Forcing a trailing slash to a URL after a subdomain rewrite - php

Question

I'm re-writing a subdomain to a 'folder' - actually a page in wordpress, and this all seems to be working correctly. I don't want the address in the URL bar to change though.
Everything works fine unless the user does not put a trailing slash after the page name, then the page is still redirected to the correct URL but the URL in the address bar changes
For example: foo.example.com/bar
Becomes: public.example.com/foo/bar
Where : foo.example.com/bar/ stays at the correct URL in the address bar but shows the redirected page (this is correct)
What rule do i need to add to add in a trailing slash if its not sent?
The code i have so far is:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
Options +FollowSymlinks
RewriteCond %{HTTP_HOST} ^foo\.example\.com$ [NC]
RewriteRule ^(.*)$ http://public.example.com/foo/$1 [P]
# rules for WordPress ...
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
#####
</IfModule>
Any help would be fantastic, I'm pretty new to htaccess. Thanks!

Answer 1

Phew, after a bit of playing around i seem to have got it working:
RewriteCond %{HTTP_HOST} ^foo\.example\.com$ [NC]
RewriteCond %{REQUEST_URI} !(.*)/$
RewriteRule ^(.*)$ http://foo.example.com/$1/ [L,R=301]
RewriteCond %{HTTP_HOST} ^foo\.example\.com$ [NC]
RewriteRule ^(.*)$ http://public.example.com/foo/$1 [P]
Basically, the first block adds a trailing slash to the URL is it's not there in the first place, then the second block does the proxy redirect for the URL.
As far as i can see this catches all cases, but let me know if there are any gaping holes!

Answer 2

This rule should do it:
RewriteRule .*[^/]$ %{REQUEST_URI}/
Put this rule in front of your other rules. You also may want to add a condition to exclude existing files:
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule .*[^/]$ %{REQUEST_URI}/