About the function code of php to obtain the content of remote files

/**

 * 读远程内容

 * @return string

 */
function get_url_content($url){

  if(function_exists("curl_init")){

    $ch = curl_init();

    $timeout = 30;

    curl_setopt($ch, CURLOPT_URL, $url);

    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout);

    $file_contents = curl_exec($ch);

    curl_close($ch);

  }else{

    $is_auf=ini_get('allow_url_fopen')?true:false;

    if($is_auf){

      $file_contents = file_get_contents($url);

    }

  }

  return $file_contents;

}