✨ AWS SNS trigger

packages/nodes-base/nodes/Aws/AwsSnsTrigger.node.ts

@@ -0,0 +1,179 @@
+import {
+	IHookFunctions,
+	IWebhookFunctions,
+} from 'n8n-core';
+
+import {
+	INodeTypeDescription,
+	INodeType,
+	IWebhookResponseData,
+	ILoadOptionsFunctions,
+	INodePropertyOptions,
+} from 'n8n-workflow';
+
+import {
+	awsApiRequestSOAP,
+} from './GenericFunctions';
+
+import { get } from 'lodash';
+
+export class AwsSnsTrigger implements INodeType {
+	description: INodeTypeDescription = {
+		displayName: 'AWS SNS Trigger',
+		subtitle: `={{$parameter["topic"].split(':')[5]}}`,
+		name: 'AwsSnsTrigger',
+		icon: 'file:sns.png',
+		group: ['trigger'],
+		version: 1,
+		description: 'Handle AWS SNS events via webhooks',
+		defaults: {
+			name: 'AWS SNS Trigger',
+			color: '#FF9900',
+		},
+		inputs: [],
+		outputs: ['main'],
+		credentials: [
+			{
+				name: 'aws',
+				required: true,
+			}
+		],
+		webhooks: [
+			{
+				name: 'default',
+				httpMethod: 'POST',
+				responseMode: 'onReceived',
+				path: 'webhook',
+			},
+		],
+		properties: [
+			{
+				displayName: 'Topic',
+				name: 'topic',
+				type: 'options',
+				required: true,
+				typeOptions: {
+					loadOptionsMethod: 'getTopics',
+				},
+				default: '',
+			},
+		],
+	};
+
+	methods = {
+		loadOptions: {
+			// Get all the available topics to display them to user so that he can
+			// select them easily
+			async getTopics(this: ILoadOptionsFunctions): Promise<INodePropertyOptions[]> {
+				const returnData: INodePropertyOptions[] = [];
+				let data;
+				try {
+					data = await awsApiRequestSOAP.call(this, 'sns', 'GET', '/?Action=ListTopics');
+				} catch (err) {
+					throw new Error(`AWS Error: ${err}`);
+				}
+
+				let topics = data.ListTopicsResponse.ListTopicsResult.Topics.member;
+
+				if (!Array.isArray(topics)) {
+					// If user has only a single topic no array get returned so we make
+					// one manually to be able to process everything identically
+					topics = [topics];
+				}
+
+				for (const topic of topics) {
+					const topicArn = topic.TopicArn as string;
+					const topicName = topicArn.split(':')[5];
+
+					returnData.push({
+						name: topicName,
+						value: topicArn,
+					});
+				}
+				return returnData;
+			}
+		},
+	};
+	// @ts-ignore
+	webhookMethods = {
+		default: {
+			async checkExists(this: IHookFunctions): Promise<boolean> {
+				const webhookData = this.getWorkflowStaticData('node');
+				const topic = this.getNodeParameter('topic') as string;
+				if (webhookData.webhookId === undefined) {
+					return false;
+				}
+				const params = [
+					`TopicArn=${topic}`,
+					'Version=2010-03-31',
+				];
+				const data = await awsApiRequestSOAP.call(this, 'sns', 'GET', '/?Action=ListSubscriptionsByTopic&' + params.join('&'));
+				const subscriptions = get(data, 'ListSubscriptionsByTopicResponse.ListSubscriptionsByTopicResult.Subscriptions.member')
+				for (const subscription of subscriptions) {
+					if (webhookData.webhookId === subscription.SubscriptionArn) {
+						return true;
+					}
+				}
+				return false;
+			},
+			async create(this: IHookFunctions): Promise<boolean> {
+				const webhookData = this.getWorkflowStaticData('node');
+				const webhookUrl = this.getNodeWebhookUrl('default');
+				const topic = this.getNodeParameter('topic') as string;
+				const params = [
+					`TopicArn=${topic}`,
+					`Endpoint=${webhookUrl}`,
+					`Protocol=${webhookUrl?.split(':')[0]}`,
+					'ReturnSubscriptionArn=true',
+					'Version=2010-03-31',
+				];
+				try {
+					const { SubscribeResponse } = await awsApiRequestSOAP.call(this, 'sns', 'GET', '/?Action=Subscribe&' + params.join('&'));
+					webhookData.webhookId = SubscribeResponse.SubscribeResult.SubscriptionArn;
+				} catch (err) {
+					throw new Error(err);
+				}
+				return true;
+			},
+			async delete(this: IHookFunctions): Promise<boolean> {
+				const webhookData = this.getWorkflowStaticData('node');
+				const params = [
+					`SubscriptionArn=${webhookData.webhookId}`,
+					'Version=2010-03-31',
+				];
+				try {
+					await awsApiRequestSOAP.call(this, 'sns', 'GET', '/?Action=Unsubscribe&' + params.join('&'));
+				} catch(error) {
+					return false;
+				}
+				delete webhookData.webhookId;
+				return true;
+			},
+		},
+	};
+
+	async webhook(this: IWebhookFunctions): Promise<IWebhookResponseData> {
+		const req = this.getRequestObject();
+		const topic = this.getNodeParameter('topic') as string;
+		if (req.body.Type === 'SubscriptionConfirmation' &&
+			req.body.TopicArn === topic) {
+			const { Token } = req.body;
+			const params = [
+				`TopicArn=${topic}`,
+				`Token=${Token}`,
+				'Version=2010-03-31',
+			];
+			await awsApiRequestSOAP.call(this, 'sns', 'GET', '/?Action=ConfirmSubscription&' + params.join('&'));
+			return {};
+		}
+		if (req.body.Type === 'UnsubscribeConfirmation') {
+			return {};
+		}
+		//TODO verify message signature
+		return {
+			workflowData: [
+				this.helpers.returnJsonArray(req.body),
+			],
+		};
+	}
+}

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

@@ -6,10 +6,11 @@ import {
 	IExecuteFunctions,
 	IHookFunctions,
 	ILoadOptionsFunctions,
+	IWebhookFunctions,
 } from 'n8n-core';
 
 
-export async function awsApiRequest(this: IHookFunctions | IExecuteFunctions | ILoadOptionsFunctions, service: string, method: string, path: string, body?: string, headers?: object): Promise<any> { // tslint:disable-line:no-any
+export async function awsApiRequest(this: IHookFunctions | IExecuteFunctions | ILoadOptionsFunctions | IWebhookFunctions, service: string, method: string, path: string, body?: string, headers?: object): Promise<any> { // tslint:disable-line:no-any
 	const credentials = this.getCredentials('aws');
 	if (credentials === undefined) {
 		throw new Error('No credentials got returned!');
@@ -59,7 +60,7 @@ export async function awsApiRequestREST(this: IHookFunctions | IExecuteFunctions
 }
 
 
-export async function awsApiRequestSOAP(this: IHookFunctions | IExecuteFunctions | ILoadOptionsFunctions, service: string, method: string, path: string, body?: string, headers?: object): Promise<any> { // tslint:disable-line:no-any
+export async function awsApiRequestSOAP(this: IHookFunctions | IExecuteFunctions | ILoadOptionsFunctions | IWebhookFunctions, service: string, method: string, path: string, body?: string, headers?: object): Promise<any> { // tslint:disable-line:no-any
 	const response = await awsApiRequest.call(this, service, method, path, body, headers);
 	try {
 		return await new Promise((resolve, reject) => {

packages/nodes-base/package.json

@@ -107,6 +107,7 @@
             "dist/nodes/Aws/AwsLambda.node.js",
             "dist/nodes/Aws/AwsSes.node.js",
             "dist/nodes/Aws/AwsSns.node.js",
+            "dist/nodes/Aws/AwsSnsTrigger.node.js",
             "dist/nodes/Bitbucket/BitbucketTrigger.node.js",
             "dist/nodes/Bitly/Bitly.node.js",
             "dist/nodes/Chargebee/Chargebee.node.js",