Easily implement command based architecture in your project.
Inspired by laracasts/commander
Install through composer by adding the package to your composer.json
{
"require": {
"studioignis/cmd": "~1.0"
}
}Or using the command:
$ composer require studioignis/cmd:~1.0It is really simple, you just need the command bus instance, then you can start executing commands! You can bootstrap the instance manually or use included Laravel service provider.
You'll need an implementation of \StudioIgnis\Cmd\Support\Container and
\StudioIgnis\Cmd\NameInflector.
You'll have to create your own container implementation, since this will depend on your framework. You can take a look at the included Laravel implementation to see how it can be implemented, it's extremely simple.
For the name inflector, on the other hand, you can use the one included
\StudioIgnis\Cmd\DefaultNameInflector, or you can create your own.
$container = new StudioIgnis\Cmd\CommandBus(
new Acme\Foo\Container($whatever),
new StudioIgnis\Cmd\DefaultNameInflector
);If you are using the Laravel framework, you can take advantage of the included
service provider. You will need to add it to the providers array in your
app/config/app.php file:
'providers' => [
// ...
'StudioIgnis\Cmd\Laravel\ServiceProvider',
],Now you can just use dependency injection to get the command bus, like so:
use StudioIgnis\Cmd\Bus;
class FooController
{
public function __construct(Bus $commandBus)
{
// ...
}
}Handlers are as complex as you need them to be, they just need to implement
the StudioIgnis\Cmd\Handler interface.
This interface defines only one method, handle(Command $command), that as you
can see, receives the corresponding command instance.
Let's see an (oversimplified) example:
namespace Acme\User\Handler;
use StudioIgnis\Cmd\Command;
use StudioIgnis\Cmd\Handler;
use Acme\User\Command\SignUp as SignUpCommand;
class SignUp implements Handler
{
public function handle(UserRepository $users)
{
$this->users = $users;
}
public function handle(Command $command)
{
/** @var SignUpCommand $command */
$this->users->add($command->name, $command->email, $command->password);
}
}There's no need to register handlers for commands, as the default name inflector will take care of it as long as the namespaces are predictable.
The inflector takes the command class name and replaces all occurences of
"Command" with "Handler", so for example Acme\User\Command\CreateUser will
result in a handler Acme\User\Handler\CreateUser.
You don't have to follow this namespace convention, since all it does is word replacement, just be aware of what would the handler counterpart of a command will end up being.
Another, less magical but sometimes preferred, way is by manually registering handlers per command:
$bus->setHandler(
'Acme\User\Command\CreateUser',
'Acme\User\Command\CreateUserHandler'
);This way you don't have to predict where would a handler end up, you just tell the bus where to find it.
As you can see in the example above, we are passing the handler's FQN string. By doing this, the command bus will use the container to resolve the handler, thus, lazy-loading it. Another way to lazy-load a handler is by passing a closure that returns a handler instance. Or you can just pass an already instantiated handler.
Command classes are simple DTOs, but they must extend from the abstract
StudioIgnis\Cmd\Command. This abstract base class ease things up a bit.
Your commands should define an array of attributes that you'll be able to get automatically, without defining getters.
This base command class also ensures the command can be converted to an array and serialized to json.
Here's an example:
namespace Acme\User\Command;
use StudioIgnis\cmd\Command;
class SignUp extends Command
{
public function __construct($name, $email, $password)
{
$this->attributes = compact('name', 'email', 'password');
}
}Now you can access the attributes like this:
// One by one
$name = $signUpCommand->name;
$email = $signUpCommand->email;
$password = $signUpCommand->password;
// As an array
$signUpCommand->toArray();
// As a json string
$json = $signUpCommand->toJson();
$json = (string) $signUpCommand;
$json = json_encode($signUpCommand);One you have your command bus instance ready and your handlers registered (or not!), executing commands is really easy. Let's use the command we defined above.
$command = new \Acme\User\Command\SignUp(
'JohnDoe',
'[email protected],
'password!'
);
$bus->execute($command);
There are two traits you can use to make command execution a little shorter. One is generic, the other one is exclusively for Laravel.
This trait adds the cmd($commandName, array $input) mehtod. It's purpose is to
initialize a command a little easier by passing the command class name and an
array of inputs that will be used as the command parameters:
$input = [
'name' => $this->input->get('name'),
'email' => $this->input->get('email'),
'password' => $this->input->get('password'),
];
$this->cmd('Acme\User\Command\SignUp', $input);This trait uses the previous one so you can just add this trait.
It adds three new methods: execute($commandName, array $input = null),
getInput(array $input = null) and getCommandBus().
The idea is the same, but it also executes the command by calling the other
trait's cmd() method.
getInput(array $input = null) will return Laravel's Input::all() if no
$input is given.
getCommandBus() will return App::make('StudioIgnis\Cmd\Bus');
Both of these methods can be overriden if you don't want to use the "facade" invocation.
Copyright (c) 2014 Luciano Longo
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.