Simple HTTP request dumper

dumper.go

// dumper is a simple HTTP server that dumps requests to stdout
// useful for debugging HTTP clients

package main

import (
	"bytes"
	"flag"
	"io"
	"io/ioutil"
	"log"
	"net/http"
	"net/http/httputil"
	"os"
)

func main() {
	var listen string

	flag.StringVar(&listen, "l", "", "Address to listen to, e.g. 127.0.0.1:3000.")
	flag.Parse()

	if port := os.Getenv("PORT"); port != "" {
		listen = "0.0.0.0:" + port
	}

	if listen == "" {
		listen = "0.0.0.0:3000"
	}

	http.HandleFunc("/", dumper)

	log.Printf("Listening on: %s\n", listen)
	err := http.ListenAndServe(listen, nil)
	if err != nil {
		log.Fatal(err)
	}
}

func dumper(w http.ResponseWriter, r *http.Request) {
	req, err := httputil.DumpRequest(r, true)
	if err != nil {
		req, err = ioutil.ReadAll(r.Body)
		defer r.Body.Close()
		if err != nil {
			http.Error(w, "Crashed", http.StatusInternalServerError)
			return
		}
	}

	log.Println("-----------------")
	log.Println("\n" + string(req))
	io.Copy(w, bytes.NewBuffer(req))
}