1 package MooseX::Storage;
4 use MooseX::Storage::Meta::Attribute::DoNotSerialize;
5 use String::RewritePrefix ();
10 return if $pkg eq 'main';
13 || confess "This package can only be used in Moose based classes";
15 $pkg->meta->add_method('Storage' => __PACKAGE__->meta->find_method_by_name('_injected_storage_role_generator'));
18 my %HORRIBLE_GC_AVOIDANCE_HACK;
20 sub _rewrite_role_name {
21 my ($self, $base, $string) = @_;
23 my $role_name = scalar String::RewritePrefix->rewrite(
25 '' => "MooseX::Storage::$base\::",
33 my ($self, $base, $value) = @_;
35 return unless defined $value;
38 confess "too many args in arrayref role declaration" if @$value > 2;
39 my ($class, $param) = @$value;
41 $class = $self->_rewrite_role_name($base => $class);
42 Class::MOP::load_class($class);
44 my $role = $class->meta->generate_role(parameters => $param);
46 $HORRIBLE_GC_AVOIDANCE_HACK{ $role->name } = $role;
49 my $class = $self->_rewrite_role_name($base, $value);
50 Class::MOP::load_class($class);
54 if ($class->meta->isa(
55 'MooseX::Role::Parameterized::Meta::Role::Parameterizable'
57 $role = $class->meta->generate_role(parameters => undef);
58 $HORRIBLE_GC_AVOIDANCE_HACK{ $role->name } = $role;
66 sub _injected_storage_role_generator {
69 $params{base} = '=MooseX::Storage::Basic' unless defined $params{base};
71 my @roles = __PACKAGE__->_expand_role(Base => $params{base});
74 # you don't have to have a format
75 # role, this just means you dont
76 # get anything other than pack/unpack
77 push @roles, __PACKAGE__->_expand_role(Format => $params{format});
80 # many IO roles don't make sense unless
81 # you have also have a format role chosen
82 # too, the exception being StorableFile
85 # we dont need this code anymore, cause
86 # the role composition will catch it for
87 # us. This allows the StorableFile to work
88 #(exists $params{'format'})
89 # || confess "You must specify a format role in order to use an IO role";
90 push @roles, __PACKAGE__->_expand_role(IO => $params{io});
93 # These traits alter the behaviour of the engine, the user can
94 # specify these per role-usage
95 for my $trait ( @{ $params{'traits'} ||= [] } ) {
96 push @roles, __PACKAGE__->_expand_role(Traits => $trait);
110 MooseX::Storage - A serialization framework for Moose classes
118 with Storage('format' => 'JSON', 'io' => 'File');
120 has 'x' => (is => 'rw', isa => 'Int');
121 has 'y' => (is => 'rw', isa => 'Int');
125 my $p = Point->new(x => 10, y => 10);
127 ## methods to pack/unpack an
128 ## object in perl data structures
130 # pack the class into a hash
131 $p->pack(); # { __CLASS__ => 'Point-0.01', x => 10, y => 10 }
133 # unpack the hash into a class
134 my $p2 = Point->unpack({ __CLASS__ => 'Point-0.01', x => 10, y => 10 });
136 ## methods to freeze/thaw into
137 ## a specified serialization format
138 ## (in this case JSON)
140 # pack the class into a JSON string
141 $p->freeze(); # { "__CLASS__" : "Point-0.01", "x" : 10, "y" : 10 }
143 # unpack the JSON string into a class
144 my $p2 = Point->thaw('{ "__CLASS__" : "Point-0.01", "x" : 10, "y" : 10 }');
146 ## methods to load/store a class
147 ## on the file system
149 $p->store('my_point.json');
151 my $p2 = Point->load('my_point.json');
155 MooseX::Storage is a serialization framework for Moose, it provides
156 a very flexible and highly pluggable way to serialize Moose classes
157 to a number of different formats and styles.
159 =head2 Important Note
161 This is still an early release of this module, so use with caution.
162 It's outward facing serialization API should be considered stable,
163 but I still reserve the right to make tweaks if I need too. Anything
164 beyond the basic pack/unpack, freeze/thaw and load/store should not
167 =head2 Levels of Serialization
169 There are 3 levels to the serialization, each of which builds upon
170 the other and each of which can be customized to the specific needs
177 The first (base) level is C<pack> and C<unpack>. In this level the
178 class is serialized into a Perl HASH reference, it is tagged with the
179 class name and each instance attribute is stored. Very simple.
181 This level is not optional, it is the bare minimum that
182 MooseX::Storage provides and all other levels build on top of this.
184 See L<MooseX::Storage::Basic> for the fundamental implementation and
185 options to C<pack> and C<unpack>
189 The second (format) level is C<freeze> and C<thaw>. In this level the
190 output of C<pack> is sent to C<freeze> or the output of C<thaw> is sent
191 to C<unpack>. This levels primary role is to convert to and from the
192 specific serialization format and Perl land.
194 This level is optional, if you don't want/need it, you don't have to
195 have it. You can just use C<pack>/C<unpack> instead.
201 The third (io) level is C<load> and C<store>. In this level we are reading
202 and writing data to file/network/database/etc.
204 This level is also optional, in most cases it does require a C<format> role
205 to also be used, the exception being the C<StorableFile> role.
209 =head2 Behaviour modifiers
211 The serialization behaviour can be changed by supplying C<traits>.
212 This can be done as follows:
215 with Storage( traits => [Trait1, Trait2,...] );
217 The following traits are currently bundled with C<MooseX::Storage>:
223 Only attributes that have been built (i.e., where the predicate returns
224 'true') will be serialized. This avoids any potentially expensive computations.
226 See L<MooseX::Storage::Traits::OnlyWhenBuilt> for details.
230 =head2 How we serialize
232 There are always limits to any serialization framework, there are just
233 some things which are really difficult to serialize properly and some
234 things which cannot be serialized at all.
236 =head2 What can be serialized?
238 Currently only numbers, string, ARRAY refs, HASH refs and other
239 MooseX::Storage enabled objects are supported.
241 With Array and Hash references the first level down is inspected and
242 any objects found are serialized/deserialized for you. We do not do
243 this recursively by default, however this feature may become an
246 =for stopwords subtypes
248 The specific serialize/deserialize routine is determined by the
249 Moose type constraint a specific attribute has. In most cases subtypes
250 of the supported types are handled correctly, and there is a facility
251 for adding handlers for custom types as well. This will get documented
252 eventually, but it is currently still in development.
254 =head2 What can not be serialized?
256 We do not support CODE references yet, but this support might be added
257 in using B::Deparse or some other deep magic.
259 Scalar refs are not supported, mostly because there is no way to know
260 if the value being referenced will be there when the object is inflated.
261 I highly doubt will be ever support this in a general sense, but it
262 would be possible to add this yourself for a small specific case.
264 Circular references are specifically disallowed, however if you break
265 the cycles yourself then re-assemble them later you can get around this.
266 The reason we disallow circular refs is because they are not always supported
267 in all formats we use, and they tend to be very tricky to do for all
268 possible cases. It is almost always something you want to have tight control
273 This is B<not> a persistence framework; changes to your object after
274 you load or store it will not be reflected in the stored class.
280 =item B<Storage (%options)>
282 This module will export the C<Storage> method and can be used to
283 load a specific set of MooseX::Storage roles to implement a specific
284 combination of features. It is meant to make things easier, but it
285 is by no means the only way. You can still compose your roles by
288 By default, options are assumed to be short forms. For example, this:
290 Storage(format => 'JSON');
292 ...will result in looking for MooseX::Storage::Format::JSON. To use a role
293 that is not under the default namespace prefix, start with an equal sign:
295 Storage(format => '=My::Private::JSONFormat');
297 =for stopwords parameterized
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
303 Storage(format => [ JSONpm => { json_opts => { pretty => 1 } } ]);
327 This module needs docs and probably a Cookbook of some kind as well.
328 This is an early release, so that is my excuse for now :)
330 For the time being, please read the tests and feel free to email me
331 if you have any questions. This module can also be discussed on IRC
332 in the #moose channel on irc.perl.org.
336 All complex software has bugs lurking in it, and this module is no
337 exception. If you find a bug please either email me, or add the bug
342 Chris Prather E<lt>chris.prather@iinteractive.comE<gt>
344 Stevan Little E<lt>stevan.little@iinteractive.comE<gt>
346 Yuval Kogman E<lt>yuval.kogman@iinteractive.comE<gt>
348 =head1 COPYRIGHT AND LICENSE
350 Copyright 2007-2008 by Infinity Interactive, Inc.
352 L<http://www.iinteractive.com>
354 This library is free software; you can redistribute it and/or modify
355 it under the same terms as Perl itself.