Check for a directory inside a subdirectory dynamically

I have a bunch of domains which points to the same directory "public_html" on my host.

There is a .htaccess file in the main folder that locally redirects each domain to a particular folder with the same name as %{HTTP_HOST} mod_rewrite variable. (eg: redirect www.domain.com to public_html/www.domain.com/)

This is the content of the .htaccess:

RewriteEngine On
RewriteBase /
RewriteCond /%{HTTP_HOST}/#%{REQUEST_URI} !^([^#]+)#\1
RewriteRule ^(.*)$ %{HTTP_HOST}/$1 [L]

I'm having a problem when it comes to the Directory Slash directive.

If I try to access a folder in the domain url without the forward slash like http://www.domain.com/folder, the mod_dir applies the DirectorySlash and externally redirects my request to http://www.domain.com/www.domain.com/folder/

I tried applying a 301 redirect AFTER the domain directory redirect like this:

RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^(.*[^/])$ $1/ [R=301,L]

But for this to work, I would have to be able to check if the %{REQUEST_FILENAME} exists inside the %{HTTP_HOST} 'folder'. I even tried the following, for no success:

RewriteCond /%{HTTP_HOST}/%{REQUEST_FILENAME} -d
RewriteRule ^(.*[^/开发者_StackOverflow])$ $1/ [R=301,L]

How can I check, Dynamically, if the %{REQUEST_FILENAME} is a directory, which would be inside a directory with the same name as %{HTTP_HOST}?

Thanks in advance

If you work with -d you need to provide an absolute filesystem path. So try this:

RewriteCond %{DOCUMENT_ROOT}/%{HTTP_HOST}%{REQUEST_URI} -d
RewriteRule ^(.*[^/])$ $1/ [R=301,L]