Regex to extract categories from URL

Question

I have a Slug aktuell/blog/cat1/cat2/cat3 and need a Regex to extract all category-segments (all segements after 'aktuell/blog') from this Slug. The count of cataegory-segements may vary from zero to infinity.

I have already tried several ways but it never works as expected... My last attempt was:

^aktuell\\/blog(?:\\/(\w+))*$/g

But this Regex returns just the last segment as match... What can i do to get all categories?

Thank's

Are you passing the segments into PHP as `$_GET` variables or is the URL only available as a string? If you're passing as variables, cycle through `$_GET` to retrieve the values. If not, then explode the string you have with the delimiter "/" and find the segments you want! — Hugo Pakula, May 23 '16 at 07:14
The URL is only available as string. I have a routing class which deals with the regex patterns (from db) and returns me the route id and all matches. So I can not use explode... :( — Nio, May 23 '16 at 07:17
Why not use this pattern: `aktuell\/blog\/(.*)` and explode on `"/"`? — Andreas, May 23 '16 at 07:31
@WiktorStribiżew thanks for the reminder, but I don't think it's worth the effort to write an answer to this question. — Sebastian Proske, May 28 '16 at 08:03

score 0 · Answer 1 · answered May 23 '16 at 07:42

0

This Regex works, but the php Regex-Engine can't handle matches in a repeating group. Every new match overrides the previous one...

So i have to repeat the group manually:

^aktuell\/blog(?:\/(\w+))?(?:\/(\w+))?(?:\/(\w+))?(?:\/(\w+))?(?:\/(\w+))?

answered May 23 '16 at 07:42

Nio

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Don't you really have access to multiple matches? See Sebastian's suggestion above that would work with `preg_match_all` function (if you remove `g` at the end). – Wiktor Stribiżew May 23 '16 at 07:44
Please let him know if his suggestion works, so that he could post an answer to get credit for his suggestion. – Wiktor Stribiżew May 25 '16 at 07:50

score 0 · Answer 2 · answered May 23 '16 at 08:28

You can use this piece of code to solve your problem:

$uri = $_SERVER['REQUEST_URI'];
$uri_arr = explode("/",$uri);
$cat = array();
array_map(function($v) use (&$cat){
    preg_match('/^cat\d$/',$v,$matches);
    if(count($matches) > 0){
        $cat[] = $matches[0];
      }
},$uri_arr);
print_r($cat);

Here is an example

score 0 · Accepted Answer · answered May 25 '16 at 07:45

0

/(?:^aktuell\/blog|\G(?!^))(?:\/(\w+))/in combination with preg_match_all() works fine!

big thanks to @WiktorStribiżew and @SebastianProske

answered May 25 '16 at 07:45

Nio

497
3
6
16

Since Sebastian does not want to provide an answer, I came up with my own suggestion. – Wiktor Stribiżew May 30 '16 at 07:22

Wiktor Stribiżew · Answer 4 · 2016-05-30T07:53:12.377

The problem is that repeated captured groups always store the last captured value in their buffer.

You can use a preg_match_all with the following regex:

/(?:^aktuell\/blog|(?!^)\G)\/\K\w+/

or (to avoid escaping the forward slash):

'~(?:^aktuell/blog|(?!^)\G)/\K\w+~'

See the regex demo

Pattern details:

(?:^aktuell\/blog|(?!^)\G) - Matches the start of string and aktuell/blog after it (see ^aktuell\/blog), or (|) the end of the previous successful match in the string (with (?!^)\G)
\/ - matches a / symbol
\K - makes the regex engine omit the text matched so far
\w+ - matches /, and then captures 1+ alphanumeric or underscore characters.

Note that accepting answer posted by another user (I guess the first time) you will get 2 additional points. — Wiktor Stribiżew, May 30 '16 at 07:23

Regex to extract categories from URL

4 Answers4