http.Server — get URL fragment

Have no luck with extracting fragment data (foo in http://domain.com/path#foo) with standard http.Server.

package main
import (
	"fmt"
	"net/http"
)
type Handler struct {
}
func (handler Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	fmt.Printf("Path = \"%v\"  Fragment = \"%v\"\n", r.URL.Path, r.URL.Fragment)
}
func main() {
	var handler Handler
	http.ListenAndServe(":30000", handler)
}

produces empty fragment for http://127.0.0.1:30000/path#foo:

Path = "/path" Fragment = ""

How can I get fragment data using golang's builtin http.Server?

You can't. This isn't a Go thing -- URL fragments are not sent to the server over HTTP. They're just a browser concept.

Here is a relevant issue, where the docs for http.Request were changed to say:

// For server requests the URL is parsed from the URI
// supplied on the Request-Line as stored in RequestURI.  For
// most requests, fields other than Path and RawQuery will be
// empty. (See RFC 2616, Section 5.1.2)

If for some reason you need it, you could probably string together some JavaScript to include the fragment in the request as a GET parameter or something.