1166 lines
30 KiB
Go
1166 lines
30 KiB
Go
// Copyright 2013 The Gorilla WebSocket Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package websocket
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import (
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"bufio"
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"encoding/binary"
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"errors"
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"io"
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"io/ioutil"
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"math/rand"
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"net"
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"strconv"
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"sync"
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"time"
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"unicode/utf8"
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)
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const (
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// Frame header byte 0 bits from Section 5.2 of RFC 6455
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finalBit = 1 << 7
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rsv1Bit = 1 << 6
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rsv2Bit = 1 << 5
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rsv3Bit = 1 << 4
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// Frame header byte 1 bits from Section 5.2 of RFC 6455
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maskBit = 1 << 7
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maxFrameHeaderSize = 2 + 8 + 4 // Fixed header + length + mask
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maxControlFramePayloadSize = 125
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writeWait = time.Second
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defaultReadBufferSize = 4096
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defaultWriteBufferSize = 4096
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continuationFrame = 0
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noFrame = -1
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)
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// Close codes defined in RFC 6455, section 11.7.
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const (
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CloseNormalClosure = 1000
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CloseGoingAway = 1001
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CloseProtocolError = 1002
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CloseUnsupportedData = 1003
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CloseNoStatusReceived = 1005
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CloseAbnormalClosure = 1006
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CloseInvalidFramePayloadData = 1007
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ClosePolicyViolation = 1008
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CloseMessageTooBig = 1009
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CloseMandatoryExtension = 1010
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CloseInternalServerErr = 1011
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CloseServiceRestart = 1012
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CloseTryAgainLater = 1013
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CloseTLSHandshake = 1015
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)
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// The message types are defined in RFC 6455, section 11.8.
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const (
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// TextMessage denotes a text data message. The text message payload is
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// interpreted as UTF-8 encoded text data.
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TextMessage = 1
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// BinaryMessage denotes a binary data message.
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BinaryMessage = 2
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// CloseMessage denotes a close control message. The optional message
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// payload contains a numeric code and text. Use the FormatCloseMessage
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// function to format a close message payload.
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CloseMessage = 8
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// PingMessage denotes a ping control message. The optional message payload
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// is UTF-8 encoded text.
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PingMessage = 9
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// PongMessage denotes a pong control message. The optional message payload
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// is UTF-8 encoded text.
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PongMessage = 10
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)
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// ErrCloseSent is returned when the application writes a message to the
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// connection after sending a close message.
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var ErrCloseSent = errors.New("websocket: close sent")
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// ErrReadLimit is returned when reading a message that is larger than the
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// read limit set for the connection.
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var ErrReadLimit = errors.New("websocket: read limit exceeded")
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// netError satisfies the net Error interface.
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type netError struct {
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msg string
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temporary bool
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timeout bool
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}
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func (e *netError) Error() string { return e.msg }
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func (e *netError) Temporary() bool { return e.temporary }
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func (e *netError) Timeout() bool { return e.timeout }
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// CloseError represents a close message.
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type CloseError struct {
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// Code is defined in RFC 6455, section 11.7.
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Code int
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// Text is the optional text payload.
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Text string
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}
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func (e *CloseError) Error() string {
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s := []byte("websocket: close ")
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s = strconv.AppendInt(s, int64(e.Code), 10)
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switch e.Code {
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case CloseNormalClosure:
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s = append(s, " (normal)"...)
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case CloseGoingAway:
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s = append(s, " (going away)"...)
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case CloseProtocolError:
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s = append(s, " (protocol error)"...)
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case CloseUnsupportedData:
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s = append(s, " (unsupported data)"...)
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case CloseNoStatusReceived:
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s = append(s, " (no status)"...)
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case CloseAbnormalClosure:
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s = append(s, " (abnormal closure)"...)
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case CloseInvalidFramePayloadData:
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s = append(s, " (invalid payload data)"...)
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case ClosePolicyViolation:
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s = append(s, " (policy violation)"...)
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case CloseMessageTooBig:
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s = append(s, " (message too big)"...)
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case CloseMandatoryExtension:
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s = append(s, " (mandatory extension missing)"...)
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case CloseInternalServerErr:
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s = append(s, " (internal server error)"...)
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case CloseTLSHandshake:
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s = append(s, " (TLS handshake error)"...)
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}
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if e.Text != "" {
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s = append(s, ": "...)
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s = append(s, e.Text...)
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}
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return string(s)
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}
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// IsCloseError returns boolean indicating whether the error is a *CloseError
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// with one of the specified codes.
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func IsCloseError(err error, codes ...int) bool {
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if e, ok := err.(*CloseError); ok {
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for _, code := range codes {
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if e.Code == code {
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return true
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}
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}
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}
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return false
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}
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// IsUnexpectedCloseError returns boolean indicating whether the error is a
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// *CloseError with a code not in the list of expected codes.
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func IsUnexpectedCloseError(err error, expectedCodes ...int) bool {
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if e, ok := err.(*CloseError); ok {
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for _, code := range expectedCodes {
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if e.Code == code {
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return false
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}
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}
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return true
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}
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return false
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}
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var (
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errWriteTimeout = &netError{msg: "websocket: write timeout", timeout: true, temporary: true}
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errUnexpectedEOF = &CloseError{Code: CloseAbnormalClosure, Text: io.ErrUnexpectedEOF.Error()}
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errBadWriteOpCode = errors.New("websocket: bad write message type")
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errWriteClosed = errors.New("websocket: write closed")
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errInvalidControlFrame = errors.New("websocket: invalid control frame")
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)
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func newMaskKey() [4]byte {
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n := rand.Uint32()
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return [4]byte{byte(n), byte(n >> 8), byte(n >> 16), byte(n >> 24)}
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}
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func hideTempErr(err error) error {
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if e, ok := err.(net.Error); ok && e.Temporary() {
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err = &netError{msg: e.Error(), timeout: e.Timeout()}
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}
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return err
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}
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func isControl(frameType int) bool {
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return frameType == CloseMessage || frameType == PingMessage || frameType == PongMessage
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}
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func isData(frameType int) bool {
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return frameType == TextMessage || frameType == BinaryMessage
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}
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var validReceivedCloseCodes = map[int]bool{
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// see http://www.iana.org/assignments/websocket/websocket.xhtml#close-code-number
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CloseNormalClosure: true,
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CloseGoingAway: true,
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CloseProtocolError: true,
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CloseUnsupportedData: true,
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CloseNoStatusReceived: false,
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CloseAbnormalClosure: false,
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CloseInvalidFramePayloadData: true,
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ClosePolicyViolation: true,
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CloseMessageTooBig: true,
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CloseMandatoryExtension: true,
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CloseInternalServerErr: true,
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CloseServiceRestart: true,
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CloseTryAgainLater: true,
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CloseTLSHandshake: false,
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}
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func isValidReceivedCloseCode(code int) bool {
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return validReceivedCloseCodes[code] || (code >= 3000 && code <= 4999)
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}
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// BufferPool represents a pool of buffers. The *sync.Pool type satisfies this
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// interface. The type of the value stored in a pool is not specified.
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type BufferPool interface {
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// Get gets a value from the pool or returns nil if the pool is empty.
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Get() interface{}
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// Put adds a value to the pool.
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Put(interface{})
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}
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// writePoolData is the type added to the write buffer pool. This wrapper is
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// used to prevent applications from peeking at and depending on the values
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// added to the pool.
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type writePoolData struct{ buf []byte }
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// The Conn type represents a WebSocket connection.
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type Conn struct {
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conn net.Conn
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isServer bool
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subprotocol string
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// Write fields
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mu chan bool // used as mutex to protect write to conn
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writeBuf []byte // frame is constructed in this buffer.
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writePool BufferPool
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writeBufSize int
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writeDeadline time.Time
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writer io.WriteCloser // the current writer returned to the application
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isWriting bool // for best-effort concurrent write detection
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writeErrMu sync.Mutex
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writeErr error
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enableWriteCompression bool
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compressionLevel int
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newCompressionWriter func(io.WriteCloser, int) io.WriteCloser
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// Read fields
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reader io.ReadCloser // the current reader returned to the application
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readErr error
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br *bufio.Reader
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readRemaining int64 // bytes remaining in current frame.
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readFinal bool // true the current message has more frames.
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readLength int64 // Message size.
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readLimit int64 // Maximum message size.
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readMaskPos int
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readMaskKey [4]byte
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handlePong func(string) error
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handlePing func(string) error
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handleClose func(int, string) error
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readErrCount int
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messageReader *messageReader // the current low-level reader
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readDecompress bool // whether last read frame had RSV1 set
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newDecompressionReader func(io.Reader) io.ReadCloser
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}
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func newConn(conn net.Conn, isServer bool, readBufferSize, writeBufferSize int, writeBufferPool BufferPool, br *bufio.Reader, writeBuf []byte) *Conn {
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if br == nil {
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if readBufferSize == 0 {
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readBufferSize = defaultReadBufferSize
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} else if readBufferSize < maxControlFramePayloadSize {
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// must be large enough for control frame
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readBufferSize = maxControlFramePayloadSize
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}
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br = bufio.NewReaderSize(conn, readBufferSize)
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}
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if writeBufferSize <= 0 {
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writeBufferSize = defaultWriteBufferSize
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}
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writeBufferSize += maxFrameHeaderSize
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if writeBuf == nil && writeBufferPool == nil {
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writeBuf = make([]byte, writeBufferSize)
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}
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mu := make(chan bool, 1)
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mu <- true
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c := &Conn{
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isServer: isServer,
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br: br,
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conn: conn,
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mu: mu,
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readFinal: true,
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writeBuf: writeBuf,
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writePool: writeBufferPool,
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writeBufSize: writeBufferSize,
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enableWriteCompression: true,
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compressionLevel: defaultCompressionLevel,
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}
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c.SetCloseHandler(nil)
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c.SetPingHandler(nil)
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c.SetPongHandler(nil)
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return c
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}
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// Subprotocol returns the negotiated protocol for the connection.
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func (c *Conn) Subprotocol() string {
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return c.subprotocol
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}
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// Close closes the underlying network connection without sending or waiting
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// for a close message.
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func (c *Conn) Close() error {
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return c.conn.Close()
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}
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// LocalAddr returns the local network address.
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func (c *Conn) LocalAddr() net.Addr {
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return c.conn.LocalAddr()
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}
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// RemoteAddr returns the remote network address.
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func (c *Conn) RemoteAddr() net.Addr {
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return c.conn.RemoteAddr()
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}
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// Write methods
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func (c *Conn) writeFatal(err error) error {
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err = hideTempErr(err)
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c.writeErrMu.Lock()
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if c.writeErr == nil {
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c.writeErr = err
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}
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c.writeErrMu.Unlock()
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return err
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}
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func (c *Conn) read(n int) ([]byte, error) {
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p, err := c.br.Peek(n)
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if err == io.EOF {
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err = errUnexpectedEOF
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}
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c.br.Discard(len(p))
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return p, err
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}
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func (c *Conn) write(frameType int, deadline time.Time, buf0, buf1 []byte) error {
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<-c.mu
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defer func() { c.mu <- true }()
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c.writeErrMu.Lock()
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err := c.writeErr
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c.writeErrMu.Unlock()
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if err != nil {
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return err
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}
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c.conn.SetWriteDeadline(deadline)
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if len(buf1) == 0 {
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_, err = c.conn.Write(buf0)
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} else {
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err = c.writeBufs(buf0, buf1)
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}
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if err != nil {
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return c.writeFatal(err)
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}
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if frameType == CloseMessage {
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c.writeFatal(ErrCloseSent)
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}
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return nil
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}
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// WriteControl writes a control message with the given deadline. The allowed
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// message types are CloseMessage, PingMessage and PongMessage.
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func (c *Conn) WriteControl(messageType int, data []byte, deadline time.Time) error {
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if !isControl(messageType) {
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return errBadWriteOpCode
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}
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if len(data) > maxControlFramePayloadSize {
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return errInvalidControlFrame
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}
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b0 := byte(messageType) | finalBit
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b1 := byte(len(data))
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if !c.isServer {
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b1 |= maskBit
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}
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buf := make([]byte, 0, maxFrameHeaderSize+maxControlFramePayloadSize)
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buf = append(buf, b0, b1)
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if c.isServer {
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buf = append(buf, data...)
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} else {
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key := newMaskKey()
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buf = append(buf, key[:]...)
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buf = append(buf, data...)
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maskBytes(key, 0, buf[6:])
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}
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d := time.Hour * 1000
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if !deadline.IsZero() {
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d = deadline.Sub(time.Now())
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if d < 0 {
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return errWriteTimeout
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}
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}
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timer := time.NewTimer(d)
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select {
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case <-c.mu:
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timer.Stop()
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case <-timer.C:
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return errWriteTimeout
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}
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defer func() { c.mu <- true }()
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c.writeErrMu.Lock()
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err := c.writeErr
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c.writeErrMu.Unlock()
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if err != nil {
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return err
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}
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c.conn.SetWriteDeadline(deadline)
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_, err = c.conn.Write(buf)
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if err != nil {
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return c.writeFatal(err)
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}
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if messageType == CloseMessage {
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c.writeFatal(ErrCloseSent)
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}
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return err
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}
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func (c *Conn) prepWrite(messageType int) error {
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// Close previous writer if not already closed by the application. It's
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// probably better to return an error in this situation, but we cannot
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// change this without breaking existing applications.
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if c.writer != nil {
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c.writer.Close()
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c.writer = nil
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}
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if !isControl(messageType) && !isData(messageType) {
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return errBadWriteOpCode
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}
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c.writeErrMu.Lock()
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err := c.writeErr
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c.writeErrMu.Unlock()
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if err != nil {
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return err
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}
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if c.writeBuf == nil {
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wpd, ok := c.writePool.Get().(writePoolData)
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if ok {
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c.writeBuf = wpd.buf
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} else {
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c.writeBuf = make([]byte, c.writeBufSize)
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}
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}
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return nil
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}
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// NextWriter returns a writer for the next message to send. The writer's Close
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// method flushes the complete message to the network.
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//
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// There can be at most one open writer on a connection. NextWriter closes the
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// previous writer if the application has not already done so.
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//
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// All message types (TextMessage, BinaryMessage, CloseMessage, PingMessage and
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// PongMessage) are supported.
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func (c *Conn) NextWriter(messageType int) (io.WriteCloser, error) {
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if err := c.prepWrite(messageType); err != nil {
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return nil, err
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}
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mw := &messageWriter{
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c: c,
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frameType: messageType,
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pos: maxFrameHeaderSize,
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}
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c.writer = mw
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if c.newCompressionWriter != nil && c.enableWriteCompression && isData(messageType) {
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w := c.newCompressionWriter(c.writer, c.compressionLevel)
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mw.compress = true
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c.writer = w
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}
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return c.writer, nil
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}
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type messageWriter struct {
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c *Conn
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compress bool // whether next call to flushFrame should set RSV1
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pos int // end of data in writeBuf.
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frameType int // type of the current frame.
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err error
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}
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func (w *messageWriter) fatal(err error) error {
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if w.err != nil {
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w.err = err
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w.c.writer = nil
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}
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return err
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}
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// flushFrame writes buffered data and extra as a frame to the network. The
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// final argument indicates that this is the last frame in the message.
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func (w *messageWriter) flushFrame(final bool, extra []byte) error {
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c := w.c
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length := w.pos - maxFrameHeaderSize + len(extra)
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// Check for invalid control frames.
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if isControl(w.frameType) &&
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(!final || length > maxControlFramePayloadSize) {
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return w.fatal(errInvalidControlFrame)
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}
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b0 := byte(w.frameType)
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if final {
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b0 |= finalBit
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}
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if w.compress {
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b0 |= rsv1Bit
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}
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w.compress = false
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b1 := byte(0)
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if !c.isServer {
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b1 |= maskBit
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}
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// Assume that the frame starts at beginning of c.writeBuf.
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framePos := 0
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if c.isServer {
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// Adjust up if mask not included in the header.
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framePos = 4
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}
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switch {
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case length >= 65536:
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c.writeBuf[framePos] = b0
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c.writeBuf[framePos+1] = b1 | 127
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binary.BigEndian.PutUint64(c.writeBuf[framePos+2:], uint64(length))
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case length > 125:
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framePos += 6
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|
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 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.fatal(err)
|
|
}
|
|
|
|
if final {
|
|
c.writer = nil
|
|
if c.writePool != nil {
|
|
c.writePool.Put(writePoolData{buf: c.writeBuf})
|
|
c.writeBuf = nil
|
|
}
|
|
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
|
|
}
|
|
w.err = errWriteClosed
|
|
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.
|
|
|
|
if err := c.prepWrite(messageType); err != nil {
|
|
return err
|
|
}
|
|
mw := messageWriter{c: c, frameType: messageType, pos: maxFrameHeaderSize}
|
|
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 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
|
|
}
|