The best trick is to not use regular Drupal file paths on your pages and
instead use an internal Drupal path, the same way the private download
method does. Just alter your links using hook_node_view.
If you want to keep the paths intact, then it takes a couple of
.htaccess tricks.
First to answer your question, yes Drupal's .htaccess rules check if a
file exists and if so it serves it directly. This is necessary for
things like css, js and theme images to load properly.
You can force .htaccess to ignore certain paths. In Drupal's .htaccess,
right before Drupal's rewrite rules (right after # RewriteBase /):
RewriteCond %{REQUEST_URI} /sites/default/files/imagecache/.*
RewriteRule ^(.*)$ index.php?q=$1 [L,QSA]
Now any file request to /sites/default/files/imagecache/* will go
through Drupal. Everything else will be handled normally.
One note of caution though. If you are using this for thumbnails and you
have a page with say 20 thumbnails on it, it will be a major performance
hit. You are requiring Drupal to bootstrap for every one of those
requests, so if a person hits that page, Drupal has to fire up 21 times
(20 for images, once for the page). Even a decent dedicated server will
have problems with that.
The better alternatives are to either watermark all your thumbnails (ie:
ImageCache Actions) and serve them directly, or to use a CDN that offers
token based authentication, like VoxCAST.
Jamie Holly
http://www.intoxination.net
http://www.hollyit.net
On 7/14/2010 5:58 AM, Lee Rowlands wrote:
Hi
I asked this one on the list during Drupalcon SF but got no response
(the list was quiet that week!) so here goes again:
*The Background*
---------------
I've got a module I'm working on that needs to force some images to go
via the private download method.
This is working fine rerouting links via system/files in combination
with a htaccess file limiting direct access to the directory.
I also need thumbnails in various sizes of the images so it makes sense
to use imagecache.
I want the site in public download method except for these files and
I've successfully got the imagecache integration working.
I've used hook_menu_alter to prevent people accessing the relevant
imagecache file path directly, rerouting the imagecache cached images
via system/files.
The problem is, once the imagecache file is created, the file is no
longer being served via Drupal, with Apache serving it direct. This
obviously does not get near my access callback.
*The Questions*
---------------
Is this down to Drupal's rewrite rules?
Are the rewrite rules not evaluated if the file actually exists?
Can I create a rewrite rule to force this file to go through Drupal -
the relevant files all contain a common element in their path so I
should be able to match it) or do I need to consider alternatives such
as creating .htaccess files in the subfolders for each imagecache
preset, monitoring for new presets?
Any suggestions welcome.
Lee Rowlands
