1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269
|
// 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"
"crypto/tls"
"errors"
"io"
"io/ioutil"
"net"
"net/http"
"net/url"
"strings"
"time"
)
// ErrBadHandshake is returned when the server response to opening handshake is
// invalid.
var ErrBadHandshake = errors.New("websocket: bad handshake")
// 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.
func NewClient(netConn net.Conn, u *url.URL, requestHeader http.Header, readBufSize, writeBufSize int) (c *Conn, response *http.Response, err error) {
challengeKey, err := generateChallengeKey()
if err != nil {
return nil, nil, err
}
acceptKey := computeAcceptKey(challengeKey)
c = newConn(netConn, false, readBufSize, writeBufSize)
p := c.writeBuf[:0]
p = append(p, "GET "...)
p = append(p, u.RequestURI()...)
p = append(p, " HTTP/1.1\r\nHost: "...)
p = append(p, u.Host...)
// "Upgrade" is capitalized for servers that do not use case insensitive
// comparisons on header tokens.
p = append(p, "\r\nUpgrade: websocket\r\nConnection: Upgrade\r\nSec-WebSocket-Version: 13\r\nSec-WebSocket-Key: "...)
p = append(p, challengeKey...)
p = append(p, "\r\n"...)
for k, vs := range requestHeader {
for _, v := range vs {
p = append(p, k...)
p = append(p, ": "...)
p = append(p, v...)
p = append(p, "\r\n"...)
}
}
p = append(p, "\r\n"...)
if _, err := netConn.Write(p); err != nil {
return nil, nil, err
}
resp, err := http.ReadResponse(c.br, &http.Request{Method: "GET", URL: u})
if err != nil {
return nil, nil, err
}
if resp.StatusCode != 101 ||
!strings.EqualFold(resp.Header.Get("Upgrade"), "websocket") ||
!strings.EqualFold(resp.Header.Get("Connection"), "upgrade") ||
resp.Header.Get("Sec-Websocket-Accept") != acceptKey {
return nil, resp, ErrBadHandshake
}
c.subprotocol = resp.Header.Get("Sec-Websocket-Protocol")
return c, resp, nil
}
// 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)
// 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
// Input and output buffer sizes. If the buffer size is zero, then a
// default value of 4096 is used.
ReadBufferSize, WriteBufferSize int
// Subprotocols specifies the client's requested subprotocols.
Subprotocols []string
}
var errMalformedURL = errors.New("malformed ws or wss URL")
// parseURL parses the URL. The url.Parse function is not used here because
// url.Parse mangles the path.
func parseURL(s string) (*url.URL, error) {
// From the RFC:
//
// ws-URI = "ws:" "//" host [ ":" port ] path [ "?" query ]
// wss-URI = "wss:" "//" host [ ":" port ] path [ "?" query ]
//
// We don't use the net/url parser here because the dialer interface does
// not provide a way for applications to work around percent deocding in
// the net/url parser.
var u url.URL
switch {
case strings.HasPrefix(s, "ws://"):
u.Scheme = "ws"
s = s[len("ws://"):]
case strings.HasPrefix(s, "wss://"):
u.Scheme = "wss"
s = s[len("wss://"):]
default:
return nil, errMalformedURL
}
u.Host = s
u.Opaque = "/"
if i := strings.Index(s, "/"); i >= 0 {
u.Host = s[:i]
u.Opaque = s[i:]
}
if strings.Contains(u.Host, "@") {
// WebSocket URIs do not contain user information.
return nil, errMalformedURL
}
return &u, nil
}
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 {
if u.Scheme == "wss" {
hostPort += ":443"
} else {
hostPort += ":80"
}
}
return hostPort, hostNoPort
}
// DefaultDialer is a dialer with all fields set to the default zero values.
var DefaultDialer *Dialer
// Dial 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).
//
// 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) Dial(urlStr string, requestHeader http.Header) (*Conn, *http.Response, error) {
u, err := parseURL(urlStr)
if err != nil {
return nil, nil, err
}
hostPort, hostNoPort := hostPortNoPort(u)
if d == nil {
d = &Dialer{}
}
var deadline time.Time
if d.HandshakeTimeout != 0 {
deadline = time.Now().Add(d.HandshakeTimeout)
}
netDial := d.NetDial
if netDial == nil {
netDialer := &net.Dialer{Deadline: deadline}
netDial = netDialer.Dial
}
netConn, err := netDial("tcp", hostPort)
if err != nil {
return nil, nil, err
}
defer func() {
if netConn != nil {
netConn.Close()
}
}()
if err := netConn.SetDeadline(deadline); err != nil {
return nil, nil, err
}
if u.Scheme == "wss" {
cfg := d.TLSClientConfig
if cfg == nil {
cfg = &tls.Config{ServerName: hostNoPort}
} else if cfg.ServerName == "" {
shallowCopy := *cfg
cfg = &shallowCopy
cfg.ServerName = hostNoPort
}
tlsConn := tls.Client(netConn, cfg)
netConn = tlsConn
if err := tlsConn.Handshake(); err != nil {
return nil, nil, err
}
if !cfg.InsecureSkipVerify {
if err := tlsConn.VerifyHostname(cfg.ServerName); err != nil {
return nil, nil, err
}
}
}
if len(d.Subprotocols) > 0 {
h := http.Header{}
for k, v := range requestHeader {
h[k] = v
}
h.Set("Sec-Websocket-Protocol", strings.Join(d.Subprotocols, ", "))
requestHeader = h
}
if len(requestHeader["Host"]) > 0 {
// This can be used to supply a Host: header which is different from
// the dial address.
u.Host = requestHeader.Get("Host")
// Drop "Host" header
h := http.Header{}
for k, v := range requestHeader {
if k == "Host" {
continue
}
h[k] = v
}
requestHeader = h
}
conn, resp, err := NewClient(netConn, u, requestHeader, d.ReadBufferSize, d.WriteBufferSize)
if err != nil {
if err == ErrBadHandshake {
// 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, err
}
netConn.SetDeadline(time.Time{})
netConn = nil // to avoid close in defer.
return conn, resp, nil
}
|