mod_rewrite aliasing a subdirectory

I'm struggling with mod_rewrite as always. We have a number of client portals running through WordPress multisite, all accessed through a subdirectory: portal.

So for example: http://www.mydomain.com/portal/clientA/

I'd like to be able to get there just by typing http://www.mydomain.com/clientA/ and it would redirect me to http://www.mydomain.com/portal/clientA/

Here's what I have so far, and it's not producing any rewrite that I can tell:

RewriteCond %{REQUEST_URI} /portal/
RewriteCond %{REQUEST_FILENAME开发者_开发百科} -f
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule . - [S=1]

RewriteRule /clientA(/?) /portal/clientA/

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress

The second part I can't touch because WordPress needs it. My pattern is also trying to anticipate someone not putting in the trailing slash, hence the (/?)

EDIT: I should also note that I don't want to create a more general rule - I'm comfortable having to add a rewrite rule for each new client and increasing the S=x number each time.

EDIT (Aug 11), So after a little more puttering this is what my .htaccess is at:

RewriteEngine On
RewriteRule ^clientA(/?) /portal/clientA/ [R]

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

Needless to say it doesn't work. However, the first part works IF I delete the entire WordPress section. I need them BOTH to work simultaneously. WHAT is it about the WordPress piece that is causing the failure of the first section? I suppose it's the combination of RewriteBase and the very last rule which aliases anything else to /index.php, which frankly is a bit of a bummer. In fact I don't truly understand how that rule could even work in a multisite context, and yet it seems to.

FINAL SOLUTION thanks to LazyOne for the correct answer! For others' reference, the final solution I used was:

RewriteEngine On
RewriteRule ^clientA(/.+)? /portal/clientA$1 [R,L]
RewriteRule ^clientB(/.+)? /portal/clientB$1 [R,L]


# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

---

As simple as this:

RewriteCond %{REQUEST_URI} !^/portal/
RewriteRule (.*) /portal/$1 [L]

It will rewrite (internal redirect) all requests into /portal/ folder (e.g. /clientA/something => /portal/clientA/something).

If you need to do it for some clients only (or, better say, only specific folders that are clients while still having some general/common folders as is), you can use this rule for each client:

RewriteRule ^clientA(.*) /portal/clientA$1 [L]

So that .htaccess will look like this:

RewriteRule ^clientA(.*) /portal/clientA$1 [L]
RewriteRule ^clientB(.*) /portal/clientB$1 [L]

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress

---

I posted part of this as a comment, but figured it might be more clear for people who land here to do this as an answer. To the OPs point, he found a way to do this using the [R] (redirect) line, but this eliminates the subdirectory URL structure you created that would be preferable in most URL Rewrites. So, the answer previously posted is right, I'm not contesting that, but depending on your implementation, you may still get WordPress 404 errors. Here is a solution to my situation, which I think might be more common.

In my case, I needed a URL structure like this:

http://mysite.com/p/profile_name/

Each user who comes to register can create his/her own profile on the fly, and aside from a few modifications to the content, for the most part all of the WordPress content at the root is what will be displayed. Essentially, I need this:

http://mysite.com/p/profile_name/(.*)

To be rewritten to this:

http://mysite.com/$1

This is the .htaccess code posted in the other answer that WILL handle that rule correctly:

RewriteRule ^p/([-a-zA-Z0-9_]+)(/.*) $2 [L]

The problem with this is that WordPress does not care about your rewrite in terms of understanding what $2 is because WordPress uses $_SERVER['REQUEST_URI'], which no matter what you rewrite to, it's always what's in the user's browser window. The OP found a way to get around this by using the [R] option, but that causes you to lose your URL:

RewriteRule ^p/([-a-zA-Z0-9_]+)(/.*) $2 [R,L]

Redirects:

http://mysite.com/p/profile/(.*)

To:

http://mysite.com/$1

But, the user loses his unique URL this way. At best you can add a query string to at least retain the data, but then you lose the point of the pretty URLs to begin with.

I did come up with a solution; however, it involves hacking the WordPress include files :( If someone has a better way, please update. Here we go:

SOLUTION

I set my .htaccess file equal to this:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
#My addition:
RewriteRule ^p/([-a-zA-Z0-9_]+)(/.*) $2 [L]

RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress

Then, I knew WordPress used the REQUEST_URI variable, so I did a recursive search, and located this line of code in /wp-includes/class-wp.php (line 147 v3.4.2):

$req_uri = $_SERVER['REQUEST_URI'];

I changed it to this:

$req_uri = preg_replace(@'/^\/?p\/([-a-zA-Z0-9_]+)\//', '', $_SERVER['REQUEST_URI']);

Which basically just tricks WordPress by filtering out the profile stuff at the beginning of the URI.

Lastly, I also needed a solution for the links within the site. For that, I added this filter:

NOTE: Some of these regexes might be a little bonkers; I was filtering out the site specific stuff, so please use this as a concept and not a copy/paste.

function mysite_wp_make_link_relative( $link ) {
    $sBaseUrl = (preg_match('/^\/(p\/[-a-zA-Z0-9_]+\/)(.*)/', $_SERVER['REQUEST_URI'], $matches)) ? $matches[1] : '';
    return preg_replace( '|https?://[^/]+/(.*)|i', '/' . $sBaseUrl . '$1', $link );
}
function rw_relative_urls() {
    $filters = array(
        'page_link', // Page link
        'home_url',
        'site_url',
        'get_site_url',
        'home_link',
    );
    foreach ( $filters as $filter ) {
        add_filter( $filter, 'mysite_wp_make_link_relative' );
    }
}

Some of those filters might not be relevant; I'm pretty sure page_link and home_url are the only important ones. Anyway, you need that code for your internal linking to work.

I hope that helps and if anyone has any comments suggestions for improving this, I would greatly appreciate it.