chatgpt proxy with gitlab auth method

main.go

package main

import (
	"log"
	"net/http"
	"net/http/httputil"
	"os"
	"strings"
)

func checkGitlab(token string) bool {
	url := "https://gitlab.yourcompany.com/api/v4/version"

	header := map[string]string{
		"Authorization": "Bearer " + token,
	}

	client := &http.Client{}
	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		log.Printf("Error creating request: %s\n", err)
		return false
	}

	// 设置 HTTP header
	for k, v := range header {
		req.Header.Set(k, v)
	}

	resp, err := client.Do(req)
	if err != nil {
		log.Printf("Error accessing '%s': %s\n", url, err)
		return false
	}
	defer resp.Body.Close()

	return resp.StatusCode == http.StatusOK
}

func hello(w http.ResponseWriter, r *http.Request) {
	if r.Method == "OPTIONS" {
		w.Header().Set("Access-Control-Allow-Origin", "*")
		w.Header().Set("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE")
		w.Header().Set("Access-Control-Allow-Headers", "Accept, Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, Authorization")
		w.Header().Set("Access-Control-Expose-Headers", "Authorization")
		w.WriteHeader(http.StatusOK)
		return
	}

	token, found := strings.CutPrefix(r.Header.Get("Authorization"), "Bearer ")
	if !found {
		http.Error(w, "Unauthorized", http.StatusUnauthorized)
		return
	}

	if !checkGitlab(token) {
		http.Error(w, "Forbidden", http.StatusForbidden)
		return
	}

	r.Header.Set("Authorization", "Bearer "+os.Getenv("OPENAI_TOKEN"))

	proxy := &httputil.ReverseProxy{
		Director: func(req *http.Request) {
			req.URL.Scheme = "https"
			req.URL.Host = "api.openai.com:443"  // or your own proxy server
			req.Host = "api.openai.com"          
		},
	}
	proxy.ServeHTTP(w, r)
}

func logRequest(handler http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		log.Printf("%s %s %s\n", r.RemoteAddr, r.Method, r.URL)
		handler.ServeHTTP(w, r)
	})
}

func main() {
	log.SetFlags(log.Ldate | log.Ltime | log.Lshortfile)
	mux := http.NewServeMux()
	mux.HandleFunc("/", hello)
	log.Println("Server starting on :8080")
	err := http.ListenAndServe(":8080", logRequest(mux))
	log.Fatal(err)
}