Yii2 Command Bus

Command Bus for Yii2

What is Command Bus?

The idea of a command bus is that you create command objects that represent what you want your application to do. Then, you toss it into the bus and the bus makes sure that the command object gets to where it needs to go. So, the command goes in -> the bus hands it off to a handler -> and then the handler actually does the job. The command essentially represents a method call to your service layer.

Shawn McCool ©

Installation

The preferred way to install this extension is through composer.

Either run

php composer.phar require --prefer-dist trntv/yii2-command-bus

or add

"trntv/yii2-command-bus": "^1.0"

to your composer.json file

Setting Up

1. Command Bus Service

After the installation, first step is to set the command bus component.

return [
    // ...
    'components' => [
        'commandBus' => [
            'class' => 'trntv\bus\CommandBus'
        ]
    ],
];

2. Background commands support (optional)

Install required package:

php composer.phar require symfony/process:^3.0

For the background commands worker, add a controller and command bus middleware in your config

'controllerMap' => [
    'background-bus' => [
        'class' => 'trntv\bus\console\BackgroundBusController',
    ]
],

'components' => [
        'commandBus' =>[
            ...
            'middlewares' => [
                [
                    'class' => '\trntv\bus\middlewares\BackgroundCommandMiddleware',
                    'backgroundHandlerPath' => '@console/yii',
                    'backgroundHandlerRoute' => 'background-bus/handle',
                ]                
            ]
            ...            
        ]        
],

Create background command

class ReportCommand extends Object implements BackgroundCommand, SelfHandlingCommand
{
    use BackgroundCommandTrait;

    public $someImportantData;

    public function handle($command) {
        // do what you need
    }
}

And run it asynchronously!

Yii::$app->commandBus->handle(new ReportCommand([
    'async' => true,
    'someImportantData' => [ // data // ]
]))

3. Queued commands support (optional)

3.1 Install required package:

php composer.phar require yiisoft/yii2-queue

3.2 Configure extensions

If you need commands to be run in queue, you need to setup middleware and yii2-queue extensions.

'components' => [
    'queue' => [
        // queue config
    ],

    'commandBus' =>[
        ...
        'middlewares' => [
            [
                'class' => '\trntv\bus\middlewares\QueuedCommandMiddleware',
                // 'delay' => 3, // You can set default delay for all commands here
            ]                
        ]
        ...            
    ]     
]

More information about yii2-queue config can be found here

3.4 Run queue worker

yii queue/listen More information here

3.5 Create and run command

class HeavyComputationsCommand extends Object implements QueuedCommand, SelfHandlingCommand
{
    use QueuedCommandTrait;

    public function handle() {
        // do work here
    }
}

$command = new HeavyComputationsCommand();
Yii::$app->commandBus->handle($command)

4. Handlers

Handlers are objects that will handle command execution There are two possible ways to execute command:

4.1 External handler

return [
    // ...
    'components' => [
        'commandBus' => [
            'class' => 'trntv\bus\CommandBus',
            'locator' => [
                'class' => 'trntv\bus\locators\ClassNameLocator',
                'handlers' => [
                    'app\commands\SomeCommand' => 'app\handlers\SomeHandler'
                ]
            ]
        ]
    ],
];

// or
$handler = new SomeHandler;
Yii::$app->commandBus->locator->addHandler($handler, 'app\commands\SomeCommand');
// or
Yii::$app->commandBus->locator->addHandler('app\handlers\SomeHandler', 'app\commands\SomeCommand');

4.1 Self-handling command

class SomeCommand implements SelfHandlingCommand
{
    public function handle($command) {
        // do what you need
    }
}

$command = Yii::$app->commandBus->handle($command);