Mod_rewrite problems

toastyman · 22 Oct 2007 at 19:25

Greetings all!

I'm just writing a mod_rewrite rule, but wanted to get a few pointers...

For $1 of the URL, it needs to match underscores, all letters (regardless of case) and all numbers.
For $2 of the URL, it needs to match $ - _ . + ! * ' ( ) , all letters (regardless of case) and all numbers.

This is what I have so far:

Code:

RewriteRule ^zones/([_a-zA-Z0-9-]+)/things/(['_a-zA-Z0-9-]+)/discussion/$ things/discussion_newtopic.php?z=$1&t=$2 [NC]

Have I done this right? How would I add the special characters - Just escape them with a backslash?

Cheers all!

SiriusB · 22 Oct 2007 at 21:12

From my limited regex knowledge, yes you can escape special characters

Sic · 22 Oct 2007 at 21:28

http://www.regular-expressions.info/reference.html

I still need to check this when writing regexes

but yeah, you'll need to escape those hyphens at the end of your character classes with the backslash

toastyman · 24 Oct 2007 at 09:11

Cheers guys!

I had a go at writing it, and in my RegExp tester (software based), and this works fine:

Code:

^[a-zA-Z0-9 '\(\)-]*$|

Running it by the string

Code:

hello world '()- gf hgfh fgh

However, when I put this in the PHP, PHP kicks up an error:

Warning: preg_match() [function.preg-match]: No ending delimiter '^' found

So I added a | to the front of the regexp, and it runs fine, but doesn't match the string

marc2003 · 24 Oct 2007 at 09:17

regular expressions are pure evil. i just use

(.+)

that matches anything. worry about cleansing the $_GET values in your script.

edit: this is probably awful advice, so ignore me.

Sic · 24 Oct 2007 at 09:28

toastyman said:
Cheers guys!

I had a go at writing it, and in my RegExp tester (software based), and this works fine:

Code:

^[a-zA-Z0-9 '-]*$|

Running it by the string

Code:

hello world '()- gf hgfh fgh

However, when I put this in the PHP, PHP kicks up an error:

So I added a | to the front of the regexp, and it runs fine, but doesn't match the string

that's because preg replace uses perl format regular expressions, whereas mod_rewrite uses posix (I think, it's a different format to preg anyway)

anyway, using preg_replace, you need to use a beginning and end delimiter. I normally use backticks, so a blank preg_replace would look like:

Code:

preg_replace('`[A-Z]*`','blah',$subject);

marc - regular expressions are INCREDIBLY useful. they're definitely worth learning to at least a basic standard (I still refer to manuals most of the time!)

marc2003 · 24 Oct 2007 at 09:45

Sic said:
marc - regular expressions are INCREDIBLY useful. they're definitely worth learning to at least a basic standard (I still refer to manuals most of the time!)

absolutely, i can see how they would be useful in scripts/other programming.

but i can't see the point for a simple mod_rewrite.