updated websocket lib

vendor/github.com/gorilla/websocket/server.go

@@ -46,6 +46,12 @@ type Upgrader struct {
 	// CheckOrigin is nil, the host in the Origin header must not be set or
 	// must match the host of the request.
 	CheckOrigin func(r *http.Request) bool
+
+	// EnableCompression specify if the server should attempt to negotiate per
+	// message compression (RFC 7692). Setting this value to true does not
+	// guarantee that compression will be supported. Currently only "no context
+	// takeover" modes are supported.
+	EnableCompression bool
 }
 
 func (u *Upgrader) returnError(w http.ResponseWriter, r *http.Request, status int, reason string) (*Conn, error) {
@@ -53,6 +59,7 @@ func (u *Upgrader) returnError(w http.ResponseWriter, r *http.Request, status in
 	if u.Error != nil {
 		u.Error(w, r, status, err)
 	} else {
+		w.Header().Set("Sec-Websocket-Version", "13")
 		http.Error(w, http.StatusText(status), status)
 	}
 	return nil, err
@@ -99,7 +106,12 @@ func (u *Upgrader) Upgrade(w http.ResponseWriter, r *http.Request, responseHeade
 	if r.Method != "GET" {
 		return u.returnError(w, r, http.StatusMethodNotAllowed, "websocket: method not GET")
 	}
-	if values := r.Header["Sec-Websocket-Version"]; len(values) == 0 || values[0] != "13" {
+
+	if _, ok := responseHeader["Sec-Websocket-Extensions"]; ok {
+		return u.returnError(w, r, http.StatusInternalServerError, "websocket: application specific Sec-Websocket-Extensions headers are unsupported")
+	}
+
+	if !tokenListContainsValue(r.Header, "Sec-Websocket-Version", "13") {
 		return u.returnError(w, r, http.StatusBadRequest, "websocket: version != 13")
 	}
 
@@ -126,6 +138,18 @@ func (u *Upgrader) Upgrade(w http.ResponseWriter, r *http.Request, responseHeade
 
 	subprotocol := u.selectSubprotocol(r, responseHeader)
 
+	// Negotiate PMCE
+	var compress bool
+	if u.EnableCompression {
+		for _, ext := range parseExtensions(r.Header) {
+			if ext[""] != "permessage-deflate" {
+				continue
+			}
+			compress = true
+			break
+		}
+	}
+
 	var (
 		netConn net.Conn
 		br      *bufio.Reader
@@ -151,6 +175,11 @@ func (u *Upgrader) Upgrade(w http.ResponseWriter, r *http.Request, responseHeade
 	c := newConn(netConn, true, u.ReadBufferSize, u.WriteBufferSize)
 	c.subprotocol = subprotocol
 
+	if compress {
+		c.newCompressionWriter = compressNoContextTakeover
+		c.newDecompressionReader = decompressNoContextTakeover
+	}
+
 	p := c.writeBuf[:0]
 	p = append(p, "HTTP/1.1 101 Switching Protocols\r\nUpgrade: websocket\r\nConnection: Upgrade\r\nSec-WebSocket-Accept: "...)
 	p = append(p, computeAcceptKey(challengeKey)...)
@@ -160,6 +189,9 @@ func (u *Upgrader) Upgrade(w http.ResponseWriter, r *http.Request, responseHeade
 		p = append(p, c.subprotocol...)
 		p = append(p, "\r\n"...)
 	}
+	if compress {
+		p = append(p, "Sec-Websocket-Extensions: permessage-deflate; server_no_context_takeover; client_no_context_takeover\r\n"...)
+	}
 	for k, vs := range responseHeader {
 		if k == "Sec-Websocket-Protocol" {
 			continue
@@ -251,3 +283,10 @@ func Subprotocols(r *http.Request) []string {
 	}
 	return protocols
 }
+
+// IsWebSocketUpgrade returns true if the client requested upgrade to the
+// WebSocket protocol.
+func IsWebSocketUpgrade(r *http.Request) bool {
+	return tokenListContainsValue(r.Header, "Connection", "upgrade") &&
+		tokenListContainsValue(r.Header, "Upgrade", "websocket")
+}