获取一个小URL的真实URL并存储为PHP变量

I want to get the video ID of a Youtube URL, but often the URL is condensed into a Tiny URL when being shared.

For example, I have a script that gets the Youtube video's thumbnail based on its video ID =

<?php $vlog = "OeqlkEymQ94"; ?>
<img src="http://img.youtube.com/vi/<?=$vlog;?>/0.jpg" alt="" />

This is easy to get when the URL I'm extracting it from is

http://www.youtube.com/watch?v=OeqlkEymQ94

but sometimes the URL is a tiny URL so I have to figure out how to return the real URL so I can use it.

http://tinyurl.com/kmx9zt6

Is it possible to retreive the real URL of a URL through PHP?

You could use get_headers() or cURL to grab the Location header:

function getFullURL($url) {
    $headers = get_headers($url);
    $headers = array_reverse($headers);
    foreach($headers as $header) {
        if (strpos($header, 'Location: ') === FALSE) {
            $url = str_replace('Location: ', '', $header);
            break;
        }
    }    
    return $url;
}

Usage:

echo getFullURL('http://tinyurl.com/kmx9zt6');

^{Note: It's a slightly modified version of the gist here.}

For future reference, I used a much simpler function because my Tiny URL's were always going to resolve to Youtube, and the headers were almost always the same :

function getFullURL($url) {
    $headers = get_headers($url);
    $url = $headers[4]; //This is the location part of the array
    $url = str_replace('Location: ', '', $url);
    $url = str_replace('location: ', '', $url);  //in my case the location was lowercase, but it can't hurt to have both
    return $url;
}

usage -

echo getFullURL('http://tinyurl.com/kmx9zt6');