[Zope3-Users] Understanding viewlets and content providers
gns24 at mythic-beasts.com
Tue Jun 24 01:15:54 EDT 2008
I've been using viewlets for a couple of projects, and have found them
very useful and a very good fit with the CA. Unfortunately I am
failing to understand how they're meant to work with regards to the
update/render pattern. According to the zope.contentprovider interface
- the update method should update persistent objects based on the
request. It should not store state about persistent objects.
- the render method should then return HTML based on the state of
Which is fine providing all content providers have their update
methods called and then their render methods called. But using the
tal:provider expression just calls the update and then render methods
on one content provider, and then moves on to the next one. The
expression implementation's docstring says: "If you want to implement
interdependent content providers, you need to consider a TAL-
independent view implementation that will complete all content
providers' stage one before rendering any of them."
Does a TAL-independent view implementation exist? What do other people
using viewlets do?
Until now I've been issuing a redirect after any update to persistent
objects. I've also been abusing the update method for calculating
values for the template. I'll stop that now!
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