aws-lambda-auth

The library allows you to write lambda custom authorizers easier.

Installation

npm install aws-lambda-auth

Using

You have to override handler (AuthHandler) that will generate a policy depends on your conditions.

Let's do it first of all. Minimal case can look so:

const {AuthHandler, utils} = require('aws-lambda-auth');

class MyHandler extends AuthHandler {
  get name() {
    // The handler have to be named
    return 'I will see this name in logs';
  }

  get policyArn() {
    // You have to restrict access to certain ARN
    return utils.buildExecutionApiArn({path: 'users/*'});
  }
}

Then you can use this handler in auth flow:

const {SingleAuthFlow, lambda} = require('aws-lambda-auth');

export default lambda(async ({lambdaEvent, lambdaContext}) => {
  // In real life you will extract token from header or context
  const jwtToken = lambdaEvent.headers.Authorization;
  // You have to decode passed token and pass payload to flow
  // so that you can compare it, check access, etc.
  const tokenPayload = decode(jwtToken);

  return new SingleAuthFlow({lambdaEvent, lambdaContext, tokenPayload})
    .useHandler(MyHandler)
    .createPolicy();
});

That's all. You can build a bundle and deploy to the AWS.

Single flow

Use this flow when there is only one type of user.

look at the example

Multiple flow

Use this flow when there are a few types of users and you want to handle each independently.

look at the example

Middlewares

Middlewares allow you to extend lambda context so that you will have a chance to use in in your handlers.

look at the example

Utils

buildExecutionApiArn

Allows you to build ARN.

Params and default:

• region = '*'
• acountId = '*'
• appId = '*'
• stage = '*'
• method = '*'
• path = '*'