PHP regex match something not starting with words like "admin", "login"... and so on?

Question

I've searched a lot but I've found many complicated examples, too hard to understand for me. Anyways I'm trying to write down a regular expression that should honor:

/foo     // should match
/foo/bar // should match

/login     // shouldn't match
/admin     // shouldn't match
/admin/foo // shouldn't match
/files     // shouldn't match

I've tried with a simple one, just with one word: #^(\/)([^admin])# that is starting with / and followed by something not starting with the word admin. It's working with /foo/bar but fails with /a/foo because it's starting with a, I suppose.

How can negate an entire set of words (admin or files or login)?

What you are looking for is called "zero-width assertions" or "lookahead" and "lookbehind". http://www.regular-expressions.info/lookaround.html — ThiefMaster, Sep 01 '13 at 12:06
@MichaelBerkowski I can't, the regex is for Symfony route matcher, accepting only regular expressions. — , Sep 01 '13 at 12:08
@Polmonino You should edit that info into to the question above. — Michael Berkowski, Sep 01 '13 at 12:09

score 4 · Answer 1 · 2013-09-01T12:35:57.187

4

Try this:

$pattern = '#^(\/)((?!admin|login).)*$#';

or

$pattern = '#^(/)((?!admin|login).)(/(.)+)*#';
$array = array(
'/foo',     // should match
'/foo/bar', // should match

'/login',     // shouldn't match
'/admin',     // shouldn't match
'/admin/foo', // shouldn't match
'/files'     // shouldn't match
);

foreach($array as $test){
 if(preg_match($pattern, $test)) echo "Matched :".$test."<br>";
 else echo "Not Matched:".$test."<br>";
}

Output:

Matched :/foo
Matched :/foo/bar
Not Matched:/login
Not Matched:/admin
Not Matched:/admin/foo
Matched :/files

edited Sep 01 '13 at 12:35

answered Sep 01 '13 at 12:11

Why you added the end of the string? – Sep 01 '13 at 12:17
Doesn’t match `/not-admin` either. – Gumbo Sep 01 '13 at 12:19
@Polmonino: I removed but the dot matches all after first group – Sep 01 '13 at 12:20
@Gumbo: OP asked for `/admin` and `/login` – Sep 01 '13 at 12:20
@Akam So it should match `/no-admin`, right? – Gumbo Sep 01 '13 at 12:21
@Akam And now after your change it does match both `/admin` and `/login`. – Gumbo Sep 01 '13 at 12:22
@Akam You don’t really know regex, do you? Use `^/(?!(admin|login|files)($|/))` instead. – Gumbo Sep 01 '13 at 12:42
@Gumbo: But I know how to talk with people! rep is nothing! you have to teach your self how to deal with people in public comminity!!! – Sep 01 '13 at 12:44
@Gumbo: http://phpfiddle.org/main/code/zpe-1ex here is your pattern! haha – Sep 01 '13 at 13:08
@Akam So what? I don’t see anything wrong there. – Gumbo Sep 01 '13 at 13:11
haha I knew, there is nothing wrong with mine also – Sep 01 '13 at 13:14
so which pattern is correct? – angry kiwi Feb 05 '15 at 04:30

PHP regex match something not starting with words like "admin", "login"... and so on?

1 Answers1