Print the HTTP response in Go

post.go

package main

import (
	"bytes"
	"compress/gzip"
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	// "debug/elf"
)

var (
	dbg   = flag.Bool("d", false, "debug mode")
	og    = flag.Bool("g", false, "out gzip mode")
	url   = flag.String("u", "", "specify a post endpoint")
	fname = flag.String("f", "", "specify a post data")
)

func main() {

	flag.Parse()

	json, err := ioutil.ReadFile(*fname)
	if err != nil {
		log.Fatalln(err)
	}

	b, err := compress(json)
	if err != nil {
		log.Fatalln(err)
	}

	gz := b.Bytes()
	r, err := gzip.NewReader(bytes.NewReader(gz))
	if err != nil {
		log.Fatalln(err)
	}

	if *og {
		fmt.Println(string(gz))
	}

	resp, err := http.DefaultClient.Post(*url, "application/json", r)
	if err != nil {
		log.Fatalln(err)
	}
	defer resp.Body.Close()

	if *dbg {
		goDbg(resp)
	}

	if resp.StatusCode < 300 {
		log.Println("StatusCode:", resp.StatusCode)
	} else {
		log.Fatalln("StatusCode:", resp.StatusCode)
	}

}

func compress(s []byte) (b bytes.Buffer, err error) {
	w := gzip.NewWriter(&b)
	if _, err = w.Write(s); err != nil {
		return
	}
	if err = w.Flush(); err != nil {
		return
	}
	if err = w.Close(); err != nil {
		return
	}
	return
}

func goDbg(resp *http.Response) {

	hJoin := func(header http.Header) (ret string) {
		for k, v := range header {
			ret += fmt.Sprintf("%s = %+v</br>", k, v)
		}
		return
	}

	d := "# *Poston DEBUG MODE*\n\n"

	d += "```" + `
__________               __
\______   \____  _______/  |_  ____   ____
 |     ___/  _ \/  ___/\   __\/  _ \ /    \
 |    |  (  <_> )___ \  |  | (  <_> )   |  \
 |____|   \____/____  > |__|  \____/|___|  /
                    \/                   \/
` + "```\n"

	d += "## HTTP\n\n"

	d += "### Request\n\n"

	d += "| Name | Value |\n"
	d += "| ---- | ----- |\n"
	d += fmt.Sprintf("| Method | %s |\n", resp.Request.Method)
	d += fmt.Sprintf("| Host | %s |\n", resp.Request.Host)
	d += fmt.Sprintf("| URL | %s |\n", resp.Request.URL)
	d += fmt.Sprintf("| Proto | %s |\n", resp.Request.Proto)
	d += fmt.Sprintf("| ProtoMajor | %d |\n", resp.Request.ProtoMajor)
	d += fmt.Sprintf("| ProtoMinor | %d |\n", resp.Request.ProtoMinor)
	d += fmt.Sprintf("| Header | %+v |\n", hJoin(resp.Request.Header))
	d += fmt.Sprintf("| Content-Length | %d |\n", resp.Request.ContentLength)
	d += fmt.Sprintf("| TransferEncoding | %+v |\n", resp.Request.TransferEncoding)
	d += fmt.Sprintf("| Close | %v |\n", resp.Request.Close)
	d += fmt.Sprintf("| Form | %+v |\n", resp.Request.Form)
	d += fmt.Sprintf("| PostForm | %+v |\n", resp.Request.PostForm)
	d += fmt.Sprintf("| MultipartForm | %+v |\n", resp.Request.MultipartForm)
	d += fmt.Sprintf("| Trailer | %+v |\n", resp.Request.Trailer)

	reqBody, _ := ioutil.ReadAll(resp.Request.Body)
	d += fmt.Sprintf("| Body | `%s` |\n", string(reqBody))
	d += "\n"

	d += "### Response\n\n"
	d += "| Name | Value |\n"
	d += "| ---- | ----- |\n"
	d += fmt.Sprintf("| Status | %s |\n", resp.Status)
	d += fmt.Sprintf("| Proto | %s |\n", resp.Proto)
	d += fmt.Sprintf("| ProtoMajor | %d |\n", resp.ProtoMajor)
	d += fmt.Sprintf("| ProtoMinor | %d |\n", resp.ProtoMinor)
	d += fmt.Sprintf("| Header | %+v |\n", hJoin(resp.Header))
	d += fmt.Sprintf("| TransferEncoding | %+v |\n", resp.TransferEncoding)
	d += fmt.Sprintf("| Trailer | %+v |\n", resp.Trailer)

	respBody, _ := ioutil.ReadAll(resp.Body)
	d += fmt.Sprintf("| Body | `%s` |\n", string(respBody))

	fmt.Fprintln(os.Stderr, d)
}