[Zope-CMF] Re: CMF and Five views: hooking up "POST"

[Tres Seaver]

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Lennart Regebro wrote:
> On 10/17/05, yuppie <y.2005- at wcm-solutions.de> wrote:
> 
>>I know that pattern, but I don't like it. [...]
>>The code on the goldegg-folder_contents branch processes the input in
>>the __call__ method of the view class. The template is only invoked if
>>needed. It's much cleaner to use the template just for displaying
>>results, not for triggering controllers.
> 
> 
> That's purely a matter of taste. From a principal standpoint I don't
> think there is any difference, really.

I think we might be able to come up with a heuristic for choosing
between the two patterns (this might be a mini pattern language, if
refined):

 - For "simple" forms, which redisplay themselves even after a
   successful POST, and which do not redirect, prefer a template-driven
   version, and make the form self-posting;  in ZCML, use <browser:page>
   with the 'template' attribute).  The classic 'document_edit' form
   fits this bill, I think.

 - If you have to add logic to the template to cope with possible
   redirects, then publish a method of the view, and have the view
   redirect or return a template;  in ZCML, use <browser:page> with
   the 'attribute' variant.  "Add" forms fit this pattern, as well
   as the folder_contents stuff that Yuppie has done.

 - For a set of inter-related pages sharing common view logic,
   you may end up mixing and matching -- the ':method' bit on submit
   button names is a way to get "off" the original template when
   needed.  ZCML for this case may either be a mixture of the
   'template' and 'attribute' variants of <browser:page>, or else
   <brower:view> with several <page> subdirectives.

How does that sound?


Tres.
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Tres Seaver          +1 202-558-7113          tseaver at palladion.com
Palladion Software   "Excellence by Design"    http://palladion.com
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