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 convenience 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, see L<DBIx::Class::FilterColumn>.
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) = @_;
78 $self->throw_exception("InflateColumn does not work with FilterColumn")
79 if $self->isa('DBIx::Class::FilterColumn') &&
80 defined $self->column_info($col)->{_filter_info};
82 $self->throw_exception("No such column $col to inflate")
83 unless $self->has_column($col);
84 $self->throw_exception("inflate_column needs attr hashref")
85 unless ref $attrs eq 'HASH';
86 $self->column_info($col)->{_inflate_info} = $attrs;
87 my $acc = $self->column_info($col)->{accessor};
88 $self->mk_group_accessors('inflated_column' => [ (defined $acc ? $acc : $col), $col]);
92 sub _inflated_column {
93 my ($self, $col, $value) = @_;
94 return $value unless defined $value; # NULL is NULL is NULL
95 my $info = $self->column_info($col)
96 or $self->throw_exception("No column info for $col");
97 return $value unless exists $info->{_inflate_info};
98 my $inflate = $info->{_inflate_info}{inflate};
99 $self->throw_exception("No inflator for $col") unless defined $inflate;
100 return $inflate->($value, $self);
103 sub _deflated_column {
104 my ($self, $col, $value) = @_;
105 # return $value unless ref $value && blessed($value); # If it's not an object, don't touch it
106 ## Leave scalar refs (ala SQL::Abstract literal SQL), untouched, deflate all other refs
107 return $value unless (ref $value && ref($value) ne 'SCALAR');
108 my $info = $self->column_info($col) or
109 $self->throw_exception("No column info for $col");
110 return $value unless exists $info->{_inflate_info};
111 my $deflate = $info->{_inflate_info}{deflate};
112 $self->throw_exception("No deflator for $col") unless defined $deflate;
113 return $deflate->($value, $self);
116 =head2 get_inflated_column
118 my $val = $obj->get_inflated_column($col);
120 Fetch a column value in its inflated state. This is directly
121 analogous to L<DBIx::Class::Row/get_column> in that it only fetches a
122 column already retrieved from the database, and then inflates it.
123 Throws an exception if the column requested is not an inflated column.
127 sub get_inflated_column {
128 my ($self, $col) = @_;
129 $self->throw_exception("$col is not an inflated column")
130 unless exists $self->column_info($col)->{_inflate_info};
131 return $self->{_inflated_column}{$col}
132 if exists $self->{_inflated_column}{$col};
134 my $val = $self->get_column($col);
135 return $val if ref $val eq 'SCALAR'; #that would be a not-yet-reloaded sclarref update
137 return $self->{_inflated_column}{$col} = $self->_inflated_column($col, $val);
140 =head2 set_inflated_column
142 my $copy = $obj->set_inflated_column($col => $val);
144 Sets a column value from an inflated value. This is directly
145 analogous to L<DBIx::Class::Row/set_column>.
149 sub set_inflated_column {
150 my ($self, $col, $inflated) = @_;
151 $self->set_column($col, $self->_deflated_column($col, $inflated));
152 # if (blessed $inflated) {
153 if (ref $inflated && ref($inflated) ne 'SCALAR') {
154 $self->{_inflated_column}{$col} = $inflated;
156 delete $self->{_inflated_column}{$col};
161 =head2 store_inflated_column
163 my $copy = $obj->store_inflated_column($col => $val);
165 Sets a column value from an inflated value without marking the column
166 as dirty. This is directly analogous to L<DBIx::Class::Row/store_column>.
170 sub store_inflated_column {
171 my ($self, $col, $inflated) = @_;
172 # unless (blessed $inflated) {
173 unless (ref $inflated && ref($inflated) ne 'SCALAR') {
174 delete $self->{_inflated_column}{$col};
175 $self->store_column($col => $inflated);
178 delete $self->{_column_data}{$col};
179 return $self->{_inflated_column}{$col} = $inflated;
186 =item L<DBIx::Class::Core> - This component is loaded as part of the
187 C<core> L<DBIx::Class> components; generally there is no need to
194 Matt S. Trout <mst@shadowcatsystems.co.uk>
198 Daniel Westermann-Clark <danieltwc@cpan.org> (documentation)
200 Jess Robinson <cpan@desert-island.demon.co.uk>
204 You may distribute this code under the same terms as Perl itself.