aws-rest-api-router

A simple Typescript-based REST API router for use with AWS Lambda functions.

Introduction

A simple way to route your REST API requests and eliminate boilerplate without the need for extensive libraries or configuration. The implementation has a very small footprint.

Provides the following:

• HTTP Method / Path routing
• Access to path parameters
• Body parsing to JSON
• Error handling
• Eliminates boilerplate

Installation

• npm i aws-rest-api-router

Basic usage

This module provides a simple routing mechanism for defining REST APIs within AWS Lambda functions. Codes speaks better than words, so the following Lambda function definition demonstrates how the AwsFunctionRouter can be used to define a group of REST API routes:

import { APIGatewayProxyEvent, APIGatewayProxyResult, Context } from 'aws-lambda';

import { AwsFunctionRouter, AwsRequestContext } from 'aws-rest-api-router';

import { PostRepository } from './PostRepository';

const postRepository = new PostRepository();

// define the router with a basePath which should match the URI for your Lambda's API Gateway
const router = new AwsFunctionRouter<Post>({
    basePath: '/post-service',
    includeCORS: true
  })
  .get('', async (route) => {
    // GET http://my-aws-url/post-service
    return route.okResponse(await postRepository.findAll());
  })
  .get('/:id', async (route, requestContext) => {
    // GET http://my-aws-url/post-service/1
    const id = route.getPathParams(requestContext).id;
    const post = await postRepository.findPostById(id);

    if (!post) {
      return route.errorResponse(StatusCodes.NOT_FOUND);
    }

    return route.okResponse(post);
  })
  .post('', async (route, requestContext) => {
    // POST http://my-aws-url/post-service
    // { "title": "My first post", "content": "This is my first post" }
    const post = await postRepository.save(route.parseBody(requestContext));

    return route.okResponse(post);
  })
  .update('/:id', async (route, requestContext) => {
    // PUT http://my-aws-url/post-service/1
    // { "id": "1", "title": "My first post", "content": "This is my first post" }
    const id = route.getPathParams(requestContext).id;
    const post = await postRepository.findPostById(id);

    if (!post) {
      return route.errorResponse(StatusCodes.NOT_FOUND);
    }

    const postUpdates = route.parseBody(requestContext);

    post.title = postUpdates.title;
    post.content = postUpdates.content;

    postRepository.update(post);

    return route.okResponse(post);
  });

export const lambdaHandler = async (event: APIGatewayProxyEvent, context: Context): Promise<APIGatewayProxyResult> => {
  return await router.handle(new AwsRequestContext(event, context));
};

Note that getting path params relies on using an AWS proxy resource within your API Gateway definition.

You can find a working example in aws-sam-rest-api-starter.