Clay Leeds wrote:
On Jan 20, 2006, at 6:28 AM, Jeroen van der Vegt wrote:
I'm not sure I correctly understand the problem anymore, but this
might be relevant:
Can't you let the JPEG servlet indicate that its output should not be
cached? I use this code to disable various cache mechanism:
private void setNoCache(HttpServletResponse resp) {
resp.setHeader("Pragma","No-Cache");
resp.setHeader("Cache-Control","no-Cache");
resp.setDateHeader("Expires", 0 );
}
Regards,
Jeroen
I understood the OP (pasted at the bottom of this msg) to mean there is
a caching problem with the JPEG image of each chart.
Are you sure? The proxy/client is getting only a PDF document (MIME
type application/pdf), no JPEGs. The JPEGs are incorporated within the
PDF documents. Nothing is sent to the proxy/client until the PDF
document is finished (would have to be, if only to solve the "Page 1 of
XXX" resolution issues.) I would think the proxy/client would be
completely oblivious to the fact that the PDF contains JPEGs within it
when it receives the application/pdf stream.
No problem whatsoever with the rest of what you're saying, just this
premise.
Glen
My previous post supported Jeremias 'simple' fix whereby each chart be
given a different URI (PATH, name, etc.)--even if the difference is just
'dummy' text. I still believe this is the case.
While you can set special caching parameters on the server end (such as
described by Jeroen above), unless there is a change in the
URI/PATH/Filename, there are other places where the file might be cached
(thereby negating any 'NEVER CACHE THIS RESOURCE' settings).
I attended a talk by Michael Radwin, Senior Engineering Manager for
Yahoo, at ApacheCon US 2005 in San Diego[1], entitled 'HTTP Caching and
Cache-busting for Content Publishers'. Among other things, Y! needs to
ensure that multiple users at an Internet Cafe checking their mail will
*never* receive the same content.
On Jan 18, 2006, at 12:32 AM, vijay visu wrote:
i am doing a code which generates the PDF in a batch
process.
These PDFs include dynamically built charts by
servlets.
I am making use of external-graphic tag to pick the
images.
These servlets throw jpeg image of the charts in the
output stream.
These servlets should be called for each PDFs
generated since each chart will be unique.
My problem is that the servlets which builds the
dynamic charts are called
for the first time only. On the subsequent calls the
old charts are
only built in PDF and the servlets are not getting
called.
Please help me out in this problem
[1] (click on 'Cache-busting techniques' at the bottom of the navigation)
http://public.yahoo.com/~radwin/talks/http-caching-apachecon2005.htm
---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
