Testing remote sites for redirection with PHP

I've a whole bunch of sites / URLs in a database that I want to parse through and find any bad links to drop, and also any that are now being redirected.

So, if I hit an article from abc.com/article and it gets 301 (or whatever) to xyz.com I want to know where it's being redirected too.

Fopen will error on 404 and follow other redirects, but I can't think as to how to see if I am being redirected, and if so, what to.

So, any clues as to how to?

 

function get_final_location($url)
{
	$headers = @get_headers($url);
	
	foreach ((array)$headers AS $header)
	{
		if (preg_match('/Location\s*:\s*(https?:[^;\s\n\r]+)/i', $header, $redirect))
		{
			return get_final_location($redirect[1]);
		}
	}
	
	return $url;
}

PHP:

This gets the final URL, even if the page is redirected multiple times.

Usage example:

echo get_final_location('http://www.hotmail.com');

PHP:

If you don't have PHP 5, you have to define get_headers() yourself. You can use this for example.

if (!function_exists('get_headers'))
{
	function get_headers($url)
	{
		@extract(@parse_url($url));
		$scheme = (isset($scheme) AND $scheme == 'https') ? 'ssl://' : '';
		
		if (!isset($port) OR empty($port))
		{
			$port = empty($scheme) ? 80 : 443;
		}
	
		if ($fp = @fsockopen($scheme . $host, $port, $errno, $errstr, 30))
		{
			fwrite($fp,
				"HEAD {$url} HTTP/1.1\r\n" .
				"HOST: {$host}\r\n" .
				"Connection: close\r\n\r\n"
			);
			
			return explode("\n", fgets($fp));
		}
		
		return false;
	}
}

PHP:

 

Fantastic help, thank you.

I'd never seen the get_headers function before, and searching php.net didn't return anything useful.