feat: Add WhatsApp Business Trigger Node (n8n-io#8840)

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

packages/nodes-base/credentials/WhatsAppTriggerApi.credentials.ts

@@ -0,0 +1,41 @@
+import type { ICredentialTestRequest, ICredentialType, INodeProperties } from 'n8n-workflow';
+
+export class WhatsAppTriggerApi implements ICredentialType {
+	name = 'whatsAppTriggerApi';
+
+	displayName = 'WhatsApp API';
+
+	documentationUrl = 'whatsApp';
+
+	properties: INodeProperties[] = [
+		{
+			displayName: 'Client ID',
+			name: 'clientId',
+			type: 'string',
+			default: '',
+			required: true,
+		},
+		{
+			displayName: 'Client Secret',
+			name: 'clientSecret',
+			type: 'string',
+			typeOptions: {
+				password: true,
+			},
+			default: '',
+			required: true,
+		},
+	];
+
+	test: ICredentialTestRequest = {
+		request: {
+			method: 'POST',
+			baseURL: 'https://graph.facebook.com/v19.0/oauth/access_token',
+			body: {
+				client_id: '={{$credentials.clientId}}',
+				client_secret: '={{$credentials.clientSecret}}',
+				grant_type: 'client_credentials',
+			},
+		},
+	};
+}

packages/nodes-base/nodes/Facebook/FacebookTrigger.node.ts

@@ -63,6 +63,17 @@ export class FacebookTrigger implements INodeType {
 				default: '',
 				description: 'Facebook APP ID',
 			},
+			{
+				displayName: 'To watch Whatsapp business account events use the Whatsapp trigger node',
+				name: 'whatsappBusinessAccountNotice',
+				type: 'notice',
+				default: '',
+				displayOptions: {
+					show: {
+						object: ['whatsappBusinessAccount'],
+					},
+				},
+			},
 			{
 				displayName: 'Object',
 				name: 'object',

packages/nodes-base/nodes/WhatsApp/GenericFunctions.ts

@@ -0,0 +1,103 @@
+import type {
+	IDataObject,
+	IExecuteFunctions,
+	IHookFunctions,
+	IHttpRequestMethods,
+	IHttpRequestOptions,
+	ILoadOptionsFunctions,
+	IWebhookFunctions,
+	JsonObject,
+} from 'n8n-workflow';
+import { NodeApiError } from 'n8n-workflow';
+import type {
+	WhatsAppAppWebhookSubscriptionsResponse,
+	WhatsAppAppWebhookSubscription,
+} from './types';
+
+async function appAccessTokenRead(
+	this: IHookFunctions | IExecuteFunctions | ILoadOptionsFunctions | IWebhookFunctions,
+): Promise<{ access_token: string }> {
+	const credentials = await this.getCredentials('whatsAppTriggerApi');
+
+	const options: IHttpRequestOptions = {
+		headers: {
+			'content-type': 'application/x-www-form-urlencoded',
+		},
+		method: 'POST',
+		body: {
+			client_id: credentials.clientId,
+			client_secret: credentials.clientSecret,
+			grant_type: 'client_credentials',
+		},
+		url: 'https://graph.facebook.com/v19.0/oauth/access_token',
+		json: true,
+	};
+	try {
+		return await this.helpers.httpRequest.call(this, options);
+	} catch (error) {
+		throw new NodeApiError(this.getNode(), error as JsonObject);
+	}
+}
+
+async function whatsappApiRequest(
+	this: IHookFunctions | IExecuteFunctions | ILoadOptionsFunctions | IWebhookFunctions,
+	method: IHttpRequestMethods,
+	resource: string,
+	body?: { type: 'json'; payload: IDataObject } | { type: 'form'; payload: IDataObject },
+	qs: IDataObject = {},
+): Promise<any> {
+	const tokenResponse = await appAccessTokenRead.call(this);
+	const appAccessToken = tokenResponse.access_token;
+
+	const options: IHttpRequestOptions = {
+		headers: {
+			accept: 'application/json',
+			authorization: `Bearer ${appAccessToken}`,
+		},
+		method,
+		qs,
+		body: body?.payload,
+		url: `https://graph.facebook.com/v19.0${resource}`,
+		json: true,
+	};
+
+	try {
+		return await this.helpers.httpRequest.call(this, options);
+	} catch (error) {
+		throw new NodeApiError(this.getNode(), error as JsonObject);
+	}
+}
+
+export async function appWebhookSubscriptionList(
+	this: IHookFunctions | IExecuteFunctions | ILoadOptionsFunctions | IWebhookFunctions,
+	appId: string,
+): Promise<WhatsAppAppWebhookSubscription[]> {
+	const response = (await whatsappApiRequest.call(
+		this,
+		'GET',
+		`/${appId}/subscriptions`,
+	)) as WhatsAppAppWebhookSubscriptionsResponse;
+	return response.data;
+}
+
+export async function appWebhookSubscriptionCreate(
+	this: IHookFunctions | IExecuteFunctions | ILoadOptionsFunctions | IWebhookFunctions,
+	appId: string,
+	subscription: IDataObject,
+) {
+	return await whatsappApiRequest.call(this, 'POST', `/${appId}/subscriptions`, {
+		type: 'form',
+		payload: { ...subscription },
+	});
+}
+
+export async function appWebhookSubscriptionDelete(
+	this: IHookFunctions | IExecuteFunctions | ILoadOptionsFunctions | IWebhookFunctions,
+	appId: string,
+	object: string,
+) {
+	return await whatsappApiRequest.call(this, 'DELETE', `/${appId}/subscriptions`, {
+		type: 'form',
+		payload: { object },
+	});
+}

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

@@ -0,0 +1,18 @@
+{
+	"node": "n8n-nodes-base.whatsAppTrigger",
+	"nodeVersion": "1.0",
+	"codexVersion": "1.0",
+	"categories": ["Communication"],
+	"resources": {
+		"credentialDocumentation": [
+			{
+				"url": "https://docs.n8n.io/integrations/credentials/whatsapp/"
+			}
+		],
+		"primaryDocumentation": [
+			{
+				"url": "https://docs.n8n.io/integrations/builtin/trigger-nodes/n8n-nodes-base.whatsapptrigger/"
+			}
+		]
+	}
+}

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)],
+		};
+	}
+}