✨ Add Facebook Trigger Node (#1106)

* ⚡ Facebook trigger from webhooks

Uses tokens just like the GraphQL API but this one requires an app token
instead of an user access token.

* ⚡ Improvements
:zap Improvements

* 🐛 Fix credential file name

Co-authored-by: Omar Ajoue <krynble@gmail.com>

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

@@ -0,0 +1,21 @@
+import {
+	ICredentialType,
+	NodePropertyTypes,
+} from 'n8n-workflow';
+
+export class FacebookGraphSubscriptionApi implements ICredentialType {
+	name = 'facebookGraphSubscriptionApi';
+	displayName = 'Facebook Graph API';
+	extends = [
+		'facebookGraphApi',
+	];
+	properties = [
+		{
+			displayName: 'APP Secret',
+			name: 'appSecret',
+			type: 'string' as NodePropertyTypes,
+			default: '',
+			description: '(Optional) When the app secret is set the node will verify this signature to validate the integrity and origin of the payload.',
+		},
+	];
+}

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

@@ -10,7 +10,9 @@ import {
 	INodeTypeDescription,
 } from 'n8n-workflow';
 
-import { OptionsWithUri } from 'request';
+import {
+	OptionsWithUri,
+} from 'request';
 
 export class FacebookGraphApi implements INodeType {
 	description: INodeTypeDescription = {
@@ -22,7 +24,7 @@ export class FacebookGraphApi implements INodeType {
 		description: 'Interacts with Facebook using the Graph API',
 		defaults: {
 			name: 'Facebook Graph API',
-			color: '#772244',
+			color: '#3B5998',
 		},
 		inputs: ['main'],
 		outputs: ['main'],

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

@@ -0,0 +1,251 @@
+import {
+	IHookFunctions,
+	IWebhookFunctions,
+} from 'n8n-core';
+
+import {
+	IDataObject,
+	INodeType,
+	INodeTypeDescription,
+	IWebhookResponseData,
+} from 'n8n-workflow';
+
+import * as uuid from 'uuid/v4';
+
+import {
+	snakeCase,
+} from 'change-case';
+
+import {
+	facebookApiRequest,
+} from './GenericFunctions';
+
+import {
+	createHmac,
+} from 'crypto';
+
+export class FacebookTrigger implements INodeType {
+	description: INodeTypeDescription = {
+		displayName: 'Facebook Trigger',
+		name: 'facebookTrigger',
+		icon: 'file:facebook.png',
+		group: ['trigger'],
+		version: 1,
+		subtitle: '={{$parameter["appId"] +"/"+ $parameter["object"]}}',
+		description: 'Starts the workflow when a Facebook events occurs.',
+		defaults: {
+			name: 'Facebook Trigger',
+			color: '#3B5998',
+		},
+		inputs: [],
+		outputs: ['main'],
+		credentials: [
+			{
+				name: 'facebookGraphSubscriptionApi',
+				required: true,
+			},
+		],
+		webhooks: [
+			{
+				name: 'setup',
+				httpMethod: 'GET',
+				responseMode: 'onReceived',
+				path: 'webhook',
+			},
+			{
+				name: 'default',
+				httpMethod: 'POST',
+				responseMode: 'onReceived',
+				path: 'webhook',
+			},
+		],
+		properties: [
+			{
+				displayName: 'Object',
+				name: 'object',
+				type: 'options',
+				options: [
+					{
+						name: 'Ad Account',
+						value: 'adAccount',
+						description: 'Get updates about Ad Account',
+					},
+					{
+						name: 'Application',
+						value: 'application',
+						description: 'Get updates about the app',
+					},
+					{
+						name: 'Certificate Transparency',
+						value: 'certificateTransparency',
+						description: 'Get updates about Certificate Transparency',
+					},
+					{
+						name: 'Group',
+						value: 'group',
+						description: 'Get updates about activity in groups and events in groups for Workplace',
+					},
+					{
+						name: 'Instagram',
+						value: 'instagram',
+						description: 'Get updates about comments on your media',
+					},
+					{
+						name: 'Link',
+						value: 'link',
+						description: 'Get updates about links for rich previews by an external provider',
+					},
+					{
+						name: 'Page',
+						value: 'page',
+						description: 'Page updates',
+					},
+					{
+						name: 'Permissions',
+						value: 'permissions',
+						description: 'Updates regarding granting or revoking permissions',
+					},
+					{
+						name: 'User',
+						value: 'user',
+						description: 'User profile updates',
+					},
+					{
+						name: 'Whatsapp Business Account',
+						value: 'whatsappBusinessAccount',
+						description: 'Get updates about Whatsapp business account',
+					},
+					{
+						name: 'Workplace Security',
+						value: 'workplaceSecurity',
+						description: 'Get updates about Workplace Security',
+					},
+				],
+				required: true,
+				default: 'user',
+				description: 'The object to subscribe to',
+			},
+			{
+				displayName: 'App ID',
+				name: 'appId',
+				type: 'string',
+				required: true,
+				default: '',
+				description: 'Facebook APP ID',
+			},
+			{
+				displayName: 'Options',
+				name: 'options',
+				type: 'collection',
+				default: {},
+				placeholder: 'Add option',
+				options: [
+					{
+						displayName: 'Include values',
+						name: 'includeValues',
+						type: 'boolean',
+						default: true,
+						description: 'Indicates if change notifications should include the new values.',
+					},
+				],
+			},
+		],
+	};
+
+	// @ts-ignore (because of request)
+	webhookMethods = {
+		default: {
+			async checkExists(this: IHookFunctions): Promise<boolean> {
+				const webhookUrl = this.getNodeWebhookUrl('default') as string;
+				const object = this.getNodeParameter('object') as string;
+				const appId = this.getNodeParameter('appId') as string;
+
+				const { data } = await facebookApiRequest.call(this, 'GET', `/${appId}/subscriptions`, {});
+
+				for (const webhook of data) {
+					if (webhook.target === webhookUrl && webhook.object === object && webhook.status === true) {
+						return true;
+					}
+				}
+				return false;
+			},
+			async create(this: IHookFunctions): Promise<boolean> {
+				const webhookData = this.getWorkflowStaticData('node');
+				const webhookUrl = this.getNodeWebhookUrl('default') as string;
+				const object = this.getNodeParameter('object') as string;
+				const appId = this.getNodeParameter('appId') as string;
+				const options = this.getNodeParameter('options') as IDataObject;
+
+				const body = {
+					object: snakeCase(object),
+					callback_url: webhookUrl,
+					verify_token: uuid(),
+				} as IDataObject;
+
+				if (options.includeValues !== undefined) {
+					body.include_values = options.includeValues;
+				}
+
+				const responseData = await facebookApiRequest.call(this, 'POST', `/${appId}/subscriptions`, body);
+
+				webhookData.verifyToken = body.verify_token;
+
+				if (responseData.success !== true) {
+					// Facebook did not return success, so something went wrong
+					throw new Error('Facebook webhook creation response did not contain the expected data.');
+				}
+				return true;
+			},
+			async delete(this: IHookFunctions): Promise<boolean> {
+				const appId = this.getNodeParameter('appId') as string;
+				const object = this.getNodeParameter('object') as string;
+
+				try {
+					await facebookApiRequest.call(this, 'DELETE', `/${appId}/subscriptions`, { object: snakeCase(object) });
+				} catch (e) {
+					return false;
+				}
+				return true;
+			},
+		},
+	};
+
+	async webhook(this: IWebhookFunctions): Promise<IWebhookResponseData> {
+		const bodyData = this.getBodyData() as IDataObject;
+		const query = this.getQueryData() as IDataObject;
+		const res = this.getResponseObject();
+		const req = this.getRequestObject();
+		const headerData = this.getHeaderData() as IDataObject;
+		const credentials = this.getCredentials('facebookGraphSubscriptionApi') as IDataObject;
+		// 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']) {
+				//TODO
+				//compare hub.verify_token with the saved token
+				//const webhookData = this.getWorkflowStaticData('node');
+				// if (webhookData.verifyToken !== query['hub.verify_token']) {
+				// 	return {};
+				// }
+				res.status(200).send(query['hub.challenge']).end();
+				return {
+					noWebhookResponse: true,
+				};
+			}
+		}
+
+		// validate signature if app secret is set
+		if (credentials.appSecret !== '') {
+			//@ts-ignore
+			const computedSignature = createHmac('sha1', credentials.appSecret as string).update(req.rawBody).digest('hex');
+			if (headerData['x-hub-signature'] !== `sha1=${computedSignature}`) {
+				return {};
+			}
+		}
+
+		return {
+			workflowData: [
+				this.helpers.returnJsonArray(bodyData.entry as IDataObject[]),
+			],
+		};
+	}
+}

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

@@ -0,0 +1,53 @@
+import {
+	OptionsWithUri,
+} from 'request';
+
+import {
+	IExecuteFunctions,
+	IExecuteSingleFunctions,
+	IHookFunctions,
+	ILoadOptionsFunctions,
+	IWebhookFunctions,
+} from 'n8n-core';
+
+import {
+	IDataObject,
+} from 'n8n-workflow';
+
+export async function facebookApiRequest(this: IHookFunctions | IExecuteFunctions | IExecuteSingleFunctions | ILoadOptionsFunctions | IWebhookFunctions, method: string, resource: string, body: any = {}, qs: IDataObject = {}, uri?: string, option: IDataObject = {}): Promise<any> { // tslint:disable-line:no-any
+
+	let credentials;
+
+	if (this.getNode().name.includes('Trigger')) {
+		credentials = this.getCredentials('facebookGraphSubscriptionApi') as IDataObject;
+	} else {
+		credentials = this.getCredentials('facebookGraphApi') as IDataObject;
+	}
+
+	qs.access_token = credentials!.accessToken;
+
+	const options: OptionsWithUri = {
+		headers: {
+			accept: 'application/json,text/*;q=0.99',
+		},
+		method,
+		qs,
+		body,
+		gzip: true,
+		uri: uri ||`https://graph.facebook.com/v8.0${resource}`,
+		json: true,
+	};
+
+	try {
+		return await this.helpers.request!(options);
+	} catch (error) {
+
+		if (error.response.body && error.response.body.error) {
+			const message = error.response.body.error.message;
+			throw new Error(
+				`Facebook Trigger error response [${error.statusCode}]: ${message}`,
+			);
+		}
+		throw new Error(error);
+	}
+}

packages/nodes-base/package.json

@@ -66,6 +66,7 @@
       "dist/credentials/EventbriteApi.credentials.js",
       "dist/credentials/EventbriteOAuth2Api.credentials.js",
       "dist/credentials/FacebookGraphApi.credentials.js",
+      "dist/credentials/FacebookGraphSubscriptionApi.credentials.js",
       "dist/credentials/FreshdeskApi.credentials.js",
       "dist/credentials/FileMaker.credentials.js",
       "dist/credentials/FlowApi.credentials.js",
@@ -266,6 +267,7 @@
       "dist/nodes/ExecuteCommand.node.js",
       "dist/nodes/ExecuteWorkflow.node.js",
       "dist/nodes/Facebook/FacebookGraphApi.node.js",
+      "dist/nodes/Facebook/FacebookTrigger.node.js",
       "dist/nodes/FileMaker/FileMaker.node.js",
       "dist/nodes/Ftp.node.js",
       "dist/nodes/Freshdesk/Freshdesk.node.js",