mirror of
https://github.com/n8n-io/n8n.git
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280 lines
8.5 KiB
TypeScript
280 lines
8.5 KiB
TypeScript
import { ContainerOptions, create_container, EventContext, Message, ReceiverOptions } from 'rhea';
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import { ITriggerFunctions } from 'n8n-core';
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import {
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deepCopy,
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IDataObject,
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INodeType,
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INodeTypeDescription,
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ITriggerResponse,
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jsonParse,
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NodeOperationError,
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} from 'n8n-workflow';
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export class AmqpTrigger implements INodeType {
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description: INodeTypeDescription = {
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displayName: 'AMQP Trigger',
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name: 'amqpTrigger',
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// eslint-disable-next-line n8n-nodes-base/node-class-description-icon-not-svg
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icon: 'file:amqp.png',
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group: ['trigger'],
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version: 1,
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description: 'Listens to AMQP 1.0 Messages',
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defaults: {
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name: 'AMQP Trigger',
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},
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inputs: [],
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outputs: ['main'],
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credentials: [
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{
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name: 'amqp',
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required: true,
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},
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],
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properties: [
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// Node properties which the user gets displayed and
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// can change on the node.
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{
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displayName: 'Queue / Topic',
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name: 'sink',
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type: 'string',
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default: '',
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placeholder: 'topic://sourcename.something',
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description: 'Name of the queue of topic to listen to',
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},
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{
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displayName: 'Clientname',
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name: 'clientname',
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type: 'string',
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default: '',
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placeholder: 'for durable/persistent topic subscriptions, example: "n8n"',
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description: 'Leave empty for non-durable topic subscriptions or queues',
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},
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{
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displayName: 'Subscription',
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name: 'subscription',
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type: 'string',
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default: '',
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placeholder: 'for durable/persistent topic subscriptions, example: "order-worker"',
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description: 'Leave empty for non-durable topic subscriptions or queues',
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},
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{
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displayName: 'Options',
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name: 'options',
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type: 'collection',
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placeholder: 'Add Option',
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default: {},
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options: [
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{
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displayName: 'Container ID',
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name: 'containerId',
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type: 'string',
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default: '',
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description: 'Will be used to pass to the RHEA Backend as container_id',
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},
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{
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displayName: 'Convert Body To String',
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name: 'jsonConvertByteArrayToString',
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type: 'boolean',
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default: false,
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description:
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'Whether to convert JSON Body content (["body"]["content"]) from Byte Array to string. Needed for Azure Service Bus.',
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},
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{
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displayName: 'JSON Parse Body',
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name: 'jsonParseBody',
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type: 'boolean',
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default: false,
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description: 'Whether to parse the body to an object',
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},
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{
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displayName: 'Messages per Cicle',
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name: 'pullMessagesNumber',
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type: 'number',
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default: 100,
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description: 'Number of messages to pull from the bus for every cicle',
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},
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{
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displayName: 'Only Body',
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name: 'onlyBody',
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type: 'boolean',
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default: false,
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description: 'Whether to return only the body property',
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},
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{
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displayName: 'Reconnect',
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name: 'reconnect',
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type: 'boolean',
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default: true,
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description: 'Whether to automatically reconnect if disconnected',
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},
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{
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displayName: 'Reconnect Limit',
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name: 'reconnectLimit',
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type: 'number',
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default: 50,
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description: 'Maximum number of reconnect attempts',
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},
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{
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displayName: 'Sleep Time',
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name: 'sleepTime',
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type: 'number',
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default: 10,
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description: 'Milliseconds to sleep after every cicle',
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},
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],
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},
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],
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};
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async trigger(this: ITriggerFunctions): Promise<ITriggerResponse> {
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const credentials = await this.getCredentials('amqp');
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const sink = this.getNodeParameter('sink', '') as string;
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const clientname = this.getNodeParameter('clientname', '') as string;
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const subscription = this.getNodeParameter('subscription', '') as string;
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const options = this.getNodeParameter('options', {}) as IDataObject;
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const pullMessagesNumber = (options.pullMessagesNumber as number) || 100;
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const containerId = options.containerId as string;
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const containerReconnect = (options.reconnect as boolean) || true;
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const containerReconnectLimit = (options.reconnectLimit as number) || 50;
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if (sink === '') {
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throw new NodeOperationError(this.getNode(), 'Queue or Topic required!');
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}
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let durable = false;
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if (subscription && clientname) {
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durable = true;
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}
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const container = create_container();
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let lastMsgId: string | number | Buffer | undefined = undefined;
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container.on('receiver_open', (context: EventContext) => {
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context.receiver?.add_credit(pullMessagesNumber);
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});
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container.on('message', (context: EventContext) => {
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// No message in the context
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if (!context.message) {
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return;
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}
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// ignore duplicate message check, don't think it's necessary, but it was in the rhea-lib example code
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if (context.message.message_id && context.message.message_id === lastMsgId) {
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return;
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}
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lastMsgId = context.message.message_id;
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let data = context.message;
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if (options.jsonConvertByteArrayToString === true && data.body.content !== undefined) {
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// The buffer is not ready... Stringify and parse back to load it.
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const cont = deepCopy(data.body.content);
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data.body = String.fromCharCode.apply(null, cont.data);
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}
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if (options.jsonConvertByteArrayToString === true && data.body.content !== undefined) {
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// The buffer is not ready... Stringify and parse back to load it.
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const cont = deepCopy(data.body.content);
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data.body = String.fromCharCode.apply(null, cont.data);
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}
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if (options.jsonConvertByteArrayToString === true && data.body.content !== undefined) {
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// The buffer is not ready... Stringify and parse back to load it.
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const content = deepCopy(data.body.content);
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data.body = String.fromCharCode.apply(null, content.data);
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}
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if (options.jsonParseBody === true) {
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data.body = jsonParse(data.body);
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}
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if (options.onlyBody === true) {
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data = data.body;
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}
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this.emit([this.helpers.returnJsonArray([data as any])]);
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if (!context.receiver?.has_credit()) {
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setTimeout(() => {
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context.receiver?.add_credit(pullMessagesNumber);
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}, (options.sleepTime as number) || 10);
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}
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});
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/*
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Values are documentet here: https://github.com/amqp/rhea#container
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*/
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const connectOptions: ContainerOptions = {
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host: credentials.hostname,
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hostname: credentials.hostname,
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port: credentials.port,
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reconnect: containerReconnect,
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reconnect_limit: containerReconnectLimit,
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username: credentials.username ? credentials.username : undefined,
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password: credentials.password ? credentials.password : undefined,
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transport: credentials.transportType ? credentials.transportType : undefined,
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container_id: containerId ? containerId : undefined,
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id: containerId ? containerId : undefined,
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};
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const connection = container.connect(connectOptions);
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const clientOptions: ReceiverOptions = {
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name: subscription ? subscription : undefined,
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source: {
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address: sink,
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durable: durable ? 2 : undefined,
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expiry_policy: durable ? 'never' : undefined,
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},
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credit_window: 0, // prefetch 1
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};
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connection.open_receiver(clientOptions);
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// The "closeFunction" function gets called by n8n whenever
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// the workflow gets deactivated and can so clean up.
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async function closeFunction() {
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container.removeAllListeners('receiver_open');
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container.removeAllListeners('message');
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connection.close();
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}
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// The "manualTriggerFunction" function gets called by n8n
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// when a user is in the workflow editor and starts the
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// workflow manually.
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// for AMQP it doesn't make much sense to wait here but
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// for a new user who doesn't know how this works, it's better to wait and show a respective info message
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const manualTriggerFunction = async () => {
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await new Promise((resolve, reject) => {
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const timeoutHandler = setTimeout(() => {
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reject(
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new Error(
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'Aborted, no message received within 30secs. This 30sec timeout is only set for "manually triggered execution". Active Workflows will listen indefinitely.',
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),
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);
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}, 30000);
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container.on('message', (context: EventContext) => {
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// Check if the only property present in the message is body
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// in which case we only emit the content of the body property
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// otherwise we emit all properties and their content
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const message = context.message as Message;
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if (Object.keys(message)[0] === 'body' && Object.keys(message).length === 1) {
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this.emit([this.helpers.returnJsonArray([message.body])]);
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} else {
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this.emit([this.helpers.returnJsonArray([message as any])]);
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}
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clearTimeout(timeoutHandler);
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resolve(true);
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});
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});
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};
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return {
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closeFunction,
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manualTriggerFunction,
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};
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}
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}
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