enet.js -- node.js wrapper for enet

This is a Node wrapper for the enet networking library. enet is a simple networking library that provides sequencing and reliability of packets sent over UDP.

Building

First, install enet. If it's installed in a non-standard location, make a note of the prefix you used, calling it ENET_PREFIX.

Then, build the module with node-waf:

node-waf configure --enet-prefix=${ENET_PREFIX}
node-waf build --enet-prefix=${ENET_PREFIX}

Then you can create a module directory via the makefile:

make module

You can then copy the directory node_modules/enet to your node_modules directory, e.g., ~/node_modules. When running, make sure that ${ENET_PREFIX}/lib is in your LD_LIBRARY_PATH.

Usage

The library follows the enet API pretty closely. Reading the docs for enet will help.

You can basically do this:

var bindaddr = new enet.Address('0.0.0.0', 1234);
var host = new enet.Host(bindaddr, 10); // bind addr, number of peers to allow at once
host.on('connect', function(peer, data) {
    // Peer connected.
    // data is an integer with out-of-band data
}).on('disconnect', function(peer, data) {
    // Peer disconnected.
}).on('message', function(peer, packet, channel, data)
{
   // Peer sent a message to us in `packet' on `channel'.
});

host.start_watcher();

var peer = host.connect(new enet.Address('a.b.c.d', 4331));
var packet = new enet.Packet('my message', enet.Packet.FLAG_RELIABLE);
peer.send(0, packet); // channel number, packet.
// Note that enet invalidates a packet when you send it, so `packet'
// there is no longer valid at this point.

Caveats

There isn't a lot of error checking in the C++ code right now. Doing something wrong will likely trigger an assertion error.

The enet loop doesn't use socket readability exclusively when calling the event loop: it also uses a timer to fire the I/O loop periodically. This is because (I think) enet requires this mode of operation; we'd like to make this work better at some point.