I would like to send the HEAD command of the Hypertext Transfer Protocol to a server in PHP to retrieve the header, but not the content or a URL. How do I do this in an efficient way?
The probably most common use-case is to check for dead web links. For this I only need the reply code of the HTTP request and not the page content.
Getting web pages in PHP can be done easily using file_get_contents("http://...")
, but for the purpose of checking links, this is really inefficient as it downloads the whole page content / image / whatever.
The HTTP HEAD method requests the headers that would be returned if the HEAD request's URL was instead requested with the HTTP GET method. For example, if a URL might produce a large download, a HEAD request could read its Content-Length header to check the filesize without actually downloading the file.
To make a HEAD request with Curl, you need to use the -I or --head command-line parameter. The -I command-line parameter tells Curl to send an HTTP HEAD request to receive only HTTP headers. The HEAD request is very similar to a GET request, except that the server only returns HTTP headers without a response body.
HEAD is a request method supported by HTTP used by the World Wide Web. The HEAD method asks for a response identical to that of a GET request, but without the response body. This is useful for retrieving meta-information written in response headers, without having to transport the entire content.
HEAD request can be handled as if it was a GET request. You can access all parameters the same way - via $_GET or $_REQUEST superglobals. The main difference is that your script should not return any content, if you want to adhere to HTTP specification.
You can do this neatly with cURL:
<?php
// create a new cURL resource
$ch = curl_init();
// set URL and other appropriate options
curl_setopt($ch, CURLOPT_URL, "http://www.example.com/");
// This changes the request method to HEAD
curl_setopt($ch, CURLOPT_NOBODY, true);
// grab URL and pass it to the browser
curl_exec($ch);
// Edit: Fetch the HTTP-code (cred: @GZipp)
$code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
// close cURL resource, and free up system resources
curl_close($ch);
As an alternative to curl you can use the http context options to set the request method to HEAD
. Then open a (http wrapper) stream with these options and fetch the meta data.
$context = stream_context_create(array('http' =>array('method'=>'HEAD')));
$fd = fopen('http://php.net', 'rb', false, $context);
var_dump(stream_get_meta_data($fd));
fclose($fd);
see also:
http://docs.php.net/stream_get_meta_data
http://docs.php.net/context.http
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With