Add Cache-Control max age 30 days to /assets

If browser has a cache version of assest, do not check server
since vite add a hash to all assets, every change in the frontend generate other file names and invalidate the cache.

server/http.go

@@ -56,9 +56,8 @@ func NewHTTPd(addr string, hub *SocketHub) *HTTPd {
 	})
 
 	static.HandleFunc("/", indexHandler())
-	for _, dir := range []string{"assets", "meta"} {
-		static.PathPrefix("/" + dir).Handler(http.FileServer(http.FS(assets.Web)))
-	}
+	static.PathPrefix("/assets").Handler(CacheControlWrapper(http.FileServer(http.FS(assets.Web))))
+	static.PathPrefix("/meta").Handler(http.FileServer(http.FS(assets.Web)))
 	static.PathPrefix("/i18n").Handler(http.StripPrefix("/i18n", http.FileServer(http.FS(assets.I18n))))
 
 	srv := &HTTPd{
@@ -76,6 +75,13 @@ func NewHTTPd(addr string, hub *SocketHub) *HTTPd {
 	return srv
 }
 
+func CacheControlWrapper(h http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Cache-Control", "max-age=2592000") // 30 days
+		h.ServeHTTP(w, r)
+	})
+}
+
 // Router returns the main router
 func (s *HTTPd) Router() *mux.Router {
 	return s.Handler.(*mux.Router)