xmate

xmate is a Go library designed to enhance the standard net/http package by providing convenient functionality specifically focused on error handling in HTTP handlers.

The name "xmate" signifies "friend of mux," highlighting its role in simplifying the creation of HTTP handlers. While it doesn't enhance routing in the standard library, xmate makes writing handlers less verbose, allowing developers to focus on building applications more efficiently and with less boilerplate code.

Features

• Less Boilerplate Code: Streamline your HTTP handler development with reduced boilerplate, allowing you to write cleaner and more maintainable code.

• Error Handling: Convert HTTP handlers that return errors into standard net/http handlers, simplifying error management and ensuring consistent responses.

• Multiple Error Handlers: Easily define different error handlers for various types of HTTP endpoints, providing tailored responses based on the specific context of each request.

• Ease of Use: Enjoy a user-friendly experience that simplifies the process of creating and managing HTTP handlers, making it accessible for developers of all skill levels.

Usage

Handlers

In the simplest scenario, wrap HTTP handlers and functional HTTP handlers with xmate.Handle and xmate.HandleFunc, respectively.

Note

These top-level functions convert the given HTTP handler into the standard http.Handler or http.HandlerFunc (depending on the function used) by handling its error.

package main

import (
	"log"
	"net/http"

	"github.com/utilyre/xmate/v3"
)

func main() {
	mux := http.NewServeMux()

	sh := statusHandler{
		Brief:       "healthy",
		Description: "service is ready to accept connections",
	}

	mux.HandleFunc("GET /{$}", xmate.HandleFunc(handleHelloWorld))
	mux.Handle("GET /status", xmate.Handle(sh))

	log.Fatal(http.ListenAndServe(":8080", mux))
}

func handleHelloWorld(w http.ResponseWriter, r *http.Request) error {
	return xmate.WriteText(w, http.StatusOK, "hello world")
}

type statusHandler struct {
	Brief       string
	Description string
}

func (sh statusHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) error {
	return xmate.WriteJSON(w, http.StatusOK, map[string]any{
		"brief":       sh.Brief,
		"description": sh.Description,
	})
}

Middlewares

Instead of wrapping the middleware itself, wrap the function returned from it with xmate.HandleFunc.

package main

import (
	"log"
	"net/http"

	"github.com/go-chi/chi/v5"
	"github.com/utilyre/xmate/v3"
)

func main() {
	r := chi.NewRouter()

	r.Use(AssertJSON)

	// ...

	log.Fatal(http.ListenAndServe(":8080", mux))
}

func AssertJSON(next http.Handler) http.Handler {
	return xmate.HandleFunc(func(w http.ResponseWriter, r *http.Request) error {
		if r.Header.Get("Content-Type") != "application/json" {
			return xmate.WriteText(w, http.StatusBadRequest, "Unsupported content type")
		}

		next.ServeHTTP(w, r)
		return nil
	})
}

Multiple error handlers

Error handling may need to vary in different contexts. That's why you can always instantiate a non-default error handler and use it on your HTTP handlers.

package main

import (
	"log"
	"net/http"

	"github.com/utilyre/xmate/v3"
)

func main() {
	mux := http.NewServeMux()

	xmate.SetDefault(handleError) // changes the error handler used by top-level functions
	apiEH := xmate.ErrorHandler(handleAPIError) // custom handler for API routes

	mux.HandleFunc("GET /signup", xmate.HandleFunc(handleSignUpPage))
	mux.HandleFunc("GET /login", xmate.HandleFunc(handleLoginPage))

	mux.Handle("GET /api/v1/auth/signup", apiEH.HandleFunc(handleSignUp))
	mux.Handle("GET /api/v1/auth/login", apiEH.HandleFunc(handleLogin))

	log.Fatal(http.ListenAndServe(":8080", mux))
}

func handleError(w http.ResponseWriter, r *http.Request, err error) {
	log.Printf("Failed to %s %s: %v", r.Method, r.URL.Path, err)
	_ = xmate.WriteText(w, http.StatusInternalServerError, "Internal Server Error")
}

func handleAPIError(w http.ResponseWriter, r *http.Request, err error) {
	log.Printf("Failed to %s %s: %v", r.Method, r.URL.Path, err)
	_ = xmate.WriteJSON(w, http.StatusInternalServerError, map[string]any{
		"message": "Internal Server Error",
	})
}