Wichert Akkerman wrote:
> Previously yuppie wrote:
>> Wichert Akkerman wrote:
>>> I have a use case where I need to put additional restrictions on object
>>> creation, in particular I need to restrict the maximum depth of items
>>> inside of a container of a specific type. The ideal place to put such a
>>> restriction seems to be the isConstructionAllowed method on the FTI.
>>> Currently this method is not very extensible, which leads to complicated
>>> code in various FTI types.
>>> I am considering to add an extension point here, something like this:
>>> class ITypeConstructionFilter(Interface):
>>> def __init__(fti, container):
>>> """Adapt on the FTI of the object being created and the target
>>> def allowed():
>>> """Check if construction is allowed."""
>>> current checks such as the workflow check that was added in CMF 2.2, or
>>> the type constraint logic Plone has in ATContentTypes could be moved to
>>> such an adapter. The standard isConstructionAllowed method could then
>>> query all registered adapters to check if construction should be possible.
>>> Does this sound sensible?
>> Question: zope.container.constraints handles this in a different way,
>> using a precondition defined in the interface. Did you have a look at
>> that code? If we switch to that pattern, we could use different
>> preconditions for containers with different interfaces. Would that be
>> sufficient for your use case?
> I don't think that is sufficient since it does not provide an extension
> point you can hook into
It's no hook for adding restrictions, but it's a hook for using
> and does not support portal types.
Do you mean "does not support per portal type hooks" or do you mean
"does not support filtering based on portal type name"?
A CMF specific precondition would look up type restrictions in the fti
of the container.
checkFactory and checkObject are quite similar to isConstructionAllowed.
I think we should reimplement this based on zope.container before we
start adding new features.
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