/ 
Object-Depot-0.01
River stage zero No dependents
/ Object::Depot

NAME

Object::Depot - Decouple object instantiation from usage.

SYNOPSIS

use Object::Depot;

my $depot = Object::Depot->new(
    class => 'CHI',
    # CHI->new returns a CHI::Driver object.
    type => InstanceOf[ 'CHI::Driver' ],
);

$depot->add_key(
    sessions => {
        driver => 'Memory',
        global => 1,
    },
);

$depot->store( ip2geo => CHI->new(...) );

my $sessions = $depot->fetch('sessions');
my $ip2geo = $depot->fetch('ip2geo');

DESCRIPTION

Object depots encapsulate object construction so that users of objects do not need to know how to create the objects in order to use them.

The primary use case for this library is for storing the connection logic to external services and making these connections globally available to all application logic. See Object::Depot::Singleton for turning your depot object into a global singleton.

ARGUMENTS

class

class => 'CHI',

The class which objects in this depot are expected to be. This argument defaults the "constructor" and "type" arguments.

Does not have a default.

Leaving this argument unset causes "fetch" to fail on keys that were not first populated with "store" as the "constructor" subroutine will just return undef.

constructor

constuctor => sub{
    my ($depot, $args) = @_;
    return $depot->class->new( $args );
},

Set this to a code ref to control how objects get constructed.

When declaring a custom constructor be careful not to create memory leaks via circular references.

"create" validates the objects produced by this constructor and will throw an exception if they do not match "type".

The default code ref is similar to the above example if "class" is set. If it is not set then the default code ref will return undef.

type

type => InstanceOf[ 'CHI::Driver' ],

Set this to a Type::Tiny type to control how objects in the depot are validated when they are stored.

Defaults to InstanceOf "class", if set. If the class is not set then this defaults to Object (both are from Types::Standard).

per_process

per_process => 1,

Turn this on to store objects per-process; meaning, if the TID (thread ID) or PID (process ID) change then this depot will act as if no objects have been stored. Generally you will not want to turn this on. On occasion, though, some objects are not thread or forking safe and it is necessary.

Defaults off.

disable_store

disable_store => 1,

When on this causes "store" to silently not store, causing all "fetch" calls for non-injected keys to return a new object.

Defaults off.

strict_keys

strict_keys => 1,

Turn this on to require that all keys used must first be declared via "add_key" before they can be stored in the depot.

Defaults to off, meaning keys may be used without having to pre-declare them.

default_key

default_key => 'generic',

If no key is passed to key-accepting methods like "fetch" then they will use this default key if available.

Defaults to no default key.

key_argument

key_argument => 'connection_key',

When set, this causes "arguments" to include an extra argument to be passed to the class during object construction. The argument's key will be whatever you set this to and the value will be the key used to fetch the object.

You will still need to write the code in your class to capture the argument, such as:

has connection_key => ( is=>'ro' );

Defaults to no key argument.

default_arguments

default_arguments => {
    arg => 'value',
    ...
},

When set, these arguments will be included in calls to "arguments".

Defaults to an empty hash ref.

export_name

export_name => 'myapp_cache',

Set the name of a function that Object::Depot::Singleton will export to importers of your depot package.

Has no default. If this is not set, then nothing will be exported.

always_export

always_export => 1,

Turning this on causes Object::Depot::Singleton to always export the "export_name", rather than only when listed in the import arguments. This is synonymous with the difference between Exporter's @EXPORT_OK and @EXPORT.

METHODS

fetch

my $object = $depot->fetch( $key );

store

$depot->store( $key => $object );

remove

$depot->remove( $key );

create

my $object = $depot->create( $key, %extra_args );

Gathers arguments from "arguments" and then calls "constructor" on them, returning a new object. Extra arguments may be passed and they will take precedence.

arguments

my $args = $depot->arguments( $key, %extra_args );

This method returns an arguments hash ref that would be used to instantiate a new "class" object. You could, for example, use this to produce a base-line set of arguments, then sprinkle in some more, and make yourself a special mock object to be injected.

declared_keys

my $keys = $depot->declared_keys();
foreach my $key (@$keys) { ... }

Returns an array ref containing all the keys declared with "add_key".

inject

$depot->inject( $key, $object );

Takes an object of your making and forces "fetch" to return the injected object. This is useful for injecting mock objects in tests.

The injected object must validate against "type".

inject_with_guard

my $guard = $depot->inject_with_guard( $key => $object );

This is just like "inject" except it returns a Guard object which, when it leaves scope and is destroyed, will automatically call "clear_injection".

clear_injection

my $object = $depot->clear_injection( $key );

Removes and returns the injected object, restoring the original behavior of "fetch".

injection

my $object = $depot->injection( $key );

Returns the injected object, or undef if none has been injected.

has_injection

if ($depot->has_injection( $key )) { ... }

Returns true if an injection is in place for the specified key.

add_key

$depot->add_key( $key, %arguments );

Declares a new key and, optionally, the arguments used to construct the "class" object.

Arguments are optional, but if present they will be saved and used by "fetch" when calling new() (via "arguments") on "class".

alias_key

$depot->alias_key( $alias_key => $real_key );

Adds a key that is an alias to another key.

SUPPORT

Please submit bugs and feature requests to the Object-Depot GitHub issue tracker:

https://github.com/bluefeet/Object-Depot/issues

ACKNOWLEDGEMENTS

Thanks to ZipRecruiter for encouraging their employees to contribute back to the open source ecosystem. Without their dedication to quality software development this distribution would not exist.

AUTHOR

Aran Clary Deltac <bluefeet@gmail.com>

COPYRIGHT AND LICENSE

Copyright (C) 2020 Aran Clary Deltac

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.