To extract the identifier from the following URL :
$url = 'www.youtube.com/watch?v=B4CRkpBGQzU&feature=youtube_gdata&par1=1&par2=2';
You can first use parse_url()
to get the query string :
$queryString = parse_url($url, PHP_URL_QUERY);
var_dump($queryString);
Which, here, would give you :
string 'v=B4CRkpBGQzU&feature=youtube_gdata&par1=1&par2=2' (length=49)
And, then, use parse_str()
to extract the parameters from that query string :
parse_str($queryString, $params);
var_dump($params);
Which would get you the following array :
array
'v' => string 'B4CRkpBGQzU' (length=11)
'feature' => string 'youtube_gdata' (length=13)
'par1' => string '1' (length=1)
'par2' => string '2' (length=1)
And, now, it's just a matter of using the v
item from that array, injecting it into the thumbnail URL :
if (isset($params['v'])) {
echo "i3.ytimg.com/vi/{$params['v']}/default.jpg";
}
Which gives :
i3.ytimg.com/vi/B4CRkpBGQzU/default.jpg