PHP检测远端文件是否存在

<?php

function get_http_response_code($theURL) {

$headers = get_headers($theURL);

return substr($headers[0], 9, 3);

}

?>

<?php
/**
 * Fetches all the real headers sent by the server in response to a HTTP request without redirects
 * 获取不包含重定向的报头
 */

function get_real_headers($url,$format=0,$follow_redirect=0) {
  if (!$follow_redirect) {
    //set new default options
    $opts = array('http' =>
        array('max_redirects'=>1,'ignore_errors'=>1)
    );
    stream_context_get_default($opts);
  }
  //get headers
    $headers=get_headers($url,$format);
    //restore default options
  if (isset($opts)) {
    $opts = array('http' =>
        array('max_redirects'=>20,'ignore_errors'=>0)
    );
    stream_context_get_default($opts);
  }
  //return
    return $headers;
}
?>
//该片段来自于http://outofmemory.cn