Original Article

Summary

In this article, I explore building a Go REST API using the standard library. I begin by setting up a simple “Hello World” server and then progressively implement CRUD operations for a sample recipe API. You will learn about key components such as http.ServeMux for request routing, creating custom HTTP handlers, and structuring your Go application effectively with separate packages for models and storage interfaces. I also cover implementing generic error handling and detailed handlers for creating, listing, retrieving, updating, and deleting recipes. Furthermore, I demonstrate how to perform integration testing using Go’s httptest package. While the standard library offers a native way to build web applications, I highlight its limitations for complex REST APIs, hinting at the need for third-party frameworks, which will be the focus of the next articles in this series.

Key Concepts

• Go Standard Library for Web Development: How Go’s built-in net/http package can be used to create HTTP servers and handle requests.
• HTTP Server and Routing (http.ServeMux): Understanding how to instantiate a request multiplexer and register URI patterns to dispatch requests to specific handlers.
• HTTP Handlers (http.Handler Interface): Implementing the ServeHTTP method within a struct to process incoming HTTP requests and generate responses.
• REST API Design Principles: Applying CRUD operations (Create, Read, Update, Delete) to a resource (/recipes).
• Application Structuring: Organizing Go code into packages (e.g., recipes for business logic and data models) and using interfaces for data storage abstraction.
• JSON Handling: Encoding and decoding JSON payloads using json.NewDecoder and json.Marshal.
• URL Slugification: Using external packages like gosimple/slug to create URL-friendly resource IDs.
• Error Handling: Implementing generic error handlers for InternalServerError and NotFound responses.
• Integration Testing (httptest): Writing comprehensive tests for REST API endpoints using Go’s httptest package.

References

• Kat Zien’s GopherCon 2018 talk about hexagonal architecture
• GitHub repository for the code samples from the article
• gosimple/slug GitHub Repository
• stretchr/testify GitHub Repository