Events

A PSR-14 event dispatcher is included for listening to events.

Filtering Query Builders

Each top level connection uses a QueryBuilder object. This QueryBuilder object may be modified to filter the data for the logged in user. This can be used as a security layer and can be used to make customizations to QueryBuilder objects. QueryBuilders are built then triggered through an event. Listen to this event and modify the passed QueryBuilder to apply your security.

Event names are passed as a second parameter to a $driver->resolve(). The default event name is ‘filter.querybuilder’.

You may specify an event name to resolve a connection. Only this event will fire when the QueryBuilder is created. The default ‘filter.querybuilder’ will not fire.

In the code below the custom event Artist::class . '.filterQueryBuilder' will fire:

<?php

use ApiSkeletons\Doctrine\GraphQL\Driver;
use App\ORM\Entity\Artist;
use GraphQL\Type\Definition\ObjectType;
use GraphQL\Type\Schema;

$schema = new Schema([
  'query' => new ObjectType([
      'name' => 'query',
      'fields' => [
          'artists' => [
              'type' => $driver->connection($driver->type(Artist::class)),
              'args' => [
                  'filter' => $driver->filter(Artist::class),
              ],
              'resolve' => $driver->resolve(Artist::class, Artist::class . '.filterQueryBuilder'),
          ],
      ],
  ]),
]);

To listen for this event and add filtering, such as filtering for the current user, create at least one listener. You may add multiple listeners.

<?php

use ApiSkeletons\Doctrine\GraphQL\Event\FilterQueryBuilder;
use League\Event\EventDispatcher;

$driver->get(EventDispatcher::class)->subscribeTo(Artist::class . '.filterQueryBuilder',
    function(FilterQueryBuilder $event) {
        $event->getQueryBuilder()
            ->innerJoin('entity.user', 'user') // The default entity alias is always `entity`
            ->andWhere($event->getQueryBuilder()->expr()->eq('user.id', ':userId'))
            ->setParameter('userId', currentUser()->getId())
            ;
    }
);

The FilterQueryBuilder event has two functions in addition to getters for all resolve parameters:

getQueryBuilder - Will return a query builder with the user specified filters already applied.
getEntityAliasMap - Returns an array of entities used in the QueryBuilder and the aliases used for each. Use this to help you apply more filters to the QueryBuider.

Filtering Criteria

When an association is resolved from an entity or another association you may listen to the filterCriteria event to add additional criteria for filtering the association if you assigned an event name in the attributes.

<?php

use ApiSkeletons\Doctrine\GraphQL\Attribute as GraphQL;
use ApiSkeletons\Doctrine\GraphQL\Event\FilterCriteria;
use App\ORM\Entity\Artist;
use League\Event\EventDispatcher;

#[GraphQL\Entity]
class Artist
{
    #[GraphQL\Field]
    public $id;

    #[GraphQL\Field]
    public $name;

    #[GraphQL\Association(filterCriteriaEventName: self::class . '.performances.filterCriteria')]
    public $performances;
}

// Add a listener to your driver
$driver->get(EventDispatcher::class)->subscribeTo(
    Artist::class . '.performances.filterCriteria',
    function (FilterCriteria $event): void {
        $event->getCriteria()->andWhere(
            $event->getCriteria()->expr()->eq('isDeleted', false)
        );
    },
);

The FilterQueryBuilder event has one function in addition to getters for all resolve parameters:

getCriteria - Will return a Criteria object with the user specified filters already applied.

Modify an Entity Definition

You may modify the array used to define an entity type before it is created. This can be used for generated data and the like. You must attach to events before defining your GraphQL schema.

Events of this type are named Entity::class . '.definition' and the event name cannot be modified.

<?php

use ApiSkeletons\Doctrine\GraphQL\Driver;
use ApiSkeletons\Doctrine\GraphQL\Event\EntityDefinition;
use App\ORM\Entity\Artist;
use GraphQL\Type\Definition\ResolveInfo;
use League\Event\EventDispatcher;

$driver = new Driver($entityManager);

$driver->get(EventDispatcher::class)->subscribeTo(
    Artist::class . '.definition',
    static function (EntityDefinition $event): void {
        $definition = $event->getDefinition();

        // In order to modify the fields you must resovle the closure
        $fields = $definition['fields']();

        // Add a custom field to show the name without a prefix of 'The'
        $fields['nameUnprefix'] = [
            'type' => Type::string(),
            'description' => 'A computed dynamically added field',
            'resolve' => static function ($objectValue, array $args, $context, ResolveInfo $info): mixed {
                return trim(str_replace('The', '', $objectValue->getName()));
            },
        ];

        $definition['fields'] = $fields;
    }
);

The EntityDefinition event has one function:

getDefinition - Will return an ArrayObject with the ObjectType definition. Because this is an ArrayObject you may manipulate it as needed and the value is set by reference, just like the QueryBuilder event above.

A clever use of this event is to add a new field for related data and specify a custom FilterQueryBuilder event in the $driver->resolve() function.

Manually change the Metadata

You may modify the metadata directly when built. This event must be subscribed to immediatly after creating the driver. See Metadata documentation.

This event is named 'metadata.build'.

<?php

use ApiSkeletons\Doctrine\GraphQL\Driver;
use ApiSkeletons\Doctrine\GraphQL\Event\BuildMetadata;
use App\ORM\Entity\Performance;
use League\Event\EventDispatcher;

$driver = new Driver($entityManager);

$driver->get(EventDispatcher::class)->subscribeTo(
    'metadata.build',
    static function (BuildMetadata $event): void {
        $metadata = $event->getMetadata();

        $metadata[Performance::class]['limit'] = 100;
    },
);

The BuildMetadata event has one function:

getMetadata - Will return an ArrayObject with the metadata. Because this is an ArrayObject you may manipulate it as needed and the value is set by reference, just like the QueryBuilder event above.

This is documentation for API-Skeletons/doctrine-graphql. Please add your ★ star to the project.

Authored by API Skeletons.