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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 qw/DBIx::Class::Row/; |
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7 | |
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8 | =head1 NAME |
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9 | |
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10 | DBIx::Class::InflateColumn - Automatically create references from column data |
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11 | |
12 | =head1 SYNOPSIS |
13 | |
14 | # In your table classes |
15 | __PACKAGE__->inflate_column('column_name', { |
16 | inflate => sub { ... }, |
17 | deflate => sub { ... }, |
18 | }); |
19 | |
20 | =head1 DESCRIPTION |
21 | |
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22 | This component translates column data into references, i.e. "inflating" |
23 | the column data. It also "deflates" references into an appropriate format |
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24 | for the database. |
25 | |
26 | It can be used, for example, to automatically convert to and from |
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27 | L<DateTime> objects for your date and time fields. There's a |
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28 | convenience component to actually do that though, try |
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29 | L<DBIx::Class::InflateColumn::DateTime>. |
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30 | |
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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' > |
36 | to work. |
37 | |
38 | If you want to filter plain scalar values and replace them with |
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39 | something else, see L<DBIx::Class::FilterColumn>. |
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40 | |
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41 | =head1 METHODS |
42 | |
43 | =head2 inflate_column |
44 | |
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45 | Instruct L<DBIx::Class> to inflate the given column. |
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46 | |
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. |
51 | |
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: |
55 | |
56 | __PACKAGE__->inflate_column('insert_time', { |
57 | inflate => sub { DateTime::Format::Pg->parse_datetime(shift); }, |
58 | deflate => sub { DateTime::Format::Pg->format_datetime(shift); }, |
59 | }); |
60 | |
61 | (Replace L<DateTime::Format::Pg> with the appropriate module for your |
62 | database, or consider L<DateTime::Format::DBI>.) |
63 | |
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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 |
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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>. |
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67 | |
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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. |
71 | |
72 | =cut |
73 | |
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74 | sub inflate_column { |
75 | my ($self, $col, $attrs) = @_; |
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76 | |
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77 | my $colinfo = $self->column_info($col); |
78 | |
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79 | $self->throw_exception("InflateColumn does not work with FilterColumn") |
80 | if $self->isa('DBIx::Class::FilterColumn') && |
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81 | defined $colinfo->{_filter_info}; |
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82 | |
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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'; |
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87 | $colinfo->{_inflate_info} = $attrs; |
88 | my $acc = $colinfo->{accessor}; |
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89 | $self->mk_group_accessors('inflated_column' => [ (defined $acc ? $acc : $col), $col]); |
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90 | return 1; |
91 | } |
92 | |
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93 | sub _inflated_column { |
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94 | my ($self, $col, $value) = @_; |
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95 | return $value unless defined $value; # NULL is NULL is NULL |
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96 | my $info = $self->column_info($col) |
97 | or $self->throw_exception("No column info for $col"); |
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98 | return $value unless exists $info->{_inflate_info}; |
99 | my $inflate = $info->{_inflate_info}{inflate}; |
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100 | $self->throw_exception("No inflator for $col") unless defined $inflate; |
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101 | return $inflate->($value, $self); |
102 | } |
103 | |
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104 | sub _deflated_column { |
105 | my ($self, $col, $value) = @_; |
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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'); |
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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); |
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115 | } |
116 | |
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117 | =head2 get_inflated_column |
118 | |
119 | my $val = $obj->get_inflated_column($col); |
120 | |
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 |
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123 | column already retrieved from the database, and then inflates it. |
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124 | Throws an exception if the column requested is not an inflated column. |
125 | |
126 | =cut |
127 | |
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128 | sub get_inflated_column { |
129 | my ($self, $col) = @_; |
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130 | $self->throw_exception("$col is not an inflated column") |
131 | unless exists $self->column_info($col)->{_inflate_info}; |
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132 | return $self->{_inflated_column}{$col} |
133 | if exists $self->{_inflated_column}{$col}; |
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134 | |
135 | my $val = $self->get_column($col); |
136 | return $val if ref $val eq 'SCALAR'; #that would be a not-yet-reloaded sclarref update |
137 | |
138 | return $self->{_inflated_column}{$col} = $self->_inflated_column($col, $val); |
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139 | } |
140 | |
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141 | =head2 set_inflated_column |
142 | |
143 | my $copy = $obj->set_inflated_column($col => $val); |
144 | |
145 | Sets a column value from an inflated value. This is directly |
146 | analogous to L<DBIx::Class::Row/set_column>. |
147 | |
148 | =cut |
149 | |
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150 | sub set_inflated_column { |
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151 | my ($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') { |
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155 | $self->{_inflated_column}{$col} = $inflated; |
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156 | } else { |
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157 | delete $self->{_inflated_column}{$col}; |
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158 | } |
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159 | return $inflated; |
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160 | } |
161 | |
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162 | =head2 store_inflated_column |
163 | |
164 | my $copy = $obj->store_inflated_column($col => $val); |
165 | |
166 | Sets a column value from an inflated value without marking the column |
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167 | as dirty. This is directly analogous to L<DBIx::Class::Row/store_column>. |
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168 | |
169 | =cut |
170 | |
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171 | sub store_inflated_column { |
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172 | my ($self, $col, $inflated) = @_; |
173 | # unless (blessed $inflated) { |
174 | unless (ref $inflated && ref($inflated) ne 'SCALAR') { |
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175 | delete $self->{_inflated_column}{$col}; |
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176 | $self->store_column($col => $inflated); |
177 | return $inflated; |
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178 | } |
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179 | delete $self->{_column_data}{$col}; |
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180 | return $self->{_inflated_column}{$col} = $inflated; |
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181 | } |
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182 | |
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183 | =head1 SEE ALSO |
184 | |
185 | =over 4 |
186 | |
187 | =item L<DBIx::Class::Core> - This component is loaded as part of the |
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188 | C<core> L<DBIx::Class> components; generally there is no need to |
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189 | load it directly |
190 | |
191 | =back |
192 | |
193 | =head1 AUTHOR |
194 | |
195 | Matt S. Trout <mst@shadowcatsystems.co.uk> |
196 | |
197 | =head1 CONTRIBUTORS |
198 | |
199 | Daniel Westermann-Clark <danieltwc@cpan.org> (documentation) |
200 | |
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201 | Jess Robinson <cpan@desert-island.demon.co.uk> |
202 | |
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203 | =head1 LICENSE |
204 | |
205 | You may distribute this code under the same terms as Perl itself. |
206 | |
207 | =cut |
208 | |
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209 | 1; |