websocket connections.
 	"createencryptedwallet": CreateEncryptedWallet,
+}
+
+// Extensions exclusive to websocket connections.
+var wsHandlers = map[string]cmdHandler{
 	"getbalances":    GetBalances,
 	"walletislocked": WalletIsLocked,
 }
@@ -58,7 +62,7 @@ var handlers = map[string]cmdHandler{
 // ProcessFrontendMsg checks the message sent from a frontend.  If the
 // message method is one that must be handled by btcwallet, the request
 // is processed here.  Otherwise, the message is sent to btcd.
-func ProcessFrontendMsg(frontend chan []byte, msg []byte) {
+func ProcessFrontendMsg(frontend chan []byte, msg []byte, ws bool) {
 	// Parse marshaled command and check
 	cmd, err := btcjson.ParseMarshaledCmd(msg)
 	if err != nil {
@@ -71,13 +75,14 @@ func ProcessFrontendMsg(frontend chan []byte, msg []byte) {
 
 		// btcwallet cannot handle this command, so defer handling
 		// to btcd.
-		fmt.Printf("deferring %v with error %v\n", string(msg), err)
 		DeferToBTCD(frontend, msg)
 		return
 	}
 
 	// Check for a handler to reply to cmd.  If none exist, defer to btcd.
-	if f, ok := handlers[cmd.Method()]; ok {
+	if f, ok := rpcHandlers[cmd.Method()]; ok {
+		f(frontend, cmd)
+	} else if f, ok := wsHandlers[cmd.Method()]; ws && ok {
 		f(frontend, cmd)
 	} else {
 		// btcwallet does not have a handler for the command.  Pass

sockets.go

@@ -84,6 +84,59 @@ var (
 	}
 )
 
+// server holds the items the RPC server may need to access (auth,
+// config, shutdown, etc.)
+type server struct {
+	port      string
+	wg        sync.WaitGroup
+	listeners []net.Listener
+}
+
+// newServer returns a new instance of the server struct.
+func newServer() (*server, error) {
+	s := server{
+		port: cfg.SvrPort,
+	}
+
+	// IPv4 listener.
+	var listeners []net.Listener
+	listenAddr4 := net.JoinHostPort("127.0.0.1", s.port)
+	listener4, err := net.Listen("tcp4", listenAddr4)
+	if err != nil {
+		log.Errorf("RPCS: Couldn't create listener: %v", err)
+		return nil, err
+	}
+	listeners = append(listeners, listener4)
+
+	// IPv6 listener.
+	listenAddr6 := net.JoinHostPort("::1", s.port)
+	listener6, err := net.Listen("tcp6", listenAddr6)
+	if err != nil {
+		log.Errorf("RPCS: Couldn't create listener: %v", err)
+		return nil, err
+	}
+	listeners = append(listeners, listener6)
+
+	s.listeners = listeners
+
+	return &s, nil
+}
+
+// handleRPCRequest processes a JSON-RPC request from a frontend.
+func (s *server) handleRPCRequest(w http.ResponseWriter, r *http.Request) {
+	frontend := make(chan []byte)
+
+	body, err := btcjson.GetRaw(r.Body)
+	if err != nil {
+		log.Errorf("RPCS: Error getting JSON message: %v", err)
+	}
+
+	ProcessFrontendMsg(frontend, body, false)
+	if _, err := w.Write(<-frontend); err != nil {
+		log.Warnf("RPCS: could not respond to RPC request: %v", err)
+	}
+}
+
 // frontendListenerDuplicator listens for new wallet listener channels
 // and duplicates messages sent to frontendNotificationMaster to all
 // connected listeners.
@@ -158,12 +211,12 @@ func NotifyBtcdConnected(reply chan []byte, conn bool) {
 	frontendNotificationMaster <- ntfn
 }
 
-// frontendReqsNotifications is the handler function for websocket
-// connections from a btcwallet instance.  It reads messages from wallet and
-// sends back replies, as well as notififying wallets of chain updates.
-// There can possibly be many of these running, one for each currently
-// connected frontend.
-func frontendReqsNotifications(ws *websocket.Conn) {
+// frontendSendRecv is the handler function for websocket connections from
+// a btcwallet instance.  It reads requests and sends responses to a
+// frontend, as well as notififying wallets of chain updates.  There can
+// possibly be many of these running, one for each currently connected
+// frontend.
+func frontendSendRecv(ws *websocket.Conn) {
 	// Add frontend notification channel to set so this handler receives
 	// updates.
 	frontendNotification := make(chan []byte)
@@ -195,8 +248,8 @@ func frontendReqsNotifications(ws *websocket.Conn) {
 				// frontend disconnected.
 				return
 			}
-			// Handle JSON message here.
-			go ProcessFrontendMsg(frontendNotification, m)
+			// Handle request here.
+			go ProcessFrontendMsg(frontendNotification, m, true)
 		case ntfn, _ := <-frontendNotification:
 			if err := websocket.Message.Send(ws, ntfn); err != nil {
 				// Frontend disconnected.
@@ -484,9 +537,9 @@ func NtfnTxMined(n btcws.Notification) {
 
 var duplicateOnce sync.Once
 
-// FrontendListenAndServe starts a HTTP server to provide websocket
-// connections for any number of btcwallet frontends.
-func FrontendListenAndServe() error {
+// Start starts a HTTP server to provide standard RPC and extension
+// websocket connections for any number of btcwallet frontends.
+func (s *server) Start() {
 	// We'll need to duplicate replies to frontends to each frontend.
 	// Replies are sent to frontendReplyMaster, and duplicated to each valid
 	// channel in frontendReplySet.  This runs a goroutine to duplicate
@@ -497,8 +550,21 @@ func FrontendListenAndServe() error {
 
 	// TODO(jrick): We need some sort of authentication before websocket
 	// connections are allowed, and perhaps TLS on the server as well.
-	http.Handle("/frontend", websocket.Handler(frontendReqsNotifications))
-	return http.ListenAndServe(net.JoinHostPort("", cfg.SvrPort), nil)
+	serveMux := http.NewServeMux()
+	httpServer := &http.Server{Handler: serveMux}
+	serveMux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		s.handleRPCRequest(w, r)
+	})
+	serveMux.Handle("/frontend", websocket.Handler(frontendSendRecv))
+	for _, listener := range s.listeners {
+		s.wg.Add(1)
+		go func(listener net.Listener) {
+			log.Infof("RPCS: RPC server listening on %s", listener.Addr())
+			httpServer.Serve(listener)
+			log.Tracef("RPCS: RPC listener done for %s", listener.Addr())
+			s.wg.Done()
+		}(listener)
+	}
 }
 
 // BtcdConnect connects to a running btcd instance over a websocket