[MM-40485] Enable receiving binary websocket messages (#19128)

* Enable receiving binary websocket messages

* Improve error message

* Prefer anonymous declaration

* Simplify

* Improve test

* Use MessagePack to clone WebSocketRequest struct

* Use short form

* Fix test

model/websocket_client.go

@@ -14,6 +14,7 @@ import (
 	"github.com/mattermost/mattermost-server/v6/shared/mlog"
 
 	"github.com/gorilla/websocket"
+	"github.com/vmihailenco/msgpack/v5"
 )
 
 const (
@@ -26,6 +27,7 @@ type msgType int
 const (
 	msgTypeJSON msgType = iota + 1
 	msgTypePong
+	msgTypeBinary
 )
 
 type writeMessage struct {
@@ -182,6 +184,10 @@ func (wsc *WebSocketClient) writer() {
 			switch msg.msgType {
 			case msgTypeJSON:
 				wsc.Conn.WriteJSON(msg.data)
+			case msgTypeBinary:
+				if data, ok := msg.data.([]byte); ok {
+					wsc.Conn.WriteMessage(websocket.BinaryMessage, data)
+				}
 			case msgTypePong:
 				wsc.Conn.WriteMessage(websocket.PongMessage, []byte{})
 			}
@@ -275,6 +281,26 @@ func (wsc *WebSocketClient) SendMessage(action string, data map[string]interface
 	}
 }
 
+func (wsc *WebSocketClient) SendBinaryMessage(action string, data map[string]interface{}) error {
+	req := &WebSocketRequest{}
+	req.Seq = wsc.Sequence
+	req.Action = action
+	req.Data = data
+
+	binaryData, err := msgpack.Marshal(req)
+	if err != nil {
+		return fmt.Errorf("failed to marshal request to msgpack: %w", err)
+	}
+
+	wsc.Sequence++
+	wsc.writeChan <- writeMessage{
+		msgType: msgTypeBinary,
+		data:    binaryData,
+	}
+
+	return nil
+}
+
 // UserTyping will push a user_typing event out to all connected users
 // who are in the specified channel
 func (wsc *WebSocketClient) UserTyping(channelId, parentId string) {

model/websocket_client_test.go

@@ -13,6 +13,7 @@ import (
 	"github.com/gorilla/websocket"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"github.com/vmihailenco/msgpack/v5"
 )
 
 func dummyWebsocketHandler(t *testing.T) http.HandlerFunc {
@@ -149,3 +150,56 @@ func TestWebSocketClose(t *testing.T) {
 		checkWriteChan(cli.writeChan)
 	})
 }
+
+func binaryWebsocketHandler(t *testing.T, clientData map[string]interface{}, doneCh chan struct{}) http.HandlerFunc {
+	return func(w http.ResponseWriter, req *http.Request) {
+		defer close(doneCh)
+		upgrader := &websocket.Upgrader{
+			ReadBufferSize:  1024,
+			WriteBufferSize: 1024,
+		}
+		conn, err := upgrader.Upgrade(w, req, nil)
+		require.NoError(t, err)
+		defer conn.Close()
+
+		for {
+			msgType, buf, err := conn.ReadMessage()
+			require.NoError(t, err)
+			if msgType == websocket.BinaryMessage {
+				require.Equal(t, msgType, websocket.BinaryMessage)
+				wsReq := &WebSocketRequest{}
+				err = msgpack.Unmarshal(buf, wsReq)
+				require.NoError(t, err)
+				require.Equal(t, clientData, wsReq.Data)
+				break
+			}
+		}
+	}
+}
+
+func TestWebSocketSendBinaryMessage(t *testing.T) {
+	clientData := map[string]interface{}{
+		"data": []byte("some data to send as binary"),
+	}
+
+	doneCh := make(chan struct{})
+	s := httptest.NewServer(binaryWebsocketHandler(t, clientData, doneCh))
+	defer s.Close()
+
+	url := strings.Replace(s.URL, "http://", "ws://", 1)
+	cli, err := NewWebSocketClient4(url, "authToken")
+	require.NoError(t, err)
+	cli.Listen()
+	defer cli.Close()
+
+	err = cli.SendBinaryMessage("binaryAction", map[string]interface{}{
+		"unmarshable": func() {},
+	})
+	require.Error(t, err)
+
+	err = cli.SendBinaryMessage("binaryAction", clientData)
+	require.NoError(t, err)
+
+	// This is to make sure the message is handled prior to exiting.
+	<-doneCh
+}

model/websocket_request.go

@@ -4,31 +4,31 @@
 package model
 
 import (
-	"encoding/json"
-
 	"github.com/mattermost/mattermost-server/v6/shared/i18n"
+
+	"github.com/vmihailenco/msgpack/v5"
 )
 
 // WebSocketRequest represents a request made to the server through a websocket.
 type WebSocketRequest struct {
 	// Client-provided fields
-	Seq    int64                  `json:"seq"`    // A counter which is incremented for every request made.
-	Action string                 `json:"action"` // The action to perform for a request. For example: get_statuses, user_typing.
-	Data   map[string]interface{} `json:"data"`   // The metadata for an action.
+	Seq    int64                  `json:"seq" msgpack:"seq"`       // A counter which is incremented for every request made.
+	Action string                 `json:"action" msgpack:"action"` // The action to perform for a request. For example: get_statuses, user_typing.
+	Data   map[string]interface{} `json:"data" msgpack:"data"`     // The metadata for an action.
 
 	// Server-provided fields
-	Session Session            `json:"-"`
-	T       i18n.TranslateFunc `json:"-"`
-	Locale  string             `json:"-"`
+	Session Session            `json:"-" msgpack:"-"`
+	T       i18n.TranslateFunc `json:"-" msgpack:"-"`
+	Locale  string             `json:"-" msgpack:"-"`
 }
 
 func (o *WebSocketRequest) Clone() (*WebSocketRequest, error) {
-	buf, err := json.Marshal(o)
+	buf, err := msgpack.Marshal(o)
 	if err != nil {
 		return nil, err
 	}
 	var ret WebSocketRequest
-	err = json.Unmarshal(buf, &ret)
+	err = msgpack.Unmarshal(buf, &ret)
 	if err != nil {
 		return nil, err
 	}