[Zope-CMF] Extending a Plone Object

[Florent Guillaume]

Raphael Ritz  <r.ritz@biologie.hu-berlin.de> wrote:
> >I would like to create a new content type by adding a new field (summary) to
> >the standard Event object. And then create new forms based on the standard
> >event forms with the new field on it.
>
> Unfortunately you can't extend existing content types by simply adding a 
> few more
> properties (I wish there were an easy way for this).

There is a very easy way to do this built into CMF, the Scriptable Type
Information.

In the Types Tool, create a new Scriptable Type Information, deriving it
from the base type you need. Name it "MyType" for instance. As
"Constructor path", type the name of a Python Script, for instance
MyType_create. Create this Python Script in the Types Tool:

##parameters=container, id, *args, **kw
# create the base object
container.invokeFactory('Some Base Portal Type', id)
ob = getattr(container, id)
# now add the properties you need
ob.manage_addProperty('foo', 1, 'int')
# finally return the object
return ob

The only thing you have to be aware of is that during script execution,
the portal_type of your object will be the base portal type and not yet
the one of your final type.

Florent
-- 
Florent Guillaume, Nuxeo (Paris, France)
+33 1 40 33 79 87  http://nuxeo.com  mailto:fg@nuxeo.com