aws-cognito-auth-lambda-nodejs

CognitoAuthFunction, which contains Node.js code that can be deployed to AWS Lambda, implements the “authenticate” part of the Amazon Cognito service.

Why Node.js

Cognito User Pools is in beta release currently and the authentication APIs are not part of the server side SDKs as of now. Recommendation is to use one of the client side SDKs (Android, iOS or JavaScript). The authentication APIs will be included in the server side SDKs with general availability release of the feature.” - Reference (Software Engineer at AWS, 19-Jun-2016)

Idea: Using amazon-cognito-identity-js in a Node.js Lambda function

The plan is to implement a Node.js Lambda function with the JavaScript lib amazon-cognito-identity-js.

Since some dependencies (e.g. navigator) are client side code and do not work with Node.js (see reference, we need to hack the code a little bit.

1. Download amazon-cognito-identity.min.js and keep a copy in this repo.
2. Replace DeviceName: navigator.userAgent to DeviceName: CognitoAuthFunction-Custom ( navigator.userAgent is used to return browser or mobile device information; e.g. “Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36””)

Deploy to AWS Lambda

Creating the deployment package

Create CognitoAuthFunction.zip containing

1. `CognitoAuthFunction.js`
2. `amazon-cognito-identity.min.js`
3. `node_modules/*`

Run from Command Line

1. Install npm and nodejs

2. Build

    npm install aws-sdk sjcl jsbn
   

3. Run/test

   1. Uncomment the last line in CognitoAuthFunction.js
   2. Change mock_event
   3. Run node CognitoAuthFunction.js