a simple proxy to convert basic auth to token auth

proxy.go

package main

import (
	"flag"
	"fmt"
	"log"
	"net/http"
	"net/http/httputil"
	"net/url"
	"strings"
)

type ReverseProxy struct {
	proxy *httputil.ReverseProxy
}

func NewReverseProxy(target string) (proxy *ReverseProxy) {
	p := ReverseProxy{}
	url, _ := url.Parse(target)

	p.proxy = httputil.NewSingleHostReverseProxy(url)
	return &p

}

func (p *ReverseProxy) handle(w http.ResponseWriter, r *http.Request) {
	if r.Method == http.MethodOptions {
		fmt.Fprintf(w, "%s", "Goodbye\n")
		return
	}
	auth := r.Header.Get("Authorization")
	if auth == "" {
		w.WriteHeader(http.StatusNotAcceptable)
		fmt.Fprintf(w, "Error with auth")
		return
	}
	if strings.HasPrefix(auth, "Basic") {
		fmt.Println("Using basic auth")
		fmt.Println("Here be token")
		token := "1234567890"
		r.Header.Set("Authorization", "Bearer "+token)
	}
	w.Header().Set("X-GoProxy", "GoProxy")
	p.proxy.ServeHTTP(w, r)
}

func main() {
	const (
		defaultPort        = "9090"
		defaultPortUsage   = "default server port, ':9090'"
		defaultTarget      = "https://postb.in/1572119126327-6632650287356"
		defaultTargetUsage = "default redirect url, 'https://postb.in/1572119126327-6632650287356'"
	)

	// flags
	port := flag.String("port", defaultPort, defaultPortUsage)
	redirecturl := flag.String("url", defaultTarget, defaultTargetUsage)

	flag.Parse()

	fmt.Println("server will run on :", *port)
	fmt.Println("redirecting to :", *redirecturl)

	// proxy
	proxy := NewReverseProxy(*redirecturl)

	// server redirection
	http.HandleFunc("/", proxy.handle)
	log.Fatal(http.ListenAndServe(":"+*port, nil))
}