How to get rid of looping in RewriteRule?

Question

Apache HTTP Server

Two virtual domains look at one htdocs. At the root of the hosting, I created directories for them htdocs/forumand htdocs/media. Next to them is this htaccess:

RewriteEngine on

RewriteCond %{HTTP_HOST} =forum.cantorsys.com [NC]
RewriteRule ^ /forum%{REQUEST_URI} [QSA,L]

RewriteCond %{HTTP_HOST} =media.cantorsys.com [NC]
RewriteRule ^ /media%{REQUEST_URI} [QSA,L]

#RewriteRule ^/(.*)/?(.*)? http://$1.cantorsys.com/$2 [QSA,R=301]

The last redirect had to be commented out because it doesn't work as expected:

• I would like the view URLs to be http://forum.cantorsys.com/forum/userlist.phpredirected to http://forum.cantorsys.com/userlist.php, that is, to be removed /forumfrom the path and the new path to be in the address bar of the browser.
  
• Now http://media.cantorsys.com/forum/userlist.phpit redirects normally, but http://forum.cantorsys.com/forumcauses a loop.
  

I can not understand the logic of Apache. What, you can not redirect to another path in your domain?

Answer 1

RewriteCond %{REQUEST_URI} ^/forum/(.*)$ [QSA,L,NC]
RewriteRule ^(.*)$ http:/forum.cantorsys.com/%1 [R=301,L]

Where %1 is what is in the brackets in RewriteCond
If you need a bracket from the RewriteRule, then there is already $1
And you have a cycle because %{REQUEST_URI} contains your forum