Re: Dynamic images

From: FLEB (soon.the.sp_at_mmers.and.evil.ones.will.bow-down-to.us)
Date: 01/24/04 

Date: Sat, 24 Jan 2004 00:42:59 -0500

Regarding this well-known quote, often attributed to CountScubula's famous
"Sat, 24 Jan 2004 01:48:37 GMT" speech:

> "Chung Leong" <chernyshevsky@hotmail.com> wrote in message
> news:iIydnbKaXIqAXIzd4p2dnA@comcast.com...
>> Nice. I think we make better use of the client cache though, by
> redirecting
>> to the generated image. As it is, the browser has to refetch the image
>> everytime.
>
> Thank you,
>
> Hmm, sounds interesting, you mean have a cache dir that is in the web server
> view, and do a Location: bla.... to point to the image?
>
> Hmm I will have to play and see, becouse as it is, if there is any change
> int he source image, there is a new image generated.
>
> also, I just added a few more functions:
>
> title - add a caption
> pan - show part of image
> zoom - show a zoomed from middle portion
> tile - tile the image

Just title the cached image uniquely --

something like:
[PATH-HASH]_[MOD-DATE].ext

where [PATH-HASH] is the full original path, run through something (md5 or
a search-replace) to purge evil chars, and [MOD-DATE] is the file's
last-modified date. When the code is run, do something like:

1.) Get all filenames containing [PATH-HASH] in the cache directory
2.) Is the latest [MOD-DATE] the same as the real file's modified-stamp?

3. Yes) Do not recreate the thumbnail. Redirect to the cached version.

3. No) Delete (unlink) all files with [PATH-HASH]_*
4. No) Create a new thumbnail, and redirect to it. 

-- 
-- Rudy Fleminger
-- sp@mmers.and.evil.ones.will.bow-down-to.us
   (put "Hey!" in the Subject line for priority processing!)
-- http://www.pixelsaredead.com

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