index.js

#!/usr/bin/env node

/**
 * Ninja Blocks WiFi Utility
 * http://ninjablocks.com/
 *
 * Copyright (c) 2012 Ninja Blocks Inc
 * Licensed under the MIT license.
 *
 * Emily Rose <emily@ninjablocks.com>
 */ 

 ;(function() {
	
	var	argv = require('optimist').argv;
	
	var	config = require('./app/config')
		, fork = require('child_process').fork
		, express = require('express')
		, port = argv.port || 80
		, confPath = argv.confPath || "/etc/wpa_supplicant.conf"
		, path = require('path')
		, util = require('util')
		, app = express()
	;

	function exit(reason) {

		process.stderr.write(

			util.format(

				"Exiting: Could not listen on port %s. %s\n"
				, port
				, reason
			)
		);
	};

	/**
	 * Messages from the monitor process
	 */
	function message(msg) {

		if(!msg.action || typeof msg.data == 'undefined' || msg.error) {

			var 
				stack = new Error().stack
				, error
			;

			if(msg.error && msg.error == "unknownAction" && msg.action) {

				error = util.format(
					'Unknown monitor action: %s'
					, msg.action
				);	
			}
			else {

				error = util.format(
					'Error from monitor: %s'
					, msg.error || "UNKNOWN"
				);
			}

			console.log(error);
			console.log(stack);
			return;
		}

		app.emit(msg.action, msg.data);
	};

	var monitor = function monitor() {

		monitor.process = fork(path.resolve(__dirname, 'monitor'), [confPath]);
		
		monitor.process
			.on('message', message)
			.on('exit', monitor)
			.send({ action : "init" })
		;
	};

	/**
	 * Messages _to_ the monitor process
	 */
	app.send = function send(action, data) {

		monitor.process.send({ 

			'action' : action
			, 'data' : data || null 
		});
	};
	
	/**
	 * Exit if we have problems. Upstart should handle restarts.
	 */
	process.on("uncaughtException", function(err) {

		if(err.code == "EACCES") {

			exit("Access denied.");

		}
		else if(err.code == "EADDRINUSE") {

			exit("Address in use.");
		}
		else {

			process.stderr.write(util.format("Exiting: %s.\n", err));
		}
		process.exit(1);
	});

	config(app).listen(port);

	monitor();

})();