[Zope] how to invalidate an object in the cache?

[Marc Boschma]

Sounds like you need to manipulate the expiry time for the objects. I'd
suggest that that can either be done in the RESPONSE or via meta tags in the
standard_html_header to mark the page and the image as non-cacheable.

I'm actually interested in a Guru's response on this as I will need to set
the expiry explicitly to save load on the server for content that is
dynamically generated but doesn't change often.

Marc

> -----Original Message-----
> From: zope-admin@zope.org [mailto:zope-admin@zope.org]On
> Behalf Of Marco
> Mariani
> Sent: Sunday, 2 July 2000 9:08 AM
> To: zope@zope.org
> Subject: [Zope] how to invalidate an object in the cache?
>
>
>
> I am working with photo rotating/resizing, via PIL on external
> method.
>
> All the images are kept on LocalFS.
>
> There is a thumbnail bonanza page, when I select a thumbnail a
> form is shown, and I can adjust rotation/contrast/brightness.
> Upon submit, the new image+thumbnail is calculated and written
> to the filesystem.
>
> Then the method calls RESPONSE.redirect to show the index page again.
>
> When I go back to the index thumbnail page, the
> image I've just rotated is displayed with the right size (which means
> that Zope gets it right), but not rotated (which means that Netscape
> reads the old image from the cache). I mean, if it was 320x200 and is
> now 200x320, the browser displays the old 320x200 image stretched to
> 200x320.
>
> I'm not digging into contrast and brightness, but the same happens.
>
> Is there a way to force the browser to discard the cache for that
> image? If I go "right-button, view image, shift+reload" the new
> image is displayed.
>
> Any idea? I'm not very knowledgeable on this matter, I don't design
> pages for a living.
>
> Might javascript help?
>
>
> Thank you.
>
> --
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> higher court."
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>
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