Grab the video ID only from youtube's URLs - php

Question

How can I grab the video ID only from the youtube's URLs?
For instance,
http://www.youtube.com/watch?v=aPm3QVKlBJg
sometime the URLs contain other information after the 'v' like
http://www.youtube.com/watch?v=Z29MkJdMKqs&feature=grec_index
but I don't want the other info, just video ID.
I only can think of using explode,
$url = "http://www.youtube.com/watch?v=aPm3QVKlBJg";
$pieces = explode("v=", $url);
but how to clean up the URLs like this?
http://www.youtube.com/watch?v=Z29MkJdMKqs&feature=grec_index

Answer 1

You should never use regular expressions when the same thing can be accomplished through purpose-built functions.
You can use parse_url to break the URL up into its segments, and parse_str to break the query string portion into a key/value array:
$url = 'http://www.youtube.com/watch?v=Z29MkJdMKqs&feature=grec_index'
// break the URL into its components
$parts = parse_url($url);
// $parts['query'] contains the query string: 'v=Z29MkJdMKqs&feature=grec_index'
// parse variables into key=>value array
$query = array();
parse_str($parts['query'], $query);
echo $query['v']; // Z29MkJdMKqs
echo $query['feature'] // grec_index
The alternate form of parse_str extracts variables into the current scope. You could build this into a function to find and return the v parameter:
// Returns null if video id doesn't exist in URL
function get_video_id($url) {
$parts = parse_url($url);
// Make sure $url had a query string
if (!array_key_exists('query', $parts))
return null;
parse_str($parts['query']);
// Return the 'v' parameter if it existed
return isset($v) ? $v : null;
}