new: TransferMode Binary/Text for Connection and hubProtocol

Author: philippseith

connection.go

@@ -6,7 +6,7 @@ import (
 	"time"
 )
 
-// Connection describes a connection between signalR client and Server
+// Connection describes a connection between signalR client and server
 type Connection interface {
 	io.Reader
 	io.Writer
@@ -16,3 +16,18 @@ type Connection interface {
 	Timeout() time.Duration
 	SetTimeout(duration time.Duration)
 }
+
+type TransferMode int
+
+// MessageType constants.
+const (
+	// TextTransferMode is for UTF-8 encoded text messages like JSON.
+	TextTransferMode TransferMode = iota + 1
+	// BinaryTransferMode is for binary messages like MessagePack.
+	BinaryTransferMode
+)
+
+type ConnectionWithTransferMode interface {
+	TransferMode() TransferMode
+	SetTransferMode(transferMode TransferMode)
+}

hubconnection.go

@@ -43,6 +43,9 @@ func newHubConnection(connection Connection, protocol hubProtocol, maximumReceiv
 		items:                     &sync.Map{},
 		info:                      info,
 	}
+	if connectionWithTransferMode, ok := connection.(ConnectionWithTransferMode); ok {
+		connectionWithTransferMode.SetTransferMode(protocol.transferMode())
+	}
 	return c
 }
 

hubprotocol.go

@@ -15,6 +15,7 @@ type hubProtocol interface {
 	WriteMessage(message interface{}, writer io.Writer) error
 	UnmarshalArgument(src interface{}, dst interface{}) error
 	setDebugLogger(dbg StructuredLogger)
+	transferMode() TransferMode
 }
 
 //easyjson:json

jsonhubprotocol.go

@@ -209,6 +209,10 @@ func (j *jsonHubProtocol) WriteMessage(message interface{}, writer io.Writer) er
 	return fmt.Errorf("%#v does not implement json.Marshaler", message)
 }
 
+func (j *jsonHubProtocol) transferMode() TransferMode {
+	return TextTransferMode
+}
+
 func (j *jsonHubProtocol) setDebugLogger(dbg StructuredLogger) {
 	j.dbg = log.WithPrefix(dbg, "ts", log.DefaultTimestampUTC, "protocol", "JSON")
 }

messagepackhubprotocol.go

@@ -300,6 +300,10 @@ func encodeMsgHeader(e *msgpack.Encoder, msgLen int, msgType int) (err error) {
 	return nil
 }
 
+func (m *messagePackHubProtocol) transferMode() TransferMode {
+	return BinaryTransferMode
+}
+
 func (m *messagePackHubProtocol) setDebugLogger(dbg StructuredLogger) {
 	m.dbg = log.WithPrefix(dbg, "ts", log.DefaultTimestampUTC, "protocol", "MSGP")
 }

websocketconnection.go

@@ -10,7 +10,8 @@ import (
 
 type webSocketConnection struct {
 	ConnectionBase
-	conn *websocket.Conn
+	conn         *websocket.Conn
+	transferMode TransferMode
 }
 
 func newWebSocketConnection(parentContext context.Context, requestContext context.Context, connectionID string, conn *websocket.Conn) *webSocketConnection {
@@ -35,7 +36,11 @@ func (w *webSocketConnection) Write(p []byte) (n int, err error) {
 		ctx, cancel = context.WithTimeout(w.ctx, w.Timeout())
 		defer cancel() // has no effect because timeoutCtx is either done or not used anymore after websocket returns. But it keeps lint quiet
 	}
-	err = w.conn.Write(ctx, websocket.MessageText, p)
+	messageType := websocket.MessageText
+	if w.transferMode == BinaryTransferMode {
+		messageType = websocket.MessageBinary
+	}
+	err = w.conn.Write(ctx, messageType, p)
 	if err != nil {
 		return 0, err
 	}
@@ -58,3 +63,11 @@ func (w *webSocketConnection) Read(p []byte) (n int, err error) {
 	}
 	return bytes.NewReader(data).Read(p)
 }
+
+func (w *webSocketConnection) TransferMode() TransferMode {
+	return w.transferMode
+}
+
+func (w *webSocketConnection) SetTransferMode(transferMode TransferMode) {
+	w.transferMode = transferMode
+}