中文
devexamples

Composable HTTP Middleware Chain

Compose HTTP handlers through middleware that wrap the next handler, adding logging, recovery, and request identifiers without duplication.

GoResilience

Code

snippet
package main

import (
	"log"
	"net/http"
	"time"
)

type Middleware func(http.Handler) http.Handler

func chain(h http.Handler, middleware ...Middleware) http.Handler {
	for i := len(middleware) - 1; i >= 0; i-- {
		h = middleware[i](h)
	}
	return h
}

func logging(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		start := time.Now()
		next.ServeHTTP(w, r)
		log.Printf("method=%s path=%s duration=%s", r.Method, r.URL.Path, time.Since(start))
	})
}

func recoverPanic(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		defer func() {
			if rec := recover(); rec != nil {
				http.Error(w, "internal error", http.StatusInternalServerError)
			}
		}()
		next.ServeHTTP(w, r)
	})
}

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