How to preg_match for a specific pattern in a url?

Question

I would like to use preg_match in PHP to test the format of a URL. The URL looks like this:

/2013/09/05/item-01.html

I'm trying to get this to work :

if (preg_match("/([0-9]{4})\/([0-9]{2})\/([0-9]{2})/[.]+[.html]$", $_SERVER['REQUEST_URI'])) :
    echo "match";
endif;

But something's not quite right. Any ideas?

**What does "not quite right" mean?** "Not quite right" is an inadequate description for us to understand the problem. What happened when you tried it? Did you get incorrect results? Did you get *no* results? If the results were incorrect, what made them incorrect? What were you expecting instead? Did you get *any* correct results? If so, what were they? Don't make us guess. — Andy Lester, May 09 '13 at 13:58
Sorry. By "not quite right" I meant it failed to match, but I felt like I was close! — user2366298, May 09 '13 at 14:04

score 0 · Accepted Answer · answered May 09 '13 at 13:37

Try:

if (preg_match('!\d{4}/\d{2}/\d{2}/.*\.html$!', $_SERVER['REQUEST_URI'])) {
    echo 'match';
}

\d is short for [0-9] and you can use different start/end delimiters (I use ! in this case) to make the regexp more readable when you're trying to match slashes.

greedybuddha · Answer 2 · 2013-05-09T13:55:51.573

It looks like you are nearly correct with what you have, though you have some minor problems

you forgot to escape your last "/" before the page.html
the [.]+ should be [^.]+, you aren't looking for 1 or more periods, you are looking for anything not a period.
You shouldnt be using the [] to match the html, but rather () or nothing at all

if (preg_match("/([0-9]{4})\/([0-9]{2})\/([0-9]{2})\/([^.]+.html)$", $_SERVER['REQUEST_URI'])) :
    echo "match";
endif;

Also you should probably learn when to use the (), these are used to make sure you are storing whatever is matched inside them. In your case I'm not sure if you want to be storing every directory up until the file or not.

score 0 · Answer 3 · answered May 09 '13 at 14:12

My guess is you had a working expression for a file path, and it stopped working when you tried to add the file name part.

preg_match() requires a pair of delimiter characters to be specified; one at each end of the expression. It looks like you have these, but you've put an extra bit of the expression (ie the file name) at the end of the string outside of the delimiters. This is invalid.

  "/([0-9]{4})\/([0-9]{2})\/([0-9]{2})/[.]+[.html]$"
   ^                                  ^
your start delimiter             your end delimiter

You need to move the expression code [.]+[.html]$ that is currently after the end delimiter so that it is inside it.

That should solve the problem.

How to preg_match for a specific pattern in a url?

3 Answers3