[Catalyst] Form validation in insert() and update()?

[mla]

Christopher H. Laco wrote:
> Damned if you do... damned if you don't. There is no one correct answer.

So true ;-|

In terms of form validation, what do you guys think of this
interface? It uses perl to handle conditional logic/dependencies
instead of using a spec language like Data::FormValidator.

   # pass a hash ref or object with param() interface to ne
   my $form = MLA::Form->new($params);

   # Validate the data. This terse syntax uses Getopt::Long-style
   # option specifiers.

   $form->check('first_name=s'); # required field first_name
   $form->check('your_email=email'); # required e-mail

   # After doing checks, see if we hit any errors.
   if ($form->error) {
     print "Error: $_\n" foreach $form->error;
   } else { # No errors, validation passed
     # data() returns a hash ref with the validated data
     my $data = $form->data;
   }

Could also check for specific fields failing by

   if ($form->error(qw/ first_name last_name /)) {
     ...
   }

By default, it will convert the field name to a label
name (e.g., first_name => First Name) and use that for the error
messages. So, for example, in the first check, if the first_name
isn't supplied, it would produce an error message like
"First name is required".

You can override that though:

   $form->check('first_name=s', label => "Mother's first name");

Usually you'd subclass the form class to implement the
data types that are specific to your domain.

Other examples of validation checks:

   $form->check('title:s'); # optional title
   # list of colors; if validation passes, $data->{fav_colors} will
   # contain an array ref. Each individual color is checked.
   $form->check('fav_colors:color@')

The verbose interface:

   $form->check(
     field => 'first_name',
     type => 'string',
     max_length => 100,
     label => 'Your first name',
   );

Any unknown arguments are passed into the validation type routine so
you can parameterize your types easily.

Anyone have a problem with this approach? What are the drawbacks?

I originally turned to it because I was hacking Data::FormValidator to
have more complex dependency logic (I think it's added some stuff since
then) and thought you can't beat code for that.

Thanks,

Maurice