Re: [fw-mvc] breakChainOnFailure

-- Seth Atkins <satkins@nortel.com> wrote
(on Friday, 17 July 2009, 01:19 PM -0500):
> Then how does one validate dependent input? If certain fields need
> certain validation criteria depending on a previous field containing
> valid data, you can't properly validate the other fields.

This has been covered many times before: add a second argument to your
validator's isValid() declaration for $context:

public function isValid($value, $context = null)
{
}

Zend_Form passes the entire array as a second argument to isValid(). If
you need to use it, it's available.

This is well documented in the manual:

http://framework.zend.com/manual/en/zend.form.elements.html#zend.form.elements.validators

and search for the heading, "Validation Context."

This feature has been available since the initial stable release of
Zend_Form in 1.5.0.

This *is* different than having a "breakChainOnFailure" feature for
Zend_Form itself, however, as this latter functionality changes the
behavior of Zend_Form substantially. The current behavior is to run
validation on *all* elements in order to return as much information
about invalid entries as possible.

> For example
> suppose you wanted to check for valid zip codes based on the entered
> state (so someone couldn't enter a NY zip code with state AZ. If someone
> entered an invalid state and that failed its check, the remaining check
> on the zip code would give a bogus "invalid" message. I'd rather it
> simply suspend the rest of the form validation since the rest cannot be
> validated properly.
>
> This may fall into the needed feature bucket for future releases, unless
> there is an easy workaround. I managed to find a clunky way of doing
> this by sort of "pre-validating" the input of the field that the others
> depend on so I can put in a conditional to addValidator for the affected
> elements. That way if the pre-validation fails, no validators are added
> at all. If the pre-validation passes, then the others are validated.
>
> The way I implemented pre-validation was to pass the field input to the
> form constructor. The form constructor has to gather some data from the
> database anyway, so I simply compare that field input to this data to
> ensure it is a valid selection. Hence it is pre-validated.
>
> I looked through the code for isValid methods and it seems that this
> would be a fairly easy feature to implement if there was a mechanism in
> Zend_Form::isValid similar to breakChainOnFailure to tell it to stop
> looping through the element validators once one comes back false. I
> could even do that myself, but I'm reluctant to start tinkering around
> changing the code base of ZF.
>
>
>
> --Seth
>
> -----Original Message-----
> From: Matthew Weier O'Phinney [mailto:matthew@zend.com]
> Sent: Thursday, July 16, 2009 4:56 PM
> To: fw-mvc@lists.zend.com
> Subject: Re: [fw-mvc] breakChainOnFailure
>
> -- Seth Atkins <satkins@nortel.com> wrote (on Thursday, 16 July 2009,
> 02:47 PM -0500):
> > I believe this feature works only within the scope of a single element
>
> > validation. I may be misunderstanding how it works, but I believe it
> > means that if the first validation fails, it stops validating and
> > outputs only the first validation error message.
>
> It means that if the given validator fails, it will not process any
> validators occurring after it in the chain.
>
> > What I am looking for is a way to break out of all form validation if
> > an element fails. If several fields have validators set, and the first
>
> > field fails its check, then I'd like the $form->isValid($data) to exit
>
> > the validation loop that takes it through the remaining elements. I
> > don't see a way to do this within the functions provided in ZF unless
> > I am missing something. Am I missing something?
>
> Zend_Form does not allow for this; it attempts to validate all elements,
> so that you can return all possible validation errors for all elements
> back to the user.
>
> You could likely write a validator that you insert at the top of each
> element that checks the parent form for any failed element validations
> and skips validation -- but it would mark that element as failed in
> validation as well.
>
> --
> Matthew Weier O'Phinney
> Project Lead | matthew@zend.com
> Zend Framework | http://framework.zend.com/
>

--
Matthew Weier O'Phinney
Project Lead | matthew@zend.com
Zend Framework | http://framework.zend.com/