How PHP can tell if a remote file exists

<?php

/*
Function: remote_file_exists
Function: Determine whether a remote file exists
Parameters: $url _file-Remote file URL
Return: Presence returns true, no presence or other reason returned false
*/
function remote_file_exists ($url _file) {
Detection input
$url _file = Trim ($url _file);
if (Empty ($url _file)) {return false;}
$url _arr = Parse_url ($url _file);
if (!is_array ($url _arr) | | empty ($url _arr)) {return false;}

GET Request data
$host = $url _arr[' host '];
$path = $url _arr[' path ']. "?". $url _arr[' query '];
$port = isset ($url _arr[' Port ')? $url _arr[' Port ']: "80";

Connecting to a server
$fp = Fsockopen ($host, $port, $err _no, $err _str,30);
if (! $fp) {return false;}

Construct the Request protocol
$request _str = "GET". $path. " Http/1.1\r\n ";
$request _str. = "Host:". $host. " \ r \ n ";
$request _str. = "connection:close\r\n\r\n";

Send Request
Fwrite ($fp, $request _str);
$first _header = fgets ($fp, 1024);
Fclose ($FP);

Determine if a file exists
if (Trim ($first _header) = = "") {return false;}
if (!preg_match ("/2002881064151/", $first _header)) {
return false;
}
return true;
}

?>

function description and examples

<?
Test code
$str _url = ' http://www.phpx.com/viewarticle.php?id=119617 ';
$exits = remote_file_exists ($str _url);
Echo $exists? "Exists": "Not Exists";
?>

How PHP can tell if a remote file exists