// Returns errAuthentication for all other errors.
func metricsRequestAuthenticate(req *http.Request) (*xjwt.MapClaims, []string, bool, error) {
	token, err := jwtreq.AuthorizationHeaderExtractor.ExtractToken(req)
	if err != nil {
		if err == jwtreq.ErrNoTokenInRequest {
			return nil, nil, false, errNoAuthToken
		}
		return nil, nil, false, err
	}
	claims := xjwt.NewMapClaims()

// Modify the request to handle the target URL
func (f *Forwarder) modifyRequest(outReq *http.Request, target *url.URL) {
	outReq.URL = copyURL(outReq.URL)
	outReq.URL.Scheme = target.Scheme
	outReq.URL.Host = target.Host

	u := f.getURLFromRequest(outReq)

	outReq.URL.Path = u.Path
	outReq.URL.RawPath = u.RawPath
	outReq.URL.RawQuery = u.RawQuery
	outReq.RequestURI = "" // Outgoing request should not have RequestURI