AWS API Gateway Handler

This repository provides a bootstrapper when creating Node.js Lambda functions, to be used as API Gateway handlers.

Getting started

Get started quickly by following the instructions below.

Installation

Use NPM to install this library into your project:

npm install --save @0to10/aws-api-gateway-handler

Setup

Quick setup:

'use strict';

import http from 'http';

import {Application, Request, Response} from '@0to10/aws-api-gateway-handler';

const application: Application = new Application();

// Any application logic, such as registering routes, may be added after instantiation
application.express.get('/test', (
    _request: Request,
    response: Response,
): void => {
    response.status(200).json({
        message: 'Test was a success!',
    });
});

application.listen(80);

// Expose the handler
export const handler = application.handler.bind(application);

Configuration

You may optionally pass in configuration options to the constructor of the Application class, as follows:

import {Application, Configuration} from '@0to10/aws-api-gateway-handler';

const config: Configuration = {
    disable: [
        'x-powered-by',
        'etag',
    ],
    cors: false,
};

const application: Application = new Application(config);

Below is an overview of the configuration options available.

| Option | Type | Default | |-----------|------------|--------------------| | disable | string[] | ['x-powered-by'] | | cors | boolean | true |

A full list of available features that may be disabled (via the disable option) is available on the Express.js website.

Events

Various events are emitted within this library, you may attach listeners to the events by following the example below:

// Application bootstrap omitted

application.events.on('listening', (port: number): void => {
    console.log('Listening on port ' + port);
});

Below is an overview of the available events.

| Event | Arguments | Notes | |---------------|---------------------------------|------------------------------------------------------| | listening | (port: number) | Emitted when the server is ready to process requests | | event | (event: APIGatewayProxyEvent) | Emitted every time a request is handled | | debug:error | (error: any) | Emitted whenever the error handler handles an error |

AWS Cognito

This library exposes a cognito object on the Request object of Express to make Cognito user data easily accessible. See the type below.

type CognitoRequestInformation = {
    identityId?: string;
    userPoolId?: string;
    username?: string;
}

Note that request.cognito will always be an object, but any of the values may be undefined.

// Application bootstrap omitted

application.express.get('/test', (
    request: express.Request,
    _response: express.Response,
): void => {
    console.info('Cognito user:', {
        cognitoIdentityId: request.cognito.identityId,
        cognitoUserPoolId: request.cognito.userPoolId,
        cognitoUsername: request.cognito.username,
    });
});