[Zope3-Users] Views for adapted components

[tom at lalisio.com]

On Monday 26 March 2007 12:57:58 pm FB wrote:
> Hi,
>
> On Mon, Mar 26, 2007 at 12:43:21PM +0200, Lorenzo Gil Sanchez wrote:
>
> [snip]
>
> > This is not so bad. The real problem is that I have to modify the
> > original IMyCompoment component to tell zope it implements IImportExport
> > even when this is false. The adapter does it, not the compoment. But I
> > don't know other way to make my view work with my components.
>
> What you trying to do sounds reasonable at the first moment, but it would
> be impossible to accomplish. You try to create an (warning: self invented
> expression :-) ) Adaption chain:
>
>  object -> some_adapter -> view
>
> which is something, zope doesn't support. Think about it: the publisher
> would have to check each possible adapter for a given object trying to
> create views for it - and this is just a 2-adaption-chain... .
>
> However, there's an easy solution: Write a view like that:
>
>  <page name="im-and-export.html"
>     for="zope.app.container.interfaces.IContained"
>     [...]
>     class=".view.ImExPortView"
>     menu="zmi_views"
>     title="Im-&Export"
>  />
>
> class ImExPortView(object):
>    def __call__(self):
>       try:
>          export=IImportExport(self.context)
>       except:
>          raise NotImportableException(self.context)
>       [...]
>

Another way to do this, if you don't like exceptions is
(in your view):

adapter = IImportExport(self.context, None)
if adapter is not None:
    .... do something
else:
    .... raise an exception or do something other

Cheers
-Tom

> Regards,
>
> Frank
> _______________________________________________
> Zope3-users mailing list
> Zope3-users at zope.org
> http://mail.zope.org/mailman/listinfo/zope3-users