Testing remote sites for redirection with PHP

[liamvictor]

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?

[nico_swd]

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;
}


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

Usage example:

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


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;
}
}

[liamvictor]

Fantastic help, thank you.

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