resultset_class/result_class now (again) auto loads the specified class; requires...
[dbsrgits/DBIx-Class-Historic.git] / lib / DBIx / Class / InflateColumn.pm
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0e5c2582 1package DBIx::Class::InflateColumn;
2
3use strict;
4use warnings;
ba026511 5use Scalar::Util qw/blessed/;
aa562407 6
75a23b3e 7use base qw/DBIx::Class::Row/;
0e5c2582 8
75d07914 9=head1 NAME
bcae85db 10
e81a6241 11DBIx::Class::InflateColumn - Automatically create references from column data
bcae85db 12
13=head1 SYNOPSIS
14
15 # In your table classes
16 __PACKAGE__->inflate_column('column_name', {
17 inflate => sub { ... },
18 deflate => sub { ... },
19 });
20
21=head1 DESCRIPTION
22
e81a6241 23This component translates column data into references, i.e. "inflating"
24the column data. It also "deflates" references into an appropriate format
bcae85db 25for the database.
26
27It can be used, for example, to automatically convert to and from
75d07914 28L<DateTime> objects for your date and time fields.
bcae85db 29
e81a6241 30It will accept arrayrefs, hashrefs and blessed references (objects),
31but not scalarrefs. Scalar references are passed through to the
32database to deal with, to allow such settings as C< \'year + 1'> and
33C< \'DEFAULT' > to work.
34
bcae85db 35=head1 METHODS
36
37=head2 inflate_column
38
75d07914 39Instruct L<DBIx::Class> to inflate the given column.
bcae85db 40
41In addition to the column name, you must provide C<inflate> and
42C<deflate> methods. The C<inflate> method is called when you access
43the field, while the C<deflate> method is called when the field needs
44to used by the database.
45
46For example, if you have a table C<events> with a timestamp field
47named C<insert_time>, you could inflate the column in the
48corresponding table class using something like:
49
50 __PACKAGE__->inflate_column('insert_time', {
51 inflate => sub { DateTime::Format::Pg->parse_datetime(shift); },
52 deflate => sub { DateTime::Format::Pg->format_datetime(shift); },
53 });
54
55(Replace L<DateTime::Format::Pg> with the appropriate module for your
56database, or consider L<DateTime::Format::DBI>.)
57
06fc5fc9 58The coderefs you set for inflate and deflate are called with two parameters,
59the first is the value of the column to be inflated/deflated, the second is the
60row object itself. Thus you can call C<< ->result_source->schema->storage->dbh >> on
61it, to feed to L<DateTime::Format::DBI>.
62
bcae85db 63In this example, calls to an event's C<insert_time> accessor return a
64L<DateTime> object. This L<DateTime> object is later "deflated" when
65used in the database layer.
66
67=cut
68
0e5c2582 69sub inflate_column {
70 my ($self, $col, $attrs) = @_;
bc0c9800 71 $self->throw_exception("No such column $col to inflate")
72 unless $self->has_column($col);
73 $self->throw_exception("inflate_column needs attr hashref")
74 unless ref $attrs eq 'HASH';
103647d5 75 $self->column_info($col)->{_inflate_info} = $attrs;
0e5c2582 76 $self->mk_group_accessors('inflated_column' => $col);
77 return 1;
78}
79
4a07648a 80sub _inflated_column {
0e5c2582 81 my ($self, $col, $value) = @_;
9f300b1b 82 return $value unless defined $value; # NULL is NULL is NULL
bc0c9800 83 my $info = $self->column_info($col)
84 or $self->throw_exception("No column info for $col");
103647d5 85 return $value unless exists $info->{_inflate_info};
86 my $inflate = $info->{_inflate_info}{inflate};
701da8c4 87 $self->throw_exception("No inflator for $col") unless defined $inflate;
0e5c2582 88 return $inflate->($value, $self);
89}
90
89279e9d 91sub _deflated_column {
92 my ($self, $col, $value) = @_;
e81a6241 93# return $value unless ref $value && blessed($value); # If it's not an object, don't touch it
94 ## Leave scalar refs (ala SQL::Abstract literal SQL), untouched, deflate all other refs
95 return $value unless (ref $value && ref($value) ne 'SCALAR');
89279e9d 96 my $info = $self->column_info($col) or
97 $self->throw_exception("No column info for $col");
98 return $value unless exists $info->{_inflate_info};
99 my $deflate = $info->{_inflate_info}{deflate};
100 $self->throw_exception("No deflator for $col") unless defined $deflate;
101 return $deflate->($value, $self);
0e5c2582 102}
103
7eb4ecc8 104=head2 get_inflated_column
105
106 my $val = $obj->get_inflated_column($col);
107
108Fetch a column value in its inflated state. This is directly
109analogous to L<DBIx::Class::Row/get_column> in that it only fetches a
110column already retreived from the database, and then inflates it.
111Throws an exception if the column requested is not an inflated column.
112
113=cut
114
0e5c2582 115sub get_inflated_column {
116 my ($self, $col) = @_;
bc0c9800 117 $self->throw_exception("$col is not an inflated column")
118 unless exists $self->column_info($col)->{_inflate_info};
0e5c2582 119 return $self->{_inflated_column}{$col}
120 if exists $self->{_inflated_column}{$col};
0e5c2582 121 return $self->{_inflated_column}{$col} =
4a07648a 122 $self->_inflated_column($col, $self->get_column($col));
0e5c2582 123}
124
7eb4ecc8 125=head2 set_inflated_column
126
127 my $copy = $obj->set_inflated_column($col => $val);
128
129Sets a column value from an inflated value. This is directly
130analogous to L<DBIx::Class::Row/set_column>.
131
132=cut
133
0e5c2582 134sub set_inflated_column {
ad5d0ee9 135 my ($self, $col, $inflated) = @_;
136 $self->set_column($col, $self->_deflated_column($col, $inflated));
137# if (blessed $inflated) {
138 if (ref $inflated && ref($inflated) ne 'SCALAR') {
139 $self->{_inflated_column}{$col} = $inflated;
9f471067 140 } else {
141 delete $self->{_inflated_column}{$col};
142 }
ad5d0ee9 143 return $inflated;
0e5c2582 144}
145
7eb4ecc8 146=head2 store_inflated_column
147
148 my $copy = $obj->store_inflated_column($col => $val);
149
150Sets a column value from an inflated value without marking the column
47c56124 151as dirty. This is directly analogous to L<DBIx::Class::Row/store_column>.
7eb4ecc8 152
153=cut
154
0e5c2582 155sub store_inflated_column {
ad5d0ee9 156 my ($self, $col, $inflated) = @_;
157# unless (blessed $inflated) {
158 unless (ref $inflated && ref($inflated) ne 'SCALAR') {
9f471067 159 delete $self->{_inflated_column}{$col};
ad5d0ee9 160 $self->store_column($col => $inflated);
161 return $inflated;
9f471067 162 }
25594f03 163 delete $self->{_column_data}{$col};
ad5d0ee9 164 return $self->{_inflated_column}{$col} = $inflated;
180c7679 165}
4a07648a 166
bcae85db 167=head1 SEE ALSO
168
169=over 4
170
171=item L<DBIx::Class::Core> - This component is loaded as part of the
172 "core" L<DBIx::Class> components; generally there is no need to
173 load it directly
174
175=back
176
177=head1 AUTHOR
178
179Matt S. Trout <mst@shadowcatsystems.co.uk>
180
181=head1 CONTRIBUTORS
182
183Daniel Westermann-Clark <danieltwc@cpan.org> (documentation)
184
e81a6241 185Jess Robinson <cpan@desert-island.demon.co.uk>
186
bcae85db 187=head1 LICENSE
188
189You may distribute this code under the same terms as Perl itself.
190
191=cut
192
0e5c2582 1931;