Caching and php: Serving generated file static to speed up requests

In code, my question is:开发者_运维百科

if(file_exists( c/ $requesturl ) 
serve( c/ $requesturl )
else
serve( index.php?blah )

---

In human form:

My script generates CSS. This is pretty intensive, so I built in caching.

People request: http://domain.com/css/1lfi4wg.css2

Which is rewritten:

RewriteRule ^([a-zA-Z0-9\-]*)\.css$  index.php?cssfilename=$1&generate

This works. After the above is visited, a cachefile is generated, which also works:

http:// domain.com/css /c/ 1lfi4wg.css2

Now I want to serve the generated file (/c/*) as the original request. I now do this in the php file itself, but I guess doing this with htaccess is quicker.

I now have this which does not work:

RewriteCond %{DOCUMENT_ROOT}/c/%{REQUEST_FILENAME} -f
RewriteRule ^(.*)\.css$ %{DOCUMENT_ROOT}/c/$1.css [L]

---

REQUEST_FILENAME already is an absolute file system path. Try the URI path in REQUEST_URI or the matched string of the RewriteRule pattern instead:

RewriteCond %{DOCUMENT_ROOT}/c%{REQUEST_URI} -f
RewriteRule ^.*\.css$ %{DOCUMENT_ROOT}/c%{REQUEST_URI} [L]
# OR
RewriteCond %{DOCUMENT_ROOT}/c/$0 -f
RewriteRule ^.*\.css$ %{DOCUMENT_ROOT}/c/$0 [L]