sub filter_column {
my ($self, $col, $attrs) = @_;
+ $self->throw_exception('FilterColumn does not work with InflateColumn')
+ if $self->isa('DBIx::Class::InflateColumn') &&
+ defined $self->column_info($col)->{_inflate_info};
+
$self->throw_exception("No such column $col to filter")
unless $self->has_column($col);
- $self->throw_exception("filter_column needs attr hashref")
+ $self->throw_exception('filter_column expects a hashref of filter specifications')
unless ref $attrs eq 'HASH';
+ $self->throw_exception('An invocation of filter_column() must specify either a filter_from_storage or filter_to_storage')
+ unless $attrs->{filter_from_storage} || $attrs->{filter_to_storage};
+
$self->column_info($col)->{_filter_info} = $attrs;
my $acc = $self->column_info($col)->{accessor};
$self->mk_group_accessors(filtered_column => [ (defined $acc ? $acc : $col), $col]);
return $value unless exists $info->{_filter_info};
my $filter = $info->{_filter_info}{filter_from_storage};
- $self->throw_exception("No inflator for $col") unless defined $filter;
- return $self->$filter($value);
+ return defined $filter ? $self->$filter($value) : $value;
}
sub _column_to_storage {
return $value unless exists $info->{_filter_info};
my $unfilter = $info->{_filter_info}{filter_to_storage};
- $self->throw_exception("No unfilter for $col") unless defined $unfilter;
- return $self->$unfilter($value);
+
+ return defined $unfilter ? $self->$unfilter($value) : $value;
}
sub get_filtered_column {
return $self->{_filtered_column}{$col} = $self->_column_from_storage($col, $val);
}
+sub get_column {
+ my ($self, $col) = @_;
+ if (exists $self->{_filtered_column}{$col}) {
+ return $self->{_column_data}{$col} ||= $self->_column_to_storage ($col, $self->{_filtered_column}{$col});
+ }
+
+ return $self->next::method ($col);
+}
+
+# sadly a separate codepath in Row.pm ( used by insert() )
+sub get_columns {
+ my $self = shift;
+
+ foreach my $col (keys %{$self->{_filtered_column}||{}}) {
+ $self->{_column_data}{$col} ||= $self->_column_to_storage ($col, $self->{_filtered_column}{$col})
+ if exists $self->{_filtered_column}{$col};
+ }
+
+ $self->next::method (@_);
+}
+
+sub store_column {
+ my ($self, $col) = (shift, @_);
+
+ # blow cache
+ delete $self->{_filtered_column}{$col};
+
+ $self->next::method(@_);
+}
+
sub set_filtered_column {
my ($self, $col, $filtered) = @_;
- $self->set_column($col, $self->_column_to_storage($col, $filtered));
+ # do not blow up the cache via set_column unless necessary
+ # (filtering may be expensive!)
+ if (exists $self->{_filtered_column}{$col}) {
+ return $filtered
+ if ($self->_eq_column_values ($col, $filtered, $self->{_filtered_column}{$col} ) );
- delete $self->{_filtered_column}{$col};
+ $self->make_column_dirty ($col); # so the comparison won't run again
+ }
- return $filtered;
+ $self->set_column($col, $self->_column_to_storage($col, $filtered));
+
+ return $self->{_filtered_column}{$col} = $filtered;
}
sub update {
my ($self, $attrs, @rest) = @_;
+
foreach my $key (keys %{$attrs||{}}) {
- if ($self->has_column($key) &&
- exists $self->column_info($key)->{_filter_info}) {
- my $val = delete $attrs->{$key};
- $self->set_filtered_column($key, $val);
- $attrs->{$key} = $self->_column_to_storage($key, $val)
+ if (
+ $self->has_column($key)
+ &&
+ exists $self->column_info($key)->{_filter_info}
+ ) {
+ $self->set_filtered_column($key, delete $attrs->{$key});
+
+ # FIXME update() reaches directly into the object-hash
+ # and we may *not* have a filtered value there - thus
+ # the void-ctx filter-trigger
+ $self->get_column($key) unless exists $self->{_column_data}{$key};
}
}
+
return $self->next::method($attrs, @rest);
}
foreach my $key (keys %{$attrs||{}}) {
if ($obj->has_column($key) &&
exists $obj->column_info($key)->{_filter_info} ) {
- my $val = delete $attrs->{$key};
- $obj->set_filtered_column($key, $val);
+ $obj->set_filtered_column($key, $attrs->{$key});
}
}
+
return $obj;
}
=head1 SYNOPSIS
- # In your result classes
+In your Schema or DB class add "FilterColumn" to the top of the component list.
+
+ __PACKAGE__->load_components(qw( FilterColumn ... ));
+
+Set up filters for the columns you want to convert.
+
__PACKAGE__->filter_column( money => {
filter_to_storage => 'to_pennies',
filter_from_storage => 'from_pennies',
1;
+
=head1 DESCRIPTION
This component is meant to be a more powerful, but less DWIM-y,
=head2 filter_column
__PACKAGE__->filter_column( colname => {
- filter_from_storage => 'method',
- filter_to_storage => 'method',
+ filter_from_storage => 'method'|\&coderef,
+ filter_to_storage => 'method'|\&coderef,
})
-This is the method that you need to call to set up a filtered column. It takes
-exactly two arguments; the first being the column name the second being a
-C<HashRef> with C<filter_from_storage> and C<filter_to_storage> having
-something that can be called as a method. The method will be called with
-the value of the column as the first non-C<$self> argument.
+This is the method that you need to call to set up a filtered column. It takes
+exactly two arguments; the first being the column name the second being a hash
+reference with C<filter_from_storage> and C<filter_to_storage> set to either
+a method name or a code reference. In either case the filter is invoked as:
+
+ $row_obj->$filter_specification ($value_to_filter)
+
+with C<$filter_specification> being chosen depending on whether the
+C<$value_to_filter> is being retrieved from or written to permanent
+storage.
+
+If a specific directional filter is not specified, the original value will be
+passed to/from storage unfiltered.
=head2 get_filtered_column
Sets the filtered value of the column
-=head2 update
+=head1 EXAMPLE OF USE
+
+Some databases have restrictions on values that can be passed to
+boolean columns, and problems can be caused by passing value that
+perl considers to be false (such as C<undef>).
-Just overridden to filter changed columns through this component
+One solution to this is to ensure that the boolean values are set
+to something that the database can handle - such as numeric zero
+and one, using code like this:-
-=head2 new
+ __PACKAGE__->filter_column(
+ my_boolean_column => {
+ filter_to_storage => sub { $_[1] ? 1 : 0 },
+ }
+ );
-Just overridden to filter columns through this component
+In this case the C<filter_from_storage> is not required, as just
+passing the database value through to perl does the right thing.