Scalable URL Rewrite Rule - apache

Question

I am organizing sub-websites into different folders on a LAMP server for ease of maintenance, but do not want the end user to know they are organized into those folders via the URL.
Directory structure example:
/category1/website1
/category1/website2
/category2/website3
/category2/website4
/category2/website5
/category3/website6
/category4/website7
etc.
Currently it shows as http://www.example.com/category1/website1 however I want it to show as http://www.example.com/website1 all the time - even if they put the category name in there.
The trick is I need to do this from a .htaccess file with X amount of categories having X amount of sub-websites in them. Currently I am using
Redirect 301 /website1 /category1/website1
for each website to allow users to use the shorter link, but ultimately they end up seeing the category in the address and the .htaccess file is long with 200+ sub-websites involved. :(
Any help would be appreciated!

Answer 1

Using mod_rewrite it's pretty straight-forward if you are going to manually enter them in:
RewriteEngine on
RewriteRule ^/website1$ /category1/website1 [L,NC]
RewriteRule ^/website2$ /category1/website2 [L,NC]
It's possible to create a RewriteMap as well. There's a lot of helpful information in the documention
Hope that helps.

Answer 2

Since there is no discernible "pattern" that links the website to the category subdirectory and you are limited to .htaccess then you have no choice but to manually list all the mappings in your .htaccess file, in the same way you have listed the redirects.
Assuming you want to internally rewrite a URL of the form /website1/<something> to /category1/website1/<something> - in the same way the Redirect directive works (which is prefix-matching).
You could do something like the following in .htaccess:
RewriteEngine On
RewriteRule ^(website1/.*) /category1/$1 [L]
RewriteRule ^(website2/.*) /category1/$1 [L]
$1 is a backreference to the captured group in the RewriteRule pattern. eg. If you request /website1/foo then it will rewrite to /category1/website1/foo.
This does require that you request at least /website1/, with a trailing slash (since this is a directory of sorts).
You can potentially group sites together that are in the same category. For example:
RewriteRule ^((website3|website4|website5)/.*) /category2/$1 [L]
I want it to show as http://www.example.com/website1 all the time - even if they put the category name in there
For this you would need to implement the reverse... a redirect to remove the category from the URL. However, an added complication is that you only want to redirect direct requests and not rewritten requests (as above).
This will need to go before the internal rewrites above.
Unless there is a discernible pattern that distinguishes category names then you will need a rule for each category. For example:
RewriteCond %{ENV:REDIRECT_STATUS} ^$
RewriteRule ^category1/(.*) /$1 [R=302,L]
...and repeat for each category.
The check against the REDIRECT_STATUS environment variable ensures that we are only targeting direct requests and not rewritten requests.
Change 302 (temporary) to 301 (permanent) - if that is the intention - only once you have confirmed that it works OK in order to avoid caching issues.
However, this may be easier (and more "scalable") to implement with an additional .htaccess file in each of the category subdirectories instead. And this would be the same directives in each category subdirectory:
RewriteEngine On
RewriteCond %{ENV:REDIRECT_STATUS} ^$
RewriteRule (.*) /$1 [R=302,L]
Since the URL-path matched by the RewriteRule pattern is relative to the directory containing the .htaccess file, the $1 backreference contains the URL-path less the /category/ prefix.