// BasicAuth returns the username and password provided in the request's
// Authorization header, if the request uses HTTP Basic Authentication.
// See RFC 2617, Section 2.
func (r *Request) BasicAuth() (username, password string, ok bool) {
	auth := r.Header.Get("Authorization")
	if auth == "" {
		return "", "", false
	}
	return parseBasicAuth(auth)
}

// parseBasicAuth parses an HTTP Basic Authentication string.
// "Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==" returns ("Aladdin", "open sesame", true).
func parseBasicAuth(auth string) (username, password string, ok bool) {
	const prefix = "Basic "
	// Case insensitive prefix match. See Issue 22736.
	if len(auth) < len(prefix) || !ascii.EqualFold(auth[:len(prefix)], prefix) {
		return "", "", false
	}
	c, err := base64.StdEncoding.DecodeString(auth[len(prefix):])
	if err != nil {
		return "", "", false
	}
	cs := string(c)
	username, password, ok = strings.Cut(cs, ":")
	if !ok {
		return "", "", false
	}
	return username, password, true
}