About

Disclaimer: This library is still work in progress.

SockJS is WebSocket emulation library. It means that you use the WebSocket API, only instead of WebSocket class you instantiate SockJS class. I highly recommend to read SockJS: WebSocket emulation on the RabbitMQ blog for more info.

Prerequisites

Even though this library uses Rack interface, Thin is required as it supports asynchronous callback. For Websockets, we use faye-websocket gem.

The Client-Side Part

For the client-side part you have to use JS library sockjs-client which provides WebSocket-like API. Here’s an example:

<script src="http://cdn.sockjs.org/sockjs-0.2.1.min.js"></script>

<script>
  var sock = new SockJS("http://mydomain.com/my_prefix");

  sock.onopen = function() {
    console.log("open");
  };

  sock.onmessage = function(e) {
    console.log("message", e.data);
  };

  sock.onclose = function() {
    console.log("close");
  };
</script>

The Server-Side Part

Now in order to have someone to talk to, we need to run a server. That’s exactly what is sockjs-ruby good for:

#!/usr/bin/env ruby
# encoding: utf-8

require "rack"
require "rack/sockjs"
require "eventmachine"

# Your custom app.
class MyHelloWorld
  def call(env)
    body = "This is the app, not SockJS."
    headers = {
      "Content-Type" => "text/plain; charset=UTF-8",
      "Content-Length" => body.bytesize.to_s
    }

    [200, headers, [body]]
  end
end


app = Rack::Builder.new do
  # Run one SockJS app on /echo.
  use SockJS, "/echo" do |connection|
    connection.subscribe do |session, message|
      session.send(message)
    end
  end

  # ... and the other one on /close.
  use SockJS, "/close" do |connection|
    connection.session_open do |session|
      session.close(3000, "Go away!")
    end
  end

  # This app will run on other URLs than /echo and /close,
  # as these has already been assigned to SockJS.
  run MyHelloWorld.new
end


EM.run do
  thin = Rack::Handler.get("thin")
  thin.run(app.to_app, Port: 8081)
end

For more complex example check examples/sockjs_apps_for_sockjs_protocol_tests.rb

SockJS Family

SockJS-client JavaScript client library.
SockJS-node Node.js server.
SockJS-ruby Ruby server.
SockJS-protocol protocol tests and documentation.
SockJS-protocol spec

Development

Get sockjs-protocol (installation information are in its README) and run rake protocol_test. Now you can run the tests against it, for instance:

# Run all the tests.
./venv/bin/python sockjs-protocol-0.2.1.py

# Run all the tests defined in XhrStreaming.
./venv/bin/python sockjs-protocol-0.2.1.py XhrStreaming

# Run only XhrStreaming.test_transport test.
./venv/bin/python sockjs-protocol-0.2.1.py XhrStreaming.test_transport

volt-sockjs