Re: Thoughts on a CDBI::AsForm::_to_new()

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--- Andreas Fromm <Andreas.Fromm@xxxxxx.xxxxxxxxxxxx.xx> wrote:

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> 
> Ithink what Peter is trying to do, is what I'm also trying to do. If you
> have the following structure:
> 
> table person:
> ~   id serial
> ~   name text
> ~   adress integer references addresses
> ~   phone integer references phones
> 
> table addresses
> ~   id serial
> ~   street text
> ~   number text
> ~   city text
> ~   zip text
> 
> tabel phones
> ~   id serial
> ~   area text
> ~   number text
> 
> - -----------
> MyClass::Person
> 
> __PACKAGE__->set-up-everything
> __PACKAGE__->has_a ( adress => MyClass::Addresses )
> __PACKAGE__->has_a ( phone => MyClass::Phones )
> 
> - -----------
> CDBI::AsForm will make a form for person with select-boxes for address
> and phone, and what Perter (and I) would like to have is a form
> containing input-boxes for the fields from person, addresses and phones.
> Peter maybe asked for some extramagic of inserting default values for
> the non-referencing fields of person (didn't understand that part
> either). This is the reason why I don't use AsForm.
> 
> I have been playing around with something like this a bit, but didn't
> found the time to finish it up. It would be nice to include something
> like this in AsFrom. My idea was to prefix the field names with the
> table name the fields belong to, such as the field 'name' would become
> 'person.name', 'street' => 'address.street' and so on. Maybe
> CDBI::FromCGI could be tweeked to process that kind of requests
> properly, but I never looked at FromCGI in more detail then the description.
> 

That's exactly it.  With a CDBI system with AsForm, the computer already knows
how to make these inputs. All it needs is for a class to tell it: "HEY, instead
of giving me a select box to choose an address, give me inputs to create a new
address (the result of address->to_cgi or something).  Basically, in its rawest
form, this functionality comes just by making to_cgi call its self with the
has_a class when signaled to and put a hashref in the relevant column slot 
instead of a single HTML::whatever object. I tried it but the recursive call
failed. 

There are some some issues. As Andreas said, column name clashes become a
problem.

 I ended up making a system with two parts  that lives in my own classes--

1) "has_a_new_inputs"  -- a part to generate other inputs for columns in a
class that are foreign keys , which lives in my base model class.

2)"has_a_new" --  a method to tell "has_a_new_inputs" what foreign keys I want
other inputs for, and further more what columns from that foreign class i want
inputs for.  This is specified in each end user class.

Attached is the code and a full synopsis. I still haven't figured out what to
do about field name clashes so I just make sure i don't have any.

I hope this is clear enough. I bet  AsForm could incorporate this
functionality. I made a feeble attempt at putting the has_a_new_inputs code
into AsForm::_to_new_inputs (new is a keyword in Template Toolkit and won't
work as a parameter). Then modifying AsForm::to_field to recognize a new_inputs
parametr. Then i could say:

# get hashref of HTML::whatever objects instead of a single one. 
my $addr_inputs = Person->to_field("address_id", "new_inputs").  

I'll try again as a proof of concept.


thanks

   

=====
pjs

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# expand foreign keys in a CDBI class to inputs for columns of the foreign class
# using AsForm methods.

# TODO make this more robust
sub BaseCDBI::has_a_new_inputs {
    my ($self, $r) = @_;
    return 0 unless $self->can("has_a_new");
    my $has_a_new_cols = $self->has_a_new;  # HAS_A_NEW called here
                                           
    foreach my $col (keys %$has_a_new_cols)
    {
        my ($has_a_class, @input_cols) = @{$has_a_new_cols->{$col}};

        unless ($has_a_class->can('to_field') ) {
            warn "Class: $has_a_class can't to_field. Needs AsForm."; 
	    next;                                     	  
        } # sanity check

        my %res = map { $_ => $has_a_class->to_field($_) }  @input_cols;
        $result{$col} =  \%res;
    }
    return  \%result;
}


sub Person::has_a_new { 
    { address_id => [ qw/Address street number city state zip/ ] }, 
    { phone_id   => [ qw/Phone area number/]
};




Synopsis: 

package Person;
Person->has_a(address_id => "Address");
Person->has_a(phone_id   => "Phone");

# specify class and columns of that class you want inputs for in place of an
# input for the key column. Class spec won't be necessary in finished version
sub has_a_new { 
    { address_id => [ qw/Address street number city state zip/ ] }, 
    { phone_id   => [ qw/Phone area number/]
};

# then in some near by code

$template_args{cgi_inputs} = Person->to_cgi; 
my $other_inputs = Person->has_a_new_inputs;  # 
$template_args{other_inputs} = $other_inputs

# then in a new_person  TT template

[% FOREACH $col IN cgi_inputs.keys;
     IF other_inputs.$col; # insert other inputs instead of to_cgi default
	other_cols = other_inputs.$col; # stupid to lookup again
        FOREACH mycol IN other_cols.keys;
           "<label> $mycol </label>" other_cols.$mycol.as_XML;
        END;
        NEXT;
     END;

     "<label> $col </label>" cgi_inputs.$col.as_XML;

  END;
%]



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