httperr

httperr is a minimal Go library that extends the standard net/http package with * explicit error handling* for HTTP handlers.

It lets you write HTTP handlers that return errors directly, while providing a simple mechanism to control how those errors are rendered to the client.

---

✨ Features

• Drop-in compatible with net/http
• Handlers can return error instead of writing directly
• Customizable error writers (plain text or JSON)
• Optional HTTP status embedding with WithStatus
• Lightweight wrapper types with no external dependencies

---

🚀 Installation

go get github.com/jorenkoyen/httperr

---

🧩 Basic Example

package main

import (
	"net/http"

	"github.com/jorenkoyen/httperr"
)

func handler(w http.ResponseWriter, r *http.Request) error {
	name := r.URL.Query().Get("name")
	if name == "" {
		return httperr.New("missing 'name' parameter", http.StatusBadRequest)
	}
	_, _ = w.Write([]byte("Hello, " + name + "!"))
	return nil
}

func main() {
	http.HandleFunc("/", httperr.StdHandler(handler))
	http.ListenAndServe(":8080", nil)
}

If the request is missing a name query parameter, the client receives:

HTTP/1.1 400 Bad Request
Content-Type: text/plain; charset=utf-8
X-Content-Type-Options: nosniff

missing 'name' parameter

---

💡 Custom Error Writers

You can provide your own ErrorWriter to control how errors are written to the response.

JSON Example

package main

import (
	"net/http"

	"github.com/jorenkoyen/httperr"
)

func handler(w http.ResponseWriter, r *http.Request) error {
	return httperr.New("invalid parameters", http.StatusBadRequest)
}

func main() {
	http.HandleFunc("/hello", httperr.StdHandlerWithError(handler, httperr.JsonErrorWriter))
}

Produces:

{
  "error": "missing 'name' parameter",
  "status": 400
}

---

🧱 Using ErrorServeMux

ErrorServeMux behaves like a regular http.ServeMux but supports ErrorHandlerFunc.

package main

import (
	"net/http"

	"github.com/jorenkoyen/httperr"
)

func main() {
	mux := httperr.NewErrorServeMux(httperr.JsonErrorWriter)

	mux.HandleFunc("/hello", func(w http.ResponseWriter, r *http.Request) error {
		return httperr.New("something went wrong", http.StatusInternalServerError)
	})

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