socket-io-server.

Provides a simple abstraction for initializing- and connecting to a socket.io server.

This module creates a singleton Object that exposes methods for listening to and emitting socket events using an existing http Server Object.

Installing.

npm install socket-io-server

Usage.

// Dependencies.
var express = require('express');
var	http = require('http');
var	socket = require('socket-io-server');
var	app = express();
var	server = http.Server(app);

// Initialize socket server.
socket.init(server);

// Initialize http server.
server.listen(8080);

// Listen for incoming events from a client.
// Note that a web socket client id is required, this id is emitted by the
// socket server when a client connects.
socket.on('ws-client-id', 'incoming', function (data) {
	// Data! :)
});

// Emit an event with data to all connected clients except for the
// client that started the event.
// Note that a web socket client id is required, this id is emitted by the
// socket server when a client connects.
socket.broadcast('ws-client-id', 'emit-client', {
	data: []
});

// Emit an event with data to a specific client.
// Note that a web socket client id is required, this id is emitted by the
// socket server when a client connects.
socket.emit('ws-client-id', 'emit-client', {
	data: []
});

// Emit an event with data to all connected clients.
socket.emitAll('emit-clients', {
	data: []
});

// Access the socketServer object (socket.io constructor).
socket.socketServer;

// Close the socket server connection.
socket.close();

// Close the http server connection.
server.close();

Because the module returns a singleton, the socket server only needs to be initialized once and can then be required from any (sub) module(s) to emit- and listen for socket events.

// 'lib/index.js'
var express = require('express');
var	http = require('http');
var	socket = require('socket-io-server');
var	app = express();
var	server = http.Server(app);

socket.init(server);
server.listen(8080);

// 'lib/sub-module.js'
var socket = require('socket-io-server');

socket.broadcast('ws-client-id', 'emit-client', {
	data: []
});

// 'lib/sub-module-2.js'
var socket = require('socket-io-server');

socket.on('ws-client-id', 'incoming', {
	data: []
});

Interface.

The module exposes the following methods and properties:

socket.socketServer

socket.io server instance.

socket.init(server)

Uses an http server instance to instantiate and connect to a socket.io server.

The init method calls the connect method internally.

socket.connect(socketServer)

Exposes the socket server via the socketServer property and listens for clients connecting and disconnecting with the socket server.

Upon successful connection the socket server will emit the connection event to the client in question sending the clients web socket id. In turn this id can be used to listen for and emit events to the correct sockets.

connection event (example) data sent by the socket server:

{
	wsClientId: '12jsdd32919ssj21',
	info: 'Client successfully connected.'
}

Whenever a client disconnects, the socket server will emit the disconnect event.

disconnect event (example) data sent by the socket server:

{
	info: 'Client disconnected.'
}

The connect method creates a mapping of all socket objects using the clients web socket id's whenever a client connects with the socket server. This is realized by calling the setSocket method internally. In turn a client web socket id is invalidated whenever a client disconnects by calling the removeSocket method.

socket.setSocket(id)

Stores a socket reference using the web socket id of a connected client.

socket.getSocket(id)

Retrieves a socket reference using the web socket id of a connected client.

socket.removeSocket(id)

Deletes a socket reference using the web socket id of a connected client.

socket.on(id, event, callback)

Registers event listeners for a connected client using it's web socket id.

socket.broadcast(id, event, data)

Emits an event with data to all connected clients except for the client that started the event. This client is identified by using the web socket id of the connected client in question.

socket.emit(id, event, data)

Emits an event with data to a specific client identified by the web socket id of the client in question.

socket.emitAll(event, data)

Emits an event with data to all connected clients.

socket.close()

Closes the socket server connection.

Testing.

npm test

Code coverage.

npm run cover

istanbul and coveralls are used to generate a code coverage report.

Linting.

JSHint is used to lint all javascript code prior running tests using the npm 'pretest' hook.

Dependencies.

• socket.io