Horizon: Engine.io endpoint breaks when extending express

Created on 26 May 2016 · 7Comments · Source: rethinkdb/horizon

Saw this on SO and reproduced.

You can repro this with the following:

// app.js
'use strict'

const express = require('express');
const horizon = require('@horizon/server');

const app = express();
app.use(express.static('public'));
const http_server = app.listen(8181);
const options = { permissions: false, auth: {allow_anonymous: true, allow_unauthenticated: true, token_secret:'test'} };
const horizon_server = horizon(http_server, options);
console.log('Listening on port 8181.');

<!-- public/index.html -->
<!doctype html>
<html>
  <head>
    <meta charset="UTF-8">
    <script src="http://localhost:8181/horizon/horizon.js"></script>
    <script>
      var horizon = Horizon({authType: 'anonymous'});
      horizon.onReady(function() {
        document.querySelector('h1').innerHTML = 'App works!'
      });
      horizon.connect();
    </script>
  </head>
  <body>
   <marquee><h1></h1></marquee>
  </body>
</html>

screenshot 2016-05-26 13 58 45

Attempting to use wsta or just `new WebSocket("localhost:8181/horizon") doesn't work either but not sure if that's expected since it's the engine.io server not vanilla websockets.

bug client

Source

dalanmiller

Most helpful comment

Struggling with the same issue, when will this be released ?

kavaro on 29 May 2016

👍3

All 7 comments

i've finally been able to figure out why these 400 / bad requests happen. at least in my case.

due to engine.ios transport upgrade, it first uses xhr and then switches to websockets if available.

now, if your server is not configured to handle this correctly, it can lead to the aforementioned 400 - Bad Request.

Also see: https://github.com/socketio/socket.io/issues/1696

In my case, I was able to work around this issue by using this in my Apache config:

<Location /horizon>
    RewriteEngine on

    RewriteCond %{QUERY_STRING} transport=polling
    RewriteRule /(.*)$ http://localhost:2000/horizon/$1 [P]

    ProxyPass ws://localhost:2000/horizon
    ProxyPassReverse ws://localhost:2000/horizon
</Location>

Of course, it largely depends on your setup, but I'm pretty sure that these 400s all came from such a server config issue.