Mod Rewrite to exclude prefixed files

[QuantumTiger]

I'm using a PHP script to dynamically put a copyright watermark on my images. My current method means that all my jpgs appear to be called watermark.jpg which is not ideal.

So I thought I could use mod rewrite to allow me to apply the watermark whilst preserving the image filename - however I cannot work out how to get it to exclude certain files.

All the images have filenames with no prefix appart from my thumbnails which start t_ and my site graphics which start qt

eg
skylark.jpg - image needs watermarking
t_skylark.jpg - thumbnail does not need watermarking
qtBanner1.jpg - banner does not need watermarking

I''ve got as far as discovering that the following

RewriteCond %{REQUEST_FILENAME} -f
RewriteRule /t_[a-z]+\.jpg$ watermark.php [QSA,NC]

will do the thumbnails only (the opposite of what I need). On my reading of regular expressions I was expecting that either

RewriteRule /!(t_[a-z]+)\.jpg$ watermark.php [QSA,NC]
or
RewriteRule /!(t_)[a-z]+\.jpg$ watermark.php [QSA,NC]

would invert that. But neither seems to do the trick. Any suggestions would be most welcome.

Thanks!

[quantumitger.org...]

[g1smd]

You need a RewriteCond line before the rule to test the filename. The following (one!) rule will only run if the condition is true.

[jdMorgan]

You need to require that the requested local URL-path both end in ".jpg" and not start with "t_" or "qt". You can handle the former requirement in the RewriteRule, and add the latter requirement using a RewriteCond as noted above.

Something like:

RewriteCond %{REQUEST_URI} !/(t_¦qt)[^/.]+\.jpg$
RewriteRule \.jpg$ /watermark.php [NC,L]

The added bit of "[^/.]+" fanciness in the RewriteCond makes the watermarking specific to the "filename" only. That is, a URL-path such as /qtrack/widget-pic.jpg WILL be watermarked, because the "qt" is part of the directory name, not the image name.

Replace the broken pipe "¦" character with a solid pipe character before use; Posting on this forum modifies the pipe characters.

Jim

[QuantumTiger]

Aha. Light dawns! I've spent a lot of time looking into the RewriteRule and regular expressions but none whatsoever looking at RewriteCond.

Many thanks to both of you for your help.

[g1smd]

Glad you got it sorted.

I've spent half of today writing and editing .htaccess code. Finally got it all working too.