1 package DBIx::Class::InflateColumn;
5 use Scalar::Util qw/blessed/;
7 use base qw/DBIx::Class::Row/;
11 DBIx::Class::InflateColumn - Automatically create references 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 references, i.e. "inflating"
24 the column data. It also "deflates" references 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. There's a
29 conveniece component to actually do that though, try
30 L<DBIx::Class::InflateColumn::DateTime>.
32 It will handle all types of references except scalar references. It
33 will not handle scalar values, these are ignored and thus passed
34 through to L<SQL::Abstract>. This is to allow setting raw values to
35 "just work". Scalar references are passed through to the database to
36 deal with, to allow such settings as C< \'year + 1'> and C< \'DEFAULT' >
39 If you want to filter plain scalar values and replace them with
40 something else, contribute a filtering component.
46 Instruct L<DBIx::Class> to inflate the given column.
48 In addition to the column name, you must provide C<inflate> and
49 C<deflate> methods. The C<inflate> method is called when you access
50 the field, while the C<deflate> method is called when the field needs
51 to used by the database.
53 For example, if you have a table C<events> with a timestamp field
54 named C<insert_time>, you could inflate the column in the
55 corresponding table class using something like:
57 __PACKAGE__->inflate_column('insert_time', {
58 inflate => sub { DateTime::Format::Pg->parse_datetime(shift); },
59 deflate => sub { DateTime::Format::Pg->format_datetime(shift); },
62 (Replace L<DateTime::Format::Pg> with the appropriate module for your
63 database, or consider L<DateTime::Format::DBI>.)
65 The coderefs you set for inflate and deflate are called with two parameters,
66 the first is the value of the column to be inflated/deflated, the second is the
67 row object itself. Thus you can call C<< ->result_source->schema->storage->dbh >> in your inflate/defalte subs, to feed to L<DateTime::Format::DBI>.
69 In this example, calls to an event's C<insert_time> accessor return a
70 L<DateTime> object. This L<DateTime> object is later "deflated" when
71 used in the database layer.
76 my ($self, $col, $attrs) = @_;
77 $self->throw_exception("No such column $col to inflate")
78 unless $self->has_column($col);
79 $self->throw_exception("inflate_column needs attr hashref")
80 unless ref $attrs eq 'HASH';
81 $self->column_info($col)->{_inflate_info} = $attrs;
82 $self->mk_group_accessors('inflated_column' => [$self->column_info($col)->{accessor} || $col, $col]);
86 sub _inflated_column {
87 my ($self, $col, $value) = @_;
88 return $value unless defined $value; # NULL is NULL is NULL
89 my $info = $self->column_info($col)
90 or $self->throw_exception("No column info for $col");
91 return $value unless exists $info->{_inflate_info};
92 my $inflate = $info->{_inflate_info}{inflate};
93 $self->throw_exception("No inflator for $col") unless defined $inflate;
94 return $inflate->($value, $self);
97 sub _deflated_column {
98 my ($self, $col, $value) = @_;
99 # return $value unless ref $value && blessed($value); # If it's not an object, don't touch it
100 ## Leave scalar refs (ala SQL::Abstract literal SQL), untouched, deflate all other refs
101 return $value unless (ref $value && ref($value) ne 'SCALAR');
102 my $info = $self->column_info($col) or
103 $self->throw_exception("No column info for $col");
104 return $value unless exists $info->{_inflate_info};
105 my $deflate = $info->{_inflate_info}{deflate};
106 $self->throw_exception("No deflator for $col") unless defined $deflate;
107 return $deflate->($value, $self);
110 =head2 get_inflated_column
112 my $val = $obj->get_inflated_column($col);
114 Fetch a column value in its inflated state. This is directly
115 analogous to L<DBIx::Class::Row/get_column> in that it only fetches a
116 column already retreived from the database, and then inflates it.
117 Throws an exception if the column requested is not an inflated column.
121 sub get_inflated_column {
122 my ($self, $col) = @_;
123 $self->throw_exception("$col is not an inflated column")
124 unless exists $self->column_info($col)->{_inflate_info};
125 return $self->{_inflated_column}{$col}
126 if exists $self->{_inflated_column}{$col};
127 return $self->{_inflated_column}{$col} =
128 $self->_inflated_column($col, $self->get_column($col));
131 =head2 set_inflated_column
133 my $copy = $obj->set_inflated_column($col => $val);
135 Sets a column value from an inflated value. This is directly
136 analogous to L<DBIx::Class::Row/set_column>.
140 sub set_inflated_column {
141 my ($self, $col, $inflated) = @_;
142 $self->set_column($col, $self->_deflated_column($col, $inflated));
143 # if (blessed $inflated) {
144 if (ref $inflated && ref($inflated) ne 'SCALAR') {
145 $self->{_inflated_column}{$col} = $inflated;
147 delete $self->{_inflated_column}{$col};
152 =head2 store_inflated_column
154 my $copy = $obj->store_inflated_column($col => $val);
156 Sets a column value from an inflated value without marking the column
157 as dirty. This is directly analogous to L<DBIx::Class::Row/store_column>.
161 sub store_inflated_column {
162 my ($self, $col, $inflated) = @_;
163 # unless (blessed $inflated) {
164 unless (ref $inflated && ref($inflated) ne 'SCALAR') {
165 delete $self->{_inflated_column}{$col};
166 $self->store_column($col => $inflated);
169 delete $self->{_column_data}{$col};
170 return $self->{_inflated_column}{$col} = $inflated;
177 =item L<DBIx::Class::Core> - This component is loaded as part of the
178 "core" L<DBIx::Class> components; generally there is no need to
185 Matt S. Trout <mst@shadowcatsystems.co.uk>
189 Daniel Westermann-Clark <danieltwc@cpan.org> (documentation)
191 Jess Robinson <cpan@desert-island.demon.co.uk>
195 You may distribute this code under the same terms as Perl itself.