Fixing Rewrite Rules and Conditions In HTACCESS file - .htaccess

Question

Well lets say I have this follow code in my htaccess file,
Options +FollowSymlinks
RewriteEngine on
RewriteCond %{HTTP_HOST} ^www\.(.*) [NC]
RewriteRule ^(.*)$ http://%1/$1 [R=301,NC,L]
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.php -f
RewriteRule ^([^/]+)$ $1.php
RewriteRule ^forums/([0-9]+) forums.php?category=$1 [NC]
I was wondering how would I, with the above code, redirect certain extensions in a url to my websites 404 page.
For instance, if this link mywebsite.com/forums has any extension at the end of it such as .asp, .php, .html, and so forth it then would get redirected to my 404 page.
And on a quick side note how can I limit the last RewriteRule to only a certain forward slash where mywebsite.com/forums/2 would show the page fine and anything after that certain limit such as mywebsite.com/forums/2/so on... would be redirected to my 404 page.
Anyone have any ideas?

Answer 1

If I understand the question properly, then you need to firm up the regular expressions to only match the patterns you really want - at the moment, they're a bit too lenient for your needs.
For example:
RewriteRule ^([^/]+)$ $1.php
This will match anything without a trailing slash, whereas if you wanted to restrict it to only match, say, things without a trailing slash and consisting of alphanumeric characters, then you might do this:
RewriteRule ^([a-zA-Z0-9]+)$ $1.php
(You could achieve the same effect for certain extensions only by using a lookahead assertion, but that complicates your regular expression. I feel it's probably saner (and easier on the mind) to think about the patterns you really want matched, and then express those up-front.)
Likewise, your latter example:
RewriteRule ^forums/([0-9]+) forums.php?category=$1 [NC]
will match anything which starts with the string forums/, followed by one or more digits, whether or not there's anything after that. Adding an end anchor ($) as you have above
RewriteRule ^forums/([0-9]+)$ ...
will assert that the string ends after the digits.
This relies on the fact that if mod_rewrite can't find a match, it won't attempt any rewrites, and will (in the absence of any explicit resource at that path) fall through to Apache's 404 handling, which is then up to you to override.