Middleware (Basic)

Hey, Philipp here!
I'd like to tell you, that my platform Go Web Examples Courses just launched. Enjoy easy to follow video courses about web devlopment in Go. Make sure to check out the special offer I have for early supporters.
We'll see us over there! :)
Learn more

Middleware (Basic)

This example will show how to create basic logging middleware in Go.

A middleware simply takes a http.HandlerFunc as one of its parameters, wraps it and returns a new http.HandlerFunc for the server to call.

// basic-middleware.go
package main

import (

func logging(f http.HandlerFunc) http.HandlerFunc {
    return func(w http.ResponseWriter, r *http.Request) {
        f(w, r)

func foo(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintln(w, "foo")

func bar(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintln(w, "bar")

func main() {
    http.HandleFunc("/foo", logging(foo))
    http.HandleFunc("/bar", logging(bar))

    http.ListenAndServe(":8080", nil)
$ go run basic-middleware.go
2017/02/10 23:59:34 /foo
2017/02/10 23:59:35 /bar
2017/02/10 23:59:36 /foo?bar

$ curl -s http://localhost:8080/foo
$ curl -s http://localhost:8080/bar
$ curl -s http://localhost:8080/foo?bar