# Go ServeMux REST API

# Go ServeMux REST API Development Guide

## Introduction
This guide provides a detailed approach to building RESTful APIs using Go's `net/http` package and the new `ServeMux` introduced in Go 1.22. It covers best practices, error handling, input validation, concurrency, middleware, rate limiting, authentication, logging, and testing.

## Key Features
- **RESTful API Design**: Follow REST principles for resource naming, HTTP methods, and status codes.
- **Error Handling**: Implement custom error types and use appropriate HTTP status codes.
- **Input Validation**: Validate API inputs to ensure data integrity and security.
- **Concurrency**: Utilize Go's goroutines and channels for performance optimization.
- **Middleware**: Implement middleware for logging, authentication, and other cross-cutting concerns.
- **Rate Limiting**: Protect your API from abuse with rate limiting.
- **Authentication**: Implement secure authentication and authorization mechanisms.
- **Logging**: Use Go's `log` package or a custom logger for structured logging.
- **Testing**: Write unit tests using Go's `testing` package to ensure API reliability.

## Getting Started
1. **Install Go**: Ensure you have Go 1.22 or newer installed.
2. **Set Up Your Project**: Create a new Go module and import the necessary packages.
3. **Define Your API Structure**: Plan your API endpoints, data models, and data flow.

## Example API Structure
```go
package main

import (
	"encoding/json"
	"log"
	"net/http"
)

type User struct {
	ID    int    `json:"id"`
	Name  string `json:"name"`
	Email string `json:"email"`
}

func main() {
	mux := http.NewServeMux()
	mux.HandleFunc("/users", usersHandler)
	log.Fatal(http.ListenAndServe(":8080", mux))
}

func usersHandler(w http.ResponseWriter, r *http.Request) {
	users := []User{{
		ID:    1,
		Name:  "John Doe",
		Email: "[email protected]",
	}}
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(users)
}
```

## Best Practices
- **Use `const` for Constants**: Prefer `const` over `let` for variable declarations.
- **CamelCase Naming**: Use camelCase for variable and function names, and PascalCase for component names.
- **Proper Logging**: Implement structured logging for better traceability.
- **Middleware**: Use middleware for common tasks like logging, authentication, and rate limiting.
- **Testing**: Write comprehensive unit tests to cover all API endpoints.

## Conclusion
By following this guide, you can build robust, secure, and scalable REST APIs using Go's `net/http` package and the new `ServeMux`. Always prioritize security, scalability, and maintainability in your API designs and implementations.