public function url_to_id($url){
    if ( $file = $this->url_to_real($url) ){
      return $this->real_to_id($file);
    }
    return false;
  }
public function url_to_id($url){
    if ( $file = $this->url_to_real($url) ){
      return $this->real_to_id($file);
    }
    return false;
  }
public function url_to_id ( $ url ) { if ( $ file = $ this -> url_to_real ( $ url ) ) { return $ this -> real_to_id ( $ file ) ; } return false ; }
Returns the file's ID from its URL

@param string $url The file's URL
@return bool|string
Returns the file s ID from its URL