irrelon-presence/Presence.js

A Node.js bluetooth presence scanner. Uses bluetooth to detect devices in range of the bluetooth antenna.

var btwatch = require('btwatch'),
	Emitter = require('irrelon-emitter'),
	fs = require('fs'),
	spawn = require('child_process').spawn,
	inRange = {};

var Presence = function () {
	// On startup, read our DB of mac addresses we should scan for
	try {
		this.macArr = require('./devices.json');
	} catch (e) {
		this.macArr = [];
	}
};

Emitter(Presence);

/**
 * Starts watching for all devices that have been added to
 * the watch list in the past.
 */
Presence.prototype.startWatch = function () {
	var self = this,
		i;

	if (!this.started) {
		this.started = true;

		console.log(new Date().toUTCString() + ' :: Started watching');

		btwatch.on('change', function (inRange, macAddress) {
			if (inRange) {
				inRange[macAddress] = true;
				console.log(new Date().toUTCString() + ' :: %s is now in range', macAddress);

				self.emit('found', macAddress);
			} else {
				inRange[macAddress] = false;
				console.log(new Date().toUTCString() + ' :: %s no longer in range', macAddress);

				self.emit('lost', macAddress);
			}
		});

		for (i = 0; i < this.macArr.length; i++) {
			console.log('Watching ' + this.macArr[i].name + ' (' + this.macArr[i].mac + ')');
			btwatch.watch(this.macArr[i].mac);
		}
	} else {
		console.log(new Date().toUTCString() + ' :: Already started watching!');
	}
};

/**
 * Stops watching for devices.
 */
Presence.prototype.stopWatch = function () {
	var i;

	if (this.started) {
		this.started = false;

		for (i = 0; i < this.macArr.length; i++) {
			console.log('Stopping watch on ' + this.macArr[i].name + ' (' + this.macArr[i].mac + ')');
			btwatch.unwatch(this.macArr[i].mac);
		}

		console.log(new Date().toUTCString() + ' :: Stopped watching');
	} else {
		console.log(new Date().toUTCString() + ' :: Cannot stop watching as we haven\'t started yet!');
	}
};

/**
 * Scans for all discoverable bluetooth devices.
 * @param {Function} callback The callback method to call once the scan has
 * finished.
 */
Presence.prototype.scan = function (callback) {
	console.log(new Date().toUTCString() + ' :: Starting device scan...');
	var hci = spawn('hcitool', ['scan']);
	var result = '';
	var arr = [];

	hci.stdout.on('data', function (data) {
		result += data;
	});

	hci.on('close', function () {
		var mac,
			name,
			hit,
			regexp = /([0-9A-Fa-f:]{17})(\t*?)(.*?)\n/g;

		while((hit = regexp.exec(result)) !== null) {
			//console.log(hit);

			if (hit && hit[0]) {
				mac = hit[1];
				name = hit[3].trim();

				arr.push({
					name: name,
					mac: mac
				});

				console.log(new Date().toUTCString() + ' :: Device found: ' + name + ' (' + mac + ')');
			}
		}

		console.log(new Date().toUTCString() + ' :: Device scan finished');

		callback(false, arr);
	});

	hci.on('error', function (err) {
		console.log('err', err);

		console.log(new Date().toUTCString() + ' :: Device scan finished');

		callback(err, arr);
	});
};

Presence.prototype.pair = function (interfaceNum, mac, channel, callback) {
	if (mac) {
		var cmd = spawn('rfcomm', ['connect', interfaceNum, mac, channel]),
			result = '';

		cmd.stdout.on('data', function (data) {
			result += data;
		});

		cmd.on('close', function () {
			console.log(new Date().toUTCString() + ' :: Pairing finished');
			callback(false, JSON.stringify(result));
		});

		cmd.on('error', function (err) {
			console.log('err', err);

			console.log(new Date().toUTCString() + ' :: Pairing finished');

			callback(err, JSON.stringify(result));
		});
	}
};

/**
 * Adds a device to the watch list via it's mac address.
 * @param {String} mac The mac address in hex format of the
 * device to watch for.
 * @param {String} name The name of the device, used when
 * outputting human-readable info in the logs.
 */
Presence.prototype.addWatch = function (mac, name) {
	console.log(new Date().toUTCString() + ' :: Added device to watch list: ' + name + ' (' + mac + ')');
	this.macArr.push({mac: mac, name: name});

	if (this.started) {
		btwatch.watch(mac);
	}
};

/**
 * Removes a device from the watch list via it's mac address.
 * @param {String} mac The mac address of a device that has been
 * previously registered via addWatch().
 */
Presence.prototype.removeWatch = function (mac) {
	var i,
		recordIndex = -1;

	// Find the record
	for (i = 0 ; i < this.macArr.length; i++) {
		if (this.macArr[i].mac === mac) {
			// Found record
			recordIndex = i;
			break;
		}
	}

	if (recordIndex > -1) {
		// Remove the watch from the stack
		if (this.started) {
			btwatch.unwatch(mac);
		}

		this.macArr.splice(recordIndex, 1);
	} else {
		// No match found!
		console.log(new Date().toUTCString() + ' :: Could not remove device from watch list as it was not found (' + mac + ')');
	}
};

/**
 * Returns an array of devices that are currently
 * on the watch list.
 */
Presence.prototype.devices = function () {
	return JSON.parse(JSON.stringify(this.macArr));
};

/**
 * Returns a boolean denoting if the device with the passed
 * mac address is currently in range or not.
 * @param {String} mac The mac address of the device to check
 * for.
 * @returns {boolean} True if in range, false if not.
 */
Presence.prototype.inRange = function (mac) {
	return Boolean(inRange[mac]);
};

/**
 * Saves the current watch list to storage so that when
 * Presence is loaded next time around, the devices added
 * will be loaded into the watch list automatically.
 */
Presence.prototype.saveData = function () {
	fs.writeFile('./devices.json', JSON.stringify(this.macArr), function () {
		console.log(new Date().toUTCString() + ' :: Device data saved');
	});
};

module.exports = Presence;