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1 | package DBIx::Class::InflateColumn; |
2 | |
3 | use strict; |
4 | use warnings; |
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5 | |
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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 | |
11 | DBIx::Class::InflateColumn - Automatically create objects from column data |
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 | |
23 | This component translates column data into objects, i.e. "inflating" |
24 | the column data. It also "deflates" objects into an appropriate format |
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. |
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29 | |
30 | =head1 METHODS |
31 | |
32 | =head2 inflate_column |
33 | |
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34 | Instruct L<DBIx::Class> to inflate the given column. |
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35 | |
36 | In addition to the column name, you must provide C<inflate> and |
37 | C<deflate> methods. The C<inflate> method is called when you access |
38 | the field, while the C<deflate> method is called when the field needs |
39 | to used by the database. |
40 | |
41 | For example, if you have a table C<events> with a timestamp field |
42 | named C<insert_time>, you could inflate the column in the |
43 | corresponding table class using something like: |
44 | |
45 | __PACKAGE__->inflate_column('insert_time', { |
46 | inflate => sub { DateTime::Format::Pg->parse_datetime(shift); }, |
47 | deflate => sub { DateTime::Format::Pg->format_datetime(shift); }, |
48 | }); |
49 | |
50 | (Replace L<DateTime::Format::Pg> with the appropriate module for your |
51 | database, or consider L<DateTime::Format::DBI>.) |
52 | |
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53 | The coderefs you set for inflate and deflate are called with two parameters, |
54 | the first is the value of the column to be inflated/deflated, the second is the |
55 | row object itself. Thus you can call C<< ->result_source->schema->storage->dbh >> on |
56 | it, to feed to L<DateTime::Format::DBI>. |
57 | |
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58 | In this example, calls to an event's C<insert_time> accessor return a |
59 | L<DateTime> object. This L<DateTime> object is later "deflated" when |
60 | used in the database layer. |
61 | |
62 | =cut |
63 | |
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64 | sub inflate_column { |
65 | my ($self, $col, $attrs) = @_; |
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66 | $self->throw_exception("No such column $col to inflate") |
67 | unless $self->has_column($col); |
68 | $self->throw_exception("inflate_column needs attr hashref") |
69 | unless ref $attrs eq 'HASH'; |
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70 | $self->column_info($col)->{_inflate_info} = $attrs; |
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71 | $self->mk_group_accessors('inflated_column' => $col); |
72 | return 1; |
73 | } |
74 | |
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75 | sub _inflated_column { |
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76 | my ($self, $col, $value) = @_; |
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77 | return $value unless defined $value; # NULL is NULL is NULL |
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78 | my $info = $self->column_info($col) |
79 | or $self->throw_exception("No column info for $col"); |
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80 | return $value unless exists $info->{_inflate_info}; |
81 | my $inflate = $info->{_inflate_info}{inflate}; |
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82 | $self->throw_exception("No inflator for $col") unless defined $inflate; |
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83 | return $inflate->($value, $self); |
84 | } |
85 | |
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86 | sub _deflated_column { |
87 | my ($self, $col, $value) = @_; |
88 | return $value unless ref $value; # If it's not an object, don't touch it |
89 | my $info = $self->column_info($col) or |
90 | $self->throw_exception("No column info for $col"); |
91 | return $value unless exists $info->{_inflate_info}; |
92 | my $deflate = $info->{_inflate_info}{deflate}; |
93 | $self->throw_exception("No deflator for $col") unless defined $deflate; |
94 | return $deflate->($value, $self); |
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95 | } |
96 | |
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97 | =head2 get_inflated_column |
98 | |
99 | my $val = $obj->get_inflated_column($col); |
100 | |
101 | Fetch a column value in its inflated state. This is directly |
102 | analogous to L<DBIx::Class::Row/get_column> in that it only fetches a |
103 | column already retreived from the database, and then inflates it. |
104 | Throws an exception if the column requested is not an inflated column. |
105 | |
106 | =cut |
107 | |
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108 | sub get_inflated_column { |
109 | my ($self, $col) = @_; |
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110 | $self->throw_exception("$col is not an inflated column") |
111 | unless exists $self->column_info($col)->{_inflate_info}; |
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112 | return $self->{_inflated_column}{$col} |
113 | if exists $self->{_inflated_column}{$col}; |
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114 | return $self->{_inflated_column}{$col} = |
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115 | $self->_inflated_column($col, $self->get_column($col)); |
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116 | } |
117 | |
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118 | =head2 set_inflated_column |
119 | |
120 | my $copy = $obj->set_inflated_column($col => $val); |
121 | |
122 | Sets a column value from an inflated value. This is directly |
123 | analogous to L<DBIx::Class::Row/set_column>. |
124 | |
125 | =cut |
126 | |
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127 | sub set_inflated_column { |
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128 | my ($self, $col, $obj) = @_; |
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129 | $self->set_column($col, $self->_deflated_column($col, $obj)); |
130 | return $self->store_inflated_column($col, $obj); |
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131 | } |
132 | |
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133 | =head2 store_inflated_column |
134 | |
135 | my $copy = $obj->store_inflated_column($col => $val); |
136 | |
137 | Sets a column value from an inflated value without marking the column |
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138 | as dirty. This is directly analogous to L<DBIx::Class::Row/store_column>. |
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139 | |
140 | =cut |
141 | |
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142 | sub store_inflated_column { |
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143 | my ($self, $col, $obj) = @_; |
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144 | return $self->{_inflated_column}{$col} = $obj; |
180c7679 |
145 | } |
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146 | |
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147 | =head2 get_column |
148 | |
149 | Gets a column value in the same way as L<DBIx::Class::Row/get_column>. If there |
150 | is an inflated value stored that has not yet been deflated, it is deflated |
151 | when the method is invoked. |
152 | |
153 | =cut |
154 | |
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155 | sub get_column { |
156 | my ($self, $col) = @_; |
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157 | use Carp; confess unless ref $self; |
158 | if (exists $self->{_inflated_column}{$col} |
159 | && !exists $self->{_column_data}{$col}) { |
160 | $self->store_column($col, $self->_deflated_column($col, $self->{_inflated_column}{$col})); |
161 | } |
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162 | return $self->next::method($col); |
163 | } |
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164 | |
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165 | sub get_columns { |
166 | my $self = shift; |
167 | if (exists $self->{_inflated_column}) { |
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168 | foreach my $col (keys %{$self->{_inflated_column}}) { |
169 | $self->store_column($col, $self->_deflated_column($col)) |
170 | unless exists $self->{_column_data}{$col}; |
171 | } |
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172 | } |
173 | return $self->next::method; |
174 | } |
175 | |
176 | sub has_column_loaded { |
177 | my ($self, $col) = @_; |
178 | return 1 if exists $self->{_inflated_column}{$col}; |
179 | return $self->next::method($col); |
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180 | } |
181 | |
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182 | =head2 update |
183 | |
184 | Updates a row in the same way as L<DBIx::Class::Row/update>, handling |
185 | inflation and deflation of columns appropriately. |
186 | |
187 | =cut |
188 | |
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189 | sub update { |
190 | my ($class, $attrs, @rest) = @_; |
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191 | foreach my $key (keys %{$attrs||{}}) { |
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192 | if (ref $attrs->{$key} |
193 | && exists $class->column_info($key)->{_inflate_info}) { |
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194 | $class->set_inflated_column($key, delete $attrs->{$key}); |
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195 | } |
196 | } |
197 | return $class->next::method($attrs, @rest); |
198 | } |
199 | |
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200 | =head2 new |
201 | |
202 | Creates a row in the same way as L<DBIx::Class::Row/new>, handling |
203 | inflation and deflation of columns appropriately. |
204 | |
205 | =cut |
206 | |
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207 | sub new { |
208 | my ($class, $attrs, @rest) = @_; |
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209 | my $inflated; |
210 | foreach my $key (keys %{$attrs||{}}) { |
211 | $inflated->{$key} = delete $attrs->{$key} |
212 | if ref $attrs->{$key} && exists $class->column_info($key)->{_inflate_info}; |
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213 | } |
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214 | my $obj = $class->next::method($attrs, @rest); |
215 | $obj->{_inflated_column} = $inflated if $inflated; |
216 | return $obj; |
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217 | } |
218 | |
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219 | =head1 SEE ALSO |
220 | |
221 | =over 4 |
222 | |
223 | =item L<DBIx::Class::Core> - This component is loaded as part of the |
224 | "core" L<DBIx::Class> components; generally there is no need to |
225 | load it directly |
226 | |
227 | =back |
228 | |
229 | =head1 AUTHOR |
230 | |
231 | Matt S. Trout <mst@shadowcatsystems.co.uk> |
232 | |
233 | =head1 CONTRIBUTORS |
234 | |
235 | Daniel Westermann-Clark <danieltwc@cpan.org> (documentation) |
236 | |
237 | =head1 LICENSE |
238 | |
239 | You may distribute this code under the same terms as Perl itself. |
240 | |
241 | =cut |
242 | |
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243 | 1; |