Replay an HTTP request from a txt file in golang

replay-http.go

package main

// src: https://gist.github.com/fyxme/25fb9bc7a3c76997ec51da30d3f3e4dd

import (
        "bufio"
        "flag"
        "fmt"
        "io/ioutil"
        "net/http"
        "net/http/httputil"
        "os"
        "strings"
)

func readRequest(raw, scheme string) (*http.Request, error) {
        r, err := http.ReadRequest(bufio.NewReader(strings.NewReader(raw)))
        if err != nil { return nil, err }
        r.RequestURI, r.URL.Scheme, r.URL.Host = "", scheme, r.Host
        return r, nil
}

func main() {

        var infile string
        flag.StringVar(&infile, "in", "", "(Input file with HTTP request to replay)")
        flag.Parse()

        if infile == "" {
                fmt.Println("[!] Missing input file")
                flag.PrintDefaults()
                os.Exit(1)
        }

        data, err := ioutil.ReadFile(infile)
        if err != nil {
                fmt.Println("Can't read file:",infile) 
                panic(err)
        }

        req, err := readRequest(string(data), "http")
        if err != nil {
                panic(err)
        }

        resp, err := new(http.Client).Do(req)
        if err != nil {
                panic(err)
        }

        respDump, err := httputil.DumpResponse(resp, true)
        if err != nil {
                panic(err)
        }

        fmt.Printf(string(respDump))
}