Laravel WorkflowSubscriber类，该类基于当前转换有条件地调用防护方法，并调用不正确的方法

Question

我在这里遇到了不必要的困惑。我只是想在此WorkflowSubscriber中创建一个方法来检查事件的过渡，创建一个看起来像$guardMethod的guardToSomePlace变量，然后如果该方法存在，则调用它。这是该概念的代码：

<?php

namespace App\Listeners;

use App\Models\BugTypes\Bug;
use Symfony\Component\Workflow\Event\GuardEvent;

class BugWorkflowSubscriber
{
    /**
     * Handle workflow guard events.
     *
     * @param \Symfony\Component\Workflow\Event\GuardEvent $event
     */
    public function onGuard(GuardEvent $event)
    {
        $transition = $event->getTransition();

        $guardMethod = 'guard' . studly_case($transition->getName());
        // this can be something like guardToAccepted and it 
        // calls guardToOnHold below

        if (method_exists($this, $guardMethod)) { // should fail
            $this->$guardMethod($event);
        }
    }

    /**
     * Guards the to_on_hold transition
     *
     * @param \Symfony\Workflow\Event\GuardEvent $event
     *
     * @return void
     */
    private function guardToOnHold(GuardEvent $event)
    {
        dd('why is it getting here for other transitions?');
    }

    /**
     * Register the listeners for the subscriber.
     *
     * @param  \Illuminate\Events\Dispatcher  $events
     */
    public function subscribe($events)
    {
        $events->listen(
            'workflow.bug.guard',
            'App\Listeners\BugWorkflowSubscriber@onGuard'
        );

        $events->listen(
            'workflow.bug.entered.*',
            'App\Listeners\Workflow\Bug\OnEntered'
        );
    }
}

[它正在调用guardToOnHold方法进行多次转换，尽管事实上我可以dd $event->getTransition()并且它是我期望的转换，并且如果我dd method_exists($this, $guardMethod)它对于除guardToOnHold之外的任何/所有方法都是错误的，因为这是我创建$guardMethod变量后唯一存在的变量。如果在if语句前加dd method_exists($this, $guardMethod)，则它为假，但将dd-C0放入具有相同事件/转换的if语句中将进入if语句和dd的true。这是使用Brexis / Laravel Symfony Workflow软件包的Laravel 5.7。活动的过渡总是我所希望的。 $event->getTransition()总是返回一个带有正确名称，froms和tos的过渡对象。

Answer 1

这实际上与我过去3天正在调查的内容有关。当您应用转换时，在symfony工作流中会发生什么，它会调用getEnabledTransitions函数，该函数又调用doCan方法，并调用guardTransition，现在guardTransition会分派workflow.guard事件，并且当您有一个侦听器（onGuard）时，您的函数将获得叫。

这是我认为正在发生的事情，我仍然不确定100％是否正确，在这种情况下应采取的措施，也许我需要更多的调查。

相关代码：

// all taken from Symfony/Component/Workflow/Workflow.php
public function apply($subject, $transitionName)
    {
        $transitions = $this->getEnabledTransitions($subject);

public function getEnabledTransitions($subject)
    {
        $enabled = array();
        $marking = $this->getMarking($subject);
        foreach ($this->definition->getTransitions() as $transition) {
            if ($this->doCan($subject, $marking, $transition)) {
                $enabled[] = $transition;
            }
        }
        return $enabled;
    }

private function doCan($subject, Marking $marking, Transition $transition)
    {
        foreach ($transition->getFroms() as $place) {
            if (!$marking->has($place)) {
                return false;
            }
        }
        if (true === $this->guardTransition($subject, $marking, $transition)) {
            return false;
        }

private function guardTransition($subject, Marking $marking, Transition $transition)
    {
        if (null === $this->dispatcher) {
            return;
        }
        $event = new GuardEvent($subject, $marking, $transition, $this->name);
        $this->dispatcher->dispatch('workflow.guard', $event);

在此处添加此内容，以便将来对某人有所帮助。