How to edit the URL BEFORE it gets into the http.FileServer() function?

Question

go

How to edit the URL that opens the static, something like this?:
The Go-server route catches the URL (like - domen.com/blog/L5566 , caught by the handler from the /blog/ fragment); then the end of URL_Path is checked; if it is correct, then we modify the URL to the static_file request format (like domen.com/pages/page10.html), and pass it to the http.FileServer() function.

Answer 1

just give the file yourself, why change the url for http.FileServer?
but in general, it's not difficult, replace the URL in r.URL.Path

func handler(w http.ResponseWriter, r *http.Request)  {
  r.URL.Path = "/pages/page10.html"
  http.FileServer(...).ServeHTTP(w,r)
}