htaccess Silent Redirect to Subdirectory: Subdirectory showing when no trailing '/'

Question

I have dug high and low around Google and StackOverflow to try and figure out my problem, trying countless solutions but nothing has completely worked.

I'm looking to move the web root of the main domain on my server to a sub-directory. What I have currently for a server path to my web root:

/home/user/public_html/MyWebFilesHere

What I'm looking to have:

/home/user/public_html/subdir/MyWebfilesHere

When I browse to mydomain.com, there should be no visible difference though (i.e. "subdir" not visible after redirect).

Unfortunately, I am restricted to doing this purely with a .htaccess file since I'm on shared hosting and don't have access to Apache config files and such. :(

What I currently have in my .htaccess in public_html is:

RewriteEngine on
RewriteCond %{HTTP_HOST} ^(www\.)?mydomain\.com$
RewriteCond %{REQUEST_URI} !^/subdir/
RewriteRule ^(.*)$ /subdir/$1 [L]

This successfully redirects all queries to the sub-directory, however there's a really weird issue. If I go to

mydomain.com/Contact/

it works great, redirecting the query to the path /subdir/Contact/ but leaving the address bar alone. If I go to

mydomain.com/Contact

(Note the lack of a trailing '/') though, what shows in the address bar is

mydomain.com/subdir/Contact/

which isn't what I want since "subdir" is showing.

For a working example on my actual site, try browsing to

colincwilliams.com/Contact/

compared with

colincwilliams.com/Contact

Do you guys have any ideas on how to make this work silently both with and without a trailing slash?

Answer 1

This is probably happening because mod_dir (the module that automatically redirects the browser if a request for a directory is missing a trailing slash to the same thing with a trailing slash. See the DirectorySlash directive in mod_dir

What's happening is:

1. You request: mydomain.com/Contact
2. mod_dir doesn't touch this since /Contact isn't a directory
3. /Contact gets rewritten to /subdir/Contact and internally redirected
4. mod_dir sees that /subdir/Contact is a directory and missing the trailing slash so it redirects the browser to mydomain.com/subdir/Contact/
5. So now, your browser's location bar has the /subdir/ in it.

You can add DirectorySlash off in your .htaccess to turn off mod_dir from redirecting. But if you want directories to have trailing slashes, you can add a separate condition for it. Based on what you already have, we can expand it to this:

RewriteEngine on

# Has a trailing slash, don't append one when rewriting
RewriteCond %{HTTP_HOST} ^(www\.)?mydomain\.com$
RewriteCond %{REQUEST_URI} !^/subdir/
RewriteCond %{THE_REQUEST} ./\ HTTP/1\.[01]$ [OR]
# OR if it's a file that ends with one of these extensions
RewriteCond %{REQUEST_URI} \.(php|html?|jpg|gif|css)$
RewriteRule ^(.*)$ /subdir/$1 [L]

# Missing trailing slash, append one
RewriteCond %{HTTP_HOST} ^(www\.)?mydomain\.com$
RewriteCond %{REQUEST_URI} !^/subdir/
RewriteCond %{THE_REQUEST} [^/]\ HTTP/1\.[01]$
# But only if it's not a file that ends with one of these extensions
RewriteCond %{REQUEST_URI} !\.(php|html?|jpg|gif|css)$
RewriteRule ^(.*)$ /subdir/$1/ [L]

Note: I changed !^/mydomain/ to !^/subdir/, figured it was a typo because without it, mod_rewrite would loop internally indefinitely (foo -> /subdir/foo -> /subdir/subdir/foo -> /subdir/subdir/subdir/foo, etc). If I got that wrong, you can change it back.

Edit: See my additions of RewriteCond's matching against \.(php|html?|jpg|gif|css). These are the file extensions that get passed through without getting trailing slashes added. You can add/remove to suit your needs.