cron.js

(function (root, factory) {
	if (typeof define === 'function' && define.amd) {
		define(['moment-timezone'], factory);
	} else if (typeof exports === 'object') {
		module.exports = factory(require('moment-timezone'), require('child_process'));
	} else {
		root.Cron = factory(root.moment);
	}
}(this, function (moment, child_process) {
	var exports = {},
		timeUnits = ['second', 'minute', 'hour', 'dayOfMonth', 'month', 'dayOfWeek'],
		spawn = child_process && child_process.spawn;

	function CronTime(source, zone, utcOffset) {
		this.source = source;

		if (zone) {
			if (moment.tz.names().indexOf(zone) === -1) {
				throw new Error('Invalid timezone.');
			}

			this.zone = zone;
		}

		if (utcOffset) this.utcOffset = utcOffset;

		var that = this;
		timeUnits.map(function(timeUnit){
			that[timeUnit] = {};
		});

	if (this.source instanceof Date || this.source._isAMomentObject) {
			this.source = moment(this.source);
			this.realDate = true;
		} else {
			this._parse();
			this._verifyParse();
		}
	}

	CronTime.constraints = [
		[0, 59],
		[0, 59],
		[0, 23],
		[1, 31],
		[0, 11],
		[0, 6]
	];
	CronTime.monthConstraints = [
		31,
		29, //support leap year...not perfect
		31,
		30,
		31,
		30,
		31,
		31,
		30,
		31,
		30,
		31
	];
	CronTime.parseDefaults = ['0', '*', '*', '*', '*', '*'];
	CronTime.aliases = {
		jan: 0,
		feb: 1,
		mar: 2,
		apr: 3,
		may: 4,
		jun: 5,
		jul: 6,
		aug: 7,
		sep: 8,
		oct: 9,
		nov: 10,
		dec: 11,
		sun: 0,
		mon: 1,
		tue: 2,
		wed: 3,
		thu: 4,
		fri: 5,
		sat: 6
	};


	CronTime.prototype = {
		_verifyParse: function() {
			var months = Object.keys(this.month);

			for (var i = 0; i < months.length; i++) {
				var m = months[i];
				var con = CronTime.monthConstraints[parseInt(m, 10)];
				var ok = false;
				var dsom = Object.keys(this.dayOfMonth);

				for (var j = 0; j < dsom.length; j++) {
					var dom = dsom[j];
					if (dom <= con)
						ok = true;
				}

				if (!ok) {
					console.warn('Month \'' + m + '\' is limited to \'' + con + '\' days.');
				}
			}
		},

		/**
		 * calculates the next send time
		 */
		sendAt: function(i) {
			var date = this.realDate ? this.source : moment();
			// Set the timezone if given (http://momentjs.com/timezone/docs/#/using-timezones/parsing-in-zone/)
			if (this.zone) {
				date = date.tz(this.zone);
			}

			if (this.utcOffset) {
				date = date.utcOffset(this.utcOffset);
			}

			if (this.realDate) {
				return date;
			}

			var now = new Date();
			var targetSecond = date.seconds();
			var diff = Math.abs(targetSecond - now.getSeconds())

			//If the i argument is not given, return the next send time
			if (isNaN(i) || i < 0) {
				date = this._getNextDateFrom(date);

				return date;
			} else {
				//Else return the next i send times
				var dates = [];
				for (; i > 0; i--) {
					date = this._getNextDateFrom(date);
					dates.push(moment(date));

				}

				return dates;
			}
		},

		/**
		 * Get the number of milliseconds in the future at which to fire our callbacks.
		 */
		getTimeout: function() {
			return Math.max(-1, this.sendAt() - moment());
		},

		/**
		 * writes out a cron string
		 */
		toString: function() {
			return this.toJSON().join(' ');
		},

		/**
		 * Json representation of the parsed cron syntax.
		 */
		toJSON: function() {
			var self = this;
			return timeUnits.map(function(timeName) {
				return self._wcOrAll(timeName);
			});
		},

		/**
		 * get next date that matches parsed cron time
		 */

		_getNextDateFrom: function(start,zone) {
			var date;
			var firstDate=moment(start).valueOf();
			if(zone){
				date=moment(start).tz(zone);
			}
			else{
			 date = moment(start);
		  }
			if (!this.realDate) {
			  const milliseconds = (start.milliseconds && start.milliseconds()) || (start.getMilliseconds && start.getMilliseconds()) || 0;
			  if (milliseconds > 0) {
			    date.milliseconds(0);
			    date.seconds(date.seconds() + 1);
			  }
			}

			if (date.toString() == 'Invalid date') {
				console.log('ERROR: You specified an invalid date.');
				return date;
			}

			if (this.realDate && start < new Date()) {
				console.log('WARNING: Date in past. Will never be fired.');
			}

			if (this.realDate) {
				return date;
			}

			//sanity check
			while (true) {
				var diff = date - start,
					origDate = new Date(date);

				if (!(date.month() in this.month) && Object.keys(this.month).length!=12) {
					date.add(1, 'M');
					date.date(1);
					date.hours(0);
					date.minutes(0);
					date.seconds(0);
					continue;
				}
				if (!(date.date() in this.dayOfMonth) && Object.keys(this.dayOfMonth).length!=31) {
					date.add(1, 'd');
					date.hours(0);
					date.minutes(0);
					date.seconds(0);
					continue;
				}

				if (!(date.day() in this.dayOfWeek) && Object.keys(this.dayOfWeek).length!=7) {
					date.add(1, 'd');
					date.hours(0);
					date.minutes(0);
					date.seconds(0);
					if (date <= origDate) {
						date = this._findDST(origDate);
					}
					continue;
				}
				if (!(date.hours() in this.hour) && Object.keys(this.hour).length!=24) {
					origDate = moment(date);
					date.hours(date.hours() == 23 && diff > 86400000 ? 0 : date.hours() + 1);
					date.minutes(0);
					date.seconds(0);
					if (date <= origDate) {
						date = this._findDST(origDate);
					}
					continue;
				}
				if (!(date.minutes() in this.minute) && Object.keys(this.minute).length!=60) {
					origDate = moment(date);
					date.minutes(date.minutes() == 59 && diff > 60 * 60 * 1000 ? 0 : date.minutes() + 1);
					date.seconds(0);
					if (date <= origDate) {
						date = this._findDST(origDate);
					}
					continue;
				}
				if (!(date.seconds() in this.second) && Object.keys(this.second).length!=60) {
					origDate = moment(date);
					date.seconds(date.seconds() == 59 && diff > 60 * 1000 ? 0 : date.seconds() + 1);
					if (date <= origDate) {
						date = this._findDST(origDate);
					}
					continue;
				}

				if(date.valueOf() === firstDate){
					date.seconds(date.seconds()+1);
					continue;
				}

				break;
			}

			return date;
		},

		/**
		 * get next date that is a valid DST date
		 */
		_findDST: function(date) {
			var newDate = moment(date);
			while (newDate <= date)
				newDate.add(1, 's');

			return newDate;
		},

		/**
		 * wildcard, or all params in array (for to string)
		 */
		_wcOrAll: function(type) {
			if (this._hasAll(type)) return '*';

			var all = [];
			for (var time in this[type]) {
				all.push(time);
			}

			return all.join(',');
		},

		_hasAll: function(type) {
			var constrain = CronTime.constraints[timeUnits.indexOf(type)];

			for (var i = constrain[0], n = constrain[1]; i < n; i++) {
				if (!(i in this[type]))
					return false;
			}

			return true;
		},


		_parse: function() {
			var aliases = CronTime.aliases;
			var source = this.source.replace(/[a-z]{1,3}/ig, function(alias) {
				alias = alias.toLowerCase();

				if (alias in aliases) {
					return aliases[alias];
				}

				throw new Error('Unknown alias: ' + alias);
			});
			var split = source.replace(/^\s\s*|\s\s*$/g, '').split(/\s+/);
			var cur;
			var i = 0;
			var len = timeUnits.length;

			for (; i < timeUnits.length; i++) {
				// If the split source string doesn't contain all digits,
				// assume defaults for first n missing digits.
				// This adds support for 5-digit standard cron syntax
				cur = split[i - (len - split.length)] || CronTime.parseDefaults[i];
				this._parseField(cur, timeUnits[i], CronTime.constraints[i]);
			}
		},

		_parseField: function(field, type, constraints) {
			var rangePattern = /^(\d+)(?:-(\d+))?(?:\/(\d+))?$/g;
			var typeObj = this[type];
			var pointer;
			var low = constraints[0];
			var high = constraints[1];

			// * is a shortcut to [lower-upper] range
			field = field.replace(/\*/g, low + '-' + high);

			//commas separate information, so split based on those
			var allRanges = field.split(',');

			for (var i = 0; i < allRanges.length; i++) {
				if (allRanges[i].match(rangePattern)) {
					allRanges[i].replace(rangePattern, function($0, lower, upper, step) {
						step = parseInt(step) || 1;
						// Positive integer higher than constraints[0]
						lower = Math.min(Math.max(low, ~~Math.abs(lower)), high);

						// Positive integer lower than constraints[1]
						upper = upper ? Math.min(high, ~~Math.abs(upper)) : lower;

						// Count from the lower barrier to the upper
						pointer = lower;

						do {
							typeObj[pointer] = true
							pointer += step;
						} while (pointer <= upper);
					});
				} else {
					throw new Error('Field (' + field + ') cannot be parsed');
				}
			}
		}
	};

	function command2function(cmd) {
		var command;
		var args;

		switch (typeof cmd) {
			case 'string':
				args = cmd.split(' ');
				command = args.shift();

				cmd = spawn.bind(undefined, command, args);
				break;

			case 'object':
				command = cmd && cmd.command;
				if (command) {
					args = cmd.args;
					var options = cmd.options;

					cmd = spawn.bind(undefined, command, args, options);
				}
				break;
		}

		return cmd
	}

	function CronJob(cronTime, onTick, onComplete, startNow, timeZone, context, runOnInit, utcOffset) {
		var _cronTime = cronTime;
		var argCount = 0;
		for (var i = 0; i < arguments.length; i++) {
			if (arguments[i] !== undefined) {
				argCount++;
			}
		}
		if (typeof cronTime != 'string' && argCount == 1) {
			//crontime is an object...
			onTick = cronTime.onTick;
			onComplete = cronTime.onComplete;
			context = cronTime.context;
			startNow = cronTime.start || cronTime.startNow || cronTime.startJob;
			timeZone = cronTime.timeZone;
			runOnInit = cronTime.runOnInit;
			_cronTime = cronTime.cronTime;
			utcOffset = cronTime.utcOffset;
		}

		this.context = (context || this);
		this._callbacks = [];
		this.onComplete = command2function(onComplete);
		this.cronTime = new CronTime(_cronTime, timeZone, utcOffset);

		addCallback.call(this, command2function(onTick));

		if (runOnInit) {
			this.lastExecution = new Date();
			fireOnTick.call(this);
		}

		if (startNow) {
			start.call(this);
		}

		return this;
	}

	var addCallback = function(callback) {
		if (typeof callback == 'function') this._callbacks.push(callback);
	}
	CronJob.prototype.addCallback = addCallback;

	CronJob.prototype.setTime = function(time) {
		if (!(time instanceof CronTime)) throw new Error('\'time\' must be an instance of CronTime.');
		this.stop();
		this.cronTime = time;
	}

	CronJob.prototype.nextDate = function() {
		return this.cronTime.sendAt();
	}

	var fireOnTick = function() {
		for (var i = (this._callbacks.length - 1); i >= 0; i--)
			this._callbacks[i].call(this.context, this.onComplete);
	}
	CronJob.prototype.fireOnTick = fireOnTick;

	CronJob.prototype.nextDates = function(i) {
		return this.cronTime.sendAt(i);
	}

	var start = function() {
		if (this.running) return;

		var MAXDELAY = 2147483647; // The maximum number of milliseconds setTimeout will wait.
		var self = this;
		var timeout = this.cronTime.getTimeout();
		var remaining = 0;
		var startTime;

		if (this.cronTime.realDate) this.runOnce = true;

		function _setTimeout(timeout) {
			startTime = Date.now();
			self._timeout = setTimeout(callbackWrapper, timeout);
		}

		// The callback wrapper checks if it needs to sleep another period or not
		// and does the real callback logic when it's time.

		function callbackWrapper() {
			var diff = startTime + timeout - Date.now();

			if (diff > 0) {
				var newTimeout = self.cronTime.getTimeout();

				if (newTimeout > diff) {
					newTimeout = diff;
				}

				remaining += newTimeout;
			}

			// If there is sleep time remaining, calculate how long and go to sleep
			// again. This processing might make us miss the deadline by a few ms
			// times the number of sleep sessions. Given a MAXDELAY of almost a
			// month, this should be no issue.

			self.lastExecution = new Date();
			if (remaining) {
				if (remaining > MAXDELAY) {
					remaining -= MAXDELAY;
					timeout = MAXDELAY;
				} else {
					timeout = remaining;
					remaining = 0;
				}

				_setTimeout(timeout);
			} else {

				// We have arrived at the correct point in time.

				self.running = false;

				//start before calling back so the callbacks have the ability to stop the cron job
				if (!(self.runOnce)) self.start();

				self.fireOnTick();
				//for (var i = (self._callbacks.length - 1); i >= 0; i--)
				//self._callbacks[i].call(self.context, self.onComplete);
			}
		}

		if (timeout >= 0) {
			this.running = true;

			// Don't try to sleep more than MAXDELAY ms at a time.

			if (timeout > MAXDELAY) {
				remaining = timeout - MAXDELAY;
				timeout = MAXDELAY;
			}

			_setTimeout(timeout);
		} else {
			this.stop();
		}
	}

	CronJob.prototype.start = start;

	CronJob.prototype.lastDate = function(){
		return this.lastExecution;
	};

	/**
	 * Stop the cronjob.
	 */
	CronJob.prototype.stop = function() {
		if (this._timeout)
			clearTimeout(this._timeout);
		this.running = false;
		if (typeof this.onComplete == 'function') this.onComplete();
	}

	exports.job = function(cronTime, onTick, onComplete, startNow, timeZone, context, runOnInit, utcOffset) {
		return new CronJob(cronTime, onTick, onComplete, startNow, timeZone, context, runOnInit, utcOffset);
	}

	exports.time = function(cronTime, timeZone) {
		return new CronTime(cronTime, timeZone);
	}

	exports.sendAt = function(cronTime) {
		return exports.time(cronTime).sendAt();
	}

	exports.timeout = function(cronTime) {
		return exports.time(cronTime).getTimeout();
	}

	exports.CronJob = CronJob;
	exports.CronTime = CronTime;

	return exports;
}));