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// Copyright (c) 2021 Tulir Asokan
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
package socket
import (
"context"
"errors"
"fmt"
"net/http"
"net/url"
"sync"
"time"
"github.com/gorilla/websocket"
waLog "go.mau.fi/whatsmeow/util/log"
)
type Proxy = func(*http.Request) (*url.URL, error)
type FrameSocket struct {
conn *websocket.Conn
ctx context.Context
cancel func()
log waLog.Logger
lock sync.Mutex
Frames chan []byte
OnDisconnect func(remote bool)
WriteTimeout time.Duration
Header []byte
Proxy Proxy
incomingLength int
receivedLength int
incoming []byte
partialHeader []byte
}
func NewFrameSocket(log waLog.Logger, header []byte, proxy Proxy) *FrameSocket {
return &FrameSocket{
conn: nil,
log: log,
Header: header,
Frames: make(chan []byte),
Proxy: proxy,
}
}
func (fs *FrameSocket) IsConnected() bool {
return fs.conn != nil
}
func (fs *FrameSocket) Context() context.Context {
return fs.ctx
}
func (fs *FrameSocket) Close(code int) {
fs.lock.Lock()
defer fs.lock.Unlock()
if fs.conn == nil {
return
}
if code > 0 {
message := websocket.FormatCloseMessage(code, "")
err := fs.conn.WriteControl(websocket.CloseMessage, message, time.Now().Add(time.Second))
if err != nil {
fs.log.Warnf("Error sending close message: %v", err)
}
}
fs.cancel()
err := fs.conn.Close()
if err != nil {
fs.log.Errorf("Error closing websocket: %v", err)
}
fs.conn = nil
fs.ctx = nil
fs.cancel = nil
if fs.OnDisconnect != nil {
go fs.OnDisconnect(code == 0)
}
}
func (fs *FrameSocket) Connect() error {
fs.lock.Lock()
defer fs.lock.Unlock()
if fs.conn != nil {
return ErrSocketAlreadyOpen
}
ctx, cancel := context.WithCancel(context.Background())
dialer := websocket.Dialer{
Proxy: fs.Proxy,
}
headers := http.Header{"Origin": []string{Origin}}
fs.log.Debugf("Dialing %s", URL)
conn, _, err := dialer.Dial(URL, headers)
if err != nil {
cancel()
return fmt.Errorf("couldn't dial whatsapp web websocket: %w", err)
}
fs.ctx, fs.cancel = ctx, cancel
fs.conn = conn
conn.SetCloseHandler(func(code int, text string) error {
fs.log.Debugf("Server closed websocket with status %d/%s", code, text)
cancel()
// from default CloseHandler
message := websocket.FormatCloseMessage(code, "")
_ = conn.WriteControl(websocket.CloseMessage, message, time.Now().Add(time.Second))
return nil
})
go fs.readPump(conn, ctx)
return nil
}
func (fs *FrameSocket) SendFrame(data []byte) error {
conn := fs.conn
if conn == nil {
return ErrSocketClosed
}
dataLength := len(data)
if dataLength >= FrameMaxSize {
return fmt.Errorf("%w (got %d bytes, max %d bytes)", ErrFrameTooLarge, len(data), FrameMaxSize)
}
headerLength := len(fs.Header)
// Whole frame is header + 3 bytes for length + data
wholeFrame := make([]byte, headerLength+FrameLengthSize+dataLength)
// Copy the header if it's there
if fs.Header != nil {
copy(wholeFrame[:headerLength], fs.Header)
// We only want to send the header once
fs.Header = nil
}
// Encode length of frame
wholeFrame[headerLength] = byte(dataLength >> 16)
wholeFrame[headerLength+1] = byte(dataLength >> 8)
wholeFrame[headerLength+2] = byte(dataLength)
// Copy actual frame data
copy(wholeFrame[headerLength+FrameLengthSize:], data)
if fs.WriteTimeout > 0 {
err := conn.SetWriteDeadline(time.Now().Add(fs.WriteTimeout))
if err != nil {
fs.log.Warnf("Failed to set write deadline: %v", err)
}
}
return conn.WriteMessage(websocket.BinaryMessage, wholeFrame)
}
func (fs *FrameSocket) frameComplete() {
data := fs.incoming
fs.incoming = nil
fs.partialHeader = nil
fs.incomingLength = 0
fs.receivedLength = 0
fs.Frames <- data
}
func (fs *FrameSocket) processData(msg []byte) {
for len(msg) > 0 {
// This probably doesn't happen a lot (if at all), so the code is unoptimized
if fs.partialHeader != nil {
msg = append(fs.partialHeader, msg...)
fs.partialHeader = nil
}
if fs.incoming == nil {
if len(msg) >= FrameLengthSize {
length := (int(msg[0]) << 16) + (int(msg[1]) << 8) + int(msg[2])
fs.incomingLength = length
fs.receivedLength = len(msg)
msg = msg[FrameLengthSize:]
if len(msg) >= length {
fs.incoming = msg[:length]
msg = msg[length:]
fs.frameComplete()
} else {
fs.incoming = make([]byte, length)
copy(fs.incoming, msg)
msg = nil
}
} else {
fs.log.Warnf("Received partial header (report if this happens often)")
fs.partialHeader = msg
msg = nil
}
} else {
if len(fs.incoming)+len(msg) >= fs.incomingLength {
copy(fs.incoming[fs.receivedLength:], msg[:fs.incomingLength-fs.receivedLength])
msg = msg[fs.incomingLength-fs.receivedLength:]
fs.frameComplete()
} else {
copy(fs.incoming[fs.receivedLength:], msg)
fs.receivedLength += len(msg)
msg = nil
}
}
}
}
func (fs *FrameSocket) readPump(conn *websocket.Conn, ctx context.Context) {
fs.log.Debugf("Frame websocket read pump starting %p", fs)
defer func() {
fs.log.Debugf("Frame websocket read pump exiting %p", fs)
go fs.Close(0)
}()
for {
msgType, data, err := conn.ReadMessage()
if err != nil {
// Ignore the error if the context has been closed
if !errors.Is(ctx.Err(), context.Canceled) {
fs.log.Errorf("Error reading from websocket: %v", err)
}
return
} else if msgType != websocket.BinaryMessage {
fs.log.Warnf("Got unexpected websocket message type %d", msgType)
continue
}
fs.processData(data)
}
}
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