Are "ping" and/or "pong" reserved events? #2414

thebinarypenguin · 2016-01-28T17:38:12Z

I have some basic code (see below) that works as expected when the events are named ding and dong but behaves very strangely when the events are named ping and pong

When the events are named ping and pong

The server code will log the "connect" and "disconnect" messages, but not the "ping" and "pong" messages
The client code will log the "ping" message and after a long wait (10+ seconds) will log the "pong" message, and if I keep waiting I'll get more "pong" message each 10+ seconds apart

Server Code

const fs             = require('fs');
const http           = require('http');
const path           = require('path');
const SocketIOServer = require('socket.io');

const app = new http.Server();
app.on('request', (req, res) => {

  const index = path.join(__dirname, 'public', 'index.html')

  fs.readFile(index, function (err, data) {
    if (err) {
      res.writeHead(500);
      return res.end('Error loading index.html');
    }

    res.writeHead(200);
    res.end(data);
  });
});
app.listen(3000, 'localhost');

const io = new SocketIOServer(app);


// could also use "connection"
io.on('connect', function (socket) {
  console.log(`${socket.id} "connect"`);

  socket.on('ping', (data) => {
    console.log('Receive "ping"');

    io.emit('pong', {});  
    console.log('Send "pong"');  
  });

  socket.on('disconnect', () => {
    console.log(`${socket.id} "disconnect"`);    
  });
});

Client Code

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">

    <title>Socket.IO Events</title>
  </head>
  <body>
    <h1>Socket.IO Events</h1>

    <script src="/socket.io/socket.io.js"></script>
    <script>
      const socket = io();

      socket.on('pong', (data) => {
        console.log('Receive "pong"');
      });

      socket.emit('ping', {});
      console.log('Send "ping"');

    </script>
  </body>
</html>

I have no idea what is going on here. Also this may be related to #1951

neutrino84 · 2016-01-29T04:10:58Z

I'm seeing strange behavior while using 'ping' / 'pong' event names - there does appear to be code in socket.io that does something with ping and pong, I don't have time to investigate further - changed name to 'drip' and 'drop'

nkzawa · 2016-01-29T12:20:50Z

ping and pong events are used in socket.io-client.
please see https://github.com/socketio/socket.io-client#events

ajhsu · 2016-04-07T11:17:42Z

Just trapped by the 'ping' event for few hours.
I think the official document may sync up with the document on GitHub?
Or maybe reserved event names can be noted on the document so that people won't be trapped again?

basilbeltran · 2016-08-23T17:55:02Z

what a time waster. We all (including the socket.io team) had the same bad idea. So what ELSE is reserved?

see: socketio/socket.io#2414

nkzawa closed this as completed Jan 29, 2016

comus mentioned this issue Sep 13, 2016

fix "ping" and/or "pong" reserved events owenashurst/agar.io-clone#454

Merged

1 task

godmar mentioned this issue Nov 24, 2016

Documentation enhancement request: make server-side nature of "room" abstraction clear and provide rationale. #2763

Closed

avenusengineer added a commit to avenusengineer/agar.io that referenced this issue Jan 15, 2023

fix "ping" and/or "pong" reserved events.

76af6ce

see: socketio/socket.io#2414

jordangeus90924 added a commit to jordangeus90924/Agar.io that referenced this issue Jan 4, 2024

fix "ping" and/or "pong" reserved events.

f664d91

see: socketio/socket.io#2414

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Are "ping" and/or "pong" reserved events? #2414

Are "ping" and/or "pong" reserved events? #2414

thebinarypenguin commented Jan 28, 2016

neutrino84 commented Jan 29, 2016

nkzawa commented Jan 29, 2016

ajhsu commented Apr 7, 2016

basilbeltran commented Aug 23, 2016 •

edited

Are "ping" and/or "pong" reserved events? #2414

Are "ping" and/or "pong" reserved events? #2414

Comments

thebinarypenguin commented Jan 28, 2016

neutrino84 commented Jan 29, 2016

nkzawa commented Jan 29, 2016

ajhsu commented Apr 7, 2016

basilbeltran commented Aug 23, 2016 • edited

basilbeltran commented Aug 23, 2016 •

edited