David K. Bainbridge | 215e024 | 2017-09-05 23:18:24 -0700 | [diff] [blame] | 1 | // Copyright 2009 The Go Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | // Package websocket implements a client and server for the WebSocket protocol |
| 6 | // as specified in RFC 6455. |
| 7 | // |
| 8 | // This package currently lacks some features found in an alternative |
| 9 | // and more actively maintained WebSocket package: |
| 10 | // |
| 11 | // https://godoc.org/github.com/gorilla/websocket |
| 12 | // |
| 13 | package websocket // import "golang.org/x/net/websocket" |
| 14 | |
| 15 | import ( |
| 16 | "bufio" |
| 17 | "crypto/tls" |
| 18 | "encoding/json" |
| 19 | "errors" |
| 20 | "io" |
| 21 | "io/ioutil" |
| 22 | "net" |
| 23 | "net/http" |
| 24 | "net/url" |
| 25 | "sync" |
| 26 | "time" |
| 27 | ) |
| 28 | |
| 29 | const ( |
| 30 | ProtocolVersionHybi13 = 13 |
| 31 | ProtocolVersionHybi = ProtocolVersionHybi13 |
| 32 | SupportedProtocolVersion = "13" |
| 33 | |
| 34 | ContinuationFrame = 0 |
| 35 | TextFrame = 1 |
| 36 | BinaryFrame = 2 |
| 37 | CloseFrame = 8 |
| 38 | PingFrame = 9 |
| 39 | PongFrame = 10 |
| 40 | UnknownFrame = 255 |
| 41 | |
| 42 | DefaultMaxPayloadBytes = 32 << 20 // 32MB |
| 43 | ) |
| 44 | |
| 45 | // ProtocolError represents WebSocket protocol errors. |
| 46 | type ProtocolError struct { |
| 47 | ErrorString string |
| 48 | } |
| 49 | |
| 50 | func (err *ProtocolError) Error() string { return err.ErrorString } |
| 51 | |
| 52 | var ( |
| 53 | ErrBadProtocolVersion = &ProtocolError{"bad protocol version"} |
| 54 | ErrBadScheme = &ProtocolError{"bad scheme"} |
| 55 | ErrBadStatus = &ProtocolError{"bad status"} |
| 56 | ErrBadUpgrade = &ProtocolError{"missing or bad upgrade"} |
| 57 | ErrBadWebSocketOrigin = &ProtocolError{"missing or bad WebSocket-Origin"} |
| 58 | ErrBadWebSocketLocation = &ProtocolError{"missing or bad WebSocket-Location"} |
| 59 | ErrBadWebSocketProtocol = &ProtocolError{"missing or bad WebSocket-Protocol"} |
| 60 | ErrBadWebSocketVersion = &ProtocolError{"missing or bad WebSocket Version"} |
| 61 | ErrChallengeResponse = &ProtocolError{"mismatch challenge/response"} |
| 62 | ErrBadFrame = &ProtocolError{"bad frame"} |
| 63 | ErrBadFrameBoundary = &ProtocolError{"not on frame boundary"} |
| 64 | ErrNotWebSocket = &ProtocolError{"not websocket protocol"} |
| 65 | ErrBadRequestMethod = &ProtocolError{"bad method"} |
| 66 | ErrNotSupported = &ProtocolError{"not supported"} |
| 67 | ) |
| 68 | |
| 69 | // ErrFrameTooLarge is returned by Codec's Receive method if payload size |
| 70 | // exceeds limit set by Conn.MaxPayloadBytes |
| 71 | var ErrFrameTooLarge = errors.New("websocket: frame payload size exceeds limit") |
| 72 | |
| 73 | // Addr is an implementation of net.Addr for WebSocket. |
| 74 | type Addr struct { |
| 75 | *url.URL |
| 76 | } |
| 77 | |
| 78 | // Network returns the network type for a WebSocket, "websocket". |
| 79 | func (addr *Addr) Network() string { return "websocket" } |
| 80 | |
| 81 | // Config is a WebSocket configuration |
| 82 | type Config struct { |
| 83 | // A WebSocket server address. |
| 84 | Location *url.URL |
| 85 | |
| 86 | // A Websocket client origin. |
| 87 | Origin *url.URL |
| 88 | |
| 89 | // WebSocket subprotocols. |
| 90 | Protocol []string |
| 91 | |
| 92 | // WebSocket protocol version. |
| 93 | Version int |
| 94 | |
| 95 | // TLS config for secure WebSocket (wss). |
| 96 | TlsConfig *tls.Config |
| 97 | |
| 98 | // Additional header fields to be sent in WebSocket opening handshake. |
| 99 | Header http.Header |
| 100 | |
| 101 | // Dialer used when opening websocket connections. |
| 102 | Dialer *net.Dialer |
| 103 | |
| 104 | handshakeData map[string]string |
| 105 | } |
| 106 | |
| 107 | // serverHandshaker is an interface to handle WebSocket server side handshake. |
| 108 | type serverHandshaker interface { |
| 109 | // ReadHandshake reads handshake request message from client. |
| 110 | // Returns http response code and error if any. |
| 111 | ReadHandshake(buf *bufio.Reader, req *http.Request) (code int, err error) |
| 112 | |
| 113 | // AcceptHandshake accepts the client handshake request and sends |
| 114 | // handshake response back to client. |
| 115 | AcceptHandshake(buf *bufio.Writer) (err error) |
| 116 | |
| 117 | // NewServerConn creates a new WebSocket connection. |
| 118 | NewServerConn(buf *bufio.ReadWriter, rwc io.ReadWriteCloser, request *http.Request) (conn *Conn) |
| 119 | } |
| 120 | |
| 121 | // frameReader is an interface to read a WebSocket frame. |
| 122 | type frameReader interface { |
| 123 | // Reader is to read payload of the frame. |
| 124 | io.Reader |
| 125 | |
| 126 | // PayloadType returns payload type. |
| 127 | PayloadType() byte |
| 128 | |
| 129 | // HeaderReader returns a reader to read header of the frame. |
| 130 | HeaderReader() io.Reader |
| 131 | |
| 132 | // TrailerReader returns a reader to read trailer of the frame. |
| 133 | // If it returns nil, there is no trailer in the frame. |
| 134 | TrailerReader() io.Reader |
| 135 | |
| 136 | // Len returns total length of the frame, including header and trailer. |
| 137 | Len() int |
| 138 | } |
| 139 | |
| 140 | // frameReaderFactory is an interface to creates new frame reader. |
| 141 | type frameReaderFactory interface { |
| 142 | NewFrameReader() (r frameReader, err error) |
| 143 | } |
| 144 | |
| 145 | // frameWriter is an interface to write a WebSocket frame. |
| 146 | type frameWriter interface { |
| 147 | // Writer is to write payload of the frame. |
| 148 | io.WriteCloser |
| 149 | } |
| 150 | |
| 151 | // frameWriterFactory is an interface to create new frame writer. |
| 152 | type frameWriterFactory interface { |
| 153 | NewFrameWriter(payloadType byte) (w frameWriter, err error) |
| 154 | } |
| 155 | |
| 156 | type frameHandler interface { |
| 157 | HandleFrame(frame frameReader) (r frameReader, err error) |
| 158 | WriteClose(status int) (err error) |
| 159 | } |
| 160 | |
| 161 | // Conn represents a WebSocket connection. |
| 162 | // |
| 163 | // Multiple goroutines may invoke methods on a Conn simultaneously. |
| 164 | type Conn struct { |
| 165 | config *Config |
| 166 | request *http.Request |
| 167 | |
| 168 | buf *bufio.ReadWriter |
| 169 | rwc io.ReadWriteCloser |
| 170 | |
| 171 | rio sync.Mutex |
| 172 | frameReaderFactory |
| 173 | frameReader |
| 174 | |
| 175 | wio sync.Mutex |
| 176 | frameWriterFactory |
| 177 | |
| 178 | frameHandler |
| 179 | PayloadType byte |
| 180 | defaultCloseStatus int |
| 181 | |
| 182 | // MaxPayloadBytes limits the size of frame payload received over Conn |
| 183 | // by Codec's Receive method. If zero, DefaultMaxPayloadBytes is used. |
| 184 | MaxPayloadBytes int |
| 185 | } |
| 186 | |
| 187 | // Read implements the io.Reader interface: |
| 188 | // it reads data of a frame from the WebSocket connection. |
| 189 | // if msg is not large enough for the frame data, it fills the msg and next Read |
| 190 | // will read the rest of the frame data. |
| 191 | // it reads Text frame or Binary frame. |
| 192 | func (ws *Conn) Read(msg []byte) (n int, err error) { |
| 193 | ws.rio.Lock() |
| 194 | defer ws.rio.Unlock() |
| 195 | again: |
| 196 | if ws.frameReader == nil { |
| 197 | frame, err := ws.frameReaderFactory.NewFrameReader() |
| 198 | if err != nil { |
| 199 | return 0, err |
| 200 | } |
| 201 | ws.frameReader, err = ws.frameHandler.HandleFrame(frame) |
| 202 | if err != nil { |
| 203 | return 0, err |
| 204 | } |
| 205 | if ws.frameReader == nil { |
| 206 | goto again |
| 207 | } |
| 208 | } |
| 209 | n, err = ws.frameReader.Read(msg) |
| 210 | if err == io.EOF { |
| 211 | if trailer := ws.frameReader.TrailerReader(); trailer != nil { |
| 212 | io.Copy(ioutil.Discard, trailer) |
| 213 | } |
| 214 | ws.frameReader = nil |
| 215 | goto again |
| 216 | } |
| 217 | return n, err |
| 218 | } |
| 219 | |
| 220 | // Write implements the io.Writer interface: |
| 221 | // it writes data as a frame to the WebSocket connection. |
| 222 | func (ws *Conn) Write(msg []byte) (n int, err error) { |
| 223 | ws.wio.Lock() |
| 224 | defer ws.wio.Unlock() |
| 225 | w, err := ws.frameWriterFactory.NewFrameWriter(ws.PayloadType) |
| 226 | if err != nil { |
| 227 | return 0, err |
| 228 | } |
| 229 | n, err = w.Write(msg) |
| 230 | w.Close() |
| 231 | return n, err |
| 232 | } |
| 233 | |
| 234 | // Close implements the io.Closer interface. |
| 235 | func (ws *Conn) Close() error { |
| 236 | err := ws.frameHandler.WriteClose(ws.defaultCloseStatus) |
| 237 | err1 := ws.rwc.Close() |
| 238 | if err != nil { |
| 239 | return err |
| 240 | } |
| 241 | return err1 |
| 242 | } |
| 243 | |
| 244 | func (ws *Conn) IsClientConn() bool { return ws.request == nil } |
| 245 | func (ws *Conn) IsServerConn() bool { return ws.request != nil } |
| 246 | |
| 247 | // LocalAddr returns the WebSocket Origin for the connection for client, or |
| 248 | // the WebSocket location for server. |
| 249 | func (ws *Conn) LocalAddr() net.Addr { |
| 250 | if ws.IsClientConn() { |
| 251 | return &Addr{ws.config.Origin} |
| 252 | } |
| 253 | return &Addr{ws.config.Location} |
| 254 | } |
| 255 | |
| 256 | // RemoteAddr returns the WebSocket location for the connection for client, or |
| 257 | // the Websocket Origin for server. |
| 258 | func (ws *Conn) RemoteAddr() net.Addr { |
| 259 | if ws.IsClientConn() { |
| 260 | return &Addr{ws.config.Location} |
| 261 | } |
| 262 | return &Addr{ws.config.Origin} |
| 263 | } |
| 264 | |
| 265 | var errSetDeadline = errors.New("websocket: cannot set deadline: not using a net.Conn") |
| 266 | |
| 267 | // SetDeadline sets the connection's network read & write deadlines. |
| 268 | func (ws *Conn) SetDeadline(t time.Time) error { |
| 269 | if conn, ok := ws.rwc.(net.Conn); ok { |
| 270 | return conn.SetDeadline(t) |
| 271 | } |
| 272 | return errSetDeadline |
| 273 | } |
| 274 | |
| 275 | // SetReadDeadline sets the connection's network read deadline. |
| 276 | func (ws *Conn) SetReadDeadline(t time.Time) error { |
| 277 | if conn, ok := ws.rwc.(net.Conn); ok { |
| 278 | return conn.SetReadDeadline(t) |
| 279 | } |
| 280 | return errSetDeadline |
| 281 | } |
| 282 | |
| 283 | // SetWriteDeadline sets the connection's network write deadline. |
| 284 | func (ws *Conn) SetWriteDeadline(t time.Time) error { |
| 285 | if conn, ok := ws.rwc.(net.Conn); ok { |
| 286 | return conn.SetWriteDeadline(t) |
| 287 | } |
| 288 | return errSetDeadline |
| 289 | } |
| 290 | |
| 291 | // Config returns the WebSocket config. |
| 292 | func (ws *Conn) Config() *Config { return ws.config } |
| 293 | |
| 294 | // Request returns the http request upgraded to the WebSocket. |
| 295 | // It is nil for client side. |
| 296 | func (ws *Conn) Request() *http.Request { return ws.request } |
| 297 | |
| 298 | // Codec represents a symmetric pair of functions that implement a codec. |
| 299 | type Codec struct { |
| 300 | Marshal func(v interface{}) (data []byte, payloadType byte, err error) |
| 301 | Unmarshal func(data []byte, payloadType byte, v interface{}) (err error) |
| 302 | } |
| 303 | |
| 304 | // Send sends v marshaled by cd.Marshal as single frame to ws. |
| 305 | func (cd Codec) Send(ws *Conn, v interface{}) (err error) { |
| 306 | data, payloadType, err := cd.Marshal(v) |
| 307 | if err != nil { |
| 308 | return err |
| 309 | } |
| 310 | ws.wio.Lock() |
| 311 | defer ws.wio.Unlock() |
| 312 | w, err := ws.frameWriterFactory.NewFrameWriter(payloadType) |
| 313 | if err != nil { |
| 314 | return err |
| 315 | } |
| 316 | _, err = w.Write(data) |
| 317 | w.Close() |
| 318 | return err |
| 319 | } |
| 320 | |
| 321 | // Receive receives single frame from ws, unmarshaled by cd.Unmarshal and stores |
| 322 | // in v. The whole frame payload is read to an in-memory buffer; max size of |
| 323 | // payload is defined by ws.MaxPayloadBytes. If frame payload size exceeds |
| 324 | // limit, ErrFrameTooLarge is returned; in this case frame is not read off wire |
| 325 | // completely. The next call to Receive would read and discard leftover data of |
| 326 | // previous oversized frame before processing next frame. |
| 327 | func (cd Codec) Receive(ws *Conn, v interface{}) (err error) { |
| 328 | ws.rio.Lock() |
| 329 | defer ws.rio.Unlock() |
| 330 | if ws.frameReader != nil { |
| 331 | _, err = io.Copy(ioutil.Discard, ws.frameReader) |
| 332 | if err != nil { |
| 333 | return err |
| 334 | } |
| 335 | ws.frameReader = nil |
| 336 | } |
| 337 | again: |
| 338 | frame, err := ws.frameReaderFactory.NewFrameReader() |
| 339 | if err != nil { |
| 340 | return err |
| 341 | } |
| 342 | frame, err = ws.frameHandler.HandleFrame(frame) |
| 343 | if err != nil { |
| 344 | return err |
| 345 | } |
| 346 | if frame == nil { |
| 347 | goto again |
| 348 | } |
| 349 | maxPayloadBytes := ws.MaxPayloadBytes |
| 350 | if maxPayloadBytes == 0 { |
| 351 | maxPayloadBytes = DefaultMaxPayloadBytes |
| 352 | } |
| 353 | if hf, ok := frame.(*hybiFrameReader); ok && hf.header.Length > int64(maxPayloadBytes) { |
| 354 | // payload size exceeds limit, no need to call Unmarshal |
| 355 | // |
| 356 | // set frameReader to current oversized frame so that |
| 357 | // the next call to this function can drain leftover |
| 358 | // data before processing the next frame |
| 359 | ws.frameReader = frame |
| 360 | return ErrFrameTooLarge |
| 361 | } |
| 362 | payloadType := frame.PayloadType() |
| 363 | data, err := ioutil.ReadAll(frame) |
| 364 | if err != nil { |
| 365 | return err |
| 366 | } |
| 367 | return cd.Unmarshal(data, payloadType, v) |
| 368 | } |
| 369 | |
| 370 | func marshal(v interface{}) (msg []byte, payloadType byte, err error) { |
| 371 | switch data := v.(type) { |
| 372 | case string: |
| 373 | return []byte(data), TextFrame, nil |
| 374 | case []byte: |
| 375 | return data, BinaryFrame, nil |
| 376 | } |
| 377 | return nil, UnknownFrame, ErrNotSupported |
| 378 | } |
| 379 | |
| 380 | func unmarshal(msg []byte, payloadType byte, v interface{}) (err error) { |
| 381 | switch data := v.(type) { |
| 382 | case *string: |
| 383 | *data = string(msg) |
| 384 | return nil |
| 385 | case *[]byte: |
| 386 | *data = msg |
| 387 | return nil |
| 388 | } |
| 389 | return ErrNotSupported |
| 390 | } |
| 391 | |
| 392 | /* |
| 393 | Message is a codec to send/receive text/binary data in a frame on WebSocket connection. |
| 394 | To send/receive text frame, use string type. |
| 395 | To send/receive binary frame, use []byte type. |
| 396 | |
| 397 | Trivial usage: |
| 398 | |
| 399 | import "websocket" |
| 400 | |
| 401 | // receive text frame |
| 402 | var message string |
| 403 | websocket.Message.Receive(ws, &message) |
| 404 | |
| 405 | // send text frame |
| 406 | message = "hello" |
| 407 | websocket.Message.Send(ws, message) |
| 408 | |
| 409 | // receive binary frame |
| 410 | var data []byte |
| 411 | websocket.Message.Receive(ws, &data) |
| 412 | |
| 413 | // send binary frame |
| 414 | data = []byte{0, 1, 2} |
| 415 | websocket.Message.Send(ws, data) |
| 416 | |
| 417 | */ |
| 418 | var Message = Codec{marshal, unmarshal} |
| 419 | |
| 420 | func jsonMarshal(v interface{}) (msg []byte, payloadType byte, err error) { |
| 421 | msg, err = json.Marshal(v) |
| 422 | return msg, TextFrame, err |
| 423 | } |
| 424 | |
| 425 | func jsonUnmarshal(msg []byte, payloadType byte, v interface{}) (err error) { |
| 426 | return json.Unmarshal(msg, v) |
| 427 | } |
| 428 | |
| 429 | /* |
| 430 | JSON is a codec to send/receive JSON data in a frame from a WebSocket connection. |
| 431 | |
| 432 | Trivial usage: |
| 433 | |
| 434 | import "websocket" |
| 435 | |
| 436 | type T struct { |
| 437 | Msg string |
| 438 | Count int |
| 439 | } |
| 440 | |
| 441 | // receive JSON type T |
| 442 | var data T |
| 443 | websocket.JSON.Receive(ws, &data) |
| 444 | |
| 445 | // send JSON type T |
| 446 | websocket.JSON.Send(ws, data) |
| 447 | */ |
| 448 | var JSON = Codec{jsonMarshal, jsonUnmarshal} |