[Html-widget] formfu - What's the best way to add dynamic defaults?

[Daisuke Maki]

thanks for the pointers.

This is what I want to do:
   - When the user hits this URL for the first time (i.e., no 
submission, etc), I want to display todays date.

   - When the user submits the form, I want to use whatever the user 
provided, except for invalid dates -- in which case today's date is 
displayed.

so I guess it's $element->default, then?

I supposed I could use Javascript too, but for now I'm trying to convert 
an old application to HTML::FormFu, and am trying to figure out how 
things fit together, so I'd rather not touch javascript.

I'll check out the deflators once I get some other stuff working.

--d



Carl Franks wrote:
> On 29/03/07, Daisuke Maki <daisuke at endeworks.jp> wrote:
>> Hi,
>>
>> I have a form that should have today's date in it unless otherwise
>> specified. I kind of hacked around this by saying:
>>
>>     my $dt = DateTime->today(time_zone => 'local');
>>     foreach my $field qw(year month day) {
>>         my $element = $form->get_field(name => $field, type => 'text');
>>         next unless $element;
>>         $element->attributes->{value} ||= $dt->$field;
>>     }
> 
> I'm not entirely sure what you mean by "unless otherwise specified".
> Otherwise specified by what / where?
> The solution might differ according to whether you mean it's set
> somewhere else in the code/config, or whether it's set by the user in
> a submitted form.
> 
> If you want to set a field's default value, which if redisplayed after
> errors will be overridden by whatever the user entered - then you
> should use:
>    $element->default( $value );
> 
> For dates, I'm tending to prefer the Dojo::DropdownDate element -
> which provides a JS date-picker GUI and fallsback to a single textbox
> if JS is switched off.
> 
> I think using a deflator would be a bit of an abuse, as they're not
> reallly designed to process multiple field's values.
> Something like this might work - but you'll need to test it.
> The deflators are only run if the form wasn't submitted.
> You might need to make sure the deflator is associated with whichever
> of the year/month/day fields was added to the form first. In my
> example, I've assumed it's the 'year' field.
> 
> 
> ---
> elements:
>  - type: text
>    name: year
>    deflators:
>      - +MyApp::Deflator::DateNow
>  - type: text
>    name: month
>  - type: text
>    name: day
> 
> 
> package MyApp::Deflator::DateNow;
> use strict;
> use warnings;
> use base 'HTML::FormFu::Deflator';
> 
> sub deflator {
>    my ( $self, $value ) = @_;
> 
>    my $year  = $self->parent;
>    my $month = $self->form->get_field({ name => 'month', type => 'text' });
>    my $day   = $self->form->get_field({ name => 'day',   type => 'text' });
> 
>    if ( !defined $value && !defined $month->default && !defined 
> $day->default )
>    {
>        my $dt = DateTime->today( time_zone => 'local' );
> 
>        $month->default( $dt->month );
>        $day->default(   $dt->day );
> 
>        return $dt->year;
>    }
> 
>    return $value;
> }
> 1;
> 
> Ideas for a more general multi-field preprocessor mechanism welcome!
> 
> Carl
> 
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