18.2. Introduction to AWS API Gateway
AWS API Gateway is a fully managed service that makes it easy to develop, deploy, and maintain APIs at scale. It acts as a "front door" for applications to access data, business logic, or functionality from your back-end services, such as worker applications, RESTful web services, data servers, or even AWS Lambda functions.
Setting up AWS API Gateway
Configuring API Gateway involves several steps, which include creating an API, defining resources and methods, configuring requests and responses, and configuring backend integrations and authorization.
Creating an API
First, you need to create an API for your service. This can be done in the AWS API Gateway console. You can choose between a REST API or a WebSocket API depending on your application needs. The REST API is more common and is suitable for most uses, while the WebSocket API is more suitable for real-time applications.
Definition of Resources and Methods
After you create the API, you define the resources and methods for that API. Resources are basically URL paths that represent specific objects in your application. For example, in an API for a blogging application, you might have resources like '/posts', '/comments', etc. Methods are the HTTP operations you can perform on these resources, such as GET, POST, PUT, DELETE, etc.
Configuring Requests and Responses
For each method, you need to configure the requests and responses. This includes defining the request parameters, the request headers, and the request body, as well as the response status codes, headers, and response body. API Gateway provides mapping templates to help you transform the format of input and output data.
Configuring Backend Integrations and Authorization
Finally, you need to configure the backend integration for each method. This means defining where API Gateway should route requests and how it should process responses. You can integrate API Gateway with a variety of backend services, including AWS Lambda functions, HTTP/HTTPS web services, or even other AWS services.
In addition, you can also configure authorization for your API. API Gateway supports multiple authorization options, including IAM, Cognito User Pools, and Lambda-based custom authorizers.
Conclusion
Setting up AWS API Gateway involves many steps and options, but the service is designed to be flexible and powerful, allowing you to create highly scalable and secure APIs for your applications. With API Gateway, you can focus on developing your application's business logic, while AWS takes care of the API infrastructure for you.
