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packages/nodes-base/nodes/Amqp/AmqpTrigger.node.ts

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+import type {
+	IDataObject,
+	INodeType,
+	INodeTypeDescription,
+	ITriggerFunctions,
+	ITriggerResponse,
+} from 'n8n-workflow';
+import { NodeConnectionTypes, NodeOperationError } from 'n8n-workflow';
+import type { ConnectionOptions, EventContext, ReceiverOptions } from 'rhea';
+import { create_container } from 'rhea';
+
+import { handleMessage } from './helpers/handleMessage';
+import type { AmqpCredential } from './types';
+
+export class AmqpTrigger implements INodeType {
+	description: INodeTypeDescription = {
+		displayName: 'AMQP Trigger',
+		name: 'amqpTrigger',
+		icon: 'file:amqp.svg',
+		group: ['trigger'],
+		version: 1,
+		description: 'Listens to AMQP 1.0 Messages',
+		defaults: {
+			name: 'AMQP Trigger',
+		},
+		inputs: [],
+		outputs: [NodeConnectionTypes.Main],
+		credentials: [
+			{
+				name: 'amqp',
+				required: true,
+			},
+		],
+		properties: [
+			// Node properties which the user gets displayed and
+			// can change on the node.
+			{
+				displayName: 'Queue / Topic',
+				name: 'sink',
+				type: 'string',
+				default: '',
+				placeholder: 'topic://sourcename.something',
+				description: 'Name of the queue of topic to listen to',
+			},
+			{
+				displayName: 'Clientname',
+				name: 'clientname',
+				type: 'string',
+				default: '',
+				placeholder: 'e.g. n8n',
+				description: 'Leave empty for non-durable topic subscriptions or queues',
+				hint: 'for durable/persistent topic subscriptions',
+			},
+			{
+				displayName: 'Subscription',
+				name: 'subscription',
+				type: 'string',
+				default: '',
+				placeholder: 'e.g. order-worker',
+				description: 'Leave empty for non-durable topic subscriptions or queues',
+				hint: 'for durable/persistent topic subscriptions',
+			},
+			{
+				displayName: 'Options',
+				name: 'options',
+				type: 'collection',
+				placeholder: 'Add option',
+				default: {},
+				options: [
+					{
+						displayName: 'Container ID',
+						name: 'containerId',
+						type: 'string',
+						default: '',
+						description: 'Will be used to pass to the RHEA Backend as container_id',
+					},
+					{
+						displayName: 'Convert Body To String',
+						name: 'jsonConvertByteArrayToString',
+						type: 'boolean',
+						default: false,
+						description:
+							'Whether to convert JSON Body content (["body"]["content"]) from Byte Array to string. Needed for Azure Service Bus.',
+					},
+					{
+						displayName: 'JSON Parse Body',
+						name: 'jsonParseBody',
+						type: 'boolean',
+						default: false,
+						description: 'Whether to parse the body to an object',
+					},
+					{
+						displayName: 'Messages per Cicle',
+						name: 'pullMessagesNumber',
+						type: 'number',
+						default: 100,
+						description: 'Number of messages to pull from the bus for every cicle',
+					},
+					{
+						displayName: 'Only Body',
+						name: 'onlyBody',
+						type: 'boolean',
+						default: false,
+						description: 'Whether to return only the body property',
+					},
+					{
+						displayName: 'Parallel Processing',
+						name: 'parallelProcessing',
+						type: 'boolean',
+						default: true,
+						description: 'Whether to process messages in parallel',
+					},
+					{
+						displayName: 'Reconnect',
+						name: 'reconnect',
+						type: 'boolean',
+						default: true,
+						description: 'Whether to automatically reconnect if disconnected',
+					},
+					{
+						displayName: 'Reconnect Limit',
+						name: 'reconnectLimit',
+						type: 'number',
+						default: 50,
+						description: 'Maximum number of reconnect attempts',
+					},
+					{
+						displayName: 'Sleep Time',
+						name: 'sleepTime',
+						type: 'number',
+						default: 10,
+						description: 'Milliseconds to sleep after every cicle',
+					},
+				],
+			},
+		],
+	};
+
+	async trigger(this: ITriggerFunctions): Promise<ITriggerResponse> {
+		const credentials = await this.getCredentials<AmqpCredential>('amqp');
+
+		const sink = this.getNodeParameter('sink', '') as string;
+		const clientname = this.getNodeParameter('clientname', '') as string;
+		const subscription = this.getNodeParameter('subscription', '') as string;
+		const options = this.getNodeParameter('options', {}) as IDataObject;
+		const parallelProcessing = this.getNodeParameter('options.parallelProcessing', true) as boolean;
+		const pullMessagesNumber = (options.pullMessagesNumber as number) || 100;
+		const containerId = options.containerId as string;
+		const containerReconnect = (options.reconnect as boolean) || true;
+		// Keep reconnecting (exponential backoff) forever unless user sets a limit
+		const containerReconnectLimit = (options.reconnectLimit as number) ?? undefined;
+
+		if (sink === '') {
+			throw new NodeOperationError(this.getNode(), 'Queue or Topic required!');
+		}
+
+		let durable = false;
+
+		if (subscription && clientname) {
+			durable = true;
+		}
+
+		const container = create_container();
+
+		let lastMsgId: string | number | Buffer | undefined = undefined;
+
+		container.on('receiver_open', (context: EventContext) => {
+			context.receiver?.add_credit(pullMessagesNumber);
+		});
+
+		container.on('message', async (context: EventContext) => {
+			try {
+				const result = await handleMessage.call(this, context, {
+					lastMessageId: lastMsgId,
+					pullMessagesNumber,
+					jsonConvertByteArrayToString: options.jsonConvertByteArrayToString as boolean,
+					jsonParseBody: options.jsonParseBody as boolean,
+					onlyBody: options.onlyBody as boolean,
+					parallelProcessing,
+					sleepTime: options.sleepTime as number,
+				});
+				if (result) {
+					lastMsgId = result.messageId;
+				}
+			} catch (error) {
+				this.saveFailedExecution(new NodeOperationError(this.getNode(), error as Error));
+			}
+		});
+
+		/*
+			Values are documented here: https://github.com/amqp/rhea#container
+		 */
+		const connectOptions: ConnectionOptions = {
+			host: credentials.hostname,
+			hostname: credentials.hostname,
+			port: credentials.port,
+			reconnect: containerReconnect,
+			reconnect_limit: containerReconnectLimit,
+			// Try reconnection even if caused by a fatal error
+			all_errors_non_fatal: true,
+			username: credentials.username ? credentials.username : undefined,
+			password: credentials.password ? credentials.password : undefined,
+			transport: credentials.transportType ? credentials.transportType : undefined,
+			container_id: containerId ? containerId : undefined,
+			id: containerId ? containerId : undefined,
+		} as unknown as ConnectionOptions;
+		const connection = container.connect(connectOptions);
+
+		const clientOptions: ReceiverOptions = {
+			name: subscription ? subscription : undefined,
+			source: {
+				address: sink,
+				durable: durable ? 2 : undefined,
+				expiry_policy: durable ? 'never' : undefined,
+			},
+			credit_window: 0, // prefetch 1
+		};
+		connection.open_receiver(clientOptions);
+
+		// The "closeFunction" function gets called by n8n whenever
+		// the workflow gets deactivated and can so clean up.
+		async function closeFunction() {
+			container.removeAllListeners('receiver_open');
+			container.removeAllListeners('message');
+			connection.close();
+		}
+
+		// The "manualTriggerFunction" function gets called by n8n
+		// when a user is in the workflow editor and starts the
+		// workflow manually.
+		// for AMQP it doesn't make much sense to wait here but
+		// for a new user who doesn't know how this works, it's better to wait and show a respective info message
+		const manualTriggerFunction = async () => {
+			await new Promise((resolve, reject) => {
+				// remove the default message listener, setup our own for test trigger
+				container.removeAllListeners('message');
+
+				const timeoutHandler = setTimeout(() => {
+					container.removeAllListeners('receiver_open');
+					container.removeAllListeners('message');
+					connection.close();
+
+					reject(
+						new NodeOperationError(
+							this.getNode(),
+							'Aborted because no message received within 15 seconds',
+							{
+								description:
+									'This 15sec timeout is only set for "manually triggered execution". Active Workflows will listen indefinitely.',
+							},
+						),
+					);
+				}, 15000);
+				container.on('message', async (context: EventContext) => {
+					try {
+						const result = await handleMessage.call(this, context, {
+							lastMessageId: lastMsgId,
+							pullMessagesNumber,
+							jsonConvertByteArrayToString: options.jsonConvertByteArrayToString as boolean,
+							jsonParseBody: options.jsonParseBody as boolean,
+							onlyBody: options.onlyBody as boolean,
+							parallelProcessing,
+							sleepTime: options.sleepTime as number,
+						});
+						if (result) {
+							lastMsgId = result.messageId;
+						}
+						clearTimeout(timeoutHandler);
+						resolve(true);
+					} catch (error) {
+						reject(error as Error);
+					} finally {
+						clearTimeout(timeoutHandler);
+					}
+				});
+			});
+		};
+
+		return {
+			closeFunction,
+			manualTriggerFunction,
+		};
+	}
+}