Lambda-restful-util NPM

Lambda RESTful Utility

A simple package to offer some quick wins for API devs!

Lambda RESTful Utility
- What is this?
- Documentation
Setup
- Using this product
  - Using the validateAndParseRequestHeaders or validateAndParseRequestBody
  - Using the withStatusCode function
    - Adding a formatter
- Testing
Contributors ✨

What is this?

A simple npm package to make API dev easy on AWS Lambda.

Documentation

We've included a docs folder with a Best Practices document. Please review this document as well as our CONTRIBUTING document before getting started with development contributions.

Setup

To contribute to development you must have NodeJS installed on your system. Additionally this project uses yarn instead of npm. Please ensure you have yarn installed globally. After you do, simply run yarn install from the project root to install all dependencies.

Using this product

To use this package in your work simply run npm install lambda-restful-util or yarn add lambda-restful-util then include it in your code as with any other dependency.

Using the `validateAndParseRequestHeaders` or `validateAndParseRequestBody`

Both the validateAndParseRequestHeaders and validateAndParseRequestBody operate very similarly. Simply pass the event from API Gateway and both return a truthy object you can use if they're valid. For example:

exports.handler = async (event: APIGatewayProxyEvent) => {
  const requestHeaders = utils.validateAndParseRequestHeaders(event)
  const requestBody = utils.validateAndParseRequestBody(event)

  if (requestHeaders.Authorization && requestBody) {
    const token = requestHeaders.Authorization.replace('Bearer ', '')
    ...
  }
  ...
}

Using the `withStatusCode` function

To use the withStatusCode you only need to specify the response code and the request origin (for CORS). An example of a simple 200 response is as follows:

import util from 'lambda-restful-util'
...
const ok = util.withStatusCode(200, 'http://localhost:8080')

exports.handler = async (event: APIGatewayProxyEvent) => {
  ...
  return ok('Hey Buddy!')
}

For convenience this package includes every HTTP response for reference. To use the HttpStatusCode enum you can modify the above example by modifying the var: const ok = util.withStatusCode(util.HttpStatusCode.OK, 'http://localhost:8080).

Adding a formatter

In addition to the HttpStatusCode you can pass a formatting function as an optional argument to withStatusCode. To add JSON.stringify simply modify the var again: const ok = util.withStatusCode(util.HttpStatusCode.OK, 'http://localhost:8080, JSON.stringify).

If you know your response is going to be JSON this will simplify converting your Object to JSON. For example:

...
const ok = util.withStatusCode(util.HttpStatusCode.OK, 'http://localhost:8080, JSON.stringify)
...
const res = {
  name: 'Homer Simpson'
  employer: 'Springfield Power Plant'
}
...
return ok(res)

The above will correctly return a JSON string as the 200 HTTP response to your API request. Consequently if you send return ok('test') that will also return a JSON 200 response. If you do not want to return JSON simply don't pass a formatting argument when declaring the ok response.