snapshot of https://github.com/mattermost/mattermost.git (master, 2026-09-16; blobs > 131072B omitted)

server/channels/api4/websocket.go

@@ -0,0 +1,125 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package api4
+
+import (
+	"net/http"
+	"strconv"
+
+	"github.com/gorilla/websocket"
+
+	"github.com/mattermost/mattermost/server/public/model"
+	"github.com/mattermost/mattermost/server/public/shared/mlog"
+	"github.com/mattermost/mattermost/server/v8/channels/app/platform"
+	"github.com/mattermost/mattermost/server/v8/channels/web"
+)
+
+const (
+	connectionIDParam      = "connection_id"
+	sequenceNumberParam    = "sequence_number"
+	postedAckParam         = "posted_ack"
+	disconnectErrCodeParam = "disconnect_err_code"
+
+	clientPingTimeoutErrCode      = 4000
+	clientSequenceMismatchErrCode = 4001
+)
+
+// validateDisconnectErrCode ensures the specified disconnect error code
+// is a valid websocket close code
+func validateDisconnectErrCode(errCode string) bool {
+	if errCode == "" {
+		return false
+	}
+
+	// Ensure the disconnect code is a standard close code
+	code, err := strconv.Atoi(errCode)
+	if err != nil {
+		return false
+	}
+
+	// We only support the standard close codes between
+	// 1000 and 1016, and a few custom application codes
+	if (code < 1000 || code > 1016) &&
+		code != clientPingTimeoutErrCode &&
+		code != clientSequenceMismatchErrCode {
+		return false
+	}
+
+	return true
+}
+
+func (api *API) InitWebSocket() {
+	// Optionally supports a trailing slash
+	api.BaseRoutes.APIRoot.Handle("/{websocket:websocket(?:\\/)?}", api.APIHandlerTrustRequester(connectWebSocket)).Methods(http.MethodGet)
+}
+
+func connectWebSocket(c *Context, w http.ResponseWriter, r *http.Request) {
+	upgrader := websocket.Upgrader{
+		ReadBufferSize:  model.SocketMaxMessageSizeKb,
+		WriteBufferSize: model.SocketMaxMessageSizeKb,
+		CheckOrigin:     c.App.OriginChecker(),
+	}
+
+	ws, err := upgrader.Upgrade(w, r, nil)
+	if err != nil {
+		params := map[string]any{
+			"BlockedOrigin": r.Header.Get("Origin"),
+		}
+		c.Err = model.NewAppError("connect", "api.web_socket.connect.upgrade.app_error", params, "", http.StatusBadRequest).Wrap(err)
+		return
+	}
+
+	// We initialize webconn with all the necessary data.
+	// If the queues are empty, they are initialized in the constructor.
+	cfg := &platform.WebConnConfig{
+		WebSocket:     ws,
+		Session:       *c.AppContext.Session(),
+		TFunc:         c.AppContext.T,
+		Locale:        "",
+		Active:        true,
+		PostedAck:     r.URL.Query().Get(postedAckParam) == "true",
+		RemoteAddress: c.AppContext.IPAddress(),
+		XForwardedFor: c.AppContext.XForwardedFor(),
+	}
+
+	disconnectErrCode := r.URL.Query().Get(disconnectErrCodeParam)
+	if codeValid := validateDisconnectErrCode(disconnectErrCode); codeValid {
+		cfg.DisconnectErrCode = disconnectErrCode
+	}
+
+	// The WebSocket upgrade request coming from mobile is missing the
+	// user agent so we need to fallback on the session's metadata.
+	if c.AppContext.Session().IsMobileApp() {
+		cfg.OriginClient = "mobile"
+	} else {
+		cfg.OriginClient = string(web.GetOriginClient(r))
+	}
+
+	cfg.ConnectionID = r.URL.Query().Get(connectionIDParam)
+	if cfg.ConnectionID == "" || c.AppContext.Session().UserId == "" {
+		// If not present, we assume client is not capable yet, or it's a fresh connection.
+		// We just create a new ID.
+		cfg.ConnectionID = model.NewId()
+		// In case of fresh connection id, sequence number is already zero.
+	} else {
+		cfg, err = c.App.Srv().Platform().PopulateWebConnConfig(c.AppContext.Session(), cfg, r.URL.Query().Get(sequenceNumberParam))
+		if err != nil {
+			c.Logger.Error("Error while populating webconn config", mlog.String("id", r.URL.Query().Get(connectionIDParam)), mlog.Err(err))
+			ws.Close()
+			return
+		}
+	}
+
+	wc := c.App.Srv().Platform().NewWebConn(cfg, c.App, c.App.Srv().Channels())
+	if c.AppContext.Session().UserId != "" {
+		err = c.App.Srv().Platform().HubRegister(wc)
+		if err != nil {
+			c.Logger.Error("Error while registering to hub", mlog.String("id", r.URL.Query().Get(connectionIDParam)), mlog.Err(err))
+			ws.Close()
+			return
+		}
+	}
+
+	wc.Pump()
+}