=pod

=encoding UTF-8

=head1 NAME

MooseX::Storage - A serialization framework for Moose classes

=head1 VERSION

version 0.53

=head1 SYNOPSIS

package Point; use Moose; use MooseX::Storage;

with Storage('format' => 'JSON', 'io' => 'File');

has 'x' => (is => 'rw', isa => 'Int'); has 'y' => (is => 'rw', isa => 'Int');

my $p = Point->new(x => 10, y => 10);

methods to pack/unpack an

object in perl data structures

pack the class into a hash

$p->pack(); # { CLASS => 'Point-0.01', x => 10, y => 10 }

unpack the hash into a class

my $p2 = Point->unpack({ CLASS => 'Point-0.01', x => 10, y => 10 });

methods to freeze/thaw into

a specified serialization format

(in this case JSON)

pack the class into a JSON string

$p->freeze(); # { "CLASS" : "Point-0.01", "x" : 10, "y" : 10 }

unpack the JSON string into a class

my $p2 = Point->thaw('{ "CLASS" : "Point-0.01", "x" : 10, "y" : 10 }');

methods to load/store a class

on the file system

$p->store('my_point.json');

my $p2 = Point->load('my_point.json');

=head1 DESCRIPTION

MooseX::Storage is a serialization framework for Moose, it provides a very flexible and highly pluggable way to serialize Moose classes to a number of different formats and styles.

=head2 Levels of Serialization

There are three levels to the serialization, each of which builds upon the other and each of which can be customized to the specific needs of your class.

=over 4

=item B

The first (base) level is C and C. In this level the class is serialized into a Perl HASH reference, it is tagged with the class name and each instance attribute is stored. Very simple.

This level is not optional, it is the bare minimum that MooseX::Storage provides and all other levels build on top of this.

See L for the fundamental implementation and options to C and C

=item B

The second (format) level is C and C. In this level the output of C is sent to C or the output of C is sent to C. This levels primary role is to convert to and from the specific serialization format and Perl land.

This level is optional, if you don't want/need it, you don't have to have it. You can just use C/C instead.

=for stopwords io

=item B

The third (io) level is C and C. In this level we are reading and writing data to file/network/database/etc.

This level is also optional, in most cases it does require a C role to also be used, the exception being the C role.

=back

=head2 Behaviour modifiers

The serialization behaviour can be changed by supplying C to either the class or an individual attribute.

This can be done as follows:

use MooseX::Storage;

adjust behaviour for the entire class

with Storage( traits => [Trait1, Trait2,...] );

adjust behaviour for an attribute

has my_attr => ( traits => [Trait1, Trait2, ...], ... );

The following B are currently bundled with L:

=over 4

=item OnlyWhenBuilt

Only attributes that have been built (i.e., where the predicate returns 'true') will be serialized. This avoids any potentially expensive computations.

See L for details.

=item DisableCycleDetection

=for stopwords serialisable

Disables the default checks for circular references, which is necessary if you use such references in your serialisable objects.

See L for details.

=back

The following B are currently bundled with L:

=over 4

=item DoNotSerialize

Skip serialization entirely for this attribute.

See L for details.

=back

=head2 How we serialize

There are always limits to any serialization framework -- there are just some things which are really difficult to serialize properly and some things which cannot be serialized at all.

=head2 What can be serialized?

Currently only numbers, string, ARRAY refs, HASH refs and other MooseX::Storage-enabled objects are supported.

With Array and Hash references the first level down is inspected and any objects found are serialized/deserialized for you. We do not do this recursively by default, however this feature may become an option eventually.

=for stopwords subtypes

The specific serialize/deserialize routine is determined by the L type constraint a specific attribute has. In most cases subtypes of the supported types are handled correctly, and there is a facility for adding handlers for custom types as well. This will get documented eventually, but it is currently still in development.

=head2 What can not be serialized?

We do not support CODE references yet, but this support might be added in using L or some other deep magic.

Scalar refs are not supported, mostly because there is no way to know if the value being referenced will be there when the object is inflated. I highly doubt will be ever support this in a general sense, but it would be possible to add this yourself for a small specific case.

Circular references are specifically disallowed, however if you break the cycles yourself then re-assemble them later you can get around this. The reason we disallow circular refs is because they are not always supported in all formats we use, and they tend to be very tricky to do for all possible cases. It is almost always something you want to have tight control over anyway.

=head1 CAVEAT

This is B a persistence framework; changes to your object after you load or store it will not be reflected in the stored class.

=head1 EXPORTS

=over 4

=item B<Storage (%options)>

This module will export the C method and can be used to load a specific set of MooseX::Storage roles to implement a specific combination of features. It is meant to make things easier, but it is by no means the only way. You can still compose your roles by hand if you like.

By default, options are assumed to be short forms. For example, this:

Storage(format => 'JSON');

...will result in looking for MooseX::Storage::Format::JSON. To use a role that is not under the default namespace prefix, start with an equal sign:

Storage(format => '=My::Private::JSONFormat');

=for stopwords parameterized

To use a parameterized role (for which, see L) you can pass an arrayref of the role name (in short or long form, as above) and its parameters:

Storage(format => [ JSONpm => { json_opts => { pretty => 1 } } ]);

=back

=head1 METHODS

=over 4

=item B

=back

=head2 Introspection

=over 4

=item B

=back

=for stopwords TODO

=head1 TODO

This module needs docs and probably a Cookbook of some kind as well. This is an early release, so that is my excuse for now :)

For the time being, please read the tests and feel free to email me if you have any questions. This module can also be discussed on IRC in the #moose channel on irc.perl.org.

=head1 SUPPORT

Bugs may be submitted through L<the RT bug tracker|https://rt.cpan.org/Public/Dist/Display.html?Name=MooseX-Storage> (or Lbug-MooseX-Storage@rt.cpan.org|mailto:bug-MooseX-Storage@rt.cpan.org).

There is also a mailing list available for users of this distribution, at Lhttp://lists.perl.org/list/moose.html.

There is also an irc channel available for users of this distribution, at L<C<#moose> on C|irc://irc.perl.org/#moose>.

=head1 AUTHORS

=over 4

=item *

Chris Prather chris.prather@iinteractive.com

=item *

Stevan Little stevan.little@iinteractive.com

=item *

יובל קוג'מן (Yuval Kogman) nothingmuch@woobling.org

=back

=head1 CONTRIBUTORS

=for stopwords Karen Etheridge Tomas Doran Ricardo Signes Chris Prather Jos Boumans Shawn M Moore Jonathan Yu Dmitry Latin Robert Boone Dagfinn Ilmari Mannsåker Cory Watson sillitoe Dan Brook David Golden Steinbrunner Florian Ragwitz Graham Knop Jason Pope Johannes Plunien Rockway Yanick Champoux

=over 4

=item *

Karen Etheridge ether@cpan.org

=item *

Tomas Doran bobtfish@bobtfish.net

=item *

Ricardo Signes rjbs@cpan.org

=item *

Chris Prather chris@prather.org

=item *

Jos Boumans jos@dwim.org

=item *