[Catalyst] In HTML::FormHandler search form (no DB schema) -- how to populate a SELECT field via DBIx::Class?

On Sun, 2011-01-16 at 16:41 +0100, will trillich wrote:
Short version: If you have a HTML::FormHandler search form without a
"has_field '+item_class'" (there's no data-base row corresponding to
its contents) how to you reach your DBIx::Class schemas to populate a
drop-down menu?




Long version: This is in the context of a Catalyst app -- however, I
do know this is either FormHandler question or a DBIC question, and
not intrinsically a Catalyst question, but... hoping the wise folks
here can nudge me in the right direction...


We have several DBIC resultsets including Incident and Country. The
Incident record has this relationship:
__PACKAGE__->belongs_to( 'country' =>
'Incident::Schema::DB::Result::Country' );


(And the country schema has_many incidents, of course)


For the CRUD form related to the actual incident table, we have a
matching HTML::FormHandler package with its
has '+item_class'
as expected. This makes it easy to create a
sub options_country {
? my $self = shift;
? return unless $self->schema;
? my $rs = $self->schema->resultset('Country');
? #...
}
subroutine for the form, for populating a country drop-down menu in
the HTML.


But!


For the SEARCH form, we are not interested in CRUD, plus we have extra
fields (for example, we want the user to be able to bracket dates with
a start-field and an end-field) so there's no one-to-one correlation
with the database table -- meaning there's no "item_class" for the
search form. And hence no schema to rely on.


What we're looking for now -- unless there's a better more obvious
paradigm -- is a way to get from an instance of the schema-object,
back to the resultset, for searching.
sub options_country {
? my $self = shift; # note $c is not available here :(
? # $self->schema will be UNDEF here
? my $obj = Spill::Schema::DB::Result::Country->new; # Hard-wired,
yes, is there a better way?
? my $rs = $obj->???
? # ?
}


I've looked at
- $obj->result_source (Can't call method "resolve" on an undefined
valued in DBIx/Class/Row)
- $obj->result_source_instance->resultset (Can't call method
"default_resultset_attributes" on an undef value in
DBIx/Class/ResultSource)
- $obj->result_source_instance->resultset_class->search({},{}) (Can't
use string as a HASH ref in DBIx/Class/ResultSet)
and a couple other dead ends.


It's likely to be something obvious I've overlooked. :( Suggestions?

--
The first step towards getting somewhere is to decide that you are not
going to stay where you are. ?-- J.P.Morgan