1 package DBIx::Class::InflateColumn;
5 use Scalar::Util qw/blessed/;
7 use base qw/DBIx::Class::Row/;
11 DBIx::Class::InflateColumn - Automatically create objects from column data
15 # In your table classes
16 __PACKAGE__->inflate_column('column_name', {
17 inflate => sub { ... },
18 deflate => sub { ... },
23 This component translates column data into objects, i.e. "inflating"
24 the column data. It also "deflates" objects into an appropriate format
27 It can be used, for example, to automatically convert to and from
28 L<DateTime> objects for your date and time fields.
34 Instruct L<DBIx::Class> to inflate the given column.
36 In addition to the column name, you must provide C<inflate> and
37 C<deflate> methods. The C<inflate> method is called when you access
38 the field, while the C<deflate> method is called when the field needs
39 to used by the database.
41 For example, if you have a table C<events> with a timestamp field
42 named C<insert_time>, you could inflate the column in the
43 corresponding table class using something like:
45 __PACKAGE__->inflate_column('insert_time', {
46 inflate => sub { DateTime::Format::Pg->parse_datetime(shift); },
47 deflate => sub { DateTime::Format::Pg->format_datetime(shift); },
50 (Replace L<DateTime::Format::Pg> with the appropriate module for your
51 database, or consider L<DateTime::Format::DBI>.)
53 The coderefs you set for inflate and deflate are called with two parameters,
54 the first is the value of the column to be inflated/deflated, the second is the
55 row object itself. Thus you can call C<< ->result_source->schema->storage->dbh >> on
56 it, to feed to L<DateTime::Format::DBI>.
58 In this example, calls to an event's C<insert_time> accessor return a
59 L<DateTime> object. This L<DateTime> object is later "deflated" when
60 used in the database layer.
65 my ($self, $col, $attrs) = @_;
66 $self->throw_exception("No such column $col to inflate")
67 unless $self->has_column($col);
68 $self->throw_exception("inflate_column needs attr hashref")
69 unless ref $attrs eq 'HASH';
70 $self->column_info($col)->{_inflate_info} = $attrs;
71 $self->mk_group_accessors('inflated_column' => $col);
75 sub _inflated_column {
76 my ($self, $col, $value) = @_;
77 return $value unless defined $value; # NULL is NULL is NULL
78 my $info = $self->column_info($col)
79 or $self->throw_exception("No column info for $col");
80 return $value unless exists $info->{_inflate_info};
81 my $inflate = $info->{_inflate_info}{inflate};
82 $self->throw_exception("No inflator for $col") unless defined $inflate;
83 return $inflate->($value, $self);
86 sub _deflated_column {
87 my ($self, $col, $value) = @_;
88 return $value unless ref $value && blessed($value); # If it's not an object, don't touch it
89 my $info = $self->column_info($col) or
90 $self->throw_exception("No column info for $col");
91 return $value unless exists $info->{_inflate_info};
92 my $deflate = $info->{_inflate_info}{deflate};
93 $self->throw_exception("No deflator for $col") unless defined $deflate;
94 return $deflate->($value, $self);
97 =head2 get_inflated_column
99 my $val = $obj->get_inflated_column($col);
101 Fetch a column value in its inflated state. This is directly
102 analogous to L<DBIx::Class::Row/get_column> in that it only fetches a
103 column already retreived from the database, and then inflates it.
104 Throws an exception if the column requested is not an inflated column.
108 sub get_inflated_column {
109 my ($self, $col) = @_;
110 $self->throw_exception("$col is not an inflated column")
111 unless exists $self->column_info($col)->{_inflate_info};
112 return $self->{_inflated_column}{$col}
113 if exists $self->{_inflated_column}{$col};
114 return $self->{_inflated_column}{$col} =
115 $self->_inflated_column($col, $self->get_column($col));
118 =head2 set_inflated_column
120 my $copy = $obj->set_inflated_column($col => $val);
122 Sets a column value from an inflated value. This is directly
123 analogous to L<DBIx::Class::Row/set_column>.
127 sub set_inflated_column {
128 my ($self, $col, $obj) = @_;
129 $self->set_column($col, $self->_deflated_column($col, $obj));
131 $self->{_inflated_column}{$col} = $obj;
133 delete $self->{_inflated_column}{$col};
138 =head2 store_inflated_column
140 my $copy = $obj->store_inflated_column($col => $val);
142 Sets a column value from an inflated value without marking the column
143 as dirty. This is directly analogous to L<DBIx::Class::Row/store_column>.
147 sub store_inflated_column {
148 my ($self, $col, $obj) = @_;
149 unless (blessed $obj) {
150 delete $self->{_inflated_column}{$col};
151 $self->store_column($col => $obj);
154 delete $self->{_column_data}{$col};
155 return $self->{_inflated_column}{$col} = $obj;
162 =item L<DBIx::Class::Core> - This component is loaded as part of the
163 "core" L<DBIx::Class> components; generally there is no need to
170 Matt S. Trout <mst@shadowcatsystems.co.uk>
174 Daniel Westermann-Clark <danieltwc@cpan.org> (documentation)
178 You may distribute this code under the same terms as Perl itself.