--- /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 (
+ "bufio"
+ "encoding/binary"
+ "errors"
+ "io"
+ "io/ioutil"
+ "math/rand"
+ "net"
+ "strconv"
+ "sync"
+ "time"
+ "unicode/utf8"
+)
+
+const (
+ // Frame header byte 0 bits from Section 5.2 of RFC 6455
+ finalBit = 1 << 7
+ rsv1Bit = 1 << 6
+ rsv2Bit = 1 << 5
+ rsv3Bit = 1 << 4
+
+ // Frame header byte 1 bits from Section 5.2 of RFC 6455
+ maskBit = 1 << 7
+
+ maxFrameHeaderSize = 2 + 8 + 4 // Fixed header + length + mask
+ maxControlFramePayloadSize = 125
+
+ writeWait = time.Second
+
+ defaultReadBufferSize = 4096
+ defaultWriteBufferSize = 4096
+
+ continuationFrame = 0
+ noFrame = -1
+)
+
+// Close codes defined in RFC 6455, section 11.7.
+const (
+ CloseNormalClosure = 1000
+ CloseGoingAway = 1001
+ CloseProtocolError = 1002
+ CloseUnsupportedData = 1003
+ CloseNoStatusReceived = 1005
+ CloseAbnormalClosure = 1006
+ CloseInvalidFramePayloadData = 1007
+ ClosePolicyViolation = 1008
+ CloseMessageTooBig = 1009
+ CloseMandatoryExtension = 1010
+ CloseInternalServerErr = 1011
+ CloseServiceRestart = 1012
+ CloseTryAgainLater = 1013
+ CloseTLSHandshake = 1015
+)
+
+// The message types are defined in RFC 6455, section 11.8.
+const (
+ // TextMessage denotes a text data message. The text message payload is
+ // interpreted as UTF-8 encoded text data.
+ TextMessage = 1
+
+ // BinaryMessage denotes a binary data message.
+ BinaryMessage = 2
+
+ // CloseMessage denotes a close control message. The optional message
+ // payload contains a numeric code and text. Use the FormatCloseMessage
+ // function to format a close message payload.
+ CloseMessage = 8
+
+ // PingMessage denotes a ping control message. The optional message payload
+ // is UTF-8 encoded text.
+ PingMessage = 9
+
+ // PongMessage denotes a pong control message. The optional message payload
+ // is UTF-8 encoded text.
+ PongMessage = 10
+)
+
+// ErrCloseSent is returned when the application writes a message to the
+// connection after sending a close message.
+var ErrCloseSent = errors.New("websocket: close sent")
+
+// ErrReadLimit is returned when reading a message that is larger than the
+// read limit set for the connection.
+var ErrReadLimit = errors.New("websocket: read limit exceeded")
+
+// netError satisfies the net Error interface.
+type netError struct {
+ msg string
+ temporary bool
+ timeout bool
+}
+
+func (e *netError) Error() string { return e.msg }
+func (e *netError) Temporary() bool { return e.temporary }
+func (e *netError) Timeout() bool { return e.timeout }
+
+// CloseError represents a close message.
+type CloseError struct {
+ // Code is defined in RFC 6455, section 11.7.
+ Code int
+
+ // Text is the optional text payload.
+ Text string
+}
+
+func (e *CloseError) Error() string {
+ s := []byte("websocket: close ")
+ s = strconv.AppendInt(s, int64(e.Code), 10)
+ switch e.Code {
+ case CloseNormalClosure:
+ s = append(s, " (normal)"...)
+ case CloseGoingAway:
+ s = append(s, " (going away)"...)
+ case CloseProtocolError:
+ s = append(s, " (protocol error)"...)
+ case CloseUnsupportedData:
+ s = append(s, " (unsupported data)"...)
+ case CloseNoStatusReceived:
+ s = append(s, " (no status)"...)
+ case CloseAbnormalClosure:
+ s = append(s, " (abnormal closure)"...)
+ case CloseInvalidFramePayloadData:
+ s = append(s, " (invalid payload data)"...)
+ case ClosePolicyViolation:
+ s = append(s, " (policy violation)"...)
+ case CloseMessageTooBig:
+ s = append(s, " (message too big)"...)
+ case CloseMandatoryExtension:
+ s = append(s, " (mandatory extension missing)"...)
+ case CloseInternalServerErr:
+ s = append(s, " (internal server error)"...)
+ case CloseTLSHandshake:
+ s = append(s, " (TLS handshake error)"...)
+ }
+ if e.Text != "" {
+ s = append(s, ": "...)
+ s = append(s, e.Text...)
+ }
+ return string(s)
+}
+
+// IsCloseError returns boolean indicating whether the error is a *CloseError
+// with one of the specified codes.
+func IsCloseError(err error, codes ...int) bool {
+ if e, ok := err.(*CloseError); ok {
+ for _, code := range codes {
+ if e.Code == code {
+ return true
+ }
+ }
+ }
+ return false
+}
+
+// IsUnexpectedCloseError returns boolean indicating whether the error is a
+// *CloseError with a code not in the list of expected codes.
+func IsUnexpectedCloseError(err error, expectedCodes ...int) bool {
+ if e, ok := err.(*CloseError); ok {
+ for _, code := range expectedCodes {
+ if e.Code == code {
+ return false
+ }
+ }
+ return true
+ }
+ return false
+}
+
+var (
+ errWriteTimeout = &netError{msg: "websocket: write timeout", timeout: true, temporary: true}
+ errUnexpectedEOF = &CloseError{Code: CloseAbnormalClosure, Text: io.ErrUnexpectedEOF.Error()}
+ errBadWriteOpCode = errors.New("websocket: bad write message type")
+ errWriteClosed = errors.New("websocket: write closed")
+ errInvalidControlFrame = errors.New("websocket: invalid control frame")
+)
+
+func newMaskKey() [4]byte {
+ n := rand.Uint32()
+ return [4]byte{byte(n), byte(n >> 8), byte(n >> 16), byte(n >> 24)}
+}
+
+func hideTempErr(err error) error {
+ if e, ok := err.(net.Error); ok && e.Temporary() {
+ err = &netError{msg: e.Error(), timeout: e.Timeout()}
+ }
+ return err
+}
+
+func isControl(frameType int) bool {
+ return frameType == CloseMessage || frameType == PingMessage || frameType == PongMessage
+}
+
+func isData(frameType int) bool {
+ return frameType == TextMessage || frameType == BinaryMessage
+}
+
+var validReceivedCloseCodes = map[int]bool{
+ // see http://www.iana.org/assignments/websocket/websocket.xhtml#close-code-number
+
+ CloseNormalClosure: true,
+ CloseGoingAway: true,
+ CloseProtocolError: true,
+ CloseUnsupportedData: true,
+ CloseNoStatusReceived: false,
+ CloseAbnormalClosure: false,
+ CloseInvalidFramePayloadData: true,
+ ClosePolicyViolation: true,
+ CloseMessageTooBig: true,
+ CloseMandatoryExtension: true,
+ CloseInternalServerErr: true,
+ CloseServiceRestart: true,
+ CloseTryAgainLater: true,
+ CloseTLSHandshake: false,
+}
+
+func isValidReceivedCloseCode(code int) bool {
+ return validReceivedCloseCodes[code] || (code >= 3000 && code <= 4999)
+}
+
+// BufferPool represents a pool of buffers. The *sync.Pool type satisfies this
+// interface. The type of the value stored in a pool is not specified.
+type BufferPool interface {
+ // Get gets a value from the pool or returns nil if the pool is empty.
+ Get() interface{}
+ // Put adds a value to the pool.
+ Put(interface{})
+}
+
+// writePoolData is the type added to the write buffer pool. This wrapper is
+// used to prevent applications from peeking at and depending on the values
+// added to the pool.
+type writePoolData struct{ buf []byte }
+
+// The Conn type represents a WebSocket connection.
+type Conn struct {
+ conn net.Conn
+ isServer bool
+ subprotocol string
+
+ // Write fields
+ mu chan bool // used as mutex to protect write to conn
+ writeBuf []byte // frame is constructed in this buffer.
+ writePool BufferPool
+ writeBufSize int
+ writeDeadline time.Time
+ writer io.WriteCloser // the current writer returned to the application
+ isWriting bool // for best-effort concurrent write detection
+
+ writeErrMu sync.Mutex
+ writeErr error
+
+ enableWriteCompression bool
+ compressionLevel int
+ newCompressionWriter func(io.WriteCloser, int) io.WriteCloser
+
+ // Read fields
+ reader io.ReadCloser // the current reader returned to the application
+ readErr error
+ br *bufio.Reader
+ readRemaining int64 // bytes remaining in current frame.
+ readFinal bool // true the current message has more frames.
+ readLength int64 // Message size.
+ readLimit int64 // Maximum message size.
+ readMaskPos int
+ readMaskKey [4]byte
+ handlePong func(string) error
+ handlePing func(string) error
+ handleClose func(int, string) error
+ readErrCount int
+ messageReader *messageReader // the current low-level reader
+
+ readDecompress bool // whether last read frame had RSV1 set
+ newDecompressionReader func(io.Reader) io.ReadCloser
+}
+
+func newConn(conn net.Conn, isServer bool, readBufferSize, writeBufferSize int, writeBufferPool BufferPool, br *bufio.Reader, writeBuf []byte) *Conn {
+
+ if br == nil {
+ if readBufferSize == 0 {
+ readBufferSize = defaultReadBufferSize
+ } else if readBufferSize < maxControlFramePayloadSize {
+ // must be large enough for control frame
+ readBufferSize = maxControlFramePayloadSize
+ }
+ br = bufio.NewReaderSize(conn, readBufferSize)
+ }
+
+ if writeBufferSize <= 0 {
+ writeBufferSize = defaultWriteBufferSize
+ }
+ writeBufferSize += maxFrameHeaderSize
+
+ if writeBuf == nil && writeBufferPool == nil {
+ writeBuf = make([]byte, writeBufferSize)
+ }
+
+ mu := make(chan bool, 1)
+ mu <- true
+ c := &Conn{
+ isServer: isServer,
+ br: br,
+ conn: conn,
+ mu: mu,
+ readFinal: true,
+ writeBuf: writeBuf,
+ writePool: writeBufferPool,
+ writeBufSize: writeBufferSize,
+ enableWriteCompression: true,
+ compressionLevel: defaultCompressionLevel,
+ }
+ c.SetCloseHandler(nil)
+ c.SetPingHandler(nil)
+ c.SetPongHandler(nil)
+ return c
+}
+
+// Subprotocol returns the negotiated protocol for the connection.
+func (c *Conn) Subprotocol() string {
+ return c.subprotocol
+}
+
+// Close closes the underlying network connection without sending or waiting
+// for a close message.
+func (c *Conn) Close() error {
+ return c.conn.Close()
+}
+
+// LocalAddr returns the local network address.
+func (c *Conn) LocalAddr() net.Addr {
+ return c.conn.LocalAddr()
+}
+
+// RemoteAddr returns the remote network address.
+func (c *Conn) RemoteAddr() net.Addr {
+ return c.conn.RemoteAddr()
+}
+
+// Write methods
+
+func (c *Conn) writeFatal(err error) error {
+ err = hideTempErr(err)
+ c.writeErrMu.Lock()
+ if c.writeErr == nil {
+ c.writeErr = err
+ }
+ c.writeErrMu.Unlock()
+ return err
+}
+
+func (c *Conn) read(n int) ([]byte, error) {
+ p, err := c.br.Peek(n)
+ if err == io.EOF {
+ err = errUnexpectedEOF
+ }
+ c.br.Discard(len(p))
+ return p, err
+}
+
+func (c *Conn) write(frameType int, deadline time.Time, buf0, buf1 []byte) error {
+ <-c.mu
+ defer func() { c.mu <- true }()
+
+ c.writeErrMu.Lock()
+ err := c.writeErr
+ c.writeErrMu.Unlock()
+ if err != nil {
+ return err
+ }
+
+ c.conn.SetWriteDeadline(deadline)
+ if len(buf1) == 0 {
+ _, err = c.conn.Write(buf0)
+ } else {
+ err = c.writeBufs(buf0, buf1)
+ }
+ if err != nil {
+ return c.writeFatal(err)
+ }
+ if frameType == CloseMessage {
+ c.writeFatal(ErrCloseSent)
+ }
+ return nil
+}
+
+// WriteControl writes a control message with the given deadline. The allowed
+// message types are CloseMessage, PingMessage and PongMessage.
+func (c *Conn) WriteControl(messageType int, data []byte, deadline time.Time) error {
+ if !isControl(messageType) {
+ return errBadWriteOpCode
+ }
+ if len(data) > maxControlFramePayloadSize {
+ return errInvalidControlFrame
+ }
+
+ b0 := byte(messageType) | finalBit
+ b1 := byte(len(data))
+ if !c.isServer {
+ b1 |= maskBit
+ }
+
+ buf := make([]byte, 0, maxFrameHeaderSize+maxControlFramePayloadSize)
+ buf = append(buf, b0, b1)
+
+ if c.isServer {
+ buf = append(buf, data...)
+ } else {
+ key := newMaskKey()
+ buf = append(buf, key[:]...)
+ buf = append(buf, data...)
+ maskBytes(key, 0, buf[6:])
+ }
+
+ d := time.Hour * 1000
+ if !deadline.IsZero() {
+ d = deadline.Sub(time.Now())
+ if d < 0 {
+ return errWriteTimeout
+ }
+ }
+
+ timer := time.NewTimer(d)
+ select {
+ case <-c.mu:
+ timer.Stop()
+ case <-timer.C:
+ return errWriteTimeout
+ }
+ defer func() { c.mu <- true }()
+
+ c.writeErrMu.Lock()
+ err := c.writeErr
+ c.writeErrMu.Unlock()
+ if err != nil {
+ return err
+ }
+
+ c.conn.SetWriteDeadline(deadline)
+ _, err = c.conn.Write(buf)
+ if err != nil {
+ return c.writeFatal(err)
+ }
+ if messageType == CloseMessage {
+ c.writeFatal(ErrCloseSent)
+ }
+ return err
+}
+
+// beginMessage prepares a connection and message writer for a new message.
+func (c *Conn) beginMessage(mw *messageWriter, messageType int) error {
+ // Close previous writer if not already closed by the application. It's
+ // probably better to return an error in this situation, but we cannot
+ // change this without breaking existing applications.
+ if c.writer != nil {
+ c.writer.Close()
+ c.writer = nil
+ }
+
+ if !isControl(messageType) && !isData(messageType) {
+ return errBadWriteOpCode
+ }
+
+ c.writeErrMu.Lock()
+ err := c.writeErr
+ c.writeErrMu.Unlock()
+ if err != nil {
+ return err
+ }
+
+ mw.c = c
+ mw.frameType = messageType
+ mw.pos = maxFrameHeaderSize
+
+ if c.writeBuf == nil {
+ wpd, ok := c.writePool.Get().(writePoolData)
+ if ok {
+ c.writeBuf = wpd.buf
+ } else {
+ c.writeBuf = make([]byte, c.writeBufSize)
+ }
+ }
+ return nil
+}
+
+// NextWriter returns a writer for the next message to send. The writer's Close
+// method flushes the complete message to the network.
+//
+// There can be at most one open writer on a connection. NextWriter closes the
+// previous writer if the application has not already done so.
+//
+// All message types (TextMessage, BinaryMessage, CloseMessage, PingMessage and
+// PongMessage) are supported.
+func (c *Conn) NextWriter(messageType int) (io.WriteCloser, error) {
+ var mw messageWriter
+ if err := c.beginMessage(&mw, messageType); err != nil {
+ return nil, err
+ }
+ c.writer = &mw
+ if c.newCompressionWriter != nil && c.enableWriteCompression && isData(messageType) {
+ w := c.newCompressionWriter(c.writer, c.compressionLevel)
+ mw.compress = true
+ c.writer = w
+ }
+ return c.writer, nil
+}
+
+type messageWriter struct {
+ c *Conn
+ compress bool // whether next call to flushFrame should set RSV1
+ pos int // end of data in writeBuf.
+ frameType int // type of the current frame.
+ err error
+}
+
+func (w *messageWriter) endMessage(err error) error {
+ if w.err != nil {
+ return err
+ }
+ c := w.c
+ w.err = err
+ c.writer = nil
+ if c.writePool != nil {
+ c.writePool.Put(writePoolData{buf: c.writeBuf})
+ c.writeBuf = nil
+ }
+ return err
+}
+
+// flushFrame writes buffered data and extra as a frame to the network. The
+// final argument indicates that this is the last frame in the message.
+func (w *messageWriter) flushFrame(final bool, extra []byte) error {
+ c := w.c
+ length := w.pos - maxFrameHeaderSize + len(extra)
+
+ // Check for invalid control frames.
+ if isControl(w.frameType) &&
+ (!final || length > maxControlFramePayloadSize) {
+ return w.endMessage(errInvalidControlFrame)
+ }
+
+ b0 := byte(w.frameType)
+ if final {
+ b0 |= finalBit
+ }
+ if w.compress {
+ b0 |= rsv1Bit
+ }
+ w.compress = false
+
+ b1 := byte(0)
+ if !c.isServer {
+ b1 |= maskBit
+ }
+
+ // Assume that the frame starts at beginning of c.writeBuf.
+ framePos := 0
+ if c.isServer {
+ // Adjust up if mask not included in the header.
+ framePos = 4
+ }
+
+ switch {
+ case length >= 65536:
+ c.writeBuf[framePos] = b0
+ c.writeBuf[framePos+1] = b1 | 127
+ binary.BigEndian.PutUint64(c.writeBuf[framePos+2:], uint64(length))
+ case length > 125:
+ framePos += 6
+ c.writeBuf[framePos] = b0
+ c.writeBuf[framePos+1] = b1 | 126
+ binary.BigEndian.PutUint16(c.writeBuf[framePos+2:], uint16(length))
+ default:
+ framePos += 8
+ c.writeBuf[framePos] = b0
+ c.writeBuf[framePos+1] = b1 | byte(length)
+ }
+
+ if !c.isServer {
+ key := newMaskKey()
+ copy(c.writeBuf[maxFrameHeaderSize-4:], key[:])
+ maskBytes(key, 0, c.writeBuf[maxFrameHeaderSize:w.pos])
+ if len(extra) > 0 {
+ return w.endMessage(c.writeFatal(errors.New("websocket: internal error, extra used in client mode")))
+ }
+ }
+
+ // Write the buffers to the connection with best-effort detection of
+ // concurrent writes. See the concurrency section in the package
+ // documentation for more info.
+
+ if c.isWriting {
+ panic("concurrent write to websocket connection")
+ }
+ c.isWriting = true
+
+ err := c.write(w.frameType, c.writeDeadline, c.writeBuf[framePos:w.pos], extra)
+
+ if !c.isWriting {
+ panic("concurrent write to websocket connection")
+ }
+ c.isWriting = false
+
+ if err != nil {
+ return w.endMessage(err)
+ }
+
+ if final {
+ w.endMessage(errWriteClosed)
+ return nil
+ }
+
+ // Setup for next frame.
+ w.pos = maxFrameHeaderSize
+ w.frameType = continuationFrame
+ return nil
+}
+
+func (w *messageWriter) ncopy(max int) (int, error) {
+ n := len(w.c.writeBuf) - w.pos
+ if n <= 0 {
+ if err := w.flushFrame(false, nil); err != nil {
+ return 0, err
+ }
+ n = len(w.c.writeBuf) - w.pos
+ }
+ if n > max {
+ n = max
+ }
+ return n, nil
+}
+
+func (w *messageWriter) Write(p []byte) (int, error) {
+ if w.err != nil {
+ return 0, w.err
+ }
+
+ if len(p) > 2*len(w.c.writeBuf) && w.c.isServer {
+ // Don't buffer large messages.
+ err := w.flushFrame(false, p)
+ if err != nil {
+ return 0, err
+ }
+ return len(p), nil
+ }
+
+ nn := len(p)
+ for len(p) > 0 {
+ n, err := w.ncopy(len(p))
+ if err != nil {
+ return 0, err
+ }
+ copy(w.c.writeBuf[w.pos:], p[:n])
+ w.pos += n
+ p = p[n:]
+ }
+ return nn, nil
+}
+
+func (w *messageWriter) WriteString(p string) (int, error) {
+ if w.err != nil {
+ return 0, w.err
+ }
+
+ nn := len(p)
+ for len(p) > 0 {
+ n, err := w.ncopy(len(p))
+ if err != nil {
+ return 0, err
+ }
+ copy(w.c.writeBuf[w.pos:], p[:n])
+ w.pos += n
+ p = p[n:]
+ }
+ return nn, nil
+}
+
+func (w *messageWriter) ReadFrom(r io.Reader) (nn int64, err error) {
+ if w.err != nil {
+ return 0, w.err
+ }
+ for {
+ if w.pos == len(w.c.writeBuf) {
+ err = w.flushFrame(false, nil)
+ if err != nil {
+ break
+ }
+ }
+ var n int
+ n, err = r.Read(w.c.writeBuf[w.pos:])
+ w.pos += n
+ nn += int64(n)
+ if err != nil {
+ if err == io.EOF {
+ err = nil
+ }
+ break
+ }
+ }
+ return nn, err
+}
+
+func (w *messageWriter) Close() error {
+ if w.err != nil {
+ return w.err
+ }
+ if err := w.flushFrame(true, nil); err != nil {
+ return err
+ }
+ return nil
+}
+
+// WritePreparedMessage writes prepared message into connection.
+func (c *Conn) WritePreparedMessage(pm *PreparedMessage) error {
+ frameType, frameData, err := pm.frame(prepareKey{
+ isServer: c.isServer,
+ compress: c.newCompressionWriter != nil && c.enableWriteCompression && isData(pm.messageType),
+ compressionLevel: c.compressionLevel,
+ })
+ if err != nil {
+ return err
+ }
+ if c.isWriting {
+ panic("concurrent write to websocket connection")
+ }
+ c.isWriting = true
+ err = c.write(frameType, c.writeDeadline, frameData, nil)
+ if !c.isWriting {
+ panic("concurrent write to websocket connection")
+ }
+ c.isWriting = false
+ return err
+}
+
+// WriteMessage is a helper method for getting a writer using NextWriter,
+// writing the message and closing the writer.
+func (c *Conn) WriteMessage(messageType int, data []byte) error {
+
+ if c.isServer && (c.newCompressionWriter == nil || !c.enableWriteCompression) {
+ // Fast path with no allocations and single frame.
+
+ var mw messageWriter
+ if err := c.beginMessage(&mw, messageType); err != nil {
+ return err
+ }
+ n := copy(c.writeBuf[mw.pos:], data)
+ mw.pos += n
+ data = data[n:]
+ return mw.flushFrame(true, data)
+ }
+
+ w, err := c.NextWriter(messageType)
+ if err != nil {
+ return err
+ }
+ if _, err = w.Write(data); err != nil {
+ return err
+ }
+ return w.Close()
+}
+
+// SetWriteDeadline sets the write deadline on the underlying network
+// connection. After a write has timed out, the websocket state is corrupt and
+// all future writes will return an error. A zero value for t means writes will
+// not time out.
+func (c *Conn) SetWriteDeadline(t time.Time) error {
+ c.writeDeadline = t
+ return nil
+}
+
+// Read methods
+
+func (c *Conn) advanceFrame() (int, error) {
+ // 1. Skip remainder of previous frame.
+
+ if c.readRemaining > 0 {
+ if _, err := io.CopyN(ioutil.Discard, c.br, c.readRemaining); err != nil {
+ return noFrame, err
+ }
+ }
+
+ // 2. Read and parse first two bytes of frame header.
+
+ p, err := c.read(2)
+ if err != nil {
+ return noFrame, err
+ }
+
+ final := p[0]&finalBit != 0
+ frameType := int(p[0] & 0xf)
+ mask := p[1]&maskBit != 0
+ c.readRemaining = int64(p[1] & 0x7f)
+
+ c.readDecompress = false
+ if c.newDecompressionReader != nil && (p[0]&rsv1Bit) != 0 {
+ c.readDecompress = true
+ p[0] &^= rsv1Bit
+ }
+
+ if rsv := p[0] & (rsv1Bit | rsv2Bit | rsv3Bit); rsv != 0 {
+ return noFrame, c.handleProtocolError("unexpected reserved bits 0x" + strconv.FormatInt(int64(rsv), 16))
+ }
+
+ switch frameType {
+ case CloseMessage, PingMessage, PongMessage:
+ if c.readRemaining > maxControlFramePayloadSize {
+ return noFrame, c.handleProtocolError("control frame length > 125")
+ }
+ if !final {
+ return noFrame, c.handleProtocolError("control frame not final")
+ }
+ case TextMessage, BinaryMessage:
+ if !c.readFinal {
+ return noFrame, c.handleProtocolError("message start before final message frame")
+ }
+ c.readFinal = final
+ case continuationFrame:
+ if c.readFinal {
+ return noFrame, c.handleProtocolError("continuation after final message frame")
+ }
+ c.readFinal = final
+ default:
+ return noFrame, c.handleProtocolError("unknown opcode " + strconv.Itoa(frameType))
+ }
+
+ // 3. Read and parse frame length.
+
+ switch c.readRemaining {
+ case 126:
+ p, err := c.read(2)
+ if err != nil {
+ return noFrame, err
+ }
+ c.readRemaining = int64(binary.BigEndian.Uint16(p))
+ case 127:
+ p, err := c.read(8)
+ if err != nil {
+ return noFrame, err
+ }
+ c.readRemaining = int64(binary.BigEndian.Uint64(p))
+ }
+
+ // 4. Handle frame masking.
+
+ if mask != c.isServer {
+ return noFrame, c.handleProtocolError("incorrect mask flag")
+ }
+
+ if mask {
+ c.readMaskPos = 0
+ p, err := c.read(len(c.readMaskKey))
+ if err != nil {
+ return noFrame, err
+ }
+ copy(c.readMaskKey[:], p)
+ }
+
+ // 5. For text and binary messages, enforce read limit and return.
+
+ if frameType == continuationFrame || frameType == TextMessage || frameType == BinaryMessage {
+
+ c.readLength += c.readRemaining
+ if c.readLimit > 0 && c.readLength > c.readLimit {
+ c.WriteControl(CloseMessage, FormatCloseMessage(CloseMessageTooBig, ""), time.Now().Add(writeWait))
+ return noFrame, ErrReadLimit
+ }
+
+ return frameType, nil
+ }
+
+ // 6. Read control frame payload.
+
+ var payload []byte
+ if c.readRemaining > 0 {
+ payload, err = c.read(int(c.readRemaining))
+ c.readRemaining = 0
+ if err != nil {
+ return noFrame, err
+ }
+ if c.isServer {
+ maskBytes(c.readMaskKey, 0, payload)
+ }
+ }
+
+ // 7. Process control frame payload.
+
+ switch frameType {
+ case PongMessage:
+ if err := c.handlePong(string(payload)); err != nil {
+ return noFrame, err
+ }
+ case PingMessage:
+ if err := c.handlePing(string(payload)); err != nil {
+ return noFrame, err
+ }
+ case CloseMessage:
+ closeCode := CloseNoStatusReceived
+ closeText := ""
+ if len(payload) >= 2 {
+ closeCode = int(binary.BigEndian.Uint16(payload))
+ if !isValidReceivedCloseCode(closeCode) {
+ return noFrame, c.handleProtocolError("invalid close code")
+ }
+ closeText = string(payload[2:])
+ if !utf8.ValidString(closeText) {
+ return noFrame, c.handleProtocolError("invalid utf8 payload in close frame")
+ }
+ }
+ if err := c.handleClose(closeCode, closeText); err != nil {
+ return noFrame, err
+ }
+ return noFrame, &CloseError{Code: closeCode, Text: closeText}
+ }
+
+ return frameType, nil
+}
+
+func (c *Conn) handleProtocolError(message string) error {
+ c.WriteControl(CloseMessage, FormatCloseMessage(CloseProtocolError, message), time.Now().Add(writeWait))
+ return errors.New("websocket: " + message)
+}
+
+// NextReader returns the next data message received from the peer. The
+// returned messageType is either TextMessage or BinaryMessage.
+//
+// There can be at most one open reader on a connection. NextReader discards
+// the previous message if the application has not already consumed it.
+//
+// Applications must break out of the application's read loop when this method
+// returns a non-nil error value. Errors returned from this method are
+// permanent. Once this method returns a non-nil error, all subsequent calls to
+// this method return the same error.
+func (c *Conn) NextReader() (messageType int, r io.Reader, err error) {
+ // Close previous reader, only relevant for decompression.
+ if c.reader != nil {
+ c.reader.Close()
+ c.reader = nil
+ }
+
+ c.messageReader = nil
+ c.readLength = 0
+
+ for c.readErr == nil {
+ frameType, err := c.advanceFrame()
+ if err != nil {
+ c.readErr = hideTempErr(err)
+ break
+ }
+ if frameType == TextMessage || frameType == BinaryMessage {
+ c.messageReader = &messageReader{c}
+ c.reader = c.messageReader
+ if c.readDecompress {
+ c.reader = c.newDecompressionReader(c.reader)
+ }
+ return frameType, c.reader, nil
+ }
+ }
+
+ // Applications that do handle the error returned from this method spin in
+ // tight loop on connection failure. To help application developers detect
+ // this error, panic on repeated reads to the failed connection.
+ c.readErrCount++
+ if c.readErrCount >= 1000 {
+ panic("repeated read on failed websocket connection")
+ }
+
+ return noFrame, nil, c.readErr
+}
+
+type messageReader struct{ c *Conn }
+
+func (r *messageReader) Read(b []byte) (int, error) {
+ c := r.c
+ if c.messageReader != r {
+ return 0, io.EOF
+ }
+
+ for c.readErr == nil {
+
+ if c.readRemaining > 0 {
+ if int64(len(b)) > c.readRemaining {
+ b = b[:c.readRemaining]
+ }
+ n, err := c.br.Read(b)
+ c.readErr = hideTempErr(err)
+ if c.isServer {
+ c.readMaskPos = maskBytes(c.readMaskKey, c.readMaskPos, b[:n])
+ }
+ c.readRemaining -= int64(n)
+ if c.readRemaining > 0 && c.readErr == io.EOF {
+ c.readErr = errUnexpectedEOF
+ }
+ return n, c.readErr
+ }
+
+ if c.readFinal {
+ c.messageReader = nil
+ return 0, io.EOF
+ }
+
+ frameType, err := c.advanceFrame()
+ switch {
+ case err != nil:
+ c.readErr = hideTempErr(err)
+ case frameType == TextMessage || frameType == BinaryMessage:
+ c.readErr = errors.New("websocket: internal error, unexpected text or binary in Reader")
+ }
+ }
+
+ err := c.readErr
+ if err == io.EOF && c.messageReader == r {
+ err = errUnexpectedEOF
+ }
+ return 0, err
+}
+
+func (r *messageReader) Close() error {
+ return nil
+}
+
+// ReadMessage is a helper method for getting a reader using NextReader and
+// reading from that reader to a buffer.
+func (c *Conn) ReadMessage() (messageType int, p []byte, err error) {
+ var r io.Reader
+ messageType, r, err = c.NextReader()
+ if err != nil {
+ return messageType, nil, err
+ }
+ p, err = ioutil.ReadAll(r)
+ return messageType, p, err
+}
+
+// SetReadDeadline sets the read deadline on the underlying network connection.
+// After a read has timed out, the websocket connection state is corrupt and
+// all future reads will return an error. A zero value for t means reads will
+// not time out.
+func (c *Conn) SetReadDeadline(t time.Time) error {
+ return c.conn.SetReadDeadline(t)
+}
+
+// SetReadLimit sets the maximum size in bytes for a message read from the peer. If a
+// message exceeds the limit, the connection sends a close message to the peer
+// and returns ErrReadLimit to the application.
+func (c *Conn) SetReadLimit(limit int64) {
+ c.readLimit = limit
+}
+
+// CloseHandler returns the current close handler
+func (c *Conn) CloseHandler() func(code int, text string) error {
+ return c.handleClose
+}
+
+// SetCloseHandler sets the handler for close messages received from the peer.
+// The code argument to h is the received close code or CloseNoStatusReceived
+// if the close message is empty. The default close handler sends a close
+// message back to the peer.
+//
+// The handler function is called from the NextReader, ReadMessage and message
+// reader Read methods. The application must read the connection to process
+// close messages as described in the section on Control Messages above.
+//
+// The connection read methods return a CloseError when a close message is
+// received. Most applications should handle close messages as part of their
+// normal error handling. Applications should only set a close handler when the
+// application must perform some action before sending a close message back to
+// the peer.
+func (c *Conn) SetCloseHandler(h func(code int, text string) error) {
+ if h == nil {
+ h = func(code int, text string) error {
+ message := FormatCloseMessage(code, "")
+ c.WriteControl(CloseMessage, message, time.Now().Add(writeWait))
+ return nil
+ }
+ }
+ c.handleClose = h
+}
+
+// PingHandler returns the current ping handler
+func (c *Conn) PingHandler() func(appData string) error {
+ return c.handlePing
+}
+
+// SetPingHandler sets the handler for ping messages received from the peer.
+// The appData argument to h is the PING message application data. The default
+// ping handler sends a pong to the peer.
+//
+// The handler function is called from the NextReader, ReadMessage and message
+// reader Read methods. The application must read the connection to process
+// ping messages as described in the section on Control Messages above.
+func (c *Conn) SetPingHandler(h func(appData string) error) {
+ if h == nil {
+ h = func(message string) error {
+ err := c.WriteControl(PongMessage, []byte(message), time.Now().Add(writeWait))
+ if err == ErrCloseSent {
+ return nil
+ } else if e, ok := err.(net.Error); ok && e.Temporary() {
+ return nil
+ }
+ return err
+ }
+ }
+ c.handlePing = h
+}
+
+// PongHandler returns the current pong handler
+func (c *Conn) PongHandler() func(appData string) error {
+ return c.handlePong
+}
+
+// SetPongHandler sets the handler for pong messages received from the peer.
+// The appData argument to h is the PONG message application data. The default
+// pong handler does nothing.
+//
+// The handler function is called from the NextReader, ReadMessage and message
+// reader Read methods. The application must read the connection to process
+// pong messages as described in the section on Control Messages above.
+func (c *Conn) SetPongHandler(h func(appData string) error) {
+ if h == nil {
+ h = func(string) error { return nil }
+ }
+ c.handlePong = h
+}
+
+// UnderlyingConn returns the internal net.Conn. This can be used to further
+// modifications to connection specific flags.
+func (c *Conn) UnderlyingConn() net.Conn {
+ return c.conn
+}
+
+// EnableWriteCompression enables and disables write compression of
+// subsequent text and binary messages. This function is a noop if
+// compression was not negotiated with the peer.
+func (c *Conn) EnableWriteCompression(enable bool) {
+ c.enableWriteCompression = enable
+}
+
+// SetCompressionLevel sets the flate compression level for subsequent text and
+// binary messages. This function is a noop if compression was not negotiated
+// with the peer. See the compress/flate package for a description of
+// compression levels.
+func (c *Conn) SetCompressionLevel(level int) error {
+ if !isValidCompressionLevel(level) {
+ return errors.New("websocket: invalid compression level")
+ }
+ c.compressionLevel = level
+ return nil
+}
+
+// FormatCloseMessage formats closeCode and text as a WebSocket close message.
+// An empty message is returned for code CloseNoStatusReceived.
+func FormatCloseMessage(closeCode int, text string) []byte {
+ if closeCode == CloseNoStatusReceived {
+ // Return empty message because it's illegal to send
+ // CloseNoStatusReceived. Return non-nil value in case application
+ // checks for nil.
+ return []byte{}
+ }
+ buf := make([]byte, 2+len(text))
+ binary.BigEndian.PutUint16(buf, uint16(closeCode))
+ copy(buf[2:], text)
+ return buf
+}
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