mod_rewrite in a subdirectory - apache

Question

Our web server is structured as follows
/path-to-docdir [Contains main pages]
./app/ [Some application not directly related to the main content]
The main pages are served fine. In the app directory I am trying to use mod_rewrite to redirect all pages to an index.php in a public directory
So a request to
/server/app/start/login/ => /server/app/public/index.php
/server/app/start/login => /server/app/public/index.php
/server/app/start/login?name=someone => /server/app/public/index.php?name=someone
The front controller relies on the last two components of the REQUEST_URI string to interpret controller and action.
To do the above I have created the following .htaccess file in the app directory
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteRule ^$ public/ [L]
RewriteRule ^(.*)$ public/$1 [L]
</IfModule>
Here, I find that the server goes in a redirect loop for the above URLs. I tried replacing $1 with index.php and that does bring up the page, but the internal references within the page to script files run into errors.
After some searching around, I added the following line:
RewriteBase /app/
And that did not seem to make any difference. I should also note that everything works as expected if I make the app directory as the server root directory.
I've also turned on debug logging and all I could gather from that was that the server was indeed going into a redirect loop.
[perdir /path-to-docdir/app/] internal redirect with /app/public/public/public/public/public/public/public/public/public/public/public/start/login/ [INTERNAL REDIRECT]
I'm not really sure where to start looking at this point, so any help or pointers to move me further would be much appreciated.
Edit:
This htaccess file worked for me - if anyone else is looking for a solution. Apparently, I was missing rewrite conditions
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{SCRIPT_FILENAME} !-f
RewriteCond %{SCRIPT_FILENAME} !-d
RewriteRule ^(.*)$ public/index.php?$1 [L]
</IfModule>

Answer 1

A few points:
A RewriteBase path does not need a trailing slash, so RewriteBase /app/ should be RewriteBase /app.
RewriteRule ^(.*)$ public/$1 makes RewriteRule ^$ public/ superfluous. The former will match http://yourserver/app and internally rewrite as http://yourserver/app/public, so there's no need for the latter.
Finally, try adding a rewrite condition:
RewriteEngine On
RewriteBase /app
RewriteCond %{REQUEST_URI} !^/app/public/
RewriteRule ^(.*)$ public/$1 [L]