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I am attempting to parse the video ID of a youtube URL using preg_match. I found a regular expression on this site that appears to work;
(?<=v=)[a-zA-Z0-9-]+(?=&)|(?<=[0-9]/)[^&\n]+|(?<=v=)[^&\n]+
As shown in this pic:
My PHP is as follows, but it doesn't work (gives Unknown modifier '[' error)...
<?
$subject = "http://www.youtube.com/watch?v=z_AbfPXTKms&NR=1";
preg_match("(?<=v=)[a-zA-Z0-9-]+(?=&)|(?<=[0-9]/)[^&\n]+|(?<=v=)[^&\n]+", $subject, $matches);
print "<pre>";
print_r($matches);
print "</pre>";
?>
Cheers
280
The preg_match() function returns whether a match was found in a string.
preg_match stops looking after the first match. preg_match_all , on the other hand, continues to look until it finishes processing the entire string. Once match is found, it uses the remainder of the string to try and apply another match.
This regex grabs the ID from all of the various URLs I could find... There may be more out there, but I couldn't find reference of them anywhere. If you come across one this doesn't match, please leave a comment with the URL, and I'll try and update the regex to match your URL.
if (preg_match('%(?:youtube(?:-nocookie)?\.com/(?:[^/]+/.+/|(?:v|e(?:mbed)?)/|.*[?&]v=)|youtu\.be/)([^"&?/\s]{11})%i', $url, $match)) {
$video_id = $match[1];
}
Here is a sample of the URLs this regex matches: (there can be more content after the given URL that will be ignored)
It also works on the youtube-nocookie.com URL with the same above options.
It will also pull the ID from the URL in an embed code (both iframe and object tags)
83
Better use parse_url and parse_str to parse the URL and query string:
$subject = "http://www.youtube.com/watch?v=z_AbfPXTKms&NR=1";
$url = parse_url($subject);
parse_str($url['query'], $query);
var_dump($query);
I had to deal with this for a PHP class i wrote a few weeks ago and ended up with a regex that matches any kind of strings: With or without URL scheme, with or without subdomain, youtube.com URL strings, youtu.be URL strings and dealing with all kind of parameter sorting. You can check it out at GitHub or simply copy and paste the code block below:
/**
* Check if input string is a valid YouTube URL
* and try to extract the YouTube Video ID from it.
* @author Stephan Schmitz <[email protected]>
* @param $url string The string that shall be checked.
* @return mixed Returns YouTube Video ID, or (boolean) false.
*/
function parse_yturl($url)
{
$pattern = '#^(?:https?://)?(?:www\.)?(?:youtu\.be/|youtube\.com(?:/embed/|/v/|/watch\?v=|/watch\?.+&v=))([\w-]{11})(?:.+)?$#x';
preg_match($pattern, $url, $matches);
return (isset($matches[1])) ? $matches[1] : false;
}
To explain the regex, here's a spilt up version:
/**
* Check if input string is a valid YouTube URL
* and try to extract the YouTube Video ID from it.
* @author Stephan Schmitz <[email protected]>
* @param $url string The string that shall be checked.
* @return mixed Returns YouTube Video ID, or (boolean) false.
*/
function parse_yturl($url)
{
$pattern = '#^(?:https?://)?'; # Optional URL scheme. Either http or https.
$pattern .= '(?:www\.)?'; # Optional www subdomain.
$pattern .= '(?:'; # Group host alternatives:
$pattern .= 'youtu\.be/'; # Either youtu.be,
$pattern .= '|youtube\.com'; # or youtube.com
$pattern .= '(?:'; # Group path alternatives:
$pattern .= '/embed/'; # Either /embed/,
$pattern .= '|/v/'; # or /v/,
$pattern .= '|/watch\?v='; # or /watch?v=,
$pattern .= '|/watch\?.+&v='; # or /watch?other_param&v=
$pattern .= ')'; # End path alternatives.
$pattern .= ')'; # End host alternatives.
$pattern .= '([\w-]{11})'; # 11 characters (Length of Youtube video ids).
$pattern .= '(?:.+)?$#x'; # Optional other ending URL parameters.
preg_match($pattern, $url, $matches);
return (isset($matches[1])) ? $matches[1] : false;
}
I perfected regex from the leader answer. It also grabs the ID from all of the various URLs, but more correctly.
if (preg_match('%(?:youtube(?:-nocookie)?\.com/(?:[\w\-?&!#=,;]+/[\w\-?&!#=/,;]+/|(?:v|e(?:mbed)?)/|[\w\-?&!#=,;]*[?&]v=)|youtu\.be/)([\w-]{11})(?:[^\w-]|\Z)%i', $url, $match)) {
$video_id = $match[1];
}
Also, it correctly handles the wrong IDs, which more than 11 characters.
http://www.youtube.com/watch?v=0zM3nApSvMgDw3qlxF
35
Use
preg_match("#(?<=v=)[a-zA-Z0-9-]+(?=&)|(?<=[0-9]/)[^&\n]+|(?<=v=)[^&\n]+#", $subject, $matches);
You forgot to escape the slash character. So this one should do the job:
preg_match("#(?<=v=)[a-zA-Z0-9-]+(?=&)|(?<=[0-9]\/)[^&\n]+|(?<=v=)[^&\n]+#", $subject, $matches);
Parse Start parameter for BBcode (https://developers.google.com/youtube/player_parameters#start)
example: [yt]http://www.youtube.com/watch?v=G059ou-7wmo#t=58[/yt]
PHP regex:
'#\[yt\]https?://(?:[0-9A-Z-]+\.)?(?:youtu\.be/|youtube\.com(?:/embed/|/v/|/watch\?v=|/ytscreeningroom\?v=|/feeds/api/videos/|/user\S*[^\w\-\s]|\S*[^\w\-\s]))([\w\-]{11})[?=#&+%\w-]*(t=(\d+))?\[/yt\]#Uim'
replace:
'<iframe id="ytplayer" type="text/html" width="639" height="360" src="http://www.youtube.com/embed/$1?rel=0&vq=hd1080&start=$3" frameborder="0" allowfullscreen></iframe>'
I didn't see anyone directly address the PHP error, so I'll try to explain.
The reason for the "Unknown modifier '['" error is that you forgot to wrap your regex in delimiters. PHP just takes the first character as a delimiter, so long as it's a non-alphanumeric, non-whitespace ASCII character. So in your regex:
preg_match("(?<=v=)[a-zA-Z0-9-]+(?=&)|(?<=[0-9]/)[^&\n]+|(?<=v=)[^&\n]+", $subject, $matches);
PHP thinks you meant ( as an opening delimiter. It then finds what it thinks is your closing delimiter, the next ) and assumes what follows are pattern modifiers. However it finds that your first pattern modifier, the next character after the first ), is [. [ is obviously not a valid pattern modifier, which is why you get the error that you do.
The solution is to simply wrap your regex in delimiters and make sure any delimiters within the regex that you want to match literally are escaped. I like to use ~ as delimiters, b/c you rarely need to match a literal ~ in a regex.
40
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