Re: [Zope] Reportlab issue

28 Aug 2006

      Jonathan wrote:
...
----- Original Message ----- From: "David H" <bluepaul@earthlink.net>
To: "zope user list" <zope@zope.org>
Sent: Sunday, August 27, 2006 8:54 PM
Subject: [Zope] Reportlab issue
...
Hi Zope List,
I have an Zope application that uses ReportLab to generate acrobat 
viewable reports. (I already posted this to reportlab list - so far 
no solutions).
Heres the problem:
I display an acrobat report (using Firefox or IE 6) and say scroll 
down to page 10.  I then use the <browser> back button to re-enter my 
Zope application.
Now, even if I click various unrelated pages in the application  
(clearing the request,etc) and then return to the Report (which is 
always freshly generated) it will try to re-display at page 10 - 
instead of top of page.
This occurs even if the data being reported has changed, and this 
occurs even if a different report is generated!
Note: that I use
import tempfile and
tmpFile2 = tempfile.mktemp()
to keep pdfPath's unique ...
I've tried combinations of "Content-Disposition" params like changing 
filename=, etc.  Nothing is changing this behavior.
I've tried (a reportlab mailing list suggestion) varying to <forms 
action= like
<form name="printform" method="post" 
action="extensions/pyBudgetReports"
        tal:attributes="action python: 
'extensions/pyBudgetReports/?random=' + context.python.pyTime()">
No help either.
I have never used ReportLab, but is there a possibility that when you 
go back to the adobe document it is being served from a cache?  You 
could try using html meta tags or response.setHeader (better) to make 
sure the document is not being served from the cache.
Just a shot in the dark!
Jonathan
Hi Jonathan,

Yes, I did try that, e.g. (report lab + external file stuff)
   # -----------------------------------------------------------
   def writeReport(self, RESPONSE):
   # -----------------------------------------------------------
      """
        generates report output
      """
         self.save()
         theFile=open( self.pdfpath,'rb')
         result = theFile.read()
         theFile.close()
         os.remove(self.pdfpath)
         # the next 3 lines were snarked from google "zope no cache"  I 
think its a casey duncan recipe ...
         RESPONSE.setHeader('Pragma', 'no-cache')
         RESPONSE.setHeader('Cache-Control','no-cache')
         RESPONSE.setHeader('Expires', 'Sat, 1 Jan 2000 00:00:00 GMT')
         # the normal fair
         RESPONSE.setHeader('Content-Type','application/pdf')

RESPONSE.setHeader('Content-Disposition','inline;filename="reportNz.pdf"')
         RESPONSE.setHeader('Content-Length',len(result))
         RESPONSE.write(result) # result is

And it didn't help. 

David