main.go

package main

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

func main() {
	// Define command line flags
	username := flag.String("user", "glzjin", "Username to impersonate")
	role := flag.String("role", "ADMIN", "Role to impersonate (will be converted to uppercase)")
	targetURL := flag.String("target", "http://127.0.0.1:8080", "Target URL to proxy to")
	listenAddr := flag.String("listen", ":8081", "Address to listen on")

	// Parse command line flags
	flag.Parse()

	// Convert role to uppercase
	upperRole := strings.ToUpper(*role)

	// Target URL
	target, err := url.Parse(*targetURL)
	if err != nil {
		log.Fatal("Error parsing target URL:", err)
	}

	// Create reverse proxy
	proxy := httputil.NewSingleHostReverseProxy(target)

	// Create a custom transport
	proxy.Transport = &http.Transport{
		Proxy: http.ProxyFromEnvironment,
	}

	// Modify the director to preserve original request
	originalDirector := proxy.Director
	proxy.Director = func(req *http.Request) {
		originalDirector(req)
		if _, ok := req.Header["User-Agent"]; !ok {
			req.Header.Set("User-Agent", "")
		}
	}

	// Create a handler that wraps the proxy
	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		// Set custom headers only once
		r.Header.Set("X-HC-User-ID", *username)
		r.Header.Set("X-HC-User-Role", upperRole)
		proxy.ServeHTTP(w, r)
	})

	// Create server
	server := &http.Server{
		Addr:    *listenAddr,
		Handler: handler,
	}

	// Start the server
	log.Printf("Starting proxy server on %s", *listenAddr)
	log.Printf("Proxying to: %s", *targetURL)
	log.Printf("Using credentials - User: %s, Role: %s", *username, upperRole)
	if err := server.ListenAndServe(); err != nil {
		log.Fatal("Error starting proxy server:", err)
	}
}