Custom authentication flow

If you are not using Express.js or if you want to write your custom authentication and error handling logic, this module exports some helpers you can use to achieve such goal.

Validating tokens

To write your custom authentication logic, you can make use of the JWTValidator class.

IMPORTANT: You must instantiate a validator only once and then use it to validate the tokens in each request. To be initialized, validators make an http request to the Cognito's JWKS endpoint. So if you instantiate a new validator for each request, you will add unnecessary overhead due to the initialization process.

'use strict';

const { JWTValidator } = require('aws-cognito-express');

const jwtValidator = new JWTValidator({
  region: 'us-east-2',
  userPoolId: 'us-east-2_6IfDT7ZUq',
  tokenUse: ['id', 'access'],
  audience: ['55plsi2cl0o267lfusmgaf67pf']
});

const token = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...';

jwtValidator.validate(token)
  .then(jwtPayload => console.log(jwtPayload))
  .catch(err => console.error(err));

Handling validation errors

This module exports a convenient function isJWTValidatorError that you can use in your custom error handlers to verify if the error was thrown by the JWT validator.

'use strict';

const { JWTValidator, isJWTValidatorError } = require('aws-cognito-express');

const jwtValidator = new JWTValidator({
  region: 'us-east-2',
  userPoolId: 'us-east-2_6IfDT7ZUq',
  tokenUse: ['id', 'access'],
  audience: ['55plsi2cl0o267lfusmgaf67pf']
});

const token = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...';

const err = new Error('Unexpected error');
isJWTValidatorError(err);
// => false

jwtValidator.validate(token)
  .catch((err) => {
    isJWTValidatorError(err);
    // => true
  });