How to Create an API Proxy Gateway with AWS HTTP API

As a full-stack developer, you know that securely integrating various backend services and APIs is crucial for building robust applications. Direct communication between clients and backend services can expose sensitive information and complicate your architecture. That‘s where an API proxy gateway comes in.

In this article, we‘ll take an in-depth look at how to simplify and secure service integration by creating an API proxy gateway using AWS HTTP API. Whether you‘re new to API gateways or looking to level up your skills, this guide will walk you through the process step-by-step. Let‘s dive in!

Understanding API Proxy Gateways

Before we get into the nitty-gritty of implementation, let‘s make sure we‘re on the same page about what an API proxy gateway is and why it‘s useful.

An API proxy gateway acts as an intermediary between clients (like web or mobile apps) and backend services. Instead of allowing clients to directly communicate with your backend APIs, the client sends requests to the API gateway. The gateway then forwards those requests to the appropriate backend service and returns the response back to the client.

This offers several benefits:

• Security: The API gateway can handle authentication and authorization, so your backend services don‘t have to. You can secure access to your APIs in one place.
• Simplicity: Clients only need to know about and communicate with the API gateway, not each individual backend service. This simplifies client code and allows you to change your backend architecture without impacting clients.
• Performance: API gateways can cache responses, throttle requests, and optimize network communication, improving overall performance.

With that context in mind, let‘s see how we can use AWS HTTP API to create our own API proxy gateway.

AWS HTTP API vs REST API

When creating an API gateway on AWS, you have two options: HTTP API and REST API. So what‘s the difference?

REST API offers more granular control and flexibility. You can define complex request/response transformations, use custom authorizers, and set up detailed access control. This power comes at the cost of higher complexity and cost.

HTTP API, on the other hand, is simpler and more streamlined. It supports basic features like JWT authorization and CORS configuration, but with less customization than REST API. The benefit is that HTTP API is cheaper and easier to use for many common API use cases.

Unless you need the advanced features of REST API, HTTP API is often the better choice – especially for creating an API proxy gateway. It allows us to define our routes, secure them, and proxy requests to our backend APIs, which is exactly what we need. Plus, the cost savings can be significant.

With that in mind, let‘s walk through creating an HTTP API proxy gateway step-by-step.

Step 1: Define Your API Gateway Routes

The first step is defining the routes for your API gateway. Routes determine what requests your gateway will accept and how they map to your backend APIs.

In the AWS API Gateway console, navigate to your HTTP API and choose "Routes". Click "Create" to define a new route.

We‘ll use a simple example route for getting information about a music track:

GET /tracks/{id}

This route accepts GET requests to the /tracks/{id} path, where {id} is a path parameter that will be passed to our backend API.

You can define your route paths to match the structure of your backend API. This allows your API gateway to provide a clean, consistent interface while still mapping to your actual backend services.

Step 2: Configure an HTTP Integration

Next, we need to create an integration that tells our gateway where to send requests that match our route. Since we‘re creating a proxy to an HTTP backend API, we‘ll use an HTTP integration.

In the API Gateway console, select your route and choose "Attach integration". Select "HTTP URI" as the integration type and enter the base URL of your backend API.

For our music track example, let‘s say our backend API has the following structure:

GET https://api.myapp.com/v1/tracks?trackId=1234

We would configure our HTTP integration with a base URL of https://api.myapp.com. We‘ll see how to map our route‘s path parameter to the query parameter in the next step.

By creating an HTTP integration, we‘re telling our API gateway where to send requests. But we still need to make sure it sends the right data…

Step 3: Map Request Parameters

Our route accepts a {id} path parameter, but our backend API expects a trackId query parameter. We need to map these together using API Gateway‘s parameter mapping.

In the Integration Request configuration, find the "Parameter Mapping" section. Here, we can define how parameters from the incoming request are mapped to the integration request.

To map our {id} path parameter to the trackId query string parameter, we‘ll add the following mapping:

• Query string name: trackId
• Mapped from: $request.path.id

This tells API Gateway to take the value of the {id} path parameter from the incoming request and send it as the trackId query string parameter in the integration request to our backend API.

You can map any incoming request data to integration request parameters, including headers, query strings, and even the request body. This allows you to transform the request to match what your backend API expects.

Step 4: Secure Your API with JWT Authorization

We have a functioning API proxy gateway now, but it‘s not very secure. Anyone could send requests to our backend API!

To secure our gateway, we can use JWT (JSON Web Token) authorization. JWT allows us to authorize requests based on a cryptographically signed token included in the request headers.

In the API Gateway console, navigate to "Authorization" and choose "Create and attach an authorizer". Select "JWT" as the authorizer type.

You‘ll need to provide the issuer URL, audience, and token source for your JWT configuration. These values depend on your specific JWT setup, but here‘s an example:

• Issuer URL: https://my-app.us.auth0.com/
• Audience: https://api.myapp.com
• Token source: $request.header.Authorization

With the JWT authorizer configured, API Gateway will check for a valid JWT in the specified header before allowing the request to reach your integration. This ensures only authorized clients can access your backend API.

Testing Your API Gateway

Let‘s test out our new API proxy gateway! We can use a tool like cURL or Postman to send a request to our gateway endpoint.

Assuming we‘ve deployed our API and have the invoke URL, we can send a GET request to the /tracks/{id} route:

curl -H "Authorization: Bearer MY_JWT_TOKEN" https://my-api-gateway-url.com/tracks/1234

If everything is set up correctly, API Gateway will validate the JWT token, map the path parameter to the query string, forward the request to our backend API, and return the response back to us. Magic!

Best Practices and Considerations

Congratulations, you‘ve created a secure API proxy gateway using AWS HTTP API! As you plan and build your API gateway, keep these best practices in mind:

• Use HTTPS for all API communication to encrypt data in transit
• Implement proper authentication and authorization for your APIs
• Set up rate limiting and throttling to protect your backend services
• Monitor API usage and errors with tools like AWS CloudWatch
• Cache API responses when appropriate to improve performance
• Document your API routes and expected request/response formats

Also remember that while AWS HTTP API is a great choice for many use cases, it‘s not the only option. For more advanced configuration and control, consider using AWS REST API or an API management platform like Kong or Apigee.

Mastering API Gateway Development

Creating an API proxy gateway is a fundamental skill for any full-stack developer working with microservices and serverless architectures. By leveraging tools like AWS HTTP API, you can build secure, performant gateways to simplify and standardize communication between clients and backend services.

As you continue your API gateway journey, dive deeper into topics like request/response transformation, custom authorizers, error handling, and API versioning. The more you learn about API gateways, the more powerful your application architectures can become.

I hope this in-depth guide has given you a solid foundation for creating API proxy gateways with AWS HTTP API. Remember, practice makes perfect – the more you build and deploy API gateways, the more comfortable and proficient you‘ll become.

Now go forth and proxy! Your backend services will thank you.