n8n/packages/nodes-base/nodes/MQTT/Mqtt.node.ts

import { IExecuteFunctions } from 'n8n-core';

import { IDataObject, INodeExecutionData, INodeType, INodeTypeDescription } from 'n8n-workflow';

import mqtt from 'mqtt';

import { IClientOptions } from 'mqtt';

export class Mqtt implements INodeType {
	description: INodeTypeDescription = {
		displayName: 'MQTT',
		name: 'mqtt',
		icon: 'file:mqtt.svg',
		group: ['input'],
		version: 1,
		description: 'Push messages to MQTT',
		defaults: {
			name: 'MQTT',
		},
		inputs: ['main'],
		outputs: ['main'],
		credentials: [
			{
				name: 'mqtt',
				required: true,
			},
		],
		properties: [
			{
				displayName: 'Topic',
				name: 'topic',
				type: 'string',
				required: true,
				default: '',
				description: 'The topic to publish to',
			},
			{
				displayName: 'Send Input Data',
				name: 'sendInputData',
				type: 'boolean',
				default: true,
				description: 'Whether to send the the data the node receives as JSON',
			},
			{
				displayName: 'Message',
				name: 'message',
				type: 'string',
				required: true,
				displayOptions: {
					show: {
						sendInputData: [false],
					},
				},
				default: '',
				description: 'The message to publish',
			},
			{
				displayName: 'Options',
				name: 'options',
				type: 'collection',
				placeholder: 'Add Option',
				default: {},
				options: [
					{
						displayName: 'QoS',
						name: 'qos',
						type: 'options',
						options: [
							{
								name: 'Received at Most Once',
								value: 0,
							},
							{
								name: 'Received at Least Once',
								value: 1,
							},
							{
								name: 'Exactly Once',
								value: 2,
							},
						],
						default: 0,
						description: 'QoS subscription level',
					},
					{
						displayName: 'Retain',
						name: 'retain',
						type: 'boolean',
						default: false,
						// eslint-disable-next-line n8n-nodes-base/node-param-description-boolean-without-whether
						description:
							'Normally if a publisher publishes a message to a topic, and no one is subscribed to that topic the message is simply discarded by the broker. However the publisher can tell the broker to keep the last message on that topic by setting the retain flag to true.',
					},
				],
			},
		],
	};

	async execute(this: IExecuteFunctions): Promise<INodeExecutionData[][]> {
		const items = this.getInputData();
		const length = items.length;
		const credentials = await this.getCredentials('mqtt');

		const protocol = (credentials.protocol as string) || 'mqtt';
		const host = credentials.host as string;
		const brokerUrl = `${protocol}://${host}`;
		const port = (credentials.port as number) || 1883;
		const clientId =
			(credentials.clientId as string) || `mqttjs_${Math.random().toString(16).substr(2, 8)}`;
		const clean = credentials.clean as boolean;
		const ssl = credentials.ssl as boolean;
		const ca = credentials.ca as string;
		const cert = credentials.cert as string;
		const key = credentials.key as string;
		const rejectUnauthorized = credentials.rejectUnauthorized as boolean;

		let client: mqtt.MqttClient;

		if (ssl === false) {
			const clientOptions: IClientOptions = {
				port,
				clean,
				clientId,
			};

			if (credentials.username && credentials.password) {
				clientOptions.username = credentials.username as string;
				clientOptions.password = credentials.password as string;
			}

			client = mqtt.connect(brokerUrl, clientOptions);
		} else {
			const clientOptions: IClientOptions = {
				port,
				clean,
				clientId,
				ca,
				cert,
				key,
				rejectUnauthorized,
			};
			if (credentials.username && credentials.password) {
				clientOptions.username = credentials.username as string;
				clientOptions.password = credentials.password as string;
			}

			client = mqtt.connect(brokerUrl, clientOptions);
		}

		const sendInputData = this.getNodeParameter('sendInputData', 0) as boolean;

		// tslint:disable-next-line: no-any
		const data = await new Promise((resolve, reject): any => {
			client.on('connect', () => {
				for (let i = 0; i < length; i++) {
					let message;
					const topic = this.getNodeParameter('topic', i) as string;
					const options = this.getNodeParameter('options', i) as IDataObject;

					try {
						if (sendInputData === true) {
							message = JSON.stringify(items[i].json);
						} else {
							message = this.getNodeParameter('message', i) as string;
						}
						client.publish(topic, message, options);
					} catch (e) {
						reject(e);
					}
				}
				//wait for the in-flight messages to be acked.
				//needed for messages with QoS 1 & 2
				client.end(false, {}, () => {
					resolve([items]);
				});

				client.on('error', (e: string | undefined) => {
					reject(e);
				});
			});
		});

		return data as INodeExecutionData[][];
	}
}