vouchedfor/rules-bundle

Rules engine for Symfony

RulesBundle

This bundle creates the facility to add a basic rules engine. It's inspired by this article: http://jwage.com/post/76799775984/using-the-symfony-expression-language-for-a-reward, _(*1)

The bundle creates a Rule entity which is comprised of three elements:, _(*2)

1. Event - the dispatched event that causes this rule to be invoked (e.g. 'user:registered')
2. Conditions - a json array of expressions. (e.g. '["data.age > 67", "data.weight > 200"]') See [http://symfony.com/doc/current/components/expression_language.html](http://symfony.com/doc/current/components/expression_language.html) for more on the ExpressionLanguage component.
3. Actions - a json array of events to be dispatched. (e.g. '["user:mark-as-retired", "user:send-email|Retirement"]'.  Note that it is possible to send a single parameter by adding a '|' after the name of the action/event to be dispatched)

Installation

First, install it with composer:, _(*3)

composer require vouchedfor/rules-bundle:dev-master

Then, add the following in your AppKernel bundles (note that 'new DataDog\AuditBundle\DataDogAuditBundle(),' may have been added previously)., _(*4)

// app/AppKernel.php
public function registerBundles()
{
    $bundles = array(
        ...
        new VouchedFor\AuditUiBundle\VouchedForRulesBundle(),
        ...
    );
    ...
}

Create the 'rule' database table used by the bundle:, _(*5)

Using Doctrine Migrations Bundle:, _(*6)

php app/console doctrine:migrations:diff
php app/console doctrine:migrations:migrate

Using Doctrine Schema:, _(*7)

php app/console doctrine:schema:update --force

Usage

Create a class that extends VouchedFor\RulesBundle\Event\RuleEvent., _(*8)

Add the events you want to listen to as tags for a RuleListener service (in this example, 'user:mark-as-retired' and 'user:send-email'):, _(*9)

// app/config/services.yml
app.rule.listener:
    class: VouchedFor\RulesBundle\EventListener\RuleListener
    arguments:
      - "@doctrine.orm.entity_manager"
      - "@event_dispatcher"
    tags:
      - { name: kernel.event_listener, event: user:registered, method: handleEvent }
      - { name: kernel.event_listener, event: user:updated, method: handleEvent }

Add a listener/subscriber to listen to the dispatched actions when a rule passes. For example:, _(*10)

<?php
namespace AppBundle\EventListener;

...

class UserSubscriber implements EventSubscriberInterface
{
    public static function getSubscribedEvents()
    {
        return [
            'user:mark-as-retired' => 'userMarkAsRetired',
            'user:send-email' => 'userSendEmail',
            ];
    }

    public function userMarkAsRequired(UserEvent $event)
    {
        $entity = $event->getEntity());
           $entity->setStatus('retired');

        ...
    }

    public function userSendEmail(UserEvent $event)
    {
        $entity = $event->getEntity());
        $parameter = $event->getActionParameter());

        $this->sendMail($entity, $parameter);  // Send email to $entity with template $parameter

        ...
    }

License

The Rules Bundle is free to use and is licensed under the MIT license, _(*11)