cleanup

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

@@ -28,8 +28,9 @@ type Upgrader struct {
 	HandshakeTimeout time.Duration
 
 	// ReadBufferSize and WriteBufferSize specify I/O buffer sizes. If a buffer
-	// size is zero, then a default value of 4096 is used. The I/O buffer sizes
-	// do not limit the size of the messages that can be sent or received.
+	// size is zero, then buffers allocated by the HTTP server are used. The
+	// I/O buffer sizes do not limit the size of the messages that can be sent
+	// or received.
 	ReadBufferSize, WriteBufferSize int
 
 	// Subprotocols specifies the server's supported protocols in order of
@@ -46,6 +47,12 @@ 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 +60,7 @@ 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
@@ -97,18 +105,23 @@ func (u *Upgrader) selectSubprotocol(r *http.Request, responseHeader http.Header
 // response.
 func (u *Upgrader) Upgrade(w http.ResponseWriter, r *http.Request, responseHeader http.Header) (*Conn, error) {
 	if r.Method != "GET" {
-		return u.returnError(w, r, http.StatusMethodNotAllowed, "websocket: method not GET")
+		return u.returnError(w, r, http.StatusMethodNotAllowed, "websocket: not a websocket handshake: request method is not GET")
 	}
-	if values := r.Header["Sec-Websocket-Version"]; len(values) == 0 || values[0] != "13" {
-		return u.returnError(w, r, http.StatusBadRequest, "websocket: version != 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, "Connection", "upgrade") {
-		return u.returnError(w, r, http.StatusBadRequest, "websocket: could not find connection header with token 'upgrade'")
+		return u.returnError(w, r, http.StatusBadRequest, "websocket: not a websocket handshake: 'upgrade' token not found in 'Connection' header")
 	}
 
 	if !tokenListContainsValue(r.Header, "Upgrade", "websocket") {
-		return u.returnError(w, r, http.StatusBadRequest, "websocket: could not find upgrade header with token 'websocket'")
+		return u.returnError(w, r, http.StatusBadRequest, "websocket: not a websocket handshake: 'websocket' token not found in 'Upgrade' header")
+	}
+
+	if !tokenListContainsValue(r.Header, "Sec-Websocket-Version", "13") {
+		return u.returnError(w, r, http.StatusBadRequest, "websocket: unsupported version: 13 not found in 'Sec-Websocket-Version' header")
 	}
 
 	checkOrigin := u.CheckOrigin
@@ -116,19 +129,30 @@ func (u *Upgrader) Upgrade(w http.ResponseWriter, r *http.Request, responseHeade
 		checkOrigin = checkSameOrigin
 	}
 	if !checkOrigin(r) {
-		return u.returnError(w, r, http.StatusForbidden, "websocket: origin not allowed")
+		return u.returnError(w, r, http.StatusForbidden, "websocket: 'Origin' header value not allowed")
 	}
 
 	challengeKey := r.Header.Get("Sec-Websocket-Key")
 	if challengeKey == "" {
-		return u.returnError(w, r, http.StatusBadRequest, "websocket: key missing or blank")
+		return u.returnError(w, r, http.StatusBadRequest, "websocket: not a websocket handshake: `Sec-Websocket-Key' header is missing or blank")
 	}
 
 	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
 		err     error
 	)
 
@@ -136,21 +160,25 @@ func (u *Upgrader) Upgrade(w http.ResponseWriter, r *http.Request, responseHeade
 	if !ok {
 		return u.returnError(w, r, http.StatusInternalServerError, "websocket: response does not implement http.Hijacker")
 	}
-	var rw *bufio.ReadWriter
-	netConn, rw, err = h.Hijack()
+	var brw *bufio.ReadWriter
+	netConn, brw, err = h.Hijack()
 	if err != nil {
 		return u.returnError(w, r, http.StatusInternalServerError, err.Error())
 	}
-	br = rw.Reader
 
-	if br.Buffered() > 0 {
+	if brw.Reader.Buffered() > 0 {
 		netConn.Close()
 		return nil, errors.New("websocket: client sent data before handshake is complete")
 	}
 
-	c := newConn(netConn, true, u.ReadBufferSize, u.WriteBufferSize)
+	c := newConnBRW(netConn, true, u.ReadBufferSize, u.WriteBufferSize, brw)
 	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 +188,9 @@ 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