codewiser / workflow
Model Workflow Laravel package
Requires
- php: ^8.0
- ext-json: *
- laravel/framework: ^9.0
Requires (Dev)
- phpunit/phpunit: ^9.0
This package is auto-updated.
Last update: 2022-06-15 10:52:36 UTC
README
Package provides workflow functionality to Eloquent Models.
Workflow is a sequence of states, document evolve through. Transitions between states inflicts the evolution road.
Setup
First, describe the workflow blueprint with available states and transitions:
class ArticleWorkflow extends \Codewiser\Workflow\WorkflowBlueprint { public function states(): array { return [ 'new', 'review', 'published', 'correction', ]; } public function transitions(): array { return [ ['new', 'review'], ['review', 'published'], ['review', 'correction'], ['correction', 'review'] ]; } }
You may use Enum
instead of scalar values:
class ArticleWorkflow extends \Codewiser\Workflow\WorkflowBlueprint { public function states(): array { return State::cases(); } public function transitions(): array { return [ [State::new, State::review], [State::review, State::published], [State::review, State::correction], [State::correction, State::review] ]; } }
Finally, include trait and cast attribute with a blueprint that you just create.
class Article extends Model { use \Codewiser\Workflow\Traits\HasWorkflow; public $casts = [ 'state' => ArticleWorkflow::class ]; }
That's it.
Consistency
Workflow observes Model and keeps state machine consistency healthy.
// creating: will set proper initial state $article = new \Codewiser\Workflow\Example\Article(); $article->save(); assert($article->state->value == 'new'); // updating: will examine state machine consistency $article->state = 'review'; $article->save(); // No exceptions thrown
State and Transition objects
In an example above we describe blueprint with scalar or enum values, but actually they will be transformed to the objects. Those objects bring some additional functionality to the states and transitions, such as caption translations, transition authorization, routing rules etc...
use \Codewiser\Workflow\State; use \Codewiser\Workflow\Transition; class ArticleWorkflow extends \Codewiser\Workflow\WorkflowBlueprint { public function states(): array { return [ State::make('new'), State::make('review'), State::make('published'), State::make('correction'), ]; } public function transitions(): array { return [ Transition::make('new', 'review'), Transition::make('review', 'published'), Transition::make('review', 'correction'), Transition::make('correction', 'review') ]; } }
Plural Transitions
You may define multiple transitions as one, passing array of source or/and target states:
use \Codewiser\Workflow\Transition; class ArticleWorkflow extends \Codewiser\Workflow\WorkflowBlueprint { public function transitions(): array { return [ Transition::make(['new', 'correction'], 'review'), Transition::make('review', 'published'), Transition::make('review', 'correction') ]; } }
Authorization
As model's actions are not allowed to any user, as changing state is not allowed to any user. You may define transition authorization rules either using Policy
or using callable
.
Using Policy
Add policy action:
class ArticlePolicy { public function transitToReview(User $user, Article $article) { return $user->is($article->author); } }
And provide action name to Transition::authorizedBy()
:
use \Codewiser\Workflow\Transition; Transition::make('new', 'review') ->authorizedBy('transitToReview');
Using Closure
use \Codewiser\Workflow\Transition; use \Illuminate\Support\Facades\Gate; Transition::make('new', 'review') ->authorizedBy(fn(Article $article) => Gate::allows('transitToReview', $article));
Authorized Transitions
To get only transitions, authorized to the current user, use authorized
method of TransitionCollection
:
$article = new \Codewiser\Workflow\Example\Article(); $transitions = $article->state // Get transitions from model's current state. ->transitions() // Filter only authorized transitions. ->authorized();
Authorizing Transition
When accepting user request, do not forget to authorize workflow state changing.
public function update(Request $request, \Codewiser\Workflow\Example\Article $article) { $this->authorize('update', $article); if ($state = $request->get('state')) { // Check if user allowed to make this transition $article->state->authorize($state); } $article->fill($request->validated()); $article->save(); }
Business Logic
Disabling transitions
Transition may have some prerequisites to a model. If model fits this conditions then the transition can be performed.
Prerequisite is a callable
with Model
argument. It may throw an exception.
To disable transition, prerequisite should throw a TransitionRecoverableException
. Leave helping instructions in
exception message.
Here is an example of issues user may resolve.
use \Codewiser\Workflow\Transition; use \Codewiser\Workflow\Exceptions\TransitionRecoverableException; Transition::make('new', 'review') ->before(function(Article $model) { if (strlen($model->body) < 1000) { throw new TransitionRecoverableException( 'Your article should contain at least 1000 symbols. Then you may send it to review.' ); } }) ->before(function(Article $model) { if ($model->images->count() == 0) { throw new TransitionRecoverableException( 'Your article should contain at least 1 image. Then you may send it to review.' ); } });
User will see the problematic transitions in a list of available transitions. User follows instructions to resolve the issue and then may try to perform the transition again.
Removing transitions
In some cases workflow routes may divide into branches. Way to go forced by business logic, not user. User even shouldn't know about other ways.
To completely remove transition from a list, prerequisite should throw a TransitionFatalException
.
use \Codewiser\Workflow\Transition; use \Codewiser\Workflow\Exceptions\TransitionFatalException; Transition::make('new', 'to-local-manager') ->before(function(Order $model) { if ($model->amount >= 1000000) { throw new TransitionFatalException("Order amount is too big for this transition."); } }); Transition::make('new', 'to-region-manager') ->before(function(Order $model) { if ($model->amount < 1000000) { throw new TransitionFatalException("Order amount is too small for this transition."); } });
User will see only one possible transition depending on order amount value.
Additional Context
Sometimes application requires an additional context to perform a transition. For example, it may be a reason the article was rejected by the reviewer.
First, declare validation rules in transition definition:
use \Codewiser\Workflow\Transition; Transition::make('review', 'reject') ->rules([ 'reason' => 'required|string|min:100' ]);
Next, set the transition context in the controller:
use Illuminate\Http\Request; public function update(Request $request, \Codewiser\Workflow\Example\Article $article) { $this->authorize('update', $article); if ($state = $request->get('state')) { $article->state // Authorize transition ->authorize($state) // Put transition context ->context($request->all()); $article->state = $state; } $article->save(); }
The context will be validated while saving, and you may catch a ValidationException
.
After all you may handle this context in events.
Translations
You may define State
and Transition
objects with translatable caption.
use \Codewiser\Workflow\State; use \Codewiser\Workflow\Transition; use \Codewiser\Workflow\WorkflowBlueprint; class ArticleWorkflow extends WorkflowBlueprint { protected function states(): array { return [ State::make('new')->as(__('Draft')), State::make('published')->as(__('Published')) ]; } protected function transitions(): array { return [ Transition::make('new', 'published')->as('Publish') ]; } }
Additional Attributes
Sometimes we need to add some additional attributes to the workflow states and transitions. For example, we may group states by levels and use this information to color states and transitions in user interface.
use \Codewiser\Workflow\State; use \Codewiser\Workflow\Transition; use \Codewiser\Workflow\WorkflowBlueprint; class ArticleWorkflow extends WorkflowBlueprint { protected function states(): array { return [ State::make('new'), State::make('review') ->set('level', 'warning'), State::make('published') ->set('level', 'success'), State::make('correction') ->set('level', 'danger') ]; } protected function transitions(): array { return [ Transition::make('new', 'review') ->set('level', 'warning'), Transition::make('review', 'published') ->set('level', 'success'), Transition::make('review', 'correction') ->set('level', 'danger'), Transition::make('correction', 'review') ->set('level', 'warning') ]; } }
Json Serialization
For user to interact with model's workflow we should pass the data to a frontend of the application:
use Illuminate\Http\Request; public function show(\Codewiser\Workflow\Example\Article $article) { $this->authorize('view', $article); $data = $article->toArray(); $data['state']['transitions'] = $article->state->transitions()->authorized()->toArray(); return $data; }
The payload will be like that:
{ "id": 1, "title": "Article title", "state": { "value": "review", "name": "Review", "transitions": [ { "source": "review", "target": "publish", "name": "Publish", "issues": [ "Publisher should provide a foreword." ], "rules": [], "level": "success" }, { "source": "review", "target": "correction", "name": "Send to Correction", "issues": [], "rules": { "reason": ["required", "string", "min:100"] }, "level": "danger" } ] } }
Events
EventListener
Transition generates ModelTransited
event. You may define EventListener
to listen to it.
use \Codewiser\Workflow\Events\ModelTransited; class ModelTransitedListener { public function handle(ModelTransited $event) { if ($event->model instanceof Article) { $article = $event->model; if ($event->transition->target()->is('correction')) { // Article was send to correction, the reason described in context $article->author->notify( new ArticleHasProblem( $article, $event->transition->context('reason') ) ); } } } }
Transition Callback
Otherwise, you may define transition callback(s), that will be called after transition were successfully performed.
Callback is a callable
with Model
and context
arguments.
use \Codewiser\Workflow\Transition; Transition::make('review', 'correcting') ->after(function(Article $article, array $context) { $article->author->notify( new ArticleHasProblem( $article, $context['reason'] ) ); });
You may define few callbacks to a single transition.
Transition History
The Package may log transitions to database table.
Register \Codewiser\Workflow\WorkflowServiceProvider
in providers
section of config/app.php
.
Run migrations:
php artisan migrate
Add workflow.history
into config/services.php
:
'workflow' => [ 'history' => true ]
It's done.
To get historical records, add \Codewiser\Workflow\Traits\HasTransitionHistory
to Model
with workflow. It brings transitions
relation.
Historical records presented by \Codewiser\Workflow\Models\TransitionHistory
model, that holds information about transition performer, source and target states and a context, if it were provided.
Blueprint Validation
The Package may validate Workflow Blueprint that you defined.
Register \Codewiser\Workflow\WorkflowServiceProvider
in providers
section of config/app.php
.
Run console command with blueprint classname:
php artisan workflow:blueprint --class=App/Workflow/ArticleWorkflow