.htaccess default directory behaviour - php

Question

I have just started learning about .htaccess files for Apache, I have a website set up so that all requests should come through my index file (which is called Main.php).
"Webpages" are then acquired through a wp GET var (such as wp=forum) - i wish to make this instead Domain/directory/Forum instead of the current Doman/directory/Main.php?wp=Forum
The problem i am facing is that all my "webpages" are stored in their own directory and are made up of "webparts" so forum will be a sub directory of "forum" with files inside it that make up the page. This is causing problems with my redirecting.
I have created the following .htacess file:
#turn redirect engine on
RewriteEngine On
#make sure URI is not a file
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^?]*)$ Main.php?wp=$1 [NC,L,QSA]
This works fine on the redirecting until it is a directory that is entered as the "wp" at which time it will add a trailing slash and corrupt the wp GET var passed (forum/ would be passed not forum as needed)
Here are 2 examples of how I think it may be working:
Main (not a file or directory)
loop 1: Hits the rewrite changes to Main.php?wp=Main
loop 2: URI is file (no change)
MainContent (is a directory)
loop 1: Hits the default directory change? (guess) Changes to
MainContent/ (note the trailing slash)
loop 2: Starts .htaccess and changes this to Main.php?wp=MainContent/
loop 3: URI is file (no change)
Moreover, whenever a file is accessed in my websever with a trailing slash after to (so example: Main.php/) it will display with no links or included files. It will just show the file being requested and seems to ignore any and all css ... php includes or anything else (is this default Apache settings?).
Sorry for the long and possible confusing post. If I need to clean anything up just shout.

Answer 1

Try with that:
#turn redirect engine on
RewriteEngine On
DirectorySlash Off
#make sure URI is not a file
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)/?$ Main.php?wp=$1 [NC,L,QSA]

Answer 2

It might be helpful to look at the .htaccess file for Drupal, which does the same thing - i.e. redirect all requests through the index file. The most relevant snippet from that file is:
# Pass all requests not referring directly to files in the filesystem to index.php?page=[rest of url]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !=/favicon.ico
RewriteRule ^(.*)$ index.php?page=$1 [L,QSA]
The second condition above "! -d" might solve the problem you describe but you might still need to do some "cleaning" in your php code. It's worth looking at the whole Drupal .htaccess file as it does other things to tighten security, such as blocking access to certain files etc.