proxycik.go

package main

import (
	"fmt"
	"net/http"
	"net/http/httputil"
	"net/url"
	"os"
)

func getEnv(key, fallback string) string {
	if value, ok := os.LookupEnv(key); ok {
		return value
	}
	return fallback
}

func getListenAddress() string {
	port := getEnv("PORT", "1338")
	return ":" + port
}

func getFCMToken() string {
	token := getEnv("FCM_TOKEN",
		"token_token_token_token_token_token_token_token")
	return token
}

func serveReverseProxy(target string, res http.ResponseWriter, req *http.Request) {
	fcmUrl, _ := url.Parse(target)

	proxy := httputil.NewSingleHostReverseProxy(fcmUrl)

	req.URL.Host = fcmUrl.Host
	req.URL.Scheme = fcmUrl.Scheme
	req.Header.Set("X-Forwarded-Host", req.Header.Get("Host"))
	req.Header.Set("Authorization", "key="+getFCMToken())
	req.Host = fcmUrl.Host

	proxy.ServeHTTP(res, req)
}

func handleRequestAndRedirect(res http.ResponseWriter, req *http.Request) {
	fmt.Println(req.Header.Get("Authorization"))//todo  magic
	serveReverseProxy("https://fcm.googleapis.com", res, req)
}

func main() {
	http.HandleFunc("/", handleRequestAndRedirect)
	if err := http.ListenAndServe(getListenAddress(), nil); err != nil {
		fmt.Println("HTTP Server", err.Error())
	}
}