2 package MooseX::Storage;
5 use MooseX::Storage::Meta::Attribute::DoNotSerialize;
6 use String::RewritePrefix ();
9 our $AUTHORITY = 'cpan:STEVAN';
14 return if $pkg eq 'main';
17 || confess "This package can only be used in Moose based classes";
19 $pkg->meta->add_method('Storage' => __PACKAGE__->meta->find_method_by_name('_injected_storage_role_generator'));
23 my ($base, $value) = @_;
25 return unless defined $value;
28 confess "references for roles are not yet handled";
30 return scalar String::RewritePrefix->rewrite(
32 '' => "MooseX::Storage::$base\::",
40 sub _injected_storage_role_generator {
43 $params{base} = '=MooseX::Storage::Basic' unless defined $params{base};
45 my @roles = __expand_role(Base => $params{base});
48 # you don't have to have a format
49 # role, this just means you dont
50 # get anything other than pack/unpack
51 push @roles, __expand_role(Format => $params{format});
54 # many IO roles don't make sense unless
55 # you have also have a format role chosen
56 # too, the exception being StorableFile
59 # we dont need this code anymore, cause
60 # the role composition will catch it for
61 # us. This allows the StorableFile to work
62 #(exists $params{'format'})
63 # || confess "You must specify a format role in order to use an IO role";
64 push @roles, __expand_role(IO => $params{io});
67 # These traits alter the behaviour of the engine, the user can
68 # specify these per role-usage
69 for my $trait ( @{ $params{'traits'} ||= [] } ) {
70 push @roles, __expand_role(Traits => $trait);
73 for my $role ( @roles ) {
74 Class::MOP::load_class($role) or die "Could not load role ($role)";
88 MooseX::Storage - A serialization framework for Moose classes
96 our $VERSION = '0.01';
98 with Storage('format' => 'JSON', 'io' => 'File');
100 has 'x' => (is => 'rw', isa => 'Int');
101 has 'y' => (is => 'rw', isa => 'Int');
105 my $p = Point->new(x => 10, y => 10);
107 ## methods to pack/unpack an
108 ## object in perl data structures
110 # pack the class into a hash
111 $p->pack(); # { __CLASS__ => 'Point-0.01', x => 10, y => 10 }
113 # unpack the hash into a class
114 my $p2 = Point->unpack({ __CLASS__ => 'Point-0.01', x => 10, y => 10 });
116 ## methods to freeze/thaw into
117 ## a specified serialization format
118 ## (in this case JSON)
120 # pack the class into a JSON string
121 $p->freeze(); # { "__CLASS__" : "Point-0.01", "x" : 10, "y" : 10 }
123 # unpack the JSON string into a class
124 my $p2 = Point->thaw('{ "__CLASS__" : "Point-0.01", "x" : 10, "y" : 10 }');
126 ## methods to load/store a class
127 ## on the file system
129 $p->store('my_point.json');
131 my $p2 = Point->load('my_point.json');
135 MooseX::Storage is a serialization framework for Moose, it provides
136 a very flexible and highly pluggable way to serialize Moose classes
137 to a number of different formats and styles.
139 =head2 Important Note
141 This is still an early release of this module, so use with caution.
142 It's outward facing serialization API should be considered stable,
143 but I still reserve the right to make tweaks if I need too. Anything
144 beyond the basic pack/unpack, freeze/thaw and load/store should not
147 =head2 Levels of Serialization
149 There are 3 levels to the serialization, each of which builds upon
150 the other and each of which can be customized to the specific needs
157 The first (base) level is C<pack> and C<unpack>. In this level the
158 class is serialized into a Perl HASH reference, it is tagged with the
159 class name and each instance attribute is stored. Very simple.
161 This level is not optional, it is the bare minumum that
162 MooseX::Storage provides and all other levels build on top of this.
164 See L<Moosex::Storage::Basic> for the fundamental implementation and
165 options to C<pack> and C<unpack>
169 The second (format) level is C<freeze> and C<thaw>. In this level the
170 output of C<pack> is sent to C<freeze> or the output of C<thaw> is sent
171 to C<unpack>. This levels primary role is to convert to and from the
172 specific serialization format and Perl land.
174 This level is optional, if you don't want/need it, you don't have to
175 have it. You can just use C<pack>/C<unpack> instead.
179 The third (io) level is C<load> and C<store>. In this level we are reading
180 and writing data to file/network/database/etc.
182 This level is also optional, in most cases it does require a C<format> role
183 to also be used, the expection being the C<StorableFile> role.
187 =head2 Behaviour modifiers
189 The serialization behaviour can be changed by supplying C<traits>.
190 This can be done as follows:
193 with Storage( traits => [Trait1, Trait2,...] );
195 The following traits are currently bundled with C<MooseX::Storage>:
201 Only attributes that have been built (ie, where the predicate returns
202 'true') will be serialized. This avoids any potentially expensive computations.
204 See L<MooseX::Storage::Traits::OnlyWhenBuilt> for details.
208 =head2 How we serialize
210 There are always limits to any serialization framework, there are just
211 some things which are really difficult to serialize properly and some
212 things which cannot be serialized at all.
214 =head2 What can be serialized?
216 Currently only numbers, string, ARRAY refs, HASH refs and other
217 MooseX::Storage enabled objects are supported.
219 With Array and Hash references the first level down is inspected and
220 any objects found are serialized/deserialized for you. We do not do
221 this recusively by default, however this feature may become an
224 The specific serialize/deserialize routine is determined by the
225 Moose type constraint a specific attribute has. In most cases subtypes
226 of the supported types are handled correctly, and there is a facility
227 for adding handlers for custom types as well. This will get documented
228 eventually, but it is currently still in development.
230 =head2 What can not be serialized?
232 We do not support CODE references yet, but this support might be added
233 in using B::Deparse or some other deep magic.
235 Scalar refs are not supported, mostly because there is no way to know
236 if the value being referenced will be there when the object is inflated.
237 I highly doubt will be ever support this in a general sense, but it
238 would be possible to add this yourself for a small specific case.
240 Circular references are specifically disallowed, however if you break
241 the cycles yourself then re-assemble them later you can get around this.
242 The reason we disallow circular refs is because they are not always supported
243 in all formats we use, and they tend to be very tricky to do for all
244 possible cases. It is almost always something you want to have tight control
249 This is B<not> a persistence framework, changes to your object after
250 you load or store it will not be reflected in the stored class.
256 =item B<Storage (%options)>
258 This module will export the C<Storage> method will can be used to
259 load a specific set of MooseX::Storage roles to implement a specific
260 combination of features. It is meant to make things easier, but it
261 is by no means the only way. You can still compose your roles by
284 This module needs docs and probably a Cookbook of some kind as well.
285 This is an early release, so that is my excuse for now :)
287 For the time being, please read the tests and feel free to email me
288 if you have any questions. This module can also be discussed on IRC
289 in the #moose channel on irc.perl.org.
293 All complex software has bugs lurking in it, and this module is no
294 exception. If you find a bug please either email me, or add the bug
299 Chris Prather E<lt>chris.prather@iinteractive.comE<gt>
301 Stevan Little E<lt>stevan.little@iinteractive.comE<gt>
303 Yuval Kogman E<lt>yuval.kogman@iinteractive.comE<gt>
305 =head1 COPYRIGHT AND LICENSE
307 Copyright 2007-2008 by Infinity Interactive, Inc.
309 L<http://www.iinteractive.com>
311 This library is free software; you can redistribute it and/or modify
312 it under the same terms as Perl itself.