Program to Create a Hello World API using AWS Lambda and API Gateway

In this blog post, we will learn how to create a simple Hello World API using AWS Lambda and API Gateway. This program will allow you to respond with a JSON message containing a greeting and the event data. Let’s dive into the details!

Code

import { APIGatewayProxyEvent, Context, APIGatewayProxyResult } from "aws-lambda"

export async function hello (event: APIGatewayProxyEvent, context: Context): Promise<APIGatewayProxyResult> {
  return {
    statusCode: 200,
    body: JSON.stringify({
      message: 'Hello world',
      input: event,
    })
  }
}

Code Explanation

The provided code snippet demonstrates a basic setup for a hello world API using AWS Lambda and API Gateway. Let’s break down the code and understand each part:

The first line imports the necessary dependencies from the “aws-lambda” package. We are importing the APIGatewayProxyEvent, Context, and APIGatewayProxyResult types.

The next line defines an asynchronous function named “hello”, which takes in two parameters – the event and context. The event parameter represents the data received from the API Gateway, while the context parameter provides runtime information.

Inside the “hello” function, we return a Promise. This Promise resolves to an object with a statusCode and body. The statusCode is set to 200, indicating a successful response, and the body is a JSON string containing a message and the event data.

To test this hello world API, we can deploy it using AWS Lambda and API Gateway. Once deployed, you can make a request to the API endpoint and receive a “Hello world” message along with the input data.

Here’s how the code can be executed:

javascript
import { APIGatewayProxyEvent, Context, APIGatewayProxyResult } from "aws-lambda"

export async function hello (event: APIGatewayProxyEvent, context: Context): Promise<APIGatewayProxyResult> {
  return {
    statusCode: 200,
    body: JSON.stringify({
      message: 'Hello world',
      input: event,
    })
  }
}

Conclusion

In this blog post, we have learned how to create a Hello World API using AWS Lambda and API Gateway. This simple program allows us to respond with a JSON message containing a greeting and the received event data. It can serve as a starting point for building more complex serverless applications using these AWS services. Happy coding!

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