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1 | package DBIx::Class::InflateColumn; |
2 | |
3 | use strict; |
4 | use warnings; |
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5 | use Scalar::Util qw/blessed/; |
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6 | |
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7 | use base qw/DBIx::Class::Row/; |
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8 | |
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9 | =head1 NAME |
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10 | |
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11 | DBIx::Class::InflateColumn - Automatically create references from column data |
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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 | |
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23 | This component translates column data into references, i.e. "inflating" |
24 | the column data. It also "deflates" references into an appropriate format |
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25 | for the database. |
26 | |
27 | It can be used, for example, to automatically convert to and from |
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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>. |
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31 | |
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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' > |
37 | to work. |
38 | |
39 | If you want to filter plain scalar values and replace them with |
40 | something else, contribute a filtering component. |
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41 | |
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42 | =head1 METHODS |
43 | |
44 | =head2 inflate_column |
45 | |
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46 | Instruct L<DBIx::Class> to inflate the given column. |
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47 | |
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. |
52 | |
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: |
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 |
63 | database, or consider L<DateTime::Format::DBI>.) |
64 | |
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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 |
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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>. |
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68 | |
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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. |
72 | |
73 | =cut |
74 | |
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75 | sub inflate_column { |
76 | my ($self, $col, $attrs) = @_; |
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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'; |
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81 | $self->column_info($col)->{_inflate_info} = $attrs; |
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82 | my $acc = $self->column_info($col)->{accessor}; |
83 | $self->mk_group_accessors('inflated_column' => [ (defined $acc ? $acc : $col), $col]); |
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84 | return 1; |
85 | } |
86 | |
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87 | sub _inflated_column { |
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88 | my ($self, $col, $value) = @_; |
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89 | return $value unless defined $value; # NULL is NULL is NULL |
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90 | my $info = $self->column_info($col) |
91 | or $self->throw_exception("No column info for $col"); |
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92 | return $value unless exists $info->{_inflate_info}; |
93 | my $inflate = $info->{_inflate_info}{inflate}; |
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94 | $self->throw_exception("No inflator for $col") unless defined $inflate; |
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95 | return $inflate->($value, $self); |
96 | } |
97 | |
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98 | sub _deflated_column { |
99 | my ($self, $col, $value) = @_; |
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100 | # return $value unless ref $value && blessed($value); # If it's not an object, don't touch it |
101 | ## Leave scalar refs (ala SQL::Abstract literal SQL), untouched, deflate all other refs |
102 | return $value unless (ref $value && ref($value) ne 'SCALAR'); |
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103 | my $info = $self->column_info($col) or |
104 | $self->throw_exception("No column info for $col"); |
105 | return $value unless exists $info->{_inflate_info}; |
106 | my $deflate = $info->{_inflate_info}{deflate}; |
107 | $self->throw_exception("No deflator for $col") unless defined $deflate; |
108 | return $deflate->($value, $self); |
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109 | } |
110 | |
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111 | =head2 get_inflated_column |
112 | |
113 | my $val = $obj->get_inflated_column($col); |
114 | |
115 | Fetch a column value in its inflated state. This is directly |
116 | analogous to L<DBIx::Class::Row/get_column> in that it only fetches a |
117 | column already retreived from the database, and then inflates it. |
118 | Throws an exception if the column requested is not an inflated column. |
119 | |
120 | =cut |
121 | |
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122 | sub get_inflated_column { |
123 | my ($self, $col) = @_; |
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124 | $self->throw_exception("$col is not an inflated column") |
125 | unless exists $self->column_info($col)->{_inflate_info}; |
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126 | return $self->{_inflated_column}{$col} |
127 | if exists $self->{_inflated_column}{$col}; |
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128 | |
129 | my $val = $self->get_column($col); |
130 | return $val if ref $val eq 'SCALAR'; #that would be a not-yet-reloaded sclarref update |
131 | |
132 | return $self->{_inflated_column}{$col} = $self->_inflated_column($col, $val); |
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133 | } |
134 | |
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135 | =head2 set_inflated_column |
136 | |
137 | my $copy = $obj->set_inflated_column($col => $val); |
138 | |
139 | Sets a column value from an inflated value. This is directly |
140 | analogous to L<DBIx::Class::Row/set_column>. |
141 | |
142 | =cut |
143 | |
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144 | sub set_inflated_column { |
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145 | my ($self, $col, $inflated) = @_; |
146 | $self->set_column($col, $self->_deflated_column($col, $inflated)); |
147 | # if (blessed $inflated) { |
148 | if (ref $inflated && ref($inflated) ne 'SCALAR') { |
149 | $self->{_inflated_column}{$col} = $inflated; |
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150 | } else { |
151 | delete $self->{_inflated_column}{$col}; |
152 | } |
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153 | return $inflated; |
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154 | } |
155 | |
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156 | =head2 store_inflated_column |
157 | |
158 | my $copy = $obj->store_inflated_column($col => $val); |
159 | |
160 | Sets a column value from an inflated value without marking the column |
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161 | as dirty. This is directly analogous to L<DBIx::Class::Row/store_column>. |
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162 | |
163 | =cut |
164 | |
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165 | sub store_inflated_column { |
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166 | my ($self, $col, $inflated) = @_; |
167 | # unless (blessed $inflated) { |
168 | unless (ref $inflated && ref($inflated) ne 'SCALAR') { |
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169 | delete $self->{_inflated_column}{$col}; |
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170 | $self->store_column($col => $inflated); |
171 | return $inflated; |
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172 | } |
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173 | delete $self->{_column_data}{$col}; |
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174 | return $self->{_inflated_column}{$col} = $inflated; |
180c7679 |
175 | } |
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176 | |
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177 | =head1 SEE ALSO |
178 | |
179 | =over 4 |
180 | |
181 | =item L<DBIx::Class::Core> - This component is loaded as part of the |
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182 | C<core> L<DBIx::Class> components; generally there is no need to |
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183 | load it directly |
184 | |
185 | =back |
186 | |
187 | =head1 AUTHOR |
188 | |
189 | Matt S. Trout <mst@shadowcatsystems.co.uk> |
190 | |
191 | =head1 CONTRIBUTORS |
192 | |
193 | Daniel Westermann-Clark <danieltwc@cpan.org> (documentation) |
194 | |
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195 | Jess Robinson <cpan@desert-island.demon.co.uk> |
196 | |
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197 | =head1 LICENSE |
198 | |
199 | You may distribute this code under the same terms as Perl itself. |
200 | |
201 | =cut |
202 | |
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203 | 1; |