Regex for retrieving description meta-tag

johncook

I'm trying a regular expression to retrieve a webpage's description from it's Description Meta-Tag (the contents of the HTML doc are in $HtmlContent). I use the following code which works in some cases but not in all. Being a bit of a reg-ex newbie, I'm not sure how to make the regular expression work for all possible permutations. Eg - the different attributes in a different order, uppercase/lowercase, etc. Any tips on how to make my regex more robust would be deeply appreciated :-)

<?php
preg_match('/<(meta|META)(.*)content="(.*)" name="description"/s',$HtmlContent,$MatchArray);
if (isset($MatchArray))
	return $MatchArray[3];
?>

Weedpacket

/<meta\s.*?content="(.*?)"\s+name="description"/si

deals to the case issue. If you don't know the order, you can either go

/<meta\s.*?(content="(.*?)"\s+name="description"|name="description"\s+content="(.*?)")/si

or use an assertion

/<meta(?=[^>]*name="description")\s[^>]*content="([^>]*)"/si

which makes sure that the <meta is followed somewhere by name="description" before the tag closes, before going on to try matching the content attribute. Replacing .? with [^>] is both an efficiency saving and also makes sure we really do stop at the end of the tag ([^>]* means "match zero or more non-> characters") if for some reason there is no content attribute (otherwise we'll end up trying possible match after possible match all the way to the end of the page before giving up).

johncook

Weedpacket, thanx heaps, your assertive regex worked perfectly. Your response time was great, so quick! I don't understand how it works at all so I've got a lot of learning to do about regexes in general. Thanx again! :-)