Workflow

Let's assume we want to develop a registration process, the main thing is storing user data, but we also want to validate input, hash the password and send a welcome email.

Now imagine this process as concentric circles: the storing of user data is the inner circle, whereas validation, hashing, email sending and any other logic are the increasingly outer circles.

Such concentric circles, or pipes, can be called all at once in a pipeline and have several advantages including running specific code before or after a given command and adding or removing any logic without even touching the controllers.

This allows you to have all your controllers with a maximum of two lines of code per action, while keeping all their functionalities.

This package is intended to automate the creation of such pipelines by using simple Artisan commands and owns other facilities like auto-validation, management of pipelines in a single file and visualization of their graphical representation in console.

Note: if you are using Laravel 4, please refer to this version that leverages the decorators design pattern.

Installation

Run this command in your application root:

composer require cerbero/workflow

and add this string to the providers array in config/app.php:

'Cerbero\Workflow\WorkflowServiceProvider',

Configuration

By default all the generated workflows are placed in app/Workflows. You can change it by running:

php artisan vendor:publish

and then edit the file config/workflow.php.

Create a workflow

Taking the introductive example, let's create the registration workflow by running:

php artisan workflow:create RegisterUser --attach="hash notify"

The following files are automatically created under the app directory:

File (click to see the code)	Description
Commands/RegisterUserCommand.php	incapsulates the current task
Http/Requests/RegisterUserRequest.php	contains the validation rules and permissions
Workflows/RegisterUser/Hash.php	the attached pipe to hash the password
Workflows/RegisterUser/Notify.php	the attached pipe to send the welcome email
Workflows/workflows.yml	contains all the created pipelines with their own pipes

While both commands and requests are well documented, let's have a look at one of the newly created pipes, let's say Hash.php.

This class has two methods: before() is run before handling the RegisterUserCommand, which is passed as argument, whereas after() is run after handling the command and also has the value returned by the handled command as parameter e.g. the User model.

You can inject whatever you need in both methods, everything is resolved by the service container automatically. Furthermore if you don't need either before() or after(), you can safely delete the unused method.

All workflows are stored within the workflows.yml file that makes it easier to read and update pipelines and their pipes even if, as you will see, there are also Artisan commands to automate these tasks.

As you may have noticed, you only created Hash and Notify but nothing to validate data. Every workflow validates the input automatically by reading the validation rules and permissions from the generated requests e.g. RegisterUserRequest.

However sometimes you may not have input to validate, in these cases you can avoid the creation of the Request class by using the --unguard flag:

php artisan workflow:create TakeItEasy --unguard

Here is a recap of the workflow:create options:

Option	Shortcut	Description
--attach	-a	The pipes to attach to the workflow
--unguard	-u	Do not make this workflow validate data

Read a workflow

To better understand the workflow of a given pipeline, you can run the command:

php artisan workflow:read RegisterUser

that will output something similar:

             ║
╔════════════╬════════════╗
║       Hash ║ before()   ║
║ ╔══════════╬══════════╗ ║
║ ║   Notify ║ before() ║ ║
║ ║ ╔════════╩════════╗ ║ ║
║ ║ ║  RegisterUser   ║ ║ ║
║ ║ ╚════════╦════════╝ ║ ║
║ ║   Notify ║ after()  ║ ║
║ ╚══════════╬══════════╝ ║
║       Hash ║ after()    ║
╚════════════╬════════════╝
             ∇

The arrow in the middle of the drawing shows the itinerary of the code within the pipeline. Please note how the Hash pipe wraps the Notify pipe that in turn wraps the RegisterUser command and how the methods of the pipes are run before and after the command respectively.

Usage

Now that you have created the registration workflow and seen how it works in theory, it's time to see it in action.

There are many ways to run the workflow. To let all controllers have a $workflow property after being resolved, edit the app/Http/Controllers/Controller.php class like so:

use Cerbero\Workflow\RunsWorkflow;
use Cerbero\Workflow\WorkflowRunner;

abstract class Controller extends BaseController implements WorkflowRunner {

	use RunsWorkflow;

}

and now you can run your workflow by calling it through the $workflow property available in every controller:

public function store()
{
	$this->workflow->registerUser();
}

Otherwise if you prefer to run workflow only in some controllers (or even non-controllers), you can type-hint the Cerbero\Workflow\Workflow class:

use Cerbero\Workflow\Workflow;

class RegisterController extends Controller {

	public function __construct(Workflow $workflow)
	{
		$this->workflow = $workflow;
	}

	public function store()
	{
		$this->workflow->registerUser();
	}

}

Finally, you can use the Workflow facade that has been automatically registered during the installation, just for you:

public function store()
{
	\Workflow::registerUser();
}

You can see a working demo here.

Update a workflow

One of the biggest advantages of using pipelines is that you can easily add and remove functionalities keeping the rest of your code intact.

The Artisan command workflow:update can attach and detach pipes of existing pipelines:

php artisan workflow:update RegisterUser --attach="upload log" --detach="notify"

By default the detached pipes are not deleted, if you want to, you can use the --force flag:

php artisan workflow:update RegisterUser --detach="notify" --force

Sometimes you may want to sort the attached pipes to carry in or out a given pipe, you can do that by editing the workflows.yml file. It contains all the created pipelines and their own pipes ordered from the outer (the first to be run) to the inner.

Here is a recap of the workflow:update options:

Option	Shortcut	Description
--attach	-a	The pipes to attach to the workflow
--detach	-d	The pipes to detach from the workflow
--force	-f	Delete the files of detached pipes

Delete a workflow

To delete an entire pipeline, you can run:

php artisan workflow:delete RegisterUser

Like the update command, the detached pipes are not deleted by default, again you can use the --force flag:

php artisan workflow:delete RegisterUser --force