Build a Telgram Bot using NodeJS and Deploy it on AWS Lambda

Project Walkthrough:

What is AWS Lambda ?

AWS Lambda is an event-driven, serverless Function as a Service provided by Amazon as a part of Amazon Web Services. It is designed to enable developers to run code without provisioning or managing servers. It executes code in response to events and automatically manages the computing resources required by that code.

Why we need an API Gateway ?

Amazon API Gateway is an AWS service for creating, publishing, maintaining, monitoring, and securing REST, HTTP, and WebSocket APIs at any scale.

It protects you lambda functions from cyber attacks such as

• DDOS Attack

• Port Flooding

• SQL Injection

What are webhooks ?

A webhook is an HTTP-based callback function that allows lightweight, event-driven communication between 2 application programming interfaces (APIs).

Setting up the project:

Steps:

1. Generate a BOT Token using BotFather

2. Create a folder and run npm init to create node modules. Also create an index.js file.

3. Create a Lambda Function.

4. Create an API gateway to add trigger for you lambda function.

Upload your code on a Lambda Function

Code:

const axios = require("axios");

const handler = async (event) => {
  let data = JSON.parse(event.body);
  let chat_id = data.message.chat.id;

  const bs = await axios.post(
    "https://api.telegram.org/bot" + process.env.BOT_TOKEN + "/sendMessage",
    {
      chat_id: chat_id,
      text: "Thank you for contacting",
    }
  );
  const response = {
    statusCode: 200,
    body: JSON.stringify("Hello from Lambda!"),
  };
  return response;
};

module.exports = { handler };

// API URL

// set webhook
// https://api.telegram.org/bot{BOT_TOKEN}/setWebhook

// sendMessage
// https://api.telegram.org/bot{BOT_TOKEN}/sendMessage

NOTE:

The index.js files needs to be in the root directory of your lambda function.

Deploy and Test your Lambda Function

Final remarks:

The main aim of this project was to get hands on practice with AWS lambda and API Gateway to handle trigger based events without managning any servers of architecture to get the understanding of serverless technology and how we can leverage cloud to build efficient solutions.