// ## Middleware

package main

import "net/http"
import "fmt"

func hello(w http.ResponseWriter, r *http.Request) {
    w.Header().Set("Content-Type", "text/plain")
    fmt.Fprintln(w, "Hello wrapped world")
}

func wrapMiddleware(f http.HandlerFunc) http.HandlerFunc {
    return func(w http.ResponseWriter, r *http.Request) {
        w.Header().Set("X-Wrapped", "true")
        f(w, r)
    }
}

func main() {
    handler := wrapMiddleware(hello)
    http.HandleFunc("/", handler)
    http.ListenAndServe(":5000", nil)
}