node-libnice

What is this?

This is a thin node.js wrapper around libnice. It provides ICE (Interactive Connectivity Establishment) support, which is a protocol for NAT traversal. ICE is primarily used in peer-to-peer applications like VoIP, video conferences, and instant messaging. It is part of SIP and WebRTC.

Setup

You have to make sure that you have libnice >=1.4 and its headers are installed. On Debian/Ubuntu/... run

apt-get install libnice-dev

Then install this library with

npm install libnice

Usage

First you have to create an agent which can create streams

var agent = new require("libnice").NiceAgent();
agent.setStunServer("132.177.123.6");

An important concept in libnice are components. A stream can consist of multiple components which are something like channels. Each component can send and receive data. To create a stream with one component call

var stream = agent.createStream(1);

Streams are EventEmitters. Register your callbacks

stream.on('gatheringDone', function(candidates) {
    // candidates is an array of sdp strings
    var credentials = stream.getLocalCredentials();
    // send credentials and candidates to remote client
});

stream.on('stateChanged', function(component, state) {
	// state is a string
}

stream.on('receive', function(component, data) {
    // data is a buffer
});

Please note that the first parameter on stateChanged and receive is the component id. Component ids are numbers starting from 1.

To start the connection process tell the stream to gather candidates

stream.gatherCandidates();

Now you have to exchange the credentials and ice candidates with the other client

stream.setRemoteCredentials(ufrag, pwd);
stream.addRemoteCandidate(candidate1);
stream.addRemoteCandidate(candidate2);

When everything is set up and the clients are able to connect to each other you should arrive in the state ready. Now you can now send and receive data

stream.send(component, data)

Full API documentation will be added shortly. Please also consult the libnice documentation for detailed information.

TODOs

• more documentation
• resolve host for stun servers
• port missing libnice functions
• get rid of the glib loop in its own thread