I am doing a chat room using socket.io. When a client is offline(just turn off the wifi), I still send a message(named offline messages A) to the server through the message will not send success. After a while, the client will receive the disconnect event, ignore that, I still send messages(named offline messages B) to the server. After doing above, I turn on the wifi, and the client will reconnect success. Ok, the problem is that the server will receive all the offline messages(A, B) after the client reconnects success. I can not figure this out, how it goes from offline to reconnect success of the socket.io.
I know that the offline messages B is stored in the sendBuffer as described in the question. And the client will resend the messages in the sendBuffer when it reconnects success, but why the offline messages A still can send to the server success? I have coded to show this problem
/*
* Client side
*/
onClickSend = (value) => {
console.log('send message:', value)
this.socket.emit('chatMessage', value);
}
connect = () => {
if (!this.socket) {
console.log('connecting...')
this.socket = io(url, {
query: {
clientId: this.clientId
},
forceNew:true,
})
}
this.socket.on('connect',()=>{
console.log('connected');
})
this.socket.on('error',(err)=>{
console.log('error happen：',err);
})
this.socket.on('disconnect',(reason)=>{
console.log('disconnect event：', reason);
})
this.socket.on('reconnect',(e)=>{
console.log('reconnect success：' , e);
})
}
/*
* Server side
*/
const app = require('express')();
const http = require('http').createServer(app);
const io = require('socket.io')(http)
const PORT = 40001;
io.on('connection', function(socket) {
const clientId = socket.handshake.query.clientId;
console.log('client come...', clientId)
socket.on('connect', function(data) {
console.log('user connects socket');
});
socket.on('disconnect', (reason)=>{
console.log('event disconnect: ', reason, clientId)
socket.removeAllListeners()
socket = null
})
socket.on('error', (err)=>{
console.log('error happen: ', err, clientId)
})
// the server will receive all the offline messages(message A, B)
// send after the network is down when the client
// reconnect success.
socket.on('chatMessage', (message)=>{
console.log('receive message: ', message, clientId)
io.emit('chatMessage', message)
})
});
http.listen(PORT, function() {
console.log('listening on *:', PORT);
});
As I see, the server will not receive the offline message, but the server receives all the offline messages when the client reconnects success.
