Wrapped HTTP server with GRPC multiplex.go

func main() {

	// We Generate a TLS grpc API
	apiserver, err := GenerateTLSApi("cert/server.crt", "cert/server.key")
	if err != nil {
		log.Fatal(err)
	}
	// Start listening on a TCP Port
	lis, err := net.Listen("tcp", "127.0.0.1:9990")
	if err != nil {
		log.Fatal(err)
	}
	// We need to tell the code WHAT TO do on each request, ie. The business logic.
	// In GRPC cases, the Server is acutally just an Interface
	// So we need a struct which fulfills the server interface
	// see server.go
	s := &Server{}
	// Register the API server as a PingPong Server
	// The register function is a generated piece by protoc.
	pingpong.RegisterPingPongServer(apiserver, s)
	// Start serving in a goroutine to not block
	go func() {
		log.Fatal(apiserver.Serve(lis))
	}()
	// Wrap the GRPC Server in grpc-web and also host the UI
	grpcWebServer := grpcweb.WrapServer(apiserver)
	// Lets put the wrapped grpc server in our multiplexer struct so
	// it can reach the grpc server in its handler
	multiplex := grpcMultiplexer{
		grpcWebServer,
	}

	// We need a http router
	r := http.NewServeMux()
	// Load the static webpage with a http fileserver
	webapp := http.FileServer(http.Dir("ui"))
	// Host the Web Application at /, and wrap it in the GRPC Multiplexer
	// This allows grpc requests to transfer over HTTP1. then be
	// routed by the multiplexer
	r.Handle("/", multiplex.Handler(webapp))
	// Create a HTTP server and bind the router to it, and set wanted address
	srv := &http.Server{
		Handler:      r,
		Addr:         "localhost:8080",
		WriteTimeout: 15 * time.Second,
		ReadTimeout:  15 * time.Second,
	}
	// Serve the webapp over TLS
	log.Fatal(srv.ListenAndServeTLS("cert/server.crt", "cert/server.key"))

}