1 package DBIx::Class::InflateColumn;
6 use base qw/DBIx::Class::Row/;
10 DBIx::Class::InflateColumn - Automatically create references from column data
14 # In your table classes
15 __PACKAGE__->inflate_column('column_name', {
16 inflate => sub { ... },
17 deflate => sub { ... },
22 This component translates column data into references, i.e. "inflating"
23 the column data. It also "deflates" references into an appropriate format
26 It can be used, for example, to automatically convert to and from
27 L<DateTime> objects for your date and time fields. There's a
28 convenience component to actually do that though, try
29 L<DBIx::Class::InflateColumn::DateTime>.
31 It will handle all types of references except scalar references. It
32 will not handle scalar values, these are ignored and thus passed
33 through to L<SQL::Abstract>. This is to allow setting raw values to
34 "just work". Scalar references are passed through to the database to
35 deal with, to allow such settings as C< \'year + 1'> and C< \'DEFAULT' >
38 If you want to filter plain scalar values and replace them with
39 something else, see L<DBIx::Class::FilterColumn>.
45 Instruct L<DBIx::Class> to inflate the given column.
47 In addition to the column name, you must provide C<inflate> and
48 C<deflate> methods. The C<inflate> method is called when you access
49 the field, while the C<deflate> method is called when the field needs
50 to used by the database.
52 For example, if you have a table C<events> with a timestamp field
53 named C<insert_time>, you could inflate the column in the
54 corresponding table class using something like:
56 __PACKAGE__->inflate_column('insert_time', {
57 inflate => sub { DateTime::Format::Pg->parse_datetime(shift); },
58 deflate => sub { DateTime::Format::Pg->format_datetime(shift); },
61 (Replace L<DateTime::Format::Pg> with the appropriate module for your
62 database, or consider L<DateTime::Format::DBI>.)
64 The coderefs you set for inflate and deflate are called with two parameters,
65 the first is the value of the column to be inflated/deflated, the second is the
66 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>.
68 In this example, calls to an event's C<insert_time> accessor return a
69 L<DateTime> object. This L<DateTime> object is later "deflated" when
70 used in the database layer.
75 my ($self, $col, $attrs) = @_;
77 my $colinfo = $self->column_info($col);
79 $self->throw_exception("InflateColumn does not work with FilterColumn")
80 if $self->isa('DBIx::Class::FilterColumn') &&
81 defined $colinfo->{_filter_info};
83 $self->throw_exception("No such column $col to inflate")
84 unless $self->has_column($col);
85 $self->throw_exception("inflate_column needs attr hashref")
86 unless ref $attrs eq 'HASH';
87 $colinfo->{_inflate_info} = $attrs;
88 my $acc = $colinfo->{accessor};
89 $self->mk_group_accessors('inflated_column' => [ (defined $acc ? $acc : $col), $col]);
93 sub _inflated_column {
94 my ($self, $col, $value) = @_;
95 return $value unless defined $value; # NULL is NULL is NULL
96 my $info = $self->column_info($col)
97 or $self->throw_exception("No column info for $col");
98 return $value unless exists $info->{_inflate_info};
99 my $inflate = $info->{_inflate_info}{inflate};
100 $self->throw_exception("No inflator for $col") unless defined $inflate;
101 return $inflate->($value, $self);
104 sub _deflated_column {
105 my ($self, $col, $value) = @_;
106 # return $value unless ref $value && blessed($value); # If it's not an object, don't touch it
107 ## Leave scalar refs (ala SQL::Abstract literal SQL), untouched, deflate all other refs
108 return $value unless (ref $value && ref($value) ne 'SCALAR');
109 my $info = $self->column_info($col) or
110 $self->throw_exception("No column info for $col");
111 return $value unless exists $info->{_inflate_info};
112 my $deflate = $info->{_inflate_info}{deflate};
113 $self->throw_exception("No deflator for $col") unless defined $deflate;
114 return $deflate->($value, $self);
117 =head2 get_inflated_column
119 my $val = $obj->get_inflated_column($col);
121 Fetch a column value in its inflated state. This is directly
122 analogous to L<DBIx::Class::Row/get_column> in that it only fetches a
123 column already retrieved from the database, and then inflates it.
124 Throws an exception if the column requested is not an inflated column.
128 sub get_inflated_column {
129 my ($self, $col) = @_;
130 $self->throw_exception("$col is not an inflated column")
131 unless exists $self->column_info($col)->{_inflate_info};
132 return $self->{_inflated_column}{$col}
133 if exists $self->{_inflated_column}{$col};
135 my $val = $self->get_column($col);
136 return $val if ref $val eq 'SCALAR'; #that would be a not-yet-reloaded sclarref update
138 return $self->{_inflated_column}{$col} = $self->_inflated_column($col, $val);
141 =head2 set_inflated_column
143 my $copy = $obj->set_inflated_column($col => $val);
145 Sets a column value from an inflated value. This is directly
146 analogous to L<DBIx::Class::Row/set_column>.
150 sub set_inflated_column {
151 my ($self, $col, $inflated) = @_;
152 $self->set_column($col, $self->_deflated_column($col, $inflated));
153 # if (blessed $inflated) {
154 if (ref $inflated && ref($inflated) ne 'SCALAR') {
155 $self->{_inflated_column}{$col} = $inflated;
157 delete $self->{_inflated_column}{$col};
162 =head2 store_inflated_column
164 my $copy = $obj->store_inflated_column($col => $val);
166 Sets a column value from an inflated value without marking the column
167 as dirty. This is directly analogous to L<DBIx::Class::Row/store_column>.
171 sub store_inflated_column {
172 my ($self, $col, $inflated) = @_;
173 # unless (blessed $inflated) {
174 unless (ref $inflated && ref($inflated) ne 'SCALAR') {
175 delete $self->{_inflated_column}{$col};
176 $self->store_column($col => $inflated);
179 delete $self->{_column_data}{$col};
180 return $self->{_inflated_column}{$col} = $inflated;
187 =item L<DBIx::Class::Core> - This component is loaded as part of the
188 C<core> L<DBIx::Class> components; generally there is no need to
195 Matt S. Trout <mst@shadowcatsystems.co.uk>
199 Daniel Westermann-Clark <danieltwc@cpan.org> (documentation)
201 Jess Robinson <cpan@desert-island.demon.co.uk>
205 You may distribute this code under the same terms as Perl itself.