PHP get_headers method to detect whether remote files exist

$url = 'http://example.com';
$hander_array = get_headers ( $url );
if ($header_array [0] == 'HTTP/1.1 200 OK' ) {
 echo 'File exists';
} else {
 echo 'File does not exist';
}

Instructions: The function of get_headers function: when accessing a remote address, return the HTTP headers sent by the server in the form of an array. And $header[0] is the status code returned by the server (the status code is usually the first one returned). Therefore, to determine that a file exists on the remote server, you only need to make sure that the status code returned by accessing the file is "HTTP/1.1 200 OK". It can also be determined that the status code is not "HTTP/1.1 404 Not Found", and the answer to the existence of the file can also be given.

I will share two more examples of get_headers function below for your reference.

1. Example of obtaining three-digit HTTP response code:

function get_http_response_code($theURL) {
 $headers = get_headers($theURL);
 return substr($headers[0], 9, 3);
}
?>

2, example of excluding redirection:

/**
 * Get headers without redirects
 * by bbs.it-home.org
*/

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;
}
?>

Attach, php get_headers ()

get_headers (PHP 5)

get_headers — Get all headers sent by the server in response to an HTTP request

Instructions array get_headers ( string $url [, int $format ] ) get_headers() returns an array containing the headers sent by the server in response to an HTTP request. If it fails, it returns FALSE and issues an E_WARNING level error message.

If the optional format parameter is set to 1, get_headers() will parse the corresponding information and set the key name of the array.

Instructions: Since PHP 5.1.3 this function uses the default stream context, which can be set and modified using the stream_context_get_default() function.

Example of get_headers():

$url = 'http://bbs.it-home.org';
print_r(get_headers($url));
print_r(get_headers($url, 1));
?>

The output is similar to:

Array ( [0] => HTTP/1.1 200 OK [1] => Date: Sat, 29 May 2004 12:28:13 GMT [2] => Server: Apache/1.3.27 (Unix) (Red-Hat/Linux) [3] => Last-Modified: Wed, 08 Jan 2003 23:11:55 GMT [4] => ETag: "3f80f-1b6-3e1cb03b" [5] => Accept-Ranges: bytes [6] => Content-Length: 438 [7] => Connection: close [8] => Content-Type: text/html )

Array ( [0] => HTTP/1.1 200 OK [Date] => Sat, 29 May 2004 12:28:14 GMT [Server] => Apache/1.3.27 (Unix) (Red-Hat/Linux) [Last-Modified] => Wed, 08 Jan 2003 23:11:55 GMT [ETag] => "3f80f-1b6-3e1cb03b" [Accept-Ranges] => bytes [Content-Length] => 438 [Connection] => close [Content-Type] => text/html )