StripPrefix in Go
StripPrefix returns a handler that serves HTTP requests by removing the given prefix from the request URL's Path and invoking the handler h. StripPrefix handles a request for a path that doesn't begin with prefix by replying with an HTTP 404 not found error.
package main
import "net/http"
func main() {
// To serve a directory on disk (/tmp) under an alternate URL
// path (/tmpfiles/), use StripPrefix to modify the request
// URL's path before the FileServer sees it:
http.Handle("/tmpfiles/", http.StripPrefix("/tmpfiles/", http.FileServer(http.Dir("/tmp"))))
}