AutobahnJS

AutobahnJS is a JavaScript client library that implements The WebSocket Application Messaging Protocol and provides asynchronous RPC and Publish/Subscribe over WebSocket.

Why?

WebSocket is already built into modern browsers and provides bidirectional low-latency messaging.

However, as such, it is quite low-level. Web apps often have a need for higher level messaging patterns:

• Publish & Subscribe
• Remote Procedure Calls

This is where The WebSocket Application Messaging Protocol (WAMP) enters. WAMP runs on top of raw WebSocket and provides asynchronous RPC and PubSub.

Technically, WAMP is a proper WebSocket subprotocol that uses JSON as message serialization format. WAMP was designed to be easy to use and simple to implement.

AutobahnJS implements WAMP in JavaScript to be used in browser based applications.

Show me some code!

Remote Procedure Calls

window.onload = function() {
 
   // WAMP server
   var wsuri = "ws://localhost:9000";
 
   ab.connect(wsuri,
 
      // WAMP session was established
      function (session) {
 
         // asynchronous RPC, returns promise object
         session.call("http://example.com/simple/calc#add", 23, 7).then(
 
            // RPC success callback
            function (res) {
               console.log("got result: " + res);
            },
 
            // RPC error callback
            function (error) {
               console.group("Error");
               console.group("URI");
               console.log(error.uri);
               console.groupEnd();
               console.group("Description");
               console.log(error.desc);
               console.groupEnd();
               console.group("Detail");
               console.log(error.detail);
               console.groupEnd();
               console.groupEnd();
            }
         );
      },
 
      // WAMP session is gone
      function (code, reason) {
         console.log(reason);
      }
   );
};

Publish and Subscribe

window.onload = function() {
 
   // WAMP server
   var wsuri = "ws://localhost:9000";
 
   ab.connect(wsuri,
 
      // WAMP session was established
      function (session) {
 
         // subscribe to topic
         session.subscribe("http://example.com/event#myevent1",
 
            // on event publication callback
            function (topic, event) {
               console.log("got event1: " + event);
            }
         );
 
         // publish event on a topic
         session.publish("http://example.com/event#myevent1", {a: 23, b: "foobar"});
      },
 
      // WAMP session is gone
      function (code, reason) {
         console.log(reason);
      }
   );
};

Features

• provides asynchronous RPC and Publish/Subscribe over WebSocket
• implements WAMP v1, should work with any WAMP server
• easy to use Deferred-based API (when.js (bundled), jQuery Deferreds, ..)
• flexible, automatic reconnect
• session authentication (WAMP-CRA)
• no dependencies
• works with AMD/CommonJS module loaders
• tiny size (111kB source, 30kB minified, 10kB compressed)
• open-source (MIT License)

Get it

You can get the latest prebuilt AutobahnJS release from here:

1. Production (minimized and gzipped)
2. Production (only minimized)
3. Development

Note: You can use those via direct linking for development purposes, but please do not hotlink for production. It won't work anyway, since we restrictions on HTTP referer.

Where to go

For more information, including getting started, tutorials and reference documentation, please visit the project's homepage.

Get in touch

Get in touch on IRC #autobahn on chat.freenode.net or the mailing list.

Acknowledgements

AutobahnJS includes code from the following open-source projects

• when.js
• CryptoJS

Special thanks to the Coders with an Unhealthy Javascript Obsession for creating when.js - A lightweight Promise and when() implementation, plus other async goodies.

Building

To build, you will need

• SCons
• Google Closure Compiler
• Taschenmesser

SCons is a Python based build tool, so you will need Python as well. Taschenmesser is an SCons toolbelt also written in Python.

Set environment variables:

1. JAVA_HOME pointing to your Java run-time, e.g.

   C:\Program Files\Java\jre7

2. adding Python & Python scripts to PATH, e.g.

   C:\Python27;C:\Python27\Scripts;

3. JS_COMPILER pointing to the Google Closure compiler.jar

   C:\Program Files\Google Closure\compiler.jar

Now clone the repo:

git clone git://github.com/tavendo/AutobahnJS.git
cd AutobahnJS

You need to get any Git submodules:

git submodule init
git submodule update 

Updating CryptoJS needs to be done manually, since they are not on Git.

For a release version, set the appropriate AutobahnJS version in version.txt.

Then start the build:

scons

This will produce 3 files inside the build directory:

build/autobahn.js
build/autobahn.min.js
build/autobahn.min.jgz

To clean up your build:

scons -uc