[Dbix-class] How to find updated fields

[RA Jones]

RA Jones wrote:
> So I created a very simple overloaded insert() method as described in 
> DBIx::Class::Manual::Component, in a new module called DBIx::Class::CRUD
> 
> package DBIx::Class::CRUD;
> use base qw/DBIx::Class/;
> 
> sub update {
>  my $self = shift;
> 
>  my %dirty_cols = $self->get_dirty_columns;
>  use Data::Dumper; # open $fh here
>  print $fh Dumper %dirty_cols;
>  return $self->next::method( @_ );
> }
> 
> And in MyApp::Schema::MyClass:
> __PACKAGE__->load_components(qw/PK::Auto CRUD Core/);
> 
> But %dirty_cols is empty. The DBIC::CRUD::insert method *is* being 
> called as a) I can dump $self to output, where there is no entry for 
> anything resembling get_dirty_columns, and b) entry confirmed with 
> $c->log->info( join "\n" => Class::C3::calculateMRO('Schema::MyClass') ):

Having completely failed to find a way to make get_dirty_columns work, I 
implemented the following alternate method of logging updated fields:

In MyApp::Controller::Locations :-

sub do_edit : Private {
   my ( $self, $c ) = @_;
   my $fields = $form->field;
   my $old_vals = { map { $_ => $location->$_ } $location->columns };
   # do the table update, then:
   $c->controller('Root')->record_changes($c, $old_vals, $fields);

}

In Root::Controller :-

sub record_changes : Private {
   my ( $self, $c, $old, $new ) = @_;
   map {
     my $vals = {
       old_value => $old->{$_},
       new_value => $new->{$_},
       dbid      => $old->{id},
       field     => $_,
     };

     $c->model('Schema::Log')->create($vals);
   } grep $old->{$_} ne $new->{$_}, keys %{ $new };

It does everything I wanted (so far). Comments welcome.
-- 
Richard Jones
Leeds, UK
ra.jones(at)dpw.clara.co.uk