n8n/packages/nodes-base/nodes/Cron.node.ts

import { ITriggerFunctions } from 'n8n-core';
import {
	INodeType,
	INodeTypeDescription,
	ITriggerResponse,
} from 'n8n-workflow';

import { CronJob } from 'cron';

interface TriggerTime {
	mode: string;
	hour: number;
	minute: number;
	dayOfMonth: number;
	weekeday: number;
	[key: string]: string | number;
}


export class Cron implements INodeType {
	description: INodeTypeDescription = {
		displayName: 'Cron',
		name: 'cron',
		icon: 'fa:calendar',
		group: ['trigger'],
		version: 1,
		description: 'Triggers the workflow at a specific time',
		defaults: {
			name: 'Cron',
			color: '#00FF00',
		},
		inputs: [],
		outputs: ['main'],
		properties: [
			{
				displayName: 'Trigger Times',
				name: 'triggerTimes',
				type: 'fixedCollection',
				typeOptions: {
					multipleValues: true,
					multipleValueButtonText: 'Add Time',
				},
				default: {},
				description: 'Triggers for the workflow',
				placeholder: 'Add Cron Time',
				options: [
					{
						name: 'item',
						displayName: 'Item',
						values: [
							{
								displayName: 'Mode',
								name: 'mode',
								type: 'options',
								options: [
									{
										name: 'Every Minute',
										value: 'everyMinute'
									},
									{
										name: 'Every Hour',
										value: 'everyHour'
									},
									{
										name: 'Every Day',
										value: 'everyDay'
									},
									{
										name: 'Every Week',
										value: 'everyWeek'
									},
									{
										name: 'Every Month',
										value: 'everyMonth'
									},
									{
										name: 'Custom',
										value: 'custom'
									},
								],
								default: 'everyDay',
								description: 'How often to trigger.',
							},
							{
								displayName: 'Hour',
								name: 'hour',
								type: 'number',
								typeOptions: {
									minValue: 0,
									maxValue: 23,
								},
								displayOptions: {
									hide: {
										mode: [
											'custom',
											'everyHour',
											'everyMinute'
										],
									},
								},
								default: 14,
								description: 'The hour of the day to trigger (24h format).',
							},
							{
								displayName: 'Minute',
								name: 'minute',
								type: 'number',
								typeOptions: {
									minValue: 0,
									maxValue: 59,
								},
								displayOptions: {
									hide: {
										mode: [
											'custom',
											'everyMinute'
										],
									},
								},
								default: 0,
								description: 'The minute of the day to trigger.',
							},
							{
								displayName: 'Day of Month',
								name: 'dayOfMonth',
								type: 'number',
								displayOptions: {
									show: {
										mode: [
											'everyMonth',
										],
									},
								},
								typeOptions: {
									minValue: 1,
									maxValue: 31,
								},
								default: 1,
								description: 'The day of the month to trigger.',
							},
							{
								displayName: 'Weekday',
								name: 'weekday',
								type: 'options',
								displayOptions: {
									show: {
										mode: [
											'everyWeek',
										],
									},
								},
								options: [
									{
										name: 'Monday',
										value: '1',
									},
									{
										name: 'Tuesday',
										value: '2',
									},
									{
										name: 'Wednesday',
										value: '3',
									},
									{
										name: 'Thursday',
										value: '4',
									},
									{
										name: 'Friday',
										value: '5',
									},
									{
										name: 'Saturday',
										value: '6',
									},
									{
										name: 'Sunday',
										value: '0',
									},
								],
								default: '1',
								description: 'The weekday to trigger.',
							},
							{
								displayName: 'Cron Expression',
								name: 'cronExpression',
								type: 'string',
								displayOptions: {
									show: {
										mode: [
											'custom',
										],
									},
								},
								default: '* * * * * *',
								description: 'Use custom cron expression. Values and ranges as follows:<ul><li>Seconds: 0-59</li><li>Minutes: 0 - 59</li><li>Hours: 0 - 23</li><li>Day of Month: 1 - 31</li><li>Months: 0 - 11 (Jan - Dec)</li><li>Day of Week: 0 - 6 (Sun - Sat)</li></ul>',
							},
						]
					},
				],
			}
		]
	};



	async trigger(this: ITriggerFunctions): Promise<ITriggerResponse> {

		const triggerTimes = this.getNodeParameter('triggerTimes') as unknown as {
			item: TriggerTime[];
		};

		// Define the order the cron-time-parameter appear
		const parameterOrder = [
			'second',     // 0 - 59
			'minute',     // 0 - 59
			'hour',       // 0 - 23
			'dayOfMonth', // 1 - 31
			'month',      // 0 - 11(Jan - Dec)
			'weekday',    // 0 - 6(Sun - Sat)
		];

		// Get all the trigger times
		const cronTimes: string[] = [];
		let cronTime: string[];
		let parameterName: string;
		if (triggerTimes.item !== undefined) {
			for (const item of triggerTimes.item) {
				cronTime = [];
				if (item.mode === 'custom') {
					cronTimes.push(item.cronExpression as string);
					continue;
				}
				if (item.mode === 'everyMinute') {
					cronTimes.push(`${Math.floor(Math.random() * 60).toString()} * * * * *`);
					continue;
				}

				for (parameterName of parameterOrder) {
					if (item[parameterName] !== undefined) {
						// Value is set so use it
						cronTime.push(item[parameterName] as string);
					} else if (parameterName === 'second') {
						// For seconds we use by default a random one to make sure to
						// balance the load a little bit over time
						cronTime.push(Math.floor(Math.random() * 60).toString());
					} else {
						// For all others set "any"
						cronTime.push('*');
					}
				}

				cronTimes.push(cronTime.join(' '));
			}
		}

		// The trigger function to execute when the cron-time got reached
		// or when manually triggered
		const executeTrigger = () => {
			this.emit([this.helpers.returnJsonArray([{}])]);
		};

		const timezone = this.getTimezone();

		// Start the cron-jobs
		const cronJobs: CronJob[] = [];
		for (const cronTime of cronTimes) {
			cronJobs.push(new CronJob(cronTime, executeTrigger, undefined, true, timezone));
		}

		// Stop the cron-jobs
		async function closeFunction() {
			for (const cronJob of cronJobs) {
				cronJob.stop();
			}
		}

		async function manualTriggerFunction() {
			executeTrigger();
		}

		return {
			closeFunction,
			manualTriggerFunction,
		};
	}
}