ashleydawson/command-bus

Command bus and executable commands with a return/response

1.0.0 2017-01-02 16:50 UTC

Requires

• php: >=5.5

Requires (Dev)

• phpunit/phpunit: ^4.0

MIT

• Ashley Dawson

• state
• command
• response
• domain
• ddd
• bus
• return

README

Super-simple command bus implementation that allows return types. Each command has a single, designated handler.

Note: Depending on your architecture - it might not be appropriate for commands to return a response. Typically, in CQS architecture, state change is observed/measured via events or queries.

Installation

Install the command bus library via Composer:

$ composer require ashleydawson/command-bus

Basic Usage

To use the command bus, start by adding a command:

<?php

namespace Acme\Command;

class MyCommand
{
    public $something;
}

Then, define a command handler for the command, command handlers must implement the magic __invoke() method, type-hinted with the command to be handled:

<?php

namespace Acme\Command;

class MyCommandHandler
{
    public function __invoke(MyCommand $command)
    {
        // Do something with the command here
        
        return 'Something useful';
    }
}

Then, put everything together (add command handler to command bus and execute command):

<?php

require __DIR__.'/vendor/autoload.php';

use AshleyDawson\CommandBus\CommandBus;
use Acme\Command\MyCommand;
use Acme\Command\MyCommandHandler;

// Instantiate a command bus
$commandBus = new CommandBus();

// Add a handler to the bus
$commandBus->addHandler(new MyCommandHandler());

// Execute a command, "Something useful" will be echoed
echo $commandBus->execute(new MyCommand());

Tests

To run the test suite, execute the following:

$ bin/phpunit