make websocket per-message compression optional

server/hdl_websock.go

@@ -159,7 +159,7 @@ func wsWrite(ws *websocket.Conn, mt int, msg any) error {
 var upgrader = websocket.Upgrader{
 	ReadBufferSize:    1024,
 	WriteBufferSize:   1024,
-	EnableCompression: true,
+	EnableCompression: globals.wsCompression,
 	// Allow connections from any Origin
 	CheckOrigin: func(r *http.Request) bool { return true },
 }

server/main.go

@@ -195,6 +195,9 @@ var globals struct {
 
 	// ICE servers config (video calling)
 	iceServers []iceServer
+
+	// Websocket per-message compression negotiation is enabled.
+	wsCompression bool
 }
 
 // Credential validator config.
@@ -245,6 +248,9 @@ type configType struct {
 	ApiPath string `json:"api_path"`
 	// Cache-Control value for static content.
 	CacheControl int `json:"cache_control"`
+	// If true, do not attempt to negotiate websocket per message compression (RFC 7692.4).
+	// It should be disabled (set to true) if you are using MSFT IIS as reverse proxy.
+	WSCompressionDisabled bool `json:"ws_compression_disabled"`
 	// Address:port to listen for gRPC clients. If blank gRPC support will not be initialized.
 	// Could be overridden from the command line with --grpc_listen.
 	GrpcListen string `json:"grpc_listen"`
@@ -545,6 +551,9 @@ func main() {
 		globals.defaultCountryCode = defaultCountryCode
 	}
 
+	// Websocket compression.
+	globals.wsCompression = !config.WSCompressionDisabled
+
 	if config.Media != nil {
 		if config.Media.UseHandler == "" {
 			config.Media = nil

server/tinode.conf

@@ -15,6 +15,10 @@
 	// Cache-Control header for static content in seconds. 39600 is 11 hours.
 	"cache_control": 39600,
 
+	// If true, do not attempt to negotiate websocket per message compression (RFC 7692.4).
+	// It should be disabled (set to true) if you are using MSFT IIS as a reverse proxy.
+	"ws_compression_disabled": false,
+
 	// URL path for mounting the directory with static files.
 	"static_mount": "/",