.htaccess RewriteRule query isn't working - .htaccess

Question

I can't get the following RewriteRule to work.
I have a PHP SQL query to display a web page. It requires a RewriteRule rule which I'm trying to achieve in a .htaccess file.
Here is the full URL at the moment.
www.example.com/category/sub-cat/page.php?art_url=a-page-of-mine
I can't get it to do
www.example.com/category/sub-cat/a-page-of-mine
My Code below:
Options +MultiViews
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^\.]+)$ $1.php [NC,L]
ErrorDocument 404 /error-404.php
#error 404
RewriteRule ^error/?$ error-404.php [NC,L]
RewriteRule ^category/sub-cat/(0-9a-zA-Z]+) category/sub-cat/page.php?art_url=$1 [NC,L]
Can someone help me out?

Answer 1

AS I said in the comments
Missing a few things here (0-9a-zA-Z]+) like [- as in ([-0-9a-zA-Z]+)
This is going to bite you too...
RewriteRule ^([^\.]+)$ $1.php [NC,L]
Match everything that doesn't have a dot and add .php to it with the [L] last flag. I would bet it will never pass that one in the first place.
Generally you want the more specific rules first, followed by the more generic ones last.
Also if I recall correctly the NC i no case, so you can get rid of the A-Z and just do [-a-z0-9]+
A better way
I try to avoid query string rewrites and rely on the URI method of rewriting common in MVC frameworks
example.com/index.php/category/sub-cat/a-page-of-mine
And then use a router and HTACCESS to only remove the index.php it's much simpler that way.
I have a pretty bare bones router on my GitHub page that shows how to route URL's like that.
https://github.com/ArtisticPhoenix/MISC/tree/master/Router
One big issue with messing with the query string is you can lose the ability to use $_GET the way it's designed to be used for things like search forms etc. So it's better to route not rewrite. Also the MVC way gives you a single entry point for all requests to go through which can make it easier to manage things like Constants, and Autoloaders....

Answer 2

Oh well, this is broken of course:
(0-9a-zA-Z]+)
The charclass lacks the opening [ and doesn't contain/match a literal - as well.

Answer 3

Right. To get this working I needed to add QSA as in [QSA,NC,L]. After how many weeks!!??