Events¶

Various events are dispatched at points in the CRUD lifecycle, all beginning with perform_base.crud.*.

You could use these events to modify how CRUD is handled for certain entities and tweak how pages look or behave.

Context events¶

Perform\BaseBundle\Event\ContextEvent instances are dispatched for each of the crud contexts, just before the controller returns its response:

perform_base.crud.list_context (or ContextEvent::CONTEXT_LIST) for the list context
perform_base.crud.view_context (or ContextEvent::CONTEXT_VIEW) for the view context
perform_base.crud.create_context (or ContextEvent::CONTEXT_CREATE) for the create context
perform_base.crud.edit_context (or ContextEvent::CONTEXT_EDIT) for the edit context

ContextEvent instances contain the current CrudRequest and an array of template variables.

You could use these events to modify the variables sent to the twig templates for each context.

Database events¶

Entity database operations¶

Perform\BaseBundle\Event\EntityEvent instances are dispatched when an entity is created, updated, or deleted:

perform_base.crud.pre_create (or EntityEvent::PRE_CREATE) before an entity is added to the database
perform_base.crud.post_create (or EntityEvent::POST_CREATE) after an entity is added to the database
perform_base.crud.pre_update (or EntityEvent::PRE_UPDATE) before an entity is updated in the database
perform_base.crud.post_update (or EntityEvent::POST_UPDATE) after an entity is updated in the database
perform_base.crud.pre_delete (or EntityEvent::PRE_DELETE) before an entity is deleted from the database
perform_base.crud.post_delete (or EntityEvent::POST_DELETE) after an entity is deleted from the database

EntityEvent instances contain the current CrudRequest and the doctrine entity that is being changed.

You could use these events to modify the entity, or throw an exception if certain conditions are not met.

You could also use the setEntity method on EntityEvent to override the entity entirely:

<?php

public function preCreate(EntityEvent $event)
{
    // create a completely new entity
    $post = new Post();

    $event->setEntity($post);
}

Of course, this technique will only work for PRE_CREATE, PRE_UPDATE, and PRE_DELETE events, as they are dispatched before the entity interacts with the database.

Select queries¶

Perform\BaseBundle\Event\QueryEvent instances are dispatched when selecting database entities.

perform_base.crud.list_query (or QueryEvent::LIST_QUERY) when selecting a collection of entities for the list context
perform_base.crud.view_query (or QueryEvent::VIEW_QUERY) when selecting a single entity to examine in the view context
perform_base.crud.edit_query (or QueryEvent::EDIT_QUERY) when selecting a single entity to be added to the form in the edit context

QueryEvent instances contain the current CrudRequest and a Doctrine\ORM\QueryBuilder used to build a select query.

You could use these events to change how entities are selected, e.g. adding an extra ‘where’ clause to the query.

Examples¶

Restrict the selected items in the list context¶

<?php
public function onListQuery(QueryEvent $event)
{
    // only applies when selecting Post entities
    if (!$event->getCrudRequest()->supportsEntityClass(Post::class)) {
        return;
    }

    // regular users cannot see drafts
    if (!$this->getUser()->hasRole('ROLE_ADMIN')) {
        $event->getQueryBuilder()->andWhere('e.draft = false');
    }
}

Set a property and enforce business logic before creation, notify on success¶

<?php
class PostListener
{
    public function preCreate(EntityEvent $event)
    {
        $post = $event->getEntity();
        if (!$post instanceof Post) {
            return;
        }
        if ($post->getAuthor() !== $this->currentUser()) {
            throw new AccessDeniedException('You are not allowed to author a post on behalf of someone else.');
        }

        $post->setDraft(true);
    }

    public function postCreate(EntityEvent $event)
    {
        $this->notify('Created a new post!', $event->getEntity());
    }
}