Send an email to an admin when the public ip changes.

ipUpdate.js

var exec = require('child_process').exec;

function getIp(callback) {
	exec('wget -qO- http://ipecho.net/plain ; echo', function (error, stdout, stderror) {
		if (error) {
			callback(error, null);
			return;
		}

		var ip = stdout.replace('\n', '');
		callback(null, ip);
	});
}

function sendEmail(subject, body, email, callback) {
	var command = [
		'echo "', body.replace("\\", "\\\\").replace('"', '\\"'), 
		'" | mail -s "', subject.replace("\\", "\\\\").replace('"', '\\"'), '" ',
		email
	].join('');

	exec(command, function (error, stdout, stderror) {
		if (callback) callback(error);
	});
}

function updateAdminOnChange(adminEmail, timeout) {
	var ipAddress = '';

	function update() {
		getIp(function (error, ip) {
			if (error) {
				sendEmail('Error', error, adminEmail);
				return;
			}

			if (ipAddress != ip) {
				var message = [
					'Old IP: ', ipAddress,
					'New Ip: ', ip
				].join('\n');
				sendEmail('Ip Update', message, adminEmail);
				ipAddress = ip;

				console.log('new ip', ip);
			}
		});
	}

	setInterval(update, timeout);
}

updateAdminOnChange('[email protected]', 86400000/4); // update 4x a day