Engine.IO-as-WebSocket

Author: Katsuyuki Ohmuro [email protected]
Mailing List: http://lists.fanout.io/mailman/listinfo/fanout-users

Engine.IO-as-WebSocket is a small library that wraps engine.io-client to provide an interface similar to the browser WebSocket class. This makes it easy to use Engine.IO in otherwise pure-WebSocket code via dependency injection.

Apparently the Engine.IO client originally did mimic the WebSocket interface but for whatever reason its interface has drifted since then.

License

Engine.IO-as-WebSocket is offered under the MIT license. See the COPYING file.

Installation

Browsers

For use in a browser script tag, clone this repository and build it:

git clone https://github.com/fanout/engine.io-as-websocket.git
cd engine.io-as-websocket
npm install
npm run build

The resulting file will be available at dist/engine.io-as-websocket.js (and dist/engine.io-as-websocket.min.js for a minified version).

or get the npm package:

npm install engine.io-as-websocket

The file will be available at node_modules/engine.io-as-websocket/dist/engine.io-as-websocket.js (and node_modules/engine.io-as-websocket/dist/engine.io-as-websocket.min.js for a minified version).

Engine.IO-as-WebSocket will become available through the EngineIoSocket global variable.

Node.js (and Browserify/Webpack/etc)

Add to your project using npm:

npm install engine.io-as-websocket --save

And then reference Engine.IO-as-WebSocket from your code file:

import EngineIoSocket from "engine.io-as-websocket";

or

const EngineIoSocket = require("engine.io-as-websocket").default;

Usage

Simply substitute WebSocket with EngineIoSocket in your code:

<script src="/path/to/engine.io-as-websocket.js"></script>
<script>
  var socket = new EngineIoSocket('ws://localhost');
  socket.onopen = function () {
    socket.onmessage = function (event) {
      console.log('received message: ' + event.data);
    };
    socket.onclose = function (event) {};
  };
</script>

Caveats

The onclose callback provides an event containing code and wasClean, however code is bogus and wasClean is always false. This is because the Engine.IO client doesn't bubble up the values reported by its underlying WebSocket. Do not rely on clean closing at the transport level when using Engine.IO.