http_debug_roundtripper.go

package main

import (
	"bufio"
	"bytes"
	"fmt"
	"net/http"
	"net/http/httputil"
	"os"
)

type DebugTransport struct {
	current *http.Request
}

func (t *DebugTransport) RoundTrip(req *http.Request) (*http.Response, error) {
	var scanner *bufio.Scanner

	t.current = req

	resp, err := http.DefaultTransport.RoundTrip(req)

	dump, err := httputil.DumpRequestOut(req, true)
	if err != nil {
		// Don't bother handling dumping error, it's not vital to the request workflow
		return resp, err
	}
	scanner = bufio.NewScanner(bytes.NewBuffer(dump))
	for scanner.Scan() {
		fmt.Fprintf(os.Stderr, "> %s\n", scanner.Text())
	}
	if err := scanner.Err(); err != nil {
		return resp, err
	}

	fmt.Fprintln(os.Stderr, "---")

	dump, err = httputil.DumpResponse(resp, true)
	if err != nil {
		// Don't bother handling dumping error, it's not vital to the request workflow
		return resp, err
	}
	scanner = bufio.NewScanner(bytes.NewBuffer(dump))
	for scanner.Scan() {
		fmt.Fprintf(os.Stderr, "< %s\n", scanner.Text())
	}
	if err := scanner.Err(); err != nil {
		return resp, err
	}

	return resp, err
}