a library for capturing midi hardware input in the browser. it is a nodejs middleware which listens for midi input on and forwards the midi message to the client via socket.io.

$ npm install midi.io  

midi.io's primary functionality is on the server. it is responsible for creatting http and websocket routes your client can use to learn about midi devices. additionally, midi.io serves a backbone client library to use for accessing these resources. the server and client components can be used together or independently. a full client and server example is contained in the repository for reference.

a basic midi.io server creates the following resources:

• GET /midi/devices - show all active midi devices
• GET /midi/devices/:id - show details for a specific midi device
• WS /midi/devices/:id - a socket.io namespace for receiving midi messages from a specific device

to enable midi.io, simply pass it into your http server as a middleware, with your socket.io instance as it's first argument. the following example is the complete code for a simple midi.io server:

var connect = require('connect'),
  socketio = require('socket.io'),
  midi = require('midi.io');

var server = connect.createServer(),
  io = socketio.listen(server);

server.use(midi(io));
server.listen(9000);

the midi.io client library is served via /midi.io/midi.io.js and requires backbone. it creates a single model and a single collection used to manage your midi devices:

• MidiDevice - a backbone model which emits midi events
• MidiDevices - a backbone collection used to browse and select midi devices

the following code shows the client library in action:

var devices = new MidiDevices(),
  midi_device = new MidiDevice({ id: 1 });

// get all active midi devices
devices.fetch({
  success: function() {
    console.log('found devices', devices.models);
  }
});

// tie the next inbound midi message to a specific function
devices.learn(function() {
  console.log('the next midi button pressed will always log me!');
});

// log all midi events for all devices
devices.on('midi', function(msg) {
  console.log('got midi', msg);
});

// only log midi events from device 1
midi_device.on('midi', function(msg) {
  console.log('got midi from device 1', msg);
});

formatted documentation is available and can be built using groc:

npm install -g groc
groc lib/**/*.js src/**/*.js readme.md