[Zope-CMF] Validation during object creation

[kapil thangavelu]

hi geoff,

one thing to note regarding validation with page contract, its useable from 
within python scripts and products. so an example python script addMyObject 
could be...

from Products.PageContract.Scripts import compile

req = context.REQUEST

contract = """
# parameters
id: integer
bar: optional, integer
# errors
default: myForm
"""
contract = compile(contract)
contract.validate(req)
vars = contract.extract_variables(req)

container.manage_addProduct['myProduct'].manage_AddFoo(
    id = vars.id,
    bar =  vars.bar
)

the original form is designated as the error handler.

another option, if you don't need pipelined input validation/transformation 
is to use something like the form_tool thats in plone.

hth,

k

On Monday 08 July 2002 08:45 am, Geoff Davis wrote:
> I'm trying to put together a basic mechanism for doing form validation
> during object creation.  Specifically, I would like to be able to bypass
> the standard "Add Content" form via the following kind of mechanism:
>
> I have a class of objects called MyObject that I want to manage.  To create
> such a MyObject, one invokes a python method called addMyObject.
> addMyObject initially sets some values and passes them to a ZPT called
> addMyObjectForm.  The form submits to addMyObject.  addMyObject then
> validates the parameters -- if they are invalid, it passes the user's
> responses back to addMyObjectForm; if they are valid, it makes the
> appropriate call to invokeFactory and then relocates to some other page.
>
> A few questions:
>
> 1) Before I reinvent a wheel, is there already an easy way to do this in
> Zope?  I haven't seen anything yet
>
> 2) I am writing a helper object that takes care of most of the validation
> process above.  At construction you designate a validation string (sort of
> like http://www.zope.org/Members/k_vertigo/Products/PageContract), a
> PageTemplate to display when prompting for parameters needed to build your
> object, a method used to construct the object once you have a valid set of
> parameters, and a URL to go to once you have finished construction.  In the
> end it should look something like this:
>
> class MyObject:
>    def modify(some args here):
>       some code here
>
>    modifyMyObject = ValidatedForm("id: required; foo: integer,
> required('Please enter an integer'); bar: string, trim, optional")
>
> addMyObject = ValidatedForm("id: required; foo: integer, required('Enter an
> integer, dammit'); bar: string, trim, optional")
>
> I have been trying to add addMyObject as an external method, but have been
> encountering weird errors that I think are arising from
> ValidatedForm.__call__ not having the right function signature.  Given that
> ExternalMethod seems to expect a method with the signature foo(self), I'm
> not sure how to write an appropriate __call__ signature (__call__(self,
> self)??).  Any ideas?  The specific error I'm getting is on line 143 of
> ExternalMethod.py (in Zope 2.5.1): ff doesn't have an attribute
> func_defaults.
>
> I am thinking the right way to do this is to not use external methods and
> rather to build a more generic factory object that uses these validated
> forms and then delegates to portal_types.  Given that this is looking more
> involved, question 1 above becomes even more relevant.
>
> Geoff Davis
> http://www.geoffdavis.net
>
>
>
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