--- /dev/null
+// Copyright 2013 The Gorilla WebSocket Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package websocket
+
+import (
+ "bytes"
+ "context"
+ "crypto/tls"
+ "errors"
+ "io"
+ "io/ioutil"
+ "net"
+ "net/http"
+ "net/http/httptrace"
+ "net/url"
+ "strings"
+ "time"
+)
+
+// ErrBadHandshake is returned when the server response to opening handshake is
+// invalid.
+var ErrBadHandshake = errors.New("websocket: bad handshake")
+
+var errInvalidCompression = errors.New("websocket: invalid compression negotiation")
+
+// NewClient creates a new client connection using the given net connection.
+// The URL u specifies the host and request URI. Use requestHeader to specify
+// the origin (Origin), subprotocols (Sec-WebSocket-Protocol) and cookies
+// (Cookie). Use the response.Header to get the selected subprotocol
+// (Sec-WebSocket-Protocol) and cookies (Set-Cookie).
+//
+// If the WebSocket handshake fails, ErrBadHandshake is returned along with a
+// non-nil *http.Response so that callers can handle redirects, authentication,
+// etc.
+//
+// Deprecated: Use Dialer instead.
+func NewClient(netConn net.Conn, u *url.URL, requestHeader http.Header, readBufSize, writeBufSize int) (c *Conn, response *http.Response, err error) {
+ d := Dialer{
+ ReadBufferSize: readBufSize,
+ WriteBufferSize: writeBufSize,
+ NetDial: func(net, addr string) (net.Conn, error) {
+ return netConn, nil
+ },
+ }
+ return d.Dial(u.String(), requestHeader)
+}
+
+// A Dialer contains options for connecting to WebSocket server.
+type Dialer struct {
+ // NetDial specifies the dial function for creating TCP connections. If
+ // NetDial is nil, net.Dial is used.
+ NetDial func(network, addr string) (net.Conn, error)
+
+ // NetDialContext specifies the dial function for creating TCP connections. If
+ // NetDialContext is nil, net.DialContext is used.
+ NetDialContext func(ctx context.Context, network, addr string) (net.Conn, error)
+
+ // Proxy specifies a function to return a proxy for a given
+ // Request. If the function returns a non-nil error, the
+ // request is aborted with the provided error.
+ // If Proxy is nil or returns a nil *URL, no proxy is used.
+ Proxy func(*http.Request) (*url.URL, error)
+
+ // TLSClientConfig specifies the TLS configuration to use with tls.Client.
+ // If nil, the default configuration is used.
+ TLSClientConfig *tls.Config
+
+ // HandshakeTimeout specifies the duration for the handshake to complete.
+ HandshakeTimeout time.Duration
+
+ // ReadBufferSize and WriteBufferSize specify I/O buffer sizes in bytes. If a buffer
+ // size is zero, then a useful default size is used. The I/O buffer sizes
+ // do not limit the size of the messages that can be sent or received.
+ ReadBufferSize, WriteBufferSize int
+
+ // WriteBufferPool is a pool of buffers for write operations. If the value
+ // is not set, then write buffers are allocated to the connection for the
+ // lifetime of the connection.
+ //
+ // A pool is most useful when the application has a modest volume of writes
+ // across a large number of connections.
+ //
+ // Applications should use a single pool for each unique value of
+ // WriteBufferSize.
+ WriteBufferPool BufferPool
+
+ // Subprotocols specifies the client's requested subprotocols.
+ Subprotocols []string
+
+ // EnableCompression specifies if the client 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
+
+ // Jar specifies the cookie jar.
+ // If Jar is nil, cookies are not sent in requests and ignored
+ // in responses.
+ Jar http.CookieJar
+}
+
+// Dial creates a new client connection by calling DialContext with a background context.
+func (d *Dialer) Dial(urlStr string, requestHeader http.Header) (*Conn, *http.Response, error) {
+ return d.DialContext(context.Background(), urlStr, requestHeader)
+}
+
+var errMalformedURL = errors.New("malformed ws or wss URL")
+
+func hostPortNoPort(u *url.URL) (hostPort, hostNoPort string) {
+ hostPort = u.Host
+ hostNoPort = u.Host
+ if i := strings.LastIndex(u.Host, ":"); i > strings.LastIndex(u.Host, "]") {
+ hostNoPort = hostNoPort[:i]
+ } else {
+ switch u.Scheme {
+ case "wss":
+ hostPort += ":443"
+ case "https":
+ hostPort += ":443"
+ default:
+ hostPort += ":80"
+ }
+ }
+ return hostPort, hostNoPort
+}
+
+// DefaultDialer is a dialer with all fields set to the default values.
+var DefaultDialer = &Dialer{
+ Proxy: http.ProxyFromEnvironment,
+ HandshakeTimeout: 45 * time.Second,
+}
+
+// nilDialer is dialer to use when receiver is nil.
+var nilDialer = *DefaultDialer
+
+// DialContext creates a new client connection. Use requestHeader to specify the
+// origin (Origin), subprotocols (Sec-WebSocket-Protocol) and cookies (Cookie).
+// Use the response.Header to get the selected subprotocol
+// (Sec-WebSocket-Protocol) and cookies (Set-Cookie).
+//
+// The context will be used in the request and in the Dialer.
+//
+// If the WebSocket handshake fails, ErrBadHandshake is returned along with a
+// non-nil *http.Response so that callers can handle redirects, authentication,
+// etcetera. The response body may not contain the entire response and does not
+// need to be closed by the application.
+func (d *Dialer) DialContext(ctx context.Context, urlStr string, requestHeader http.Header) (*Conn, *http.Response, error) {
+ if d == nil {
+ d = &nilDialer
+ }
+
+ challengeKey, err := generateChallengeKey()
+ if err != nil {
+ return nil, nil, err
+ }
+
+ u, err := url.Parse(urlStr)
+ if err != nil {
+ return nil, nil, err
+ }
+
+ switch u.Scheme {
+ case "ws":
+ u.Scheme = "http"
+ case "wss":
+ u.Scheme = "https"
+ default:
+ return nil, nil, errMalformedURL
+ }
+
+ if u.User != nil {
+ // User name and password are not allowed in websocket URIs.
+ return nil, nil, errMalformedURL
+ }
+
+ req := &http.Request{
+ Method: "GET",
+ URL: u,
+ Proto: "HTTP/1.1",
+ ProtoMajor: 1,
+ ProtoMinor: 1,
+ Header: make(http.Header),
+ Host: u.Host,
+ }
+ req = req.WithContext(ctx)
+
+ // Set the cookies present in the cookie jar of the dialer
+ if d.Jar != nil {
+ for _, cookie := range d.Jar.Cookies(u) {
+ req.AddCookie(cookie)
+ }
+ }
+
+ // Set the request headers using the capitalization for names and values in
+ // RFC examples. Although the capitalization shouldn't matter, there are
+ // servers that depend on it. The Header.Set method is not used because the
+ // method canonicalizes the header names.
+ req.Header["Upgrade"] = []string{"websocket"}
+ req.Header["Connection"] = []string{"Upgrade"}
+ req.Header["Sec-WebSocket-Key"] = []string{challengeKey}
+ req.Header["Sec-WebSocket-Version"] = []string{"13"}
+ if len(d.Subprotocols) > 0 {
+ req.Header["Sec-WebSocket-Protocol"] = []string{strings.Join(d.Subprotocols, ", ")}
+ }
+ for k, vs := range requestHeader {
+ switch {
+ case k == "Host":
+ if len(vs) > 0 {
+ req.Host = vs[0]
+ }
+ case k == "Upgrade" ||
+ k == "Connection" ||
+ k == "Sec-Websocket-Key" ||
+ k == "Sec-Websocket-Version" ||
+ k == "Sec-Websocket-Extensions" ||
+ (k == "Sec-Websocket-Protocol" && len(d.Subprotocols) > 0):
+ return nil, nil, errors.New("websocket: duplicate header not allowed: " + k)
+ case k == "Sec-Websocket-Protocol":
+ req.Header["Sec-WebSocket-Protocol"] = vs
+ default:
+ req.Header[k] = vs
+ }
+ }
+
+ if d.EnableCompression {
+ req.Header["Sec-WebSocket-Extensions"] = []string{"permessage-deflate; server_no_context_takeover; client_no_context_takeover"}
+ }
+
+ if d.HandshakeTimeout != 0 {
+ var cancel func()
+ ctx, cancel = context.WithTimeout(ctx, d.HandshakeTimeout)
+ defer cancel()
+ }
+
+ // Get network dial function.
+ var netDial func(network, add string) (net.Conn, error)
+
+ if d.NetDialContext != nil {
+ netDial = func(network, addr string) (net.Conn, error) {
+ return d.NetDialContext(ctx, network, addr)
+ }
+ } else if d.NetDial != nil {
+ netDial = d.NetDial
+ } else {
+ netDialer := &net.Dialer{}
+ netDial = func(network, addr string) (net.Conn, error) {
+ return netDialer.DialContext(ctx, network, addr)
+ }
+ }
+
+ // If needed, wrap the dial function to set the connection deadline.
+ if deadline, ok := ctx.Deadline(); ok {
+ forwardDial := netDial
+ netDial = func(network, addr string) (net.Conn, error) {
+ c, err := forwardDial(network, addr)
+ if err != nil {
+ return nil, err
+ }
+ err = c.SetDeadline(deadline)
+ if err != nil {
+ c.Close()
+ return nil, err
+ }
+ return c, nil
+ }
+ }
+
+ // If needed, wrap the dial function to connect through a proxy.
+ if d.Proxy != nil {
+ proxyURL, err := d.Proxy(req)
+ if err != nil {
+ return nil, nil, err
+ }
+ if proxyURL != nil {
+ dialer, err := proxy_FromURL(proxyURL, netDialerFunc(netDial))
+ if err != nil {
+ return nil, nil, err
+ }
+ netDial = dialer.Dial
+ }
+ }
+
+ hostPort, hostNoPort := hostPortNoPort(u)
+ trace := httptrace.ContextClientTrace(ctx)
+ if trace != nil && trace.GetConn != nil {
+ trace.GetConn(hostPort)
+ }
+
+ netConn, err := netDial("tcp", hostPort)
+ if trace != nil && trace.GotConn != nil {
+ trace.GotConn(httptrace.GotConnInfo{
+ Conn: netConn,
+ })
+ }
+ if err != nil {
+ return nil, nil, err
+ }
+
+ defer func() {
+ if netConn != nil {
+ netConn.Close()
+ }
+ }()
+
+ if u.Scheme == "https" {
+ cfg := cloneTLSConfig(d.TLSClientConfig)
+ if cfg.ServerName == "" {
+ cfg.ServerName = hostNoPort
+ }
+ tlsConn := tls.Client(netConn, cfg)
+ netConn = tlsConn
+
+ var err error
+ if trace != nil {
+ err = doHandshakeWithTrace(trace, tlsConn, cfg)
+ } else {
+ err = doHandshake(tlsConn, cfg)
+ }
+
+ if err != nil {
+ return nil, nil, err
+ }
+ }
+
+ conn := newConn(netConn, false, d.ReadBufferSize, d.WriteBufferSize, d.WriteBufferPool, nil, nil)
+
+ if err := req.Write(netConn); err != nil {
+ return nil, nil, err
+ }
+
+ if trace != nil && trace.GotFirstResponseByte != nil {
+ if peek, err := conn.br.Peek(1); err == nil && len(peek) == 1 {
+ trace.GotFirstResponseByte()
+ }
+ }
+
+ resp, err := http.ReadResponse(conn.br, req)
+ if err != nil {
+ return nil, nil, err
+ }
+
+ if d.Jar != nil {
+ if rc := resp.Cookies(); len(rc) > 0 {
+ d.Jar.SetCookies(u, rc)
+ }
+ }
+
+ if resp.StatusCode != 101 ||
+ !strings.EqualFold(resp.Header.Get("Upgrade"), "websocket") ||
+ !strings.EqualFold(resp.Header.Get("Connection"), "upgrade") ||
+ resp.Header.Get("Sec-Websocket-Accept") != computeAcceptKey(challengeKey) {
+ // Before closing the network connection on return from this
+ // function, slurp up some of the response to aid application
+ // debugging.
+ buf := make([]byte, 1024)
+ n, _ := io.ReadFull(resp.Body, buf)
+ resp.Body = ioutil.NopCloser(bytes.NewReader(buf[:n]))
+ return nil, resp, ErrBadHandshake
+ }
+
+ for _, ext := range parseExtensions(resp.Header) {
+ if ext[""] != "permessage-deflate" {
+ continue
+ }
+ _, snct := ext["server_no_context_takeover"]
+ _, cnct := ext["client_no_context_takeover"]
+ if !snct || !cnct {
+ return nil, resp, errInvalidCompression
+ }
+ conn.newCompressionWriter = compressNoContextTakeover
+ conn.newDecompressionReader = decompressNoContextTakeover
+ break
+ }
+
+ resp.Body = ioutil.NopCloser(bytes.NewReader([]byte{}))
+ conn.subprotocol = resp.Header.Get("Sec-Websocket-Protocol")
+
+ netConn.SetDeadline(time.Time{})
+ netConn = nil // to avoid close in defer.
+ return conn, resp, nil
+}
+
+func doHandshake(tlsConn *tls.Conn, cfg *tls.Config) error {
+ if err := tlsConn.Handshake(); err != nil {
+ return err
+ }
+ if !cfg.InsecureSkipVerify {
+ if err := tlsConn.VerifyHostname(cfg.ServerName); err != nil {
+ return err
+ }
+ }
+ return nil
+}
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