import { ITriggerFunctions, } from 'n8n-core'; import { IDataObject, INodeType, INodeTypeDescription, ITriggerResponse, NodeOperationError, } from 'n8n-workflow'; import * as mqtt from 'mqtt'; import { IClientOptions, ISubscriptionMap, } from 'mqtt'; export class MqttTrigger implements INodeType { description: INodeTypeDescription = { displayName: 'MQTT Trigger', name: 'mqttTrigger', icon: 'file:mqtt.svg', group: ['trigger'], version: 1, description: 'Listens to MQTT events', defaults: { name: 'MQTT Trigger', color: '#9b27af', }, inputs: [], outputs: ['main'], credentials: [ { name: 'mqtt', required: true, }, ], properties: [ { displayName: 'Topics', name: 'topics', type: 'string', default: '', description: `Topics to subscribe to, multiple can be defined with comma.
wildcard characters are supported (+ - for single level and # - for multi level)
By default all subscription used QoS=0. To set a different QoS, write the QoS desired
after the topic preceded by a colom. For Example: topicA:1,topicB:2`, }, { displayName: 'Options', name: 'options', type: 'collection', placeholder: 'Add Option', default: {}, options: [ { displayName: 'JSON Parse Body', name: 'jsonParseBody', type: 'boolean', default: false, description: 'Try to parse the message to an object.', }, { displayName: 'Only Message', name: 'onlyMessage', type: 'boolean', default: false, description: 'Returns only the message property.', }, ], }, ], }; async trigger(this: ITriggerFunctions): Promise { const credentials = this.getCredentials('mqtt'); if (!credentials) { throw new NodeOperationError(this.getNode(), 'Credentials are mandatory!'); } const topics = (this.getNodeParameter('topics') as string).split(','); const topicsQoS: IDataObject = {}; for (const data of topics) { const [topic, qos] = data.split(':'); topicsQoS[topic] = (qos) ? { qos: parseInt(qos, 10) } : { qos: 0 }; } const options = this.getNodeParameter('options') as IDataObject; if (!topics) { throw new NodeOperationError(this.getNode(), 'Topics are mandatory!'); } 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 clientOptions: IClientOptions = { port, clean, clientId, }; if (credentials.username && credentials.password) { clientOptions.username = credentials.username as string; clientOptions.password = credentials.password as string; } const client = mqtt.connect(brokerUrl, clientOptions); const self = this; async function manualTriggerFunction() { await new Promise((resolve, reject) => { client.on('connect', () => { client.subscribe(topicsQoS as ISubscriptionMap, (err, granted) => { if (err) { reject(err); } client.on('message', (topic: string, message: Buffer | string) => { // tslint:disable-line:no-any let result: IDataObject = {}; message = message.toString() as string; if (options.jsonParseBody) { try { message = JSON.parse(message.toString()); } catch (err) { } } result.message = message; result.topic = topic; if (options.onlyMessage) { //@ts-ignore result = [message as string]; } self.emit([self.helpers.returnJsonArray(result)]); resolve(true); }); }); }); client.on('error', (error) => { reject(error); }); }); } if (this.getMode() === 'trigger') { manualTriggerFunction(); } async function closeFunction() { client.end(); } return { closeFunction, manualTriggerFunction, }; } }