feat: Add WhatsApp Business Trigger Node (#8840)

Co-authored-by: Giulio Andreini <andreini@netseven.it>
Co-authored-by: Michael Kret <michael.k@radency.com>

packages/nodes-base/nodes/WhatsApp/WhatsAppTrigger.node.ts

@@ -0,0 +1,185 @@
+import { createHmac } from 'crypto';
+import {
+	NodeOperationError,
+	type IDataObject,
+	type IHookFunctions,
+	type INodeType,
+	type INodeTypeDescription,
+	type IWebhookFunctions,
+	type IWebhookResponseData,
+} from 'n8n-workflow';
+import {
+	appWebhookSubscriptionCreate,
+	appWebhookSubscriptionDelete,
+	appWebhookSubscriptionList,
+} from './GenericFunctions';
+import type { WhatsAppPageEvent } from './types';
+import { whatsappTriggerDescription } from './WhatsappDescription';
+
+export class WhatsAppTrigger implements INodeType {
+	description: INodeTypeDescription = {
+		displayName: 'WhatsApp Trigger',
+		name: 'whatsAppTrigger',
+		icon: 'file:whatsapp.svg',
+		group: ['trigger'],
+		version: 1,
+		subtitle: '={{$parameter["event"]}}',
+		description: 'Handle WhatsApp events via webhooks',
+		defaults: {
+			name: 'WhatsApp Trigger',
+		},
+		inputs: [],
+		outputs: ['main'],
+		credentials: [
+			{
+				name: 'whatsAppTriggerApi',
+				required: true,
+			},
+		],
+		webhooks: [
+			{
+				name: 'setup',
+				httpMethod: 'GET',
+				responseMode: 'onReceived',
+				path: 'webhook',
+			},
+			{
+				name: 'default',
+				httpMethod: 'POST',
+				responseMode: 'onReceived',
+				path: 'webhook',
+			},
+		],
+		properties: [
+			{
+				displayName:
+					'Due to Facebook API limitations, you can use just one WhatsApp trigger for each Facebook App',
+				name: 'whatsAppNotice',
+				type: 'notice',
+				default: '',
+			},
+			...whatsappTriggerDescription,
+		],
+	};
+
+	webhookMethods = {
+		default: {
+			async checkExists(this: IHookFunctions): Promise<boolean> {
+				const webhookUrl = this.getNodeWebhookUrl('default') as string;
+				const credentials = await this.getCredentials('whatsAppTriggerApi');
+				const updates = this.getNodeParameter('updates', []) as IDataObject[];
+				const subscribedEvents = updates.sort().join(',');
+				const appId = credentials.clientId as string;
+
+				const webhooks = await appWebhookSubscriptionList.call(this, appId);
+
+				const subscription = webhooks.find(
+					(webhook) =>
+						webhook.object === 'whatsapp_business_account' &&
+						webhook.fields
+							.map((x) => x.name)
+							.sort()
+							.join(',') === subscribedEvents &&
+						webhook.active,
+				);
+
+				if (!subscription) {
+					return false;
+				}
+
+				if (subscription.callback_url !== webhookUrl) {
+					throw new NodeOperationError(
+						this.getNode(),
+						`The WhatsApp App ID ${appId} already has a webhook subscription. Delete it or use another App before executing the trigger. Due to WhatsApp API limitations, you can have just one trigger per App.`,
+						{ level: 'warning' },
+					);
+				}
+
+				if (
+					subscription?.fields
+						.map((x) => x.name)
+						.sort()
+						.join(',') !== subscribedEvents
+				) {
+					await appWebhookSubscriptionDelete.call(this, appId, 'whatsapp_business_account');
+					return false;
+				}
+
+				return true;
+			},
+			async create(this: IHookFunctions): Promise<boolean> {
+				const webhookUrl = this.getNodeWebhookUrl('default') as string;
+				const credentials = await this.getCredentials('whatsAppTriggerApi');
+				const appId = credentials.clientId as string;
+				const updates = this.getNodeParameter('updates', []) as IDataObject[];
+				const verifyToken = this.getNode().id;
+
+				await appWebhookSubscriptionCreate.call(this, appId, {
+					object: 'whatsapp_business_account',
+					callback_url: webhookUrl,
+					verify_token: verifyToken,
+					fields: JSON.stringify(updates),
+					include_values: true,
+				});
+
+				return true;
+			},
+			async delete(this: IHookFunctions): Promise<boolean> {
+				const credentials = await this.getCredentials('whatsAppTriggerApi');
+				const appId = credentials.clientId as string;
+
+				await appWebhookSubscriptionDelete.call(this, appId, 'whatsapp_business_account');
+
+				return true;
+			},
+		},
+	};
+
+	async webhook(this: IWebhookFunctions): Promise<IWebhookResponseData> {
+		const bodyData = this.getBodyData() as unknown as WhatsAppPageEvent;
+		const query = this.getQueryData() as IDataObject;
+		const res = this.getResponseObject();
+		const req = this.getRequestObject();
+		const headerData = this.getHeaderData() as IDataObject;
+		const credentials = await this.getCredentials('whatsAppTriggerApi');
+
+		// Check if we're getting facebook's challenge request (https://developers.facebook.com/docs/graph-api/webhooks/getting-started)
+		if (this.getWebhookName() === 'setup') {
+			if (query['hub.challenge']) {
+				if (this.getNode().id !== query['hub.verify_token']) {
+					return {};
+				}
+
+				res.status(200).send(query['hub.challenge']).end();
+
+				return { noWebhookResponse: true };
+			}
+		}
+
+		const computedSignature = createHmac('sha256', credentials.clientSecret as string)
+			.update(req.rawBody)
+			.digest('hex');
+		if (headerData['x-hub-signature-256'] !== `sha256=${computedSignature}`) {
+			return {};
+		}
+
+		if (bodyData.object !== 'whatsapp_business_account') {
+			return {};
+		}
+
+		const events = await Promise.all(
+			bodyData.entry
+				.map((entry) => entry.changes)
+				.flat()
+				.map((change) => ({ ...change.value, field: change.field })),
+		);
+
+		if (events.length === 0) {
+			return {};
+		}
+
+		return {
+			workflowData: [this.helpers.returnJsonArray(events)],
+		};
+	}
+}