README

Introduction

This package simplify controlling the transition between model states, allowing you to prevent unlogically transition and also controlling the initial state of the model using the PHP enums. Each enum allows you to define your states, the allowed transitions and the initial state, all in one place.

Laravel Enum State Machine, also allows you to automatically record the history of the state transition for each define state machine.

This package is built to help developers with the least amount of work needed to get it working.

Installation

You can install the package via composer:

composer require tamkeen-tech/laravel-enum-state-machine

Next, if you going to record the history

php artisan vendor:publish --tag=enum-state-machine-migrations

To publish the config file, you can use the following command:

php artisan vendor:publish --tag=enum-state-machine-configs

Usage

Imagine you have bill with statuses, so at your bill model you will need to use HasStateMachines trait, and define your protected $stateMachines array variable to include all the fields that you going to apply the state machine on, and finally an optional variable protected $recordStateHistory boolean to either save history or not.

use TamkeenTech\LaravelEnumStateMachine\Traits\HasStateMachines;

class Bill extends Model
{
    use HasStateMachines;

    protected $fillable = [
        'status',
    ];

    protected $casts = [
        'status' => BillStatus::class,
    ];

    protected $recordStateHistory = true;

    protected $stateMachines = [
        'status'
    ];
}

In your BillStatus class you need to use trait StateMachine and to add two methods transitions to define your transition array and initialState to define the allowed initial states, both must return array.

use TamkeenTech\LaravelEnumStateMachine\Traits\StateMachine;

enum BillStatus: string
{
    use StateMachine;

    case PENDING = 'PENDING';
    case PAID = 'PAID';
    case EXPIRED = 'EXPIRED';
    case REFUNDED = 'REFUNDED';

    public function transitions(): array
    {
        return match ($this) {
            self::PENDING => [self::PAID, self::EXPIRED],
            self::PAID => [self::REFUNDED]
        };
    }

    public function initialState(): array
    {
        return [self::PENDING];
    }
}

From the example above the allowed transitions for PENDING case are PAID and EXPIRED, and the initail state for bill must be only PENDING

Now you are all done, you can start writing your code safely. So now if your tried to create a bill with different state you will receive an exception.

Example

• create bill with different initail state

  // throw InitailStateIsNotAllowedException with message "Only allowed initial states: PENDING"
  Bill::create([
    'status' => BillStatus::PAID
  ]);

• try to update to invalid transition

  $bill = Bill::create([
    'status' => BillStatus::PENDING
  ]);
  
  // throw StateTransitionNotAllowedException with message "Only allowed transition states: PAID, EXPIRED"
  $bill->update([
    'status' => BillStatus::REFUNDED
  ]);

State History Recording

When you enable state history recording by setting protected $recordStateHistory = true in your model, the package will automatically track all state changes for the fields defined in $stateMachines.

Each state change will be recorded in the state_machine_histories table with the following information:

• The previous state (from)
• The new state (to)
• The field name that changed
• The model type and ID
• Timestamps of the change

You can access the state history through the stateHistory relationship:

$bill = Bill::find(1);
$bill->stateHistory;

Flow Diagram Generation

You can generate a flow diagram of your state machine using the following command:

php artisan enum:flow-diagram "App\Enums\BillStatus"

You can specify a custom output directory using the --output option

php artisan enum:flow-diagram "App\Enums\BillStatus" --output=/custom/path

This command will create a visual representation of your state machine as a PNG file, making it easier to understand the transitions between states.

Helper Methods

The StateMachine trait provides several helper methods to make working with state transitions easier.

canTransitTo

This method checks if the current state can transition to a given state.

Example

$billStatus = BillStatus::PENDING;

if ($billStatus->canTransitTo(BillStatus::PAID)) {
    // Do something
}

inInitialState

This method checks if the current state is one of the allowed initial states.

Example

$billStatus = BillStatus::PENDING;

if ($billStatus->inInitialState()) {
    // Do something
}

is

This method checks if the current state is equal to a given state.

Example

$billStatus = BillStatus::PENDING;

if ($billStatus->is(BillStatus::PENDING)) {
    // Do something
}

Changelog

Please see CHANGELOG for more information what has changed recently.

Contributing

Please see CONTRIBUTING for details.

Security

If you discover any security related issues, please email theshreif@gmail.com instead of using the issue tracker.

Credits

• Andrés laravel-eloquent-state-machines

License

The MIT License (MIT). Please see License File for more information.