EvenSource Broker

A simple bridge between EventSource and an AMQP fanout exchange.

EventSource is a new browser standard released as part of the HTML5 spec.

It lets the browser send a never-ending HTTP request to a server and provides a javascript API for binding to events pushed from the server.

EventSource is very handy when you don't need the full bidirectional communication that Websockets offers. it plays well with load-balancers, intermediary proxies and HTTPS termination.

This library sets up an EventSource that clients can connect to specifying a channel to listen to in the query string. The server connects to a fanout AMQP exchange and routes AMQP messages as events to the javascript clients.

MongoDB is used to store user and connection information.

The server expects the AMQP messages to be JSON following the format:

{
    "channel": "some-channel", // Required
    "data": "{/"msg/": /"data/"}", // Required
    "id": "event-id", // optional
    "name": "event-name" // optional
}

To open connections to a channel a user with an key and a secret is expected to exist in the database. Before opening a connection a socket id must be aquired from by calling POST /socket

A simple example of how to interact with this API can be found in the [https://github.com/eshq/eshq-gem](eshq ruby gem).

Installation

Clone the repository, cd to the root of it and execute

cabal install

Run as:

eventsource-broker -p <port>

The broker will look for an AMQP_URL environment variable for a broker to connect to. It also takes a MONGO_URL for configuring the database connection and an ORIGIN variable that should be a url the server runs on for cross domain requests.

License

Copyright (c)2011, Mathias Biilmann [email protected]

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright
  notice, this list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above
  copyright notice, this list of conditions and the following
  disclaimer in the documentation and/or other materials provided
  with the distribution.

* Neither the name of Mathias Biilman <[email protected]>
  nor the names of other contributors may be used to endorse or
  promote products derived from this software without specific prior
  written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE