Dynamic <IMG>

[Niall Kavanagh]

On Wed, 16 Aug 2000, Ron Peterson wrote:

> > print ("Content-type:  image/png\n\n");
> > ...{send image}
> 
> I'd better confirm that this was indeed the problem before my inbox
> explodes.  :-)  I was under the mistaken impression that you only did
> this when you wanted to send an image to a browser naked and alone.
> 

Every image gets sent to the browser naked and alone, as every image is
returned after an individual GET request.

> So things work now, but not really.  Now I have to figure out why even
> dynamically generated images get cached by the browser, and what do I do
> about it.  Bleh.
> 

If you're setting your own headers, a variety of things. 

1) Have the script return 201 (Created) instead of 200 (OK)

2) Set the headers:

Expires: <some date>
Last-Modified: <some date (current to defeat cache)>
Cache-Control: no-cache

Of course, no solution works for every agent. See the RFC and try and
cover yer ass:

http://www.w3.org/Protocols/rfc2068/rfc2068

Good luck! ;)

--
Niall Kavanagh, niall at kst.com
News, articles, and resources for web professionals and developers:
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