A Caching Issue - I Suspect

From: Smithers (a_at_b.com)
Date: 02/08/05 

Date: Tue, 8 Feb 2005 09:15:38 -0800

My ASP.NET app enables users to upload photos - after which they can
optionally rotate the photo (90 degrees to the left or right). They just
click a link that causes a postback, and server-side code then manipulates
the image file - after which the aspx page refreshes on the client, showing
the rotated version of the photo.

In testing I have observed that sometimes the image will in fact get rotated
(on the server), but the aspx page in the client will refresh but will not
show the current version of the photo.

Here is a typical test scenario with a test client running XP/Pro/SP2 IE6
connecting to separate Windows Server 2003/IIS6 in a data center accessible
via the Internet (i.e., this testing happens over the Internet):
1. Upload a photo. The aspx page shows original photo. This is good.
2. Click to rotate the photo 90 to the right. The aspx page shows the photo
rotated 90 to the right. This is good.
3. Click again to rotate the photo 90 to the right. The aspx shows the photo
rotated 90 from original, NOT 180 degrees as is saved on the server. The
photo should be upside-down at this point and it's not. This is not good.
4. At this point I can click to rotate the photo 90 degrees right or left -
and the aspx page continues to show it rotated 90 to the right - which was
the very first rotation (in step 2). After every rotation request sent from
the browser, I have verified that the image does, in fact, get rotated. I
verify this by viewing the image directly on/from the server (not through
the browser).

I suspected that the image was getting cached on the test client - but
purging the cache has no effect; rebooting the client has no effect, etc.
The only thing that seems to actually result in the current version of the
rotated photo showing up in the browser is waiting - about 10 minutes or so.

FWIW: the aspx has this at the top:<%@ OutputCache Location="none" %>

Any ideas for where the images are getting cached? What I need is the
ability to rotate the photos in any direction, any number of times during a
session, and have the current version show up in the browser.

Thanks!

Relevant Pages

  • Re: A Caching Issue - I Suspect
    ... > optionally rotate the photo. ... > rotated (on the server), but the aspx page in the client will refresh ... After every rotation request sent from the browser, ...
    (microsoft.public.dotnet.framework.aspnet)
  • Re: A Caching Issue - I Suspect
    ... > optionally rotate the photo. ... > the image file - after which the aspx page refreshes on the client, ... > connecting to separate Windows Server 2003/IIS6 in a data center ...
    (microsoft.public.dotnet.framework.aspnet)
  • Re: MacBook Air
    ... Move a window by double-tap and move. ... Rotate a photo by pivoting your ...
    (it.comp.macintosh)
  • Re: A Caching Issue - I Suspect
    ... >> optionally rotate the photo. ... >> the client, showing the rotated version of the photo. ... After every rotation request sent from the browser, ...
    (microsoft.public.dotnet.framework.aspnet)
  • Re: A Caching Issue - I Suspect
    ... > When you write the image to the page try making the src link in the ... >> optionally rotate the photo. ... >> the server (not through the browser). ...
    (microsoft.public.dotnet.framework.aspnet)