[Zope-dev] [Checkins] SVN: z3c.form/trunk/ merged branch icemac_validate_NOT_CHANGED

[Michael Howitz]

Am 24.05.2009 um 10:46 schrieb Adam GROSZER:
> Hello Michael,
>
> After some simple thinking there are some fears that this wrecks other
> basic fields validation.
>
> Something like the field is required, has a default value but is
> omitted on input. What will be the result?

When the field is omitted on input it should not have the value  
interfaces.NOT_CHANGED but no value, so special handling for  
NOT_CHANGED does not apply.

> Accepting the default value
> instead of raising an error is definitely a problem.
>
> Also, values in the system might not be needed to re-validate?
> Image passing around a 100mb uploaded file.

z3c.form has definitely a problem with this use-case. Not only the  
validator but also the edit form reads the whole file into RAM.

> If this is meant only for a file upload field, then I think there  
> should
> be a special validator registered for those.

interfaces.NOT_CHANGED is currently only used for file uploads, but it  
might be used for other fields as well, so I see no reason to put the  
handling into a special validator.

> Would be nice to see some (functional) tests closing out the above  
> fears.
> Functional, because on the unittest level you can force the widget to
> a lot of unexpected things, but that might not be inline with what
> happens when it's really done by the framework.
> Or better said, revert the changes locally, add those tests, apply the
> changes back and see whether the tests still pass.

File upload fields did not work at all after someone introduced  
interfaces.NOT_CHANGED and before adding my changes.

Jacob Holm, who suggested the patch, wrote in http://mail.zope.org/pipermail/zope-dev/2009-April/036258.html
The "code should compute the same value as  
z3c.form.widget.Widget.update would when ignoreRequest is True.   Thus  
effectively converting NOT_CHANGED into the "existing" value before  
validating."

> MH> Modified: z3c.form/trunk/src/z3c/form/validator.py
> MH>  
> ===================================================================
> MH> --- z3c.form/trunk/src/z3c/form/validator.py    2009-05-17  
> 13:18:11 UTC (rev 100027)
> MH> +++ z3c.form/trunk/src/z3c/form/validator.py    2009-05-17  
> 13:21:18 UTC (rev 100028)
> MH> @@ -42,9 +42,28 @@
> MH>
> MH>      def validate(self, value):
> MH>          """See interfaces.IValidator"""
> MH> +        context = self.context
> MH>          field = self.field
> MH> -        if self.context is not None:
> MH> -            field = field.bind(self.context)
> MH> +        widget = self.widget
> MH> +        if context is not None:
> MH> +            field = field.bind(context)
> MH> +        if value is interfaces.NOT_CHANGED:
> MH> +            if (interfaces.IContextAware.providedBy(widget) and
> MH> +                not widget.ignoreContext):
> MH> +                # get value from context
> MH> +                value = zope.component.getMultiAdapter(
> MH> +                    (context, field),
> MH> +                    interfaces.IDataManager).query()
> MH> +            else:
> MH> +                value = interfaces.NO_VALUE
> MH> +            if value is interfaces.NO_VALUE:
> MH> +                # look up default value
> MH> +                value = field.default
> MH> +                adapter = zope.component.queryMultiAdapter(
> MH> +                    (context, self.request, self.view, field,  
> widget),
> MH> +                    interfaces.IValue, name='default')
> MH> +                if adapter:
> MH> +                    value = adapter.get()
> MH>          return field.validate(value)
> MH>
> MH>      def __repr__(self):

Yours sincerely,
-- 
Michael Howitz · mh at gocept.com · software developer
gocept gmbh & co. kg · forsterstraße 29 · 06112 halle (saale) · germany
http://gocept.com · tel +49 345 1229889 8 · fax +49 345 1229889 1
Zope and Plone consulting and development