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matterbridge/vendor/github.com/Rhymen/go-whatsapp/conn.go
2019-02-21 20:28:13 +01:00

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//Package whatsapp provides a developer API to interact with the WhatsAppWeb-Servers.
package whatsapp
import (
"crypto/hmac"
"crypto/sha256"
"encoding/json"
"fmt"
"math/rand"
"net/http"
"os"
"strconv"
"strings"
"sync"
"time"
"github.com/Rhymen/go-whatsapp/binary"
"github.com/Rhymen/go-whatsapp/crypto/cbc"
"github.com/gorilla/websocket"
)
type metric byte
const (
debugLog metric = iota + 1
queryResume
queryReceipt
queryMedia
queryChat
queryContacts
queryMessages
presence
presenceSubscribe
group
read
chat
received
pic
status
message
queryActions
block
queryGroup
queryPreview
queryEmoji
queryMessageInfo
spam
querySearch
queryIdentity
queryUrl
profile
contact
queryVcard
queryStatus
queryStatusUpdate
privacyStatus
queryLiveLocations
liveLocation
queryVname
queryLabels
call
queryCall
queryQuickReplies
)
type flag byte
const (
ignore flag = 1 << (7 - iota)
ackRequest
available
notAvailable
expires
skipOffline
)
/*
Conn is created by NewConn. Interacting with the initialized Conn is the main way of interacting with our package.
It holds all necessary information to make the package work internally.
*/
type Conn struct {
wsConn *websocket.Conn
wsConnOK bool
wsConnMutex sync.RWMutex
session *Session
listener map[string]chan string
listenerMutex sync.RWMutex
writeChan chan wsMsg
handler []Handler
msgCount int
msgTimeout time.Duration
Info *Info
Store *Store
ServerLastSeen time.Time
longClientName string
shortClientName string
}
type wsMsg struct {
messageType int
data []byte
}
/*
Creates a new connection with a given timeout. The websocket connection to the WhatsAppWeb servers get´s established.
The goroutine for handling incoming messages is started
*/
func NewConn(timeout time.Duration) (*Conn, error) {
wac := &Conn{
wsConn: nil, // will be set in connect()
wsConnMutex: sync.RWMutex{},
listener: make(map[string]chan string),
listenerMutex: sync.RWMutex{},
writeChan: make(chan wsMsg),
handler: make([]Handler, 0),
msgCount: 0,
msgTimeout: timeout,
Store: newStore(),
longClientName: "github.com/rhymen/go-whatsapp",
shortClientName: "go-whatsapp",
}
if err := wac.connect(); err != nil {
return nil, err
}
go wac.readPump()
go wac.writePump()
go wac.keepAlive(20000, 90000)
return wac, nil
}
func (wac *Conn) isConnected() bool {
wac.wsConnMutex.RLock()
defer wac.wsConnMutex.RUnlock()
if wac.wsConn == nil {
return false
}
if wac.wsConnOK {
return true
}
// just send a keepalive to test the connection
wac.sendKeepAlive()
// this method is expected to be called by loops. So we can just return false
return false
}
// connect should be guarded with wsConnMutex
func (wac *Conn) connect() error {
dialer := &websocket.Dialer{
ReadBufferSize: 25 * 1024 * 1024,
WriteBufferSize: 10 * 1024 * 1024,
HandshakeTimeout: wac.msgTimeout,
}
headers := http.Header{"Origin": []string{"https://web.whatsapp.com"}}
wsConn, _, err := dialer.Dial("wss://web.whatsapp.com/ws", headers)
if err != nil {
return fmt.Errorf("couldn't dial whatsapp web websocket: %v", err)
}
wsConn.SetCloseHandler(func(code int, text string) error {
fmt.Fprintf(os.Stderr, "websocket connection closed(%d, %s)\n", code, text)
// from default CloseHandler
message := websocket.FormatCloseMessage(code, "")
wsConn.WriteControl(websocket.CloseMessage, message, time.Now().Add(time.Second))
// our close handling
if websocket.IsUnexpectedCloseError(err, websocket.CloseNormalClosure, websocket.CloseGoingAway) {
fmt.Println("Trigger reconnect")
go wac.reconnect()
}
return nil
})
wac.wsConn = wsConn
wac.wsConnOK = true
return nil
}
// reconnect should be run as go routine
func (wac *Conn) reconnect() {
wac.wsConnMutex.Lock()
wac.wsConn.Close()
wac.wsConn = nil
wac.wsConnOK = false
wac.wsConnMutex.Unlock()
// wait up to 60 seconds and then reconnect. As writePump should send immediately, it might
// reconnect as well. So we check its existance before reconnecting
for !wac.isConnected() {
time.Sleep(time.Duration(rand.Intn(60)) * time.Second)
wac.wsConnMutex.Lock()
if wac.wsConn == nil {
if err := wac.connect(); err != nil {
fmt.Fprintf(os.Stderr, "could not reconnect to websocket: %v\n", err)
}
}
wac.wsConnMutex.Unlock()
}
}
func (wac *Conn) write(data []interface{}) (<-chan string, error) {
d, err := json.Marshal(data)
if err != nil {
return nil, err
}
ts := time.Now().Unix()
messageTag := fmt.Sprintf("%d.--%d", ts, wac.msgCount)
msg := fmt.Sprintf("%s,%s", messageTag, d)
ch := make(chan string, 1)
wac.listenerMutex.Lock()
wac.listener[messageTag] = ch
wac.listenerMutex.Unlock()
wac.writeChan <- wsMsg{websocket.TextMessage, []byte(msg)}
wac.msgCount++
return ch, nil
}
func (wac *Conn) writeBinary(node binary.Node, metric metric, flag flag, tag string) (<-chan string, error) {
if len(tag) < 2 {
return nil, fmt.Errorf("no tag specified or to short")
}
b, err := binary.Marshal(node)
if err != nil {
return nil, err
}
cipher, err := cbc.Encrypt(wac.session.EncKey, nil, b)
if err != nil {
return nil, err
}
h := hmac.New(sha256.New, wac.session.MacKey)
h.Write(cipher)
hash := h.Sum(nil)
data := []byte(tag + ",")
data = append(data, byte(metric), byte(flag))
data = append(data, hash[:32]...)
data = append(data, cipher...)
ch := make(chan string, 1)
wac.listenerMutex.Lock()
wac.listener[tag] = ch
wac.listenerMutex.Unlock()
msg := wsMsg{websocket.BinaryMessage, data}
wac.writeChan <- msg
wac.msgCount++
return ch, nil
}
func (wac *Conn) readPump() {
defer wac.wsConn.Close()
for {
msgType, msg, err := wac.wsConn.ReadMessage()
if err != nil {
wac.wsConnOK = false
if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway) {
wac.handle(fmt.Errorf("unexpected websocket close: %v", err))
}
// sleep for a second and retry reading the next message
time.Sleep(time.Second)
continue
}
wac.wsConnOK = true
data := strings.SplitN(string(msg), ",", 2)
//Kepp-Alive Timestmap
if data[0][0] == '!' {
msecs, err := strconv.ParseInt(data[0][1:], 10, 64)
if err != nil {
fmt.Fprintf(os.Stderr, "Error converting time string to uint: %v\n", err)
continue
}
wac.ServerLastSeen = time.Unix(msecs/1000, (msecs%1000)*int64(time.Millisecond))
continue
}
wac.listenerMutex.RLock()
listener, hasListener := wac.listener[data[0]]
wac.listenerMutex.RUnlock()
if len(data[1]) == 0 {
continue
} else if hasListener {
listener <- data[1]
wac.listenerMutex.Lock()
delete(wac.listener, data[0])
wac.listenerMutex.Unlock()
} else if msgType == 2 && wac.session != nil && wac.session.EncKey != nil {
message, err := wac.decryptBinaryMessage([]byte(data[1]))
if err != nil {
wac.handle(fmt.Errorf("error decoding binary: %v", err))
continue
}
wac.dispatch(message)
} else {
wac.handle(string(data[1]))
}
}
}
func (wac *Conn) writePump() {
for msg := range wac.writeChan {
for !wac.isConnected() {
// reconnect to send the message ASAP
wac.wsConnMutex.Lock()
if wac.wsConn == nil {
if err := wac.connect(); err != nil {
fmt.Fprintf(os.Stderr, "could not reconnect to websocket: %v\n", err)
}
}
wac.wsConnMutex.Unlock()
if !wac.isConnected() {
// reconnecting failed. Sleep for a while and try again afterwards
time.Sleep(time.Duration(rand.Intn(5)) * time.Second)
}
}
if err := wac.wsConn.WriteMessage(msg.messageType, msg.data); err != nil {
fmt.Fprintf(os.Stderr, "error writing to socket: %v\n", err)
wac.wsConnOK = false
// add message to channel again to no loose it
go func() {
wac.writeChan <- msg
}()
}
}
}
func (wac *Conn) sendKeepAlive() {
// whatever issues might be there allow sending this message
wac.wsConnOK = true
wac.writeChan <- wsMsg{
messageType: websocket.TextMessage,
data: []byte("?,,"),
}
}
func (wac *Conn) keepAlive(minIntervalMs int, maxIntervalMs int) {
for {
wac.sendKeepAlive()
interval := rand.Intn(maxIntervalMs-minIntervalMs) + minIntervalMs
<-time.After(time.Duration(interval) * time.Millisecond)
}
}
func (wac *Conn) decryptBinaryMessage(msg []byte) (*binary.Node, error) {
//message validation
h2 := hmac.New(sha256.New, wac.session.MacKey)
h2.Write([]byte(msg[32:]))
if !hmac.Equal(h2.Sum(nil), msg[:32]) {
return nil, fmt.Errorf("message received with invalid hmac")
}
// message decrypt
d, err := cbc.Decrypt(wac.session.EncKey, nil, msg[32:])
if err != nil {
return nil, fmt.Errorf("error decrypting message with AES: %v", err)
}
// message unmarshal
message, err := binary.Unmarshal(d)
if err != nil {
return nil, fmt.Errorf("error decoding binary: %v", err)
}
return message, nil
}