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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, $self); |
84 | } |
85 | |
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86 | sub _deflated_column { |
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87 | my ($self, $col, $value) = @_; |
88 | return $value unless ref $value; # If it's not an object, don't touch it |
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89 | my $info = $self->column_info($col) or |
90 | $self->throw_exception("No column info for $col"); |
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91 | return $value unless exists $info->{_inflate_info}; |
92 | my $deflate = $info->{_inflate_info}{deflate}; |
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93 | $self->throw_exception("No deflator for $col") unless defined $deflate; |
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94 | return $deflate->($value, $self); |
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 | |
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113 | return $self->{_inflated_column}{$col} |
114 | if exists $self->{_inflated_column}{$col}; |
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115 | return $self->{_inflated_column}{$col} = |
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116 | $self->_inflated_column($col, $self->get_column($col)); |
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117 | } |
118 | |
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119 | =head2 set_inflated_column |
120 | |
121 | my $copy = $obj->set_inflated_column($col => $val); |
122 | |
123 | Sets a column value from an inflated value. This is directly |
124 | analogous to L<DBIx::Class::Row/set_column>. |
125 | |
126 | =cut |
127 | |
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128 | sub set_inflated_column { |
129 | my ($self, $col, @rest) = @_; |
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130 | my $ret = $self->_inflated_column_op('set', $col, @rest); |
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131 | return $ret; |
132 | } |
133 | |
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134 | =head2 store_inflated_column |
135 | |
136 | my $copy = $obj->store_inflated_column($col => $val); |
137 | |
138 | Sets a column value from an inflated value without marking the column |
139 | as dirty. This is directly analogous to |
140 | L<DBIx::Class::Row/store_column>. |
141 | |
142 | =cut |
143 | |
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144 | sub store_inflated_column { |
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145 | my ($self, $col, @rest) = @_; |
146 | my $ret = $self->_inflated_column_op('store', $col, @rest); |
147 | return $ret; |
148 | } |
149 | |
150 | sub _inflated_column_op { |
151 | my ($self, $op, $col, $obj) = @_; |
152 | my $meth = "${op}_column"; |
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153 | unless (ref $obj) { |
154 | delete $self->{_inflated_column}{$col}; |
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155 | return $self->$meth($col, $obj); |
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156 | } |
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157 | |
158 | my $deflated = $self->_deflated_column($col, $obj); |
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159 | # Do this now so we don't store if it's invalid |
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160 | |
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161 | $self->{_inflated_column}{$col} = $obj; |
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162 | $self->$meth($col, $deflated); |
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163 | return $obj; |
164 | } |
165 | |
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166 | =head2 update |
167 | |
168 | Updates a row in the same way as L<DBIx::Class::Row/update>, handling |
169 | inflation and deflation of columns appropriately. |
170 | |
171 | =cut |
172 | |
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173 | sub update { |
174 | my ($class, $attrs, @rest) = @_; |
175 | $attrs ||= {}; |
176 | foreach my $key (keys %$attrs) { |
177 | if (ref $attrs->{$key} |
178 | && exists $class->column_info($key)->{_inflate_info}) { |
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179 | # $attrs->{$key} = $class->_deflated_column($key, $attrs->{$key}); |
180 | $class->set_inflated_column ($key, delete $attrs->{$key}); |
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181 | } |
182 | } |
183 | return $class->next::method($attrs, @rest); |
184 | } |
185 | |
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186 | =head2 new |
187 | |
188 | Creates a row in the same way as L<DBIx::Class::Row/new>, handling |
189 | inflation and deflation of columns appropriately. |
190 | |
191 | =cut |
192 | |
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193 | sub new { |
194 | my ($class, $attrs, @rest) = @_; |
195 | $attrs ||= {}; |
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196 | foreach my $key (keys %$attrs) { |
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197 | if (ref $attrs->{$key} |
198 | && exists $class->column_info($key)->{_inflate_info}) { |
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199 | $attrs->{$key} = $class->_deflated_column($key, $attrs->{$key}); |
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200 | } |
201 | } |
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202 | return $class->next::method($attrs, @rest); |
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203 | } |
204 | |
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205 | =head1 SEE ALSO |
206 | |
207 | =over 4 |
208 | |
209 | =item L<DBIx::Class::Core> - This component is loaded as part of the |
210 | "core" L<DBIx::Class> components; generally there is no need to |
211 | load it directly |
212 | |
213 | =back |
214 | |
215 | =head1 AUTHOR |
216 | |
217 | Matt S. Trout <mst@shadowcatsystems.co.uk> |
218 | |
219 | =head1 CONTRIBUTORS |
220 | |
221 | Daniel Westermann-Clark <danieltwc@cpan.org> (documentation) |
222 | |
223 | =head1 LICENSE |
224 | |
225 | You may distribute this code under the same terms as Perl itself. |
226 | |
227 | =cut |
228 | |
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229 | 1; |