Please help with this mod_rewrite issue

This current system in place needs to allow periods (.) optionally inside of the rewrite condition.

For example: /john.doe should work, since we allow periods in our user names.

However when I add . or \\. or [.] to the following rewrite rule, it either gets stuck in an endless loop, having to restart apache2. Amazingly, the behaviour has changed and I am not sure why. Now it just appends the new string to the existing URL.

For example: /john.doe will become /john.doe/?pg=user&username=john.doe

RewriteRule ^/([a-z0-9_]+)$ /?pg=user&username=$1 [NC,PT]

I am going crazy trying to fix this开发者_Python百科, please help!

This should work (I'm saying "should" as I do not know how your whole system is set up and what other redirects etc are in place -- I see you are using PT flag (maybe you are using aliases)):

RewriteCond %{REQUEST_URI} !^/index\.php
RewriteRule ^([a-z0-9_\.]+)$ /index.php?pg=user&username=$1 [NC,QSA,L]

OR

RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([a-z0-9_\.]+)$ /index.php?pg=user&username=$1 [NC,QSA,L]

I have specified the script file directly -- it's much more easier to write a rule if you know how it works behind.