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diff --git a/static/talks/bread_board_yapc_na_2012/slides.vroom b/static/talks/bread_board_yapc_na_2012/slides.vroom new file mode 100644 index 0000000..404431f --- /dev/null +++ b/static/talks/bread_board_yapc_na_2012/slides.vroom @@ -0,0 +1,508 @@ +# urxvt -fg black -bg white +# setfont 'xft:DejaVuSansMono-19:bold' +# echo 'set exrc' >> ~/.vimrc + +---- config +title: Dependency Injection with Bread::Board +indent: 4 +auto_size: 1 + +---- center +Dependency Injection with Bread::Board + +Jesse Luehrs +Infinity Interactive +doy@cpan.org +---- +== A Motivating Example +---- perl,i0 +package MyApp; +use MyFramework; + +sub call { + my $self = shift; + + my $dbh = DBI->connect('dbi:mysql:myapp_db'); + my $hello = $dbh->selectall_arrayref('SELECT * FROM my_table')->[0][0]; + + my $template = Template->new(INCLUDE_PATH => 'root/template'); + $template->process('hello.tt', { hello => $hello }, \(my $output)); + + return $output; +} +---- perl,i0 +package MyApp; +use MyFramework; + +has model => (is => 'ro', isa => 'Model', default => sub { Model->new }); +has view => (is => 'ro', isa => 'View', default => sub { View->new }); + +sub call { + my $self = shift; + my $hello = $self->model->get_hello; + return $self->view->render($hello); +} +---- perl,i0 +package MyApp; +use MyFramework; + +has logger => ( + is => 'ro', isa => 'Logger', + default => sub { Logger->new } +); +has model => ( + is => 'ro', isa => 'Model', lazy => 1, + default => sub { Model->new(logger => $_[0]->logger) }, +); +has view => ( + is => 'ro', isa => 'View', lazy => 1, + default => sub { View->new(logger => $_[0]->logger) }, +); + +sub call { + my $self = shift; + my $hello = $self->model->get_hello; + return $self->view->render($hello); +} +---- perl,i0 +package MyApp; +use MyFramework; + +has dsn => (is => 'ro', isa => 'Str', default => 'dbi:mysql:myapp_db'); +has tt_root => (is => 'ro', isa => 'Str', default => 'root/template'); +has logger => (is => 'ro', isa => 'Logger', default => sub {Logger->new}); +has model => ( + is => 'ro', isa => 'Model', lazy => 1, + default => sub { + my $m = Model->connect($_[0]->dsn); + $m->set_logger($_[0]->logger); + return $m; + }, +); +has view => ( + is => 'ro', isa => 'View', lazy => 1, + default => sub { + View->new(logger => $_[0]->logger, tt_root => $_[0]->tt_root); + }, +); + +sub call { ... } +---- +Dependency Injection + ++ · a form of inversion of control ++ · "the inverse of garbage collection" ++ · manages object construction +---- +Benefits to Dependency Injection + ++ · provides access to the same object creation code + that your app will actually use ++ · removes need for globals ++ · testing and reuse +---- center,-i1 +== Bread::Board + ++ +-----------------------------------------+ + | 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 | + +-----------------------------------------+ +---- perl,i0 +== Bread::Board + +my $c = container MyApp => as { + service dsn => 'dbi:mysql:myapp_db'; + service logger => (class => 'Logger', lifecycle => 'Singleton'); + service view => (class => 'View', dependencies => ['logger']); + + service model => ( + class => 'Model', + dependencies => ['logger', 'dsn'], + block => sub { + my $m = Model->connect($_[0]->param('dsn')); + $m->set_logger($_[0]->param('logger')); + return $m; + }, + ); + service app => ( + class => 'MyApp', + dependencies => ['model', 'view'], + ); +}; +$c->resolve(service => 'app'); +---- +== Services + ++ · represent the data you're storing ++ · access contents via the ->get method ++ · three built-in types: +---- perl +== Bread::Board::ConstructorInjection + +service view => ( + class => 'View', +); +---- perl +== Bread::Board::BlockInjection + +service model => ( + class => 'Model', # optional + block => sub { + my $m = Model->new + $m->initialize; + return $m; + }, +); +---- perl +== Bread::Board::Literal + +service dsn => 'dbi:mysql:myapp_db'; +---- +== Containers + ++ · hold services and other containers ++ · access contents via the ->fetch method ++ · ->resolve is a shortcut method for ->fetch(...)->get +---- +== Dependencies + ++ · tells Bread::Board how your classes are related ++ · specified as a map of names to service paths + (there are shortcuts for common cases) +---- perl,i0 +== Dependencies + +service logger => (class => 'Logger'); +service view => ( + class => 'View', + dependencies => ['logger'], +); +---- perl,i0 +== Dependencies + +service dsn => 'dbi:mysql:myapp_db'; +service model => ( + class => 'Model', + dependencies => ['dsn'], + block => sub { + my $service = shift; + return Model->connect($service->param('dsn')); + }, +); +---- perl,i0 +== Dependencies + +container MyApp => as { + container Model => as { + service dsn => 'dbi:mysql:myapp_db'; + service model => ( + class => 'Model', + dependencies => ['dsn'], + block => sub { + my $service = shift; + return Model->connect($service->param('dsn')); + }, + ); + }; + service app => ( + class => 'MyApp', + dependencies => ['Model/model'], + ); +}; +---- +== Parameters + ++ · like dependencies, but supplied when calling ->get or ->resolve +---- perl,i0 +== Parameters + +my $c = container MyApp => as { + service user => ( + class => 'User', + parameters => { + name => { isa => 'Str' }, + }, + ); +}; +$c->resolve(service => 'user', parameters => { name => 'doy' }); +---- perl,i0 +== Parameters + +my $c = container MyApp => as { + service user => ( + class => 'User', + parameters => { + name => { isa => 'Str' }, + }, + ); + service superusers => ( + block => sub { [ $_[0]->param('root') ] }, + dependencies => { + root => { user => { name => 'root' } }, + }, + ); +}; +---- perl,i0 +== Parameters + +my $c = container MyApp => as { + service user => ( + class => 'User', + parameters => { + name => { isa => 'Str' }, + }, + ); + service superusers => ( + block => sub { + [ $_[0]->param('user')->inflate(name => 'root') ] + }, + dependencies => ['user'], + ); +}; +---- perl,i0 +== Parameters + +my $c = container MyApp => as { + service default_username => 'guest'; + service user => ( + class => 'User', + parameters => { + name => { isa => 'Str', optional => 1 }, + }, + dependencies => { + name => 'default_username', + }, + ); +}; +# user with name 'guest' +$c->resolve(service => 'user'); +# user with name 'doy' +$c->resolve(service => 'user', parameters => { name => 'doy' }); +---- perl,i0 +== Parameters + +my $c = container MyApp => as { + service user => ( + class => 'User', + parameters => { + name => { isa => 'Str', optional => 1, default => 'guest' }, + }, + ); +}; +# user with name 'guest' +$c->resolve(service => 'user'); +# user with name 'doy' +$c->resolve(service => 'user', parameters => { name => 'doy' }); +---- +== Lifecycles + ++ · this is what determines what happens when ->get is called ++ · by default, each call to ->get creates a new object ++ · by specifying «lifecycle => 'Singleton'» when creating the service, + the same object will be returned each time +---- perl,i0 +== Bread::Board + +my $c = container MyApp => as { + service dsn => 'dbi:mysql:myapp_db'; + service logger => (class => 'Logger', lifecycle => 'Singleton'); + service view => (class => 'View', dependencies => ['logger']); + + service model => ( + class => 'Model', + dependencies => ['logger', 'dsn'], + block => sub { + my $m = Model->connect($_[0]->param('dsn')); + $m->set_logger($_[0]->param('logger')); + return $m; + }, + ); + service app => ( + class => 'MyApp', + dependencies => ['model', 'view'], + ); +}; +$c->resolve(service => 'app'); +---- +== Best Practices + ++ · only use containers during initialization ++ · factories ++ · avoid unnecessary subcontainers ++ · container classes +---- perl,i0 +package MyApp::Container; +use Moose; +extends 'Bread::Board::Container'; + +sub BUILD { + container $self => as { + ...; + }; +} +---- perl,i0 +container SomethingElse => as { + container MyApp::Container->new; +}; +---- +== Typemaps + ++ · defines a mapping from a class_type to a service ++ · instead of requesting a particular service, you can request an + object of a particular type: $c->resolve(type => 'Model'); ++ · with this, we can (mostly) infer the dependencies for a given class +---- perl,i0 +package Model +use Moose; +has logger => (is => 'ro', isa => 'Logger', required => 1); + +package Logger; +use Moose; +---- perl,i0 +my $c = container MyApp => as { + typemap Logger => infer; + typemap Model => infer; +}; +$c->resolve(type => 'Model')->logger; # a valid logger object +---- +== Typemaps + ++ · required attributes are automatically inferred, becoming either + dependencies (on types) or parameters (if the type doesn't exist + in the typemap) ++ · non-required attributes can still be satisfied by parameters +---- perl,i0 +== Bread::Board::Declare + +package MyApp::Container; +use Moose; +use Bread::Board::Declare; + +has dsn => (is => 'ro', isa => 'Str', value => 'dbi:mysql:myapp_db'); +has logger => (is => 'ro', isa => 'Logger'); +has view => (is => 'ro', isa => 'View', infer => 1); + +has model => ( + is => 'ro', + isa => 'Model', + infer => 1, + dependencies => ['dsn'], + block => sub { + my $m = Model->connect($_[0]->param('dsn')); + $m->set_logger($_[0]->param('logger')); + return $m; + }, +); +has app => (is => 'ro', isa => 'MyApp', infer => 1); +---- +== Bread::Board::Declare + ++ · services are declared just by defining attributes ++ · attribute accessors resolve the service if no value is set ++ · if the attribute has a value, it is used in dependency resolution ++ · MyApp::Container->new(dsn => 'dbi:mysql:other_db')->model +---- +== Bread::Board::Declare + ++ · typemaps are much simplified ++ · attributes with class_type constraints automatically get a typemap ++ · «infer => 1» infers as many dependencies as possible +---- perl,i0 +== MongoDBx::Bread::Board::Container + +container MyApp => as { + container MongoDBx::Bread::Board::Container->new( + name => 'myapp_db', + host => 'localhost', + database_layout => { + user_db => ['standard_users', 'super_users'], + }, + ); + + service authenticator => ( + class => 'Authenticator', + dependencies => ['myapp_db/user_db/standard_users'], + ); +}; +---- perl,i0 +== Catalyst::Plugin::Bread::Board + +package MyApp; +use Catalyst 'Bread::Board'; + +__PACKAGE__->config( + 'Plugin::Bread::Board' => { + container => MyApp::Container->new, + } +); + +---- perl,i0 +== OX + +package MyApp; +use OX; + +has model => (is => 'ro', isa => 'Model'); +has view => (is => 'ro', isa => 'View'); + +has controller => ( + is => 'ro', + isa => 'Controller', + infer => 1, +); + +router as { + route '/' => 'controller.index'; +}; + +---- center +Questions? + +https://metacpan.org/module/Bread::Board +https://metacpan.org/module/Bread::Board::Declare +https://github.com/stevan/OX +---- skip +motivating example (5m, 5s) +- everything inline +- separate model/view classes +- model and view classes both want a logger +- model and logger both want configuration +overview of dependency injection (5m, 1s) +- high level description +- ...??? +bread::board (15m, 4s) +- simple example (translation of intro?) +- services and containers +- dependencies, parameters +- lifecycles +- typemaps +- best practices + - not global - factory classes/closures, etc + - container classes +bread::board::declare (10m) +- show example +- attributes are services are attributes +- automatic typemapping +- subclassing, roles +- subcontainers +real world usage (10m) +- bread::board::container::mongodb +- catalyst::plugin::bread::board +- ox +questions (5m) |