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1 | |
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2 | package MooseX::Storage; |
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3 | use Moose qw(confess); |
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4 | |
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5 | use MooseX::Storage::Meta::Attribute::DoNotSerialize; |
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6 | use String::RewritePrefix (); |
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7 | |
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8 | our $VERSION = '0.31'; |
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9 | our $AUTHORITY = 'cpan:STEVAN'; |
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10 | |
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11 | sub import { |
12 | my $pkg = caller(); |
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13 | |
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14 | return if $pkg eq 'main'; |
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15 | |
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16 | ($pkg->can('meta')) |
17 | || confess "This package can only be used in Moose based classes"; |
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18 | |
19 | $pkg->meta->add_method('Storage' => __PACKAGE__->meta->find_method_by_name('_injected_storage_role_generator')); |
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20 | } |
21 | |
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22 | my %HORRIBLE_GC_AVOIDANCE_HACK; |
23 | |
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24 | sub _rewrite_role_name { |
25 | my ($self, $base, $string) = @_; |
26 | |
27 | my $role_name = scalar String::RewritePrefix->rewrite( |
28 | { |
29 | '' => "MooseX::Storage::$base\::", |
30 | '=' => '', |
31 | }, |
32 | $string, |
33 | ); |
34 | } |
35 | |
36 | sub _expand_role { |
37 | my ($self, $base, $value) = @_; |
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38 | |
39 | return unless defined $value; |
40 | |
41 | if (ref $value) { |
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42 | confess "too many args in arrayref role declaration" if @$value > 2; |
43 | my ($class, $param) = @$value; |
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44 | |
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45 | $class = $self->_rewrite_role_name($base => $class); |
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46 | Class::MOP::load_class($class); |
47 | |
48 | my $role = $class->meta->generate_role(parameters => $param); |
49 | |
50 | $HORRIBLE_GC_AVOIDANCE_HACK{ $role->name } = $role; |
51 | return $role->name; |
f35d2054 |
52 | } else { |
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53 | my $class = $self->_rewrite_role_name($base, $value); |
54 | Class::MOP::load_class($class); |
55 | |
56 | my $role = $class; |
57 | |
58 | if ($class->meta->isa( |
59 | 'MooseX::Role::Parameterized::Meta::Role::Parameterizable' |
60 | )) { |
61 | $role = $class->meta->generate_role(parameters => undef); |
62 | $HORRIBLE_GC_AVOIDANCE_HACK{ $role->name } = $role; |
63 | return $role->name; |
64 | } |
65 | |
66 | return $class; |
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67 | } |
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68 | } |
69 | |
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70 | sub _injected_storage_role_generator { |
71 | my %params = @_; |
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72 | |
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73 | $params{base} = '=MooseX::Storage::Basic' unless defined $params{base}; |
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74 | |
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75 | my @roles = __PACKAGE__->_expand_role(Base => $params{base}); |
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76 | |
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77 | # NOTE: |
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78 | # you don't have to have a format |
79 | # role, this just means you dont |
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80 | # get anything other than pack/unpack |
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81 | push @roles, __PACKAGE__->_expand_role(Format => $params{format}); |
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82 | |
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83 | # NOTE: |
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84 | # many IO roles don't make sense unless |
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85 | # you have also have a format role chosen |
86 | # too, the exception being StorableFile |
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87 | # |
88 | # NOTE: |
89 | # we dont need this code anymore, cause |
90 | # the role composition will catch it for |
91 | # us. This allows the StorableFile to work |
92 | #(exists $params{'format'}) |
93 | # || confess "You must specify a format role in order to use an IO role"; |
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94 | push @roles, __PACKAGE__->_expand_role(IO => $params{io}); |
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95 | |
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96 | # Note: |
97 | # These traits alter the behaviour of the engine, the user can |
98 | # specify these per role-usage |
99 | for my $trait ( @{ $params{'traits'} ||= [] } ) { |
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100 | push @roles, __PACKAGE__->_expand_role(Traits => $trait); |
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101 | } |
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102 | |
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103 | return @roles; |
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104 | } |
105 | |
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106 | 1; |
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107 | |
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108 | __END__ |
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109 | |
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110 | =pod |
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111 | |
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112 | =head1 NAME |
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113 | |
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114 | MooseX::Storage - A serialization framework for Moose classes |
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115 | |
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116 | =head1 SYNOPSIS |
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117 | |
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118 | package Point; |
119 | use Moose; |
120 | use MooseX::Storage; |
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121 | |
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122 | our $VERSION = '0.01'; |
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123 | |
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124 | with Storage('format' => 'JSON', 'io' => 'File'); |
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125 | |
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126 | has 'x' => (is => 'rw', isa => 'Int'); |
127 | has 'y' => (is => 'rw', isa => 'Int'); |
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128 | |
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129 | 1; |
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130 | |
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131 | my $p = Point->new(x => 10, y => 10); |
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132 | |
133 | ## methods to pack/unpack an |
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134 | ## object in perl data structures |
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135 | |
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136 | # pack the class into a hash |
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137 | $p->pack(); # { __CLASS__ => 'Point-0.01', x => 10, y => 10 } |
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138 | |
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139 | # unpack the hash into a class |
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140 | my $p2 = Point->unpack({ __CLASS__ => 'Point-0.01', x => 10, y => 10 }); |
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141 | |
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142 | ## methods to freeze/thaw into |
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143 | ## a specified serialization format |
144 | ## (in this case JSON) |
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145 | |
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146 | # pack the class into a JSON string |
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147 | $p->freeze(); # { "__CLASS__" : "Point-0.01", "x" : 10, "y" : 10 } |
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148 | |
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149 | # unpack the JSON string into a class |
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150 | my $p2 = Point->thaw('{ "__CLASS__" : "Point-0.01", "x" : 10, "y" : 10 }'); |
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151 | |
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152 | ## methods to load/store a class |
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153 | ## on the file system |
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154 | |
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155 | $p->store('my_point.json'); |
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156 | |
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157 | my $p2 = Point->load('my_point.json'); |
158 | |
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159 | =head1 DESCRIPTION |
160 | |
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161 | MooseX::Storage is a serialization framework for Moose, it provides |
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162 | a very flexible and highly pluggable way to serialize Moose classes |
163 | to a number of different formats and styles. |
164 | |
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165 | =head2 Important Note |
166 | |
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167 | This is still an early release of this module, so use with caution. |
168 | It's outward facing serialization API should be considered stable, |
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169 | but I still reserve the right to make tweaks if I need too. Anything |
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170 | beyond the basic pack/unpack, freeze/thaw and load/store should not |
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171 | be relied on. |
172 | |
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173 | =head2 Levels of Serialization |
174 | |
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175 | There are 3 levels to the serialization, each of which builds upon |
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176 | the other and each of which can be customized to the specific needs |
177 | of your class. |
178 | |
179 | =over 4 |
180 | |
181 | =item B<base> |
182 | |
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183 | The first (base) level is C<pack> and C<unpack>. In this level the |
184 | class is serialized into a Perl HASH reference, it is tagged with the |
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185 | class name and each instance attribute is stored. Very simple. |
186 | |
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187 | This level is not optional, it is the bare minumum that |
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188 | MooseX::Storage provides and all other levels build on top of this. |
189 | |
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190 | See L<MooseX::Storage::Basic> for the fundamental implementation and |
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191 | options to C<pack> and C<unpack> |
192 | |
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193 | =item B<format> |
194 | |
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195 | The second (format) level is C<freeze> and C<thaw>. In this level the |
196 | output of C<pack> is sent to C<freeze> or the output of C<thaw> is sent |
197 | to C<unpack>. This levels primary role is to convert to and from the |
198 | specific serialization format and Perl land. |
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199 | |
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200 | This level is optional, if you don't want/need it, you don't have to |
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201 | have it. You can just use C<pack>/C<unpack> instead. |
202 | |
203 | =item B<io> |
204 | |
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205 | The third (io) level is C<load> and C<store>. In this level we are reading |
206 | and writing data to file/network/database/etc. |
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207 | |
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208 | This level is also optional, in most cases it does require a C<format> role |
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209 | to also be used, the exception being the C<StorableFile> role. |
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210 | |
211 | =back |
212 | |
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213 | =head2 Behaviour modifiers |
214 | |
215 | The serialization behaviour can be changed by supplying C<traits>. |
216 | This can be done as follows: |
217 | |
218 | use MooseX::Storage; |
219 | with Storage( traits => [Trait1, Trait2,...] ); |
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220 | |
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221 | The following traits are currently bundled with C<MooseX::Storage>: |
222 | |
223 | =over 4 |
224 | |
225 | =item OnlyWhenBuilt |
226 | |
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227 | Only attributes that have been built (ie, where the predicate returns |
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228 | 'true') will be serialized. This avoids any potentially expensive computations. |
229 | |
230 | See L<MooseX::Storage::Traits::OnlyWhenBuilt> for details. |
231 | |
232 | =back |
233 | |
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234 | =head2 How we serialize |
235 | |
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236 | There are always limits to any serialization framework, there are just |
237 | some things which are really difficult to serialize properly and some |
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238 | things which cannot be serialized at all. |
239 | |
240 | =head2 What can be serialized? |
241 | |
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242 | Currently only numbers, string, ARRAY refs, HASH refs and other |
243 | MooseX::Storage enabled objects are supported. |
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244 | |
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245 | With Array and Hash references the first level down is inspected and |
246 | any objects found are serialized/deserialized for you. We do not do |
247 | this recusively by default, however this feature may become an |
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248 | option eventually. |
249 | |
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250 | The specific serialize/deserialize routine is determined by the |
251 | Moose type constraint a specific attribute has. In most cases subtypes |
252 | of the supported types are handled correctly, and there is a facility |
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253 | for adding handlers for custom types as well. This will get documented |
254 | eventually, but it is currently still in development. |
255 | |
256 | =head2 What can not be serialized? |
257 | |
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258 | We do not support CODE references yet, but this support might be added |
259 | in using B::Deparse or some other deep magic. |
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260 | |
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261 | Scalar refs are not supported, mostly because there is no way to know |
262 | if the value being referenced will be there when the object is inflated. |
263 | I highly doubt will be ever support this in a general sense, but it |
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264 | would be possible to add this yourself for a small specific case. |
265 | |
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266 | Circular references are specifically disallowed, however if you break |
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267 | the cycles yourself then re-assemble them later you can get around this. |
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268 | The reason we disallow circular refs is because they are not always supported |
269 | in all formats we use, and they tend to be very tricky to do for all |
270 | possible cases. It is almost always something you want to have tight control |
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271 | over anyway. |
272 | |
273 | =head1 CAVEAT |
274 | |
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275 | This is B<not> a persistence framework; changes to your object after |
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276 | you load or store it will not be reflected in the stored class. |
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277 | |
278 | =head1 EXPORTS |
279 | |
280 | =over 4 |
281 | |
282 | =item B<Storage (%options)> |
283 | |
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284 | This module will export the C<Storage> method and can be used to |
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285 | load a specific set of MooseX::Storage roles to implement a specific |
286 | combination of features. It is meant to make things easier, but it |
287 | is by no means the only way. You can still compose your roles by |
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288 | hand if you like. |
289 | |
25697231 |
290 | By default, options are assumed to be short forms. For example, this: |
291 | |
292 | Storage(format => 'JSON'); |
293 | |
294 | ...will result in looking for MooseX::Storage::Format::JSON. To use a role |
295 | that is not under the default namespace prefix, start with an equal sign: |
296 | |
297 | Storage(format => '=My::Private::JSONFormat'); |
298 | |
299 | To use a parameterized role (for which, see L<MooseX::Role::Parameterized>) you |
300 | can pass an arrayref of the role name (in short or long form, as above) and its |
301 | parameters: |
302 | |
303 | Storage(format => [ JSONpm => { json_opts => { pretty => 1 } } ]); |
304 | |
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305 | =back |
306 | |
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307 | =head1 METHODS |
308 | |
309 | =over 4 |
310 | |
311 | =item B<import> |
312 | |
313 | =back |
314 | |
315 | =head2 Introspection |
316 | |
317 | =over 4 |
318 | |
319 | =item B<meta> |
320 | |
321 | =back |
322 | |
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323 | =head1 TODO |
324 | |
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325 | This module needs docs and probably a Cookbook of some kind as well. |
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326 | This is an early release, so that is my excuse for now :) |
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327 | |
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328 | For the time being, please read the tests and feel free to email me |
329 | if you have any questions. This module can also be discussed on IRC |
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330 | in the #moose channel on irc.perl.org. |
331 | |
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332 | =head1 BUGS |
333 | |
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334 | All complex software has bugs lurking in it, and this module is no |
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335 | exception. If you find a bug please either email me, or add the bug |
336 | to cpan-RT. |
337 | |
338 | =head1 AUTHOR |
339 | |
340 | Chris Prather E<lt>chris.prather@iinteractive.comE<gt> |
341 | |
342 | Stevan Little E<lt>stevan.little@iinteractive.comE<gt> |
343 | |
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344 | Yuval Kogman E<lt>yuval.kogman@iinteractive.comE<gt> |
345 | |
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346 | =head1 COPYRIGHT AND LICENSE |
347 | |
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348 | Copyright 2007-2008 by Infinity Interactive, Inc. |
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349 | |
350 | L<http://www.iinteractive.com> |
351 | |
352 | This library is free software; you can redistribute it and/or modify |
353 | it under the same terms as Perl itself. |
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354 | |
355 | =cut |