1) changed all 4 space indentation to 2 space style indents for replication code...
[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
ef7a8b67 28L<DateTime> objects for your date and time fields. There's a
29conveniece component to actually do that though, try
30L<DBIx::Class::InflateColumn::DateTime>.
bcae85db 31
ef7a8b67 32It will handle all types of references except scalar references. It
33will not handle scalar values, these are ignored and thus passed
34through to L<SQL::Abstract>. This is to allow setting raw values to
35"just work". Scalar references are passed through to the database to
36deal with, to allow such settings as C< \'year + 1'> and C< \'DEFAULT' >
37to work.
38
39If you want to filter plain scalar values and replace them with
40something else, contribute a filtering component.
e81a6241 41
bcae85db 42=head1 METHODS
43
44=head2 inflate_column
45
75d07914 46Instruct L<DBIx::Class> to inflate the given column.
bcae85db 47
48In addition to the column name, you must provide C<inflate> and
49C<deflate> methods. The C<inflate> method is called when you access
50the field, while the C<deflate> method is called when the field needs
51to used by the database.
52
53For example, if you have a table C<events> with a timestamp field
54named C<insert_time>, you could inflate the column in the
55corresponding table class using something like:
56
57 __PACKAGE__->inflate_column('insert_time', {
58 inflate => sub { DateTime::Format::Pg->parse_datetime(shift); },
59 deflate => sub { DateTime::Format::Pg->format_datetime(shift); },
60 });
61
62(Replace L<DateTime::Format::Pg> with the appropriate module for your
63database, or consider L<DateTime::Format::DBI>.)
64
06fc5fc9 65The coderefs you set for inflate and deflate are called with two parameters,
66the first is the value of the column to be inflated/deflated, the second is the
ef7a8b67 67row object itself. Thus you can call C<< ->result_source->schema->storage->dbh >> in your inflate/defalte subs, to feed to L<DateTime::Format::DBI>.
06fc5fc9 68
bcae85db 69In this example, calls to an event's C<insert_time> accessor return a
70L<DateTime> object. This L<DateTime> object is later "deflated" when
71used in the database layer.
72
73=cut
74
0e5c2582 75sub inflate_column {
76 my ($self, $col, $attrs) = @_;
bc0c9800 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';
103647d5 81 $self->column_info($col)->{_inflate_info} = $attrs;
43556c5d 82 $self->mk_group_accessors('inflated_column' => [$self->column_info($col)->{accessor} || $col, $col]);
0e5c2582 83 return 1;
84}
85
4a07648a 86sub _inflated_column {
0e5c2582 87 my ($self, $col, $value) = @_;
9f300b1b 88 return $value unless defined $value; # NULL is NULL is NULL
bc0c9800 89 my $info = $self->column_info($col)
90 or $self->throw_exception("No column info for $col");
103647d5 91 return $value unless exists $info->{_inflate_info};
92 my $inflate = $info->{_inflate_info}{inflate};
701da8c4 93 $self->throw_exception("No inflator for $col") unless defined $inflate;
0e5c2582 94 return $inflate->($value, $self);
95}
96
89279e9d 97sub _deflated_column {
98 my ($self, $col, $value) = @_;
e81a6241 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');
89279e9d 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);
0e5c2582 108}
109
7eb4ecc8 110=head2 get_inflated_column
111
112 my $val = $obj->get_inflated_column($col);
113
114Fetch a column value in its inflated state. This is directly
115analogous to L<DBIx::Class::Row/get_column> in that it only fetches a
116column already retreived from the database, and then inflates it.
117Throws an exception if the column requested is not an inflated column.
118
119=cut
120
0e5c2582 121sub get_inflated_column {
122 my ($self, $col) = @_;
bc0c9800 123 $self->throw_exception("$col is not an inflated column")
124 unless exists $self->column_info($col)->{_inflate_info};
0e5c2582 125 return $self->{_inflated_column}{$col}
126 if exists $self->{_inflated_column}{$col};
0e5c2582 127 return $self->{_inflated_column}{$col} =
4a07648a 128 $self->_inflated_column($col, $self->get_column($col));
0e5c2582 129}
130
7eb4ecc8 131=head2 set_inflated_column
132
133 my $copy = $obj->set_inflated_column($col => $val);
134
135Sets a column value from an inflated value. This is directly
136analogous to L<DBIx::Class::Row/set_column>.
137
138=cut
139
0e5c2582 140sub set_inflated_column {
ad5d0ee9 141 my ($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;
9f471067 146 } else {
147 delete $self->{_inflated_column}{$col};
148 }
ad5d0ee9 149 return $inflated;
0e5c2582 150}
151
7eb4ecc8 152=head2 store_inflated_column
153
154 my $copy = $obj->store_inflated_column($col => $val);
155
156Sets a column value from an inflated value without marking the column
47c56124 157as dirty. This is directly analogous to L<DBIx::Class::Row/store_column>.
7eb4ecc8 158
159=cut
160
0e5c2582 161sub store_inflated_column {
ad5d0ee9 162 my ($self, $col, $inflated) = @_;
163# unless (blessed $inflated) {
164 unless (ref $inflated && ref($inflated) ne 'SCALAR') {
9f471067 165 delete $self->{_inflated_column}{$col};
ad5d0ee9 166 $self->store_column($col => $inflated);
167 return $inflated;
9f471067 168 }
25594f03 169 delete $self->{_column_data}{$col};
ad5d0ee9 170 return $self->{_inflated_column}{$col} = $inflated;
180c7679 171}
4a07648a 172
bcae85db 173=head1 SEE ALSO
174
175=over 4
176
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
179 load it directly
180
181=back
182
183=head1 AUTHOR
184
185Matt S. Trout <mst@shadowcatsystems.co.uk>
186
187=head1 CONTRIBUTORS
188
189Daniel Westermann-Clark <danieltwc@cpan.org> (documentation)
190
e81a6241 191Jess Robinson <cpan@desert-island.demon.co.uk>
192
bcae85db 193=head1 LICENSE
194
195You may distribute this code under the same terms as Perl itself.
196
197=cut
198
0e5c2582 1991;