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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 | use base 'DBIx::Class::Row'; |
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7 | use SQL::Abstract 'is_literal_value'; |
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8 | use namespace::clean; |
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9 | |
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10 | =head1 NAME |
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11 | |
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12 | DBIx::Class::InflateColumn - Automatically create references from column data |
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13 | |
14 | =head1 SYNOPSIS |
15 | |
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16 | # In your table classes |
17 | __PACKAGE__->inflate_column('column_name', { |
18 | inflate => sub { |
19 | my ($raw_value_from_db, $result_object) = @_; |
20 | ... |
21 | }, |
22 | deflate => sub { |
23 | my ($inflated_value_from_user, $result_object) = @_; |
24 | ... |
25 | }, |
26 | }); |
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27 | |
28 | =head1 DESCRIPTION |
29 | |
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30 | This component translates column data into references, i.e. "inflating" |
31 | the column data. It also "deflates" references into an appropriate format |
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32 | for the database. |
33 | |
34 | It can be used, for example, to automatically convert to and from |
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35 | L<DateTime> objects for your date and time fields. There's a |
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36 | convenience component to actually do that though, try |
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37 | L<DBIx::Class::InflateColumn::DateTime>. |
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38 | |
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39 | It will handle all types of references except scalar references. It |
40 | will not handle scalar values, these are ignored and thus passed |
41 | through to L<SQL::Abstract>. This is to allow setting raw values to |
42 | "just work". Scalar references are passed through to the database to |
43 | deal with, to allow such settings as C< \'year + 1'> and C< \'DEFAULT' > |
44 | to work. |
45 | |
46 | If you want to filter plain scalar values and replace them with |
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47 | something else, see L<DBIx::Class::FilterColumn>. |
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48 | |
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49 | =head1 METHODS |
50 | |
51 | =head2 inflate_column |
52 | |
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53 | Instruct L<DBIx::Class> to inflate the given column. |
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54 | |
55 | In addition to the column name, you must provide C<inflate> and |
56 | C<deflate> methods. The C<inflate> method is called when you access |
57 | the field, while the C<deflate> method is called when the field needs |
58 | to used by the database. |
59 | |
60 | For example, if you have a table C<events> with a timestamp field |
61 | named C<insert_time>, you could inflate the column in the |
62 | corresponding table class using something like: |
63 | |
64 | __PACKAGE__->inflate_column('insert_time', { |
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65 | inflate => sub { |
66 | my ($insert_time_raw_value, $event_result_object) = @_; |
67 | DateTime->from_epoch( epoch => $insert_time_raw_value ); |
68 | }, |
69 | deflate => sub { |
70 | my ($insert_time_dt_object, $event_result_object) = @_; |
71 | $insert_time_dt_object->epoch; |
72 | }, |
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73 | }); |
74 | |
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75 | The coderefs you set for inflate and deflate are called with two parameters, |
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76 | the first is the value of the column to be inflated/deflated, the second is |
77 | the result object itself. |
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78 | |
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79 | In this example, calls to an event's C<insert_time> accessor return a |
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80 | L<DateTime> object. This L<DateTime> object is later "deflated" back |
81 | to the integer epoch representation when used in the database layer. |
82 | For a much more thorough handling of the above example, please see |
83 | L<DBIx::Class::DateTime::Epoch> |
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84 | |
85 | =cut |
86 | |
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87 | sub inflate_column { |
88 | my ($self, $col, $attrs) = @_; |
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89 | |
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90 | my $colinfo = $self->result_source->columns_info([$col])->{$col}; |
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91 | |
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92 | $self->throw_exception("InflateColumn can not be used on a column with a declared FilterColumn filter") |
93 | if defined $colinfo->{_filter_info} and $self->isa('DBIx::Class::FilterColumn'); |
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94 | |
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95 | $self->throw_exception("inflate_column needs attr hashref") |
96 | unless ref $attrs eq 'HASH'; |
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97 | |
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98 | $colinfo->{_inflate_info} = $attrs; |
99 | my $acc = $colinfo->{accessor}; |
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100 | $self->mk_group_accessors('inflated_column' => [ (defined $acc ? $acc : $col), $col]); |
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101 | return 1; |
102 | } |
103 | |
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104 | sub _inflated_column { |
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105 | my ($self, $col, $value) = @_; |
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106 | |
107 | return $value if ( |
108 | ! defined $value # NULL is NULL is NULL |
109 | or |
110 | is_literal_value($value) #that would be a not-yet-reloaded literal update |
111 | ); |
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112 | |
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113 | my $info = $self->result_source->columns_info([$col])->{$col}; |
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114 | |
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115 | return $value unless exists $info->{_inflate_info}; |
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116 | |
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117 | return ( |
118 | $info->{_inflate_info}{inflate} |
119 | || |
120 | $self->throw_exception("No inflator found for '$col'") |
121 | )->($value, $self); |
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122 | } |
123 | |
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124 | sub _deflated_column { |
125 | my ($self, $col, $value) = @_; |
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126 | |
127 | ## Deflate any refs except for literals, pass through plain values |
128 | return $value if ( |
129 | ! length ref $value |
130 | or |
131 | is_literal_value($value) |
132 | ); |
133 | |
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134 | my $info = $self->result_source->columns_info([$col])->{$col}; |
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135 | |
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136 | return $value unless exists $info->{_inflate_info}; |
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137 | |
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138 | return ( |
139 | $info->{_inflate_info}{deflate} |
140 | || |
141 | $self->throw_exception("No deflator found for '$col'") |
142 | )->($value, $self); |
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143 | } |
144 | |
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145 | =head2 get_inflated_column |
146 | |
147 | my $val = $obj->get_inflated_column($col); |
148 | |
149 | Fetch a column value in its inflated state. This is directly |
150 | analogous to L<DBIx::Class::Row/get_column> in that it only fetches a |
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151 | column already retrieved from the database, and then inflates it. |
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152 | Throws an exception if the column requested is not an inflated column. |
153 | |
154 | =cut |
155 | |
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156 | sub get_inflated_column { |
157 | my ($self, $col) = @_; |
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158 | |
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159 | $self->throw_exception("$col is not an inflated column") |
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160 | unless exists $self->result_source->columns_info->{$col}{_inflate_info}; |
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161 | |
162 | # we take care of keeping things in sync |
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163 | return $self->{_inflated_column}{$col} |
164 | if exists $self->{_inflated_column}{$col}; |
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165 | |
166 | my $val = $self->get_column($col); |
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167 | |
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168 | return $self->{_inflated_column}{$col} = $self->_inflated_column($col, $val); |
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169 | } |
170 | |
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171 | =head2 set_inflated_column |
172 | |
173 | my $copy = $obj->set_inflated_column($col => $val); |
174 | |
175 | Sets a column value from an inflated value. This is directly |
176 | analogous to L<DBIx::Class::Row/set_column>. |
177 | |
178 | =cut |
179 | |
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180 | sub set_inflated_column { |
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181 | my ($self, $col, $value) = @_; |
182 | |
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183 | # pass through deflated stuff |
184 | if (! length ref $value or is_literal_value($value)) { |
185 | $self->set_column($col, $value); |
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186 | delete $self->{_inflated_column}{$col}; |
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187 | } |
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188 | # need to call set_column with the deflate cycle so that |
189 | # relationship caches are nuked if any |
190 | # also does the compare-for-dirtyness and change tracking dance |
191 | else { |
192 | $self->set_column($col, $self->_deflated_column($col, $value)); |
193 | $self->{_inflated_column}{$col} = $value; |
194 | } |
195 | |
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196 | return $value; |
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197 | } |
198 | |
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199 | =head2 store_inflated_column |
200 | |
201 | my $copy = $obj->store_inflated_column($col => $val); |
202 | |
203 | Sets a column value from an inflated value without marking the column |
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204 | as dirty. This is directly analogous to L<DBIx::Class::Row/store_column>. |
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205 | |
206 | =cut |
207 | |
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208 | sub store_inflated_column { |
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209 | my ($self, $col, $value) = @_; |
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210 | |
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211 | if (! length ref $value or is_literal_value($value)) { |
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212 | delete $self->{_inflated_column}{$col}; |
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213 | $self->store_column($col => $value); |
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214 | } |
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215 | else { |
216 | delete $self->{_column_data}{$col}; |
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217 | $self->{_inflated_column}{$col} = $value; |
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218 | } |
219 | |
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220 | return $value; |
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221 | } |
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222 | |
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223 | =head1 SEE ALSO |
224 | |
225 | =over 4 |
226 | |
227 | =item L<DBIx::Class::Core> - This component is loaded as part of the |
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228 | C<core> L<DBIx::Class> components; generally there is no need to |
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229 | load it directly |
230 | |
231 | =back |
232 | |
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233 | =head1 FURTHER QUESTIONS? |
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234 | |
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235 | Check the list of L<additional DBIC resources|DBIx::Class/GETTING HELP/SUPPORT>. |
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236 | |
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237 | =head1 COPYRIGHT AND LICENSE |
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238 | |
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239 | This module is free software L<copyright|DBIx::Class/COPYRIGHT AND LICENSE> |
240 | by the L<DBIx::Class (DBIC) authors|DBIx::Class/AUTHORS>. You can |
241 | redistribute it and/or modify it under the same terms as the |
242 | L<DBIx::Class library|DBIx::Class/COPYRIGHT AND LICENSE>. |
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243 | |
244 | =cut |
245 | |
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246 | 1; |