Re: Validation and Events

> George Lee <georgeleejr@...> writes:
> 
> > Is it possible yet to hook in a validator to an Archetypes object using
> > Five/Zope3 events?
> > 
> > it's clear how that could be used to add in a validator just for one
> > new field, but not how we could validate that the data from two fields
> > satisfy some condition (e.g., min < max).
>
> You want zope.interface's invariants.  See 
> http://svn.zope.org/Zope3/trunk/src/zope/interface/README.txt?rev=70082&view=auto


The thought was maybe there was an event that fired up upon validation through
base_edit and process_form, that would allow one to add some more work to the
validation process of a product without touching its code.

With Plone 2.5 and Zope 2.9.4, I've been able to do most of the adding fields
and schema to an existing Archetypes product without touching the original
product's code, using Five -- but I haven't been able to figure out how to add
validation machinery. It looks like I may have to suck it up and just change the
original product's validation methods.


> If you want to add validators that are not field-specific (e.g. via 
> validate_foo() method) then I don't think that's quite in scope.

That's too bad ... in this case I'm adding a "Deadline Date" and "Deadline Text"
field to multiple content types, but want to valdiate that either neither is
entered or both are entered. It seems like allowing some of this multiple-field
validation would be key down the road to the work to use schemas by interface or
otherwise generalize Schema(). Are there any plans to build Zope3 invariants
into the Archetypes machinery?


Peace,
George


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