CODEWITHSUNDEEP
gowebsocketgopherjs
Raggaer
Raggaer

Reputation: 3318

Go websockets data gopherjs

I'm currently trying to communicate using websockets and my code is the following (im using gorilla)

buff := bytes.NewBuffer([]byte{})
binary.Write(buff, binary.LittleEndian, uint64(1))
binary.Write(buff, binary.LittleEndian, len(message))
binary.Write(buff, binary.LittleEndian, message)
client.Write <- buff.Bytes()

The c.Write channel its inside a for select loop

case msg := <-client.Write:
    buffer := &bytes.Buffer{}
    err := binary.Write(buffer, binary.LittleEndian, msg)
    if err != nil {
        return
    }
    err = client.Ws.WriteMessage(websocket.BinaryMessage, buffer.Bytes())
    if err != nil {
        return
    }
    buffer.Reset()

And client is just a struct

type Client struct {
    Ws      *websocket.Conn
    Read    chan []byte
    Write   chan []byte
    Account *models.Account
}

The message is sent successfully and I read it like this

b, err := conn.Read(buff)
if err != nil {
    utils.Log("Error while reading from socket " + err.Error())
    return
}
buffer := bytes.NewBuffer(buff[:b])
t, err := binary.ReadUvarint(buffer)
utils.Log(t)
if err != nil {
    utils.Log("Error while reading from socket " + err.Error())
    return
}
switch t {
case 1:
    roomsLen, err := binary.ReadUvarint(buffer)
    if err != nil {
        utils.Log("Error while reading rooms len " + err.Error())
        return
    }
    utils.Log(roomsLen)
    roomsBytes := make([]byte, roomsLen)
    binary.Read(buffer, binary.LittleEndian, roomsBytes)
    rooms := []*Room{}
    err = json.Unmarshal(roomsBytes, rooms)
    if err != nil {
        utils.Log("Error while unmarshaling room list " + err.Error())
        return
    }
    utils.Log(rooms)

The utils.Log function is just this

func Log(msg interface{}) {
    n := time.Now()
    console.Call("log", fmt.Sprintf("[%v:%v:%v] %v", n.Hour(), n.Minute(),    n.Second(), msg))
}

Thing is the first uint64 is the one im waiting (1) but the second uint64 im reading is always 0 while loggin it (len(message)) gives me 52

And since its always 0 I cant unmarshal it properly

So I'm not sure what I am doing wrong or if this is not a correct way to use websockets.

Upvotes: 0

Views: 211

Answers (1)

DanRedux
DanRedux

Reputation: 9359

Small error. You're writing uint64 but using "ReadUvarint" to read it (a varint is a different type of data).

package main

import (
    "bytes"
    "encoding/binary"
    "fmt"
)

func main() {
    b := bytes.NewBuffer([]byte{})
    e1 := binary.Write(b, binary.LittleEndian, uint64(10))
    e2 := binary.Write(b, binary.LittleEndian, uint64(20))

    fmt.Println("writing 10 and 20", e1, e2)

    {
        r := bytes.NewBuffer(b.Bytes())
        res, e := binary.ReadUvarint(r)
        res2, e2 := binary.ReadUvarint(r)
        fmt.Println("using readuvarint here        :", res, res2, e, e2, b.Bytes())
    }
    {
        r := bytes.NewBuffer(b.Bytes())
        var res, res2 uint64
        e := binary.Read(r, binary.LittleEndian, &res)
        e2 := binary.Read(r, binary.LittleEndian, &res2)
        fmt.Println("using read into uint64's here :", res, res2, e, e2, b.Bytes())
    }
}

Upvotes: 1

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