Provided by: libbread-board-perl_0.29-1_all 
NAME
Bread::Board - A solderless way to wire up your application components
VERSION
version 0.29
SYNOPSIS
use Bread::Board;
my $c = container 'MyApp' => as {
service 'log_file_name' => "logfile.log";
service 'logger' => (
class => 'FileLogger',
lifecycle => 'Singleton',
dependencies => [
depends_on('log_file_name'),
]
);
container 'Database' => as {
service 'dsn' => "dbi:SQLite:dbname=my-app.db";
service 'username' => "user234";
service 'password' => "****";
service 'dbh' => (
block => sub {
my $s = shift;
require DBI;
DBI->connect(
$s->param('dsn'),
$s->param('username'),
$s->param('password'),
) || die "Could not connect";
},
dependencies => wire_names(qw[dsn username password])
);
};
service 'application' => (
class => 'MyApplication',
dependencies => {
logger => depends_on('logger'),
dbh => depends_on('Database/dbh'),
}
);
};
no Bread::Board; # removes keywords
# get an instance of MyApplication
# from the container
my $app = $c->resolve( service => 'application' );
# now user your MyApplication
# as you normally would ...
$app->run;
DESCRIPTION
Bread::Board is an inversion of control framework with a focus on dependency injection and lifecycle
management. It's goal is to help you write more decoupled objects and components by removing the need for
you to manually wire those objects/components together.
Want to know more? See the Bread::Board::Manual.
+-----------------------------------------+
| A B C D E F G H I J |
|-----------------------------------------|
| o o | 1 o-o-o-o-o v o-o-o-o-o 1 | o o |
| o o | 2 o-o-o-o-o o-o-o-o-o 2 | o o |
| o o | 3 o-o-o-o-o o-o-o-o-o 3 | o o |
| o o | 4 o-o-o-o-o o-o-o-o-o 4 | o o |
| o o | 5 o-o-o-o-o o-o-o-o-o 5 | o o |
| | 6 o-o-o-o-o o-o-o-o-o 6 | |
| o o | 7 o-o-o-o-o o-o-o-o-o 7 | o o |
| o o | 8 o-o-o-o-o o-o-o-o-o 8 | o o |
| o o | 9 o-o-o-o-o o-o-o-o-o 9 | o o |
| o o | 10 o-o-o-o-o o-o-o-o-o 10 | o o |
| o o | 11 o-o-o-o-o o-o-o-o-o 11 | o o |
| | 12 o-o-o-o-o o-o-o-o-o 12 | |
| o o | 13 o-o-o-o-o o-o-o-o-o 13 | o o |
| o o | 14 o-o-o-o-o o-o-o-o-o 14 | o o |
| o o | 15 o-o-o-o-o o-o-o-o-o 15 | o o |
| o o | 16 o-o-o-o-o o-o-o-o-o 16 | o o |
| o o | 17 o-o-o-o-o o-o-o-o-o 17 | o o |
| | 18 o-o-o-o-o o-o-o-o-o 18 | |
| o o | 19 o-o-o-o-o o-o-o-o-o 19 | o o |
| o o | 20 o-o-o-o-o o-o-o-o-o 20 | o o |
| o o | 21 o-o-o-o-o o-o-o-o-o 21 | o o |
| o o | 22 o-o-o-o-o o-o-o-o-o 22 | o o |
| o o | 22 o-o-o-o-o o-o-o-o-o 22 | o o |
| | 23 o-o-o-o-o o-o-o-o-o 23 | |
| o o | 24 o-o-o-o-o o-o-o-o-o 24 | o o |
| o o | 25 o-o-o-o-o o-o-o-o-o 25 | o o |
| o o | 26 o-o-o-o-o o-o-o-o-o 26 | o o |
| o o | 27 o-o-o-o-o o-o-o-o-o 27 | o o |
| o o | 28 o-o-o-o-o ^ o-o-o-o-o 28 | o o |
+-----------------------------------------+
Loading this package will automatically load the rest of the packages needed by your Bread::Board
configuration.
EXPORTED FUNCTIONS
The functions of this package provide syntactic sugar to help you build your Bread::Board configuration.
You can build such a configuration by constructing the objects manually instead, but your code may be
more difficult to understand.
container ($name, &body)
This function constructs and returns an instance of Bread::Board::Container. The (optional) &body
block may be used to add services or sub-containers within the newly constructed container. Usually,
the block is not passed directly, but passed using the "as" function.
For example,
container 'MyWebApp' => as {
service my_dispatcher => (
class => 'MyWebApp::Dispatcher',
);
};
If $name starts with '+', and the container is being declared inside another container, then this
declaration will instead extend an existing container with the name $name (without the '+').
container ($container_instance, &body)
In many cases, subclassing Bread::Board::Container is the easiest route to getting access to this
framework. You can do this and still get all the benefits of the syntactic sugar for configuring that
class by passing an instance of your container subclass to "container".
You could, for example, configure your container inside the "BUILD" method of your class:
package MyWebApp;
use Moose;
extends 'Bread::Board::Container';
sub BUILD {
my $self = shift;
container $self => as {
service dbh => ( ... );
};
}
container ($name, [ @parameters ], &body)
A third way of using the "container" function is to build a parameterized container. These are useful
as a way of providing a placeholder for parts of the configuration that may be provided later. You
may not use an instance object in place of the $name in this case.
For more detail on how you might use parameterized containers, see "Parameterized Containers" in
Bread::Board::Manual::Concepts::Advanced.
as (&body)
This is just a replacement for the "sub" keyword that is easier to read when defining containers.
service ($name, $literal | %service_description)
Within the "as" blocks for your containers, you may construct services using the "service" function.
This can construct several different kinds of services based upon how it is called.
To build a literal service (a Bread::Board::Literal object), just specify a scalar value or reference
you want to use as the literal value:
# In case you need to adjust the gravitational constant of the Universe
service gravitational_constant => 6.673E-11;
To build a service using one of the injection services, just fill in all the details required to use
that sort of injection:
service search_service => (
class => 'MyApp::Search',
block => sub {
my $s = shift;
MyApp::Search->new($s->param('url'), $s->param('type'));
},
dependencies => {
url => 'search_url',
},
parameters => {
type => { isa => 'Str', default => 'text' },
},
);
The type of injection performed depends on the parameters used. You may use the "service_class"
parameter to pick a specific injector class. For instance, this is useful if you need to use
Bread::Board::SetterInjection or have defined a custom injection service. If you specify a "block",
block injection will be performed using Bread::Board::BlockInjection. If neither of these is present,
constructor injection will be used with Bread::Board::ConstructorInjection (and you must provide the
"class" option).
If the $name starts with a '+', the service definition will instead extend an existing service with
the given $name (without the '+'). This works similarly to the "has '+foo'" syntax in Moose. It is
most useful when defining a container class where the container is built up in "BUILD" methods, as
each class in the inheritance hierarchy can modify services defined in superclasses. The
"dependencies" and "parameters" options will be merged with the existing values, rather than
overridden. Note that literal services can't be extended, because there's nothing to extend. You can
still override them entirely by declaring the service name without a leading '+'.
depends_on ($service_path)
The "depends_on" function creates a Bread::Board::Dependency object for the named $service_path and
returns it.
wire_names (@service_names)
This function is just a shortcut for passing a hash reference of dependencies into the service.
service foo => (
class => "Pity::TheFoo',
dependencies => wire_names(qw( foo bar baz )),
);
The above is identical to:
service foo => (
class => 'Pity::TheFoo',
dependencies => {
foo => depends_on('foo'),
bar => depends_on('bar'),
baz => depends_on('baz'),
},
);
typemap ($type, $service | $service_path)
This creates a type mapping for the named type. Typically, it is paired with the "infer" call like
so:
typemap 'MyApp::Model::UserAccount' => infer;
For more details on what type mapping is and how it works, see
Bread::Board::Manual::Concepts::Typemap.
infer (?%hints)
This is used with "typemap" to help create the typemap inference. It can be used with no arguments to
do everything automatically. However, in some cases, you may want to pass a service instance as the
argument or a hash of service arguments to change how the type map works. For example, if your type
needs to be constructed using a setter injection, you can use an inference similar to this:
typemap 'MyApp::Model::UserPassword' => infer(
service_class => 'Bread::Board::SetterInjection',
);
For more details on what type mapping is and how it works, see
Bread::Board::Manual::Concepts::Typemap.
include ($file)
This is a shortcut for loading a Bread::Board configuration from another file.
include "filename.pl";
The above is pretty much identical to running:
do "filename.pl";
However, you might find it more readable to use "include".
alias ($service_name, $service_path, %service_description)
This helper allows for the creation of service aliases, which allows you to define a service in one
place and then reuse that service with a different name somewhere else. This is sort of like a
symbolic link for services. Aliases will be resolved recursively, so an alias can alias an alias.
For example,
service file_logger => (
class => 'MyApp::Logger::File',
);
alias my_logger => 'file_logger';
OTHER FUNCTIONS
These are not exported, but might be helpful to you.
set_root_container ($container)
You may use this to set a top-level root container for all container definitions.
For example,
my $app = container MyApp => as { ... };
Bread::Board::set_root_container($app);
my $config = container Config => as { ... };
Here the $config container would be created as a sub-container of $app.
ACKNOWLEDGEMENTS
Thanks to Daisuke Maki for his contributions and for really pushing the development of this module along.
Chuck "sprongie" Adams, for testing/using early (pre-release) versions of this module, and some good
suggestions for naming it.
Matt "mst" Trout, for finally coming up with the best name for this module.
ARTICLES
Bread::Board is the right tool for this job
<http://domm.plix.at/perl/2013_04_bread_board_is_the_right_rool_for_this_job.html> Thomas Klausner
showing a use-case for Bread::Board.
SEE ALSO
Bread::Board::Declare
This provides more powerful syntax for writing Bread::Board container classes.
IOC Bread::Board is basically my re-write of IOC.
<http://en.wikipedia.org/wiki/Breadboard>
BUGS
All complex software has bugs lurking in it, and this module is no exception. If you find a bug please
either email me, or add the bug to Github Issues.
AUTHOR
Stevan Little <stevan@iinteractive.com>
COPYRIGHT AND LICENSE
This software is copyright (c) 2013 by Infinity Interactive.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5
programming language system itself.
perl v5.18.2 2013-11-21 Bread::Board(3pm)