[reportlab-users] Reportlab, Zope, and Large/Long Reports

reportlab-users@reportlab.com reportlab-users@reportlab.com
Tue, 14 Sep 2004 13:52:32 -0700


Document-generation is inherently CPU intensive and will
hog all the CPU cycles it can until done. The problem is nothing
to do with reportlab per se - you need to find a way to run
a command or piece of code asynchronously.  I'm sure there
will be some standard way to do this in Zope but don't know it
myself.

Steve Alexander described to me a system where the
Zope front end would check every few seconds if a report
was done and display a wait page - 4 years ago.  You could
try asking him :-)

BTW, the older I get, the more I like a very old-fashioned and
low-tech way of doing things:  write out the 'facts' for
each report in XML or some other readable intermediate
format, and make each report a script which can convert
such an input file into a PDF.   This not only lets you develop
the reports at maximum speed and test them in isolation
from your app or database server; it also makes choices
like running on a separate server or separate process
easy.

Good luck and please share any answers here...

Andy Robinson
CEO/Chief Architect
RepoortLab Europe Ltd.
tel +44 20 8544 8049

-----Original Message-----
From: Michael Mauws <michael@mauws.net>
To: reportlab-users@reportlab.com
Sent: Tue, 14 Sep 2004 13:16:18 -0600
Subject: [reportlab-users] Reportlab, Zope, and Large/Long Reports

Does anyone know of a How-To document that explains what I need to do to
avoid having large reports temporarily(?) cripple my Zope instance? I've
surfed through the archives of this list and found a posting or two 
(e.g.,
http://two.pairlist.net/pipermail/reportlab-users/2004-March/002782.html)
that suggest something needs to be done, but it's not obvious to me 
WHAT it
is that needs to be done.

Just to clarify, everything runs fine when I launch a short report 
(e.g., an
invoice) from within Zope, presumably because it's generated quickly 
enough
that other users aren't inconvenienced. But when I generate a 
looooooooong
report (e.g., an inventory listing), everyone else is effectively 
locked out
of the site.

I'm assuming the solution lies with somehow generating the PDF in the
background but as much as I hate to admit it, I don't know how to 
accomplish
that. So if someone can give me some guidance in this regard, it will be
very much appreciated...


...michael


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