PHP检测远端资料是否存在

<?php$url = 'http://example.com';$hander_array = get_headers ( $url );if ($header_array [0] == 'HTTP/1.1 200 OK') {	echo '文件存在';} else {	echo '文件不存在';} 

<?phpfunction 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;}?>