AWS APIGatewayv2 Authorizers

AWS CDK v1 has reached End-of-Support on 2023-06-01. This package is no longer being updated, and users should migrate to AWS CDK v2.

For more information on how to migrate, see the Migrating to AWS CDK v2 guide.

Table of Contents

• Introduction
• HTTP APIs
  • Default Authorization
  • Route Authorization
  • JWT Authorizers
    • User Pool Authorizer
  • Lambda Authorizers
  • IAM Authorizers
• WebSocket APIs
  • Lambda Authorizer

Introduction

API Gateway supports multiple mechanisms for controlling and managing access to your HTTP API. They are mainly classified into Lambda Authorizers, JWT authorizers and standard AWS IAM roles and policies. More information is available at Controlling and managing access to an HTTP API.

HTTP APIs

Access control for Http Apis is managed by restricting which routes can be invoked via.

Authorizers and scopes can either be applied to the api, or specifically for each route.

Default Authorization

When using default authorization, all routes of the api will inherit the configuration.

In the example below, all routes will require the manage:books scope present in order to invoke the integration.

import { HttpJwtAuthorizer } from '@aws-cdk/aws-apigatewayv2-authorizers';

const issuer = 'https://test.us.auth0.com';
const authorizer = new HttpJwtAuthorizer('DefaultAuthorizer', issuer, {
  jwtAudience: ['3131231'],
});

const api = new apigwv2.HttpApi(this, 'HttpApi', {
  defaultAuthorizer: authorizer,
  defaultAuthorizationScopes: ['manage:books'],
});

Route Authorization

Authorization can also configured for each Route. When a route authorization is configured, it takes precedence over default authorization.

The example below showcases default authorization, along with route authorization. It also shows how to remove authorization entirely for a route.

• GET /books and GET /books/{id} use the default authorizer settings on the api
• POST /books will require the [write:books] scope
• POST /login removes the default authorizer (unauthenticated route)

import { HttpJwtAuthorizer } from '@aws-cdk/aws-apigatewayv2-authorizers';
import { HttpUrlIntegration } from '@aws-cdk/aws-apigatewayv2-integrations';

const issuer = 'https://test.us.auth0.com';
const authorizer = new HttpJwtAuthorizer('DefaultAuthorizer', issuer, {
  jwtAudience: ['3131231'],
});

const api = new apigwv2.HttpApi(this, 'HttpApi', {
  defaultAuthorizer: authorizer,
  defaultAuthorizationScopes: ['read:books'],
});

api.addRoutes({
  integration: new HttpUrlIntegration('BooksIntegration', 'https://get-books-proxy.myproxy.internal'),
  path: '/books',
  methods: [apigwv2.HttpMethod.GET],
});

api.addRoutes({
  integration: new HttpUrlIntegration('BooksIdIntegration', 'https://get-books-proxy.myproxy.internal'),
  path: '/books/{id}',
  methods: [apigwv2.HttpMethod.GET],
});

api.addRoutes({
  integration: new HttpUrlIntegration('BooksIntegration', 'https://get-books-proxy.myproxy.internal'),
  path: '/books',
  methods: [apigwv2.HttpMethod.POST],
  authorizationScopes: ['write:books']
});

api.addRoutes({
  integration: new HttpUrlIntegration('LoginIntegration', 'https://get-books-proxy.myproxy.internal'),
  path: '/login',
  methods: [apigwv2.HttpMethod.POST],
  authorizer: new apigwv2.HttpNoneAuthorizer(),
});

JWT Authorizers

JWT authorizers allow the use of JSON Web Tokens (JWTs) as part of OpenID Connect and OAuth 2.0 frameworks to allow and restrict clients from accessing HTTP APIs.

When configured, API Gateway validates the JWT submitted by the client, and allows or denies access based on its content.

The location of the token is defined by the identitySource which defaults to the http Authorization header. However it also supports a number of other options. It then decodes the JWT and validates the signature and claims, against the options defined in the authorizer and route (scopes). For more information check the JWT Authorizer documentation.

Clients that fail authorization are presented with either 2 responses:

• 401 - Unauthorized - When the JWT validation fails
• 403 - Forbidden - When the JWT validation is successful but the required scopes are not met

import { HttpJwtAuthorizer } from '@aws-cdk/aws-apigatewayv2-authorizers';
import { HttpUrlIntegration } from '@aws-cdk/aws-apigatewayv2-integrations';

const issuer = 'https://test.us.auth0.com';
const authorizer = new HttpJwtAuthorizer('BooksAuthorizer', issuer, {
  jwtAudience: ['3131231'],
});

const api = new apigwv2.HttpApi(this, 'HttpApi');

api.addRoutes({
  integration: new HttpUrlIntegration('BooksIntegration', 'https://get-books-proxy.myproxy.internal'),
  path: '/books',
  authorizer,
});

User Pool Authorizer

User Pool Authorizer is a type of JWT Authorizer that uses a Cognito user pool and app client to control who can access your Api. After a successful authorization from the app client, the generated access token will be used as the JWT.

Clients accessing an API that uses a user pool authorizer must first sign in to a user pool and obtain an identity or access token. They must then use this token in the specified identitySource for the API call. More information is available at using Amazon Cognito user pools as authorizer.

import * as cognito from '@aws-cdk/aws-cognito';
import { HttpUserPoolAuthorizer } from '@aws-cdk/aws-apigatewayv2-authorizers';
import { HttpUrlIntegration } from '@aws-cdk/aws-apigatewayv2-integrations';

const userPool = new cognito.UserPool(this, 'UserPool');

const authorizer = new HttpUserPoolAuthorizer('BooksAuthorizer', userPool);

const api = new apigwv2.HttpApi(this, 'HttpApi');

api.addRoutes({
  integration: new HttpUrlIntegration('BooksIntegration', 'https://get-books-proxy.myproxy.internal'),
  path: '/books',
  authorizer,
});

Lambda Authorizers

Lambda authorizers use a Lambda function to control access to your HTTP API. When a client calls your API, API Gateway invokes your Lambda function and uses the response to determine whether the client can access your API.

Lambda authorizers depending on their response, fall into either two types - Simple or IAM. You can learn about differences here.

import { HttpLambdaAuthorizer, HttpLambdaResponseType } from '@aws-cdk/aws-apigatewayv2-authorizers';
import { HttpUrlIntegration } from '@aws-cdk/aws-apigatewayv2-integrations';

// This function handles your auth logic
declare const authHandler: lambda.Function;

const authorizer = new HttpLambdaAuthorizer('BooksAuthorizer', authHandler, {
  responseTypes: [HttpLambdaResponseType.SIMPLE], // Define if returns simple and/or iam response
});

const api = new apigwv2.HttpApi(this, 'HttpApi');

api.addRoutes({
  integration: new HttpUrlIntegration('BooksIntegration', 'https://get-books-proxy.myproxy.internal'),
  path: '/books',
  authorizer,
});

IAM Authorizers

API Gateway supports IAM via the included HttpIamAuthorizer and grant syntax:

import { HttpIamAuthorizer } from '@aws-cdk/aws-apigatewayv2-authorizers';
import { HttpUrlIntegration } from '@aws-cdk/aws-apigatewayv2-integrations';

declare const principal: iam.AnyPrincipal;

const authorizer = new HttpIamAuthorizer();

const httpApi = new apigwv2.HttpApi(this, 'HttpApi', {
  defaultAuthorizer: authorizer,
});

const routes = httpApi.addRoutes({
  integration: new HttpUrlIntegration('BooksIntegration', 'https://get-books-proxy.myproxy.internal'),
  path: '/books/{book}',
});

routes[0].grantInvoke(principal);

WebSocket APIs

You can set an authorizer to your WebSocket API's $connect route to control access to your API.

Lambda Authorizer

Lambda authorizers use a Lambda function to control access to your WebSocket API. When a client connects to your API, API Gateway invokes your Lambda function and uses the response to determine whether the client can access your API.

import { WebSocketLambdaAuthorizer } from '@aws-cdk/aws-apigatewayv2-authorizers';
import { WebSocketLambdaIntegration } from '@aws-cdk/aws-apigatewayv2-integrations';

// This function handles your auth logic
declare const authHandler: lambda.Function;

// This function handles your WebSocket requests
declare const handler: lambda.Function;

const authorizer = new WebSocketLambdaAuthorizer('Authorizer', authHandler);

const integration = new WebSocketLambdaIntegration(
  'Integration',
  handler,
);

new apigwv2.WebSocketApi(this, 'WebSocketApi', {
  connectRouteOptions: {
    integration,
    authorizer,
  },
});