feat(schema): Allow altering of schemas by introducing alter events i…

…n a new base class (#1301) (#1302)

src/Event/AlterSchemaDataEvent.php

@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\graphql\Event;
+
+use Drupal\Component\EventDispatcher\Event;
+
+/**
+ * Represents an event that is triggered to alter schema data.
+ */
+class AlterSchemaDataEvent extends Event {
+
+  /**
+   * Event fired to alter schema data.
+   *
+   * @var string
+   */
+  const EVENT_NAME = 'graphql.sdl.alter_schema';
+
+  /**
+   * The schema array data.
+   *
+   * @var array
+   */
+  protected $schemaData;
+
+  /**
+   * AlterSchemaDataEvent constructor.
+   *
+   * @param array $schemaData
+   *   The schema data reference.
+   */
+  public function __construct(array &$schemaData) {
+    $this->schemaData = $schemaData;
+  }
+
+  /**
+   * Returns the schema data.
+   *
+   * @return array
+   *   The schema data.
+   */
+  public function getSchemaData(): array {
+    return $this->schemaData;
+  }
+
+  /**
+   * Sets the schema data.
+   *
+   * @param array $schemaData
+   *   The schema data.
+   */
+  public function setSchemaData(array $schemaData): void {
+    $this->schemaData = $schemaData;
+  }
+
+}

src/Event/AlterSchemaExtensionDataEvent.php

@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\graphql\Event;
+
+use Drupal\Component\EventDispatcher\Event;
+
+/**
+ * Represents an event that is triggered to alter schema extension data.
+ */
+class AlterSchemaExtensionDataEvent extends Event {
+
+  /**
+   * Event fired to alter schema extension data.
+   *
+   * @var string
+   */
+  const EVENT_NAME = 'graphql.sdl.alter_schema_extension';
+
+  /**
+   * The schema array data.
+   *
+   * @var array
+   */
+  protected $schemaExtensionData;
+
+  /**
+   * AlterSchemaExtensionDataEvent constructor.
+   *
+   * @param array $schemaExtensionData
+   *   The schema extension data.
+   */
+  public function __construct(array $schemaExtensionData) {
+    $this->schemaExtensionData = $schemaExtensionData;
+  }
+
+  /**
+   * Returns the schema extension data.
+   *
+   * @return array
+   *   The schema extension data.
+   */
+  public function getSchemaExtensionData(): array {
+    return $this->schemaExtensionData;
+  }
+
+  /**
+   * Returns the schema extension data.
+   *
+   * @param array $schemaExtensionData
+   *   The schema extension data.
+   */
+  public function setSchemaExtensionData(array $schemaExtensionData): void {
+    $this->schemaExtensionData = $schemaExtensionData;
+  }
+
+}

src/Plugin/GraphQL/Schema/AlterableComposableSchema.php

@@ -0,0 +1,183 @@
+<?php
+
+namespace Drupal\graphql\Plugin\GraphQL\Schema;
+
+use Drupal\Core\Cache\CacheBackendInterface;
+use Drupal\graphql\Event\AlterSchemaDataEvent;
+use Drupal\graphql\Event\AlterSchemaExtensionDataEvent;
+use Drupal\graphql\Plugin\SchemaExtensionPluginInterface;
+use GraphQL\Language\Parser;
+use Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher;
+use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\graphql\Plugin\SchemaExtensionPluginManager;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Allows to alter the graphql files data before parsing.
+ *
+ * @see \Drupal\graphql\Event\AlterSchemaDataEvent
+ * @see \Drupal\graphql\Event\AlterSchemaExtensionDataEvent
+ *
+ * @Schema(
+ *   id = "alterable_composable",
+ *   name = "Alterable composable schema"
+ * )
+ */
+class AlterableComposableSchema extends ComposableSchema {
+
+  /**
+   * The event dispatcher service.
+   *
+   * @var \Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher
+   */
+  protected $dispatcher;
+
+  /**
+   * {@inheritdoc}
+   *
+   * @codeCoverageIgnore
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
+    return new static(
+      $configuration,
+      $plugin_id,
+      $plugin_definition,
+      $container->get('cache.graphql.ast'),
+      $container->get('module_handler'),
+      $container->get('plugin.manager.graphql.schema_extension'),
+      $container->getParameter('graphql.config'),
+      $container->get('event_dispatcher')
+    );
+  }
+
+  /**
+   * AlterableComposableSchema constructor.
+   *
+   * @param array $configuration
+   *   The plugin configuration array.
+   * @param string $pluginId
+   *   The plugin id.
+   * @param array $pluginDefinition
+   *   The plugin definition array.
+   * @param \Drupal\Core\Cache\CacheBackendInterface $astCache
+   *   The cache bin for caching the parsed SDL.
+   * @param \Drupal\Core\Extension\ModuleHandlerInterface $moduleHandler
+   *   The module handler service.
+   * @param \Drupal\graphql\Plugin\SchemaExtensionPluginManager $extensionManager
+   *   The schema extension plugin manager.
+   * @param array $config
+   *   The service configuration.
+   * @param \Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher $dispatcher
+   *   The event dispatcher.
+   *
+   * @codeCoverageIgnore
+   */
+  public function __construct(
+    array $configuration,
+    $pluginId,
+    array $pluginDefinition,
+    CacheBackendInterface $astCache,
+    ModuleHandlerInterface $moduleHandler,
+    SchemaExtensionPluginManager $extensionManager,
+    array $config,
+    ContainerAwareEventDispatcher $dispatcher
+  ) {
+    parent::__construct(
+      $configuration,
+      $pluginId,
+      $pluginDefinition,
+      $astCache,
+      $moduleHandler,
+      $extensionManager,
+      $config
+    );
+    $this->dispatcher = $dispatcher;
+  }
+
+  /**
+   * Retrieves the parsed AST of the schema definition.
+   *
+   * Almost copy of the original method except it
+   * provides alter schema event in order to manipulate data.
+   *
+   * @param array $extensions
+   *   The Drupal GraphQl schema plugins data.
+   *
+   * @return \GraphQL\Language\AST\DocumentNode
+   *   The parsed schema document.
+   *
+   * @throws \GraphQL\Error\SyntaxError
+   * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
+   *
+   * @see \Drupal\graphql\Plugin\GraphQL\Schema\ComposableSchema::getSchemaDocument()
+   */
+  protected function getSchemaDocument(array $extensions = []) {
+    // Only use caching of the parsed document if we aren't in development mode.
+    $cid = "schema:{$this->getPluginId()}";
+    if (empty($this->inDevelopment) && $cache = $this->astCache->get($cid)) {
+      return $cache->data;
+    }
+
+    $extensions = array_filter(array_map(function (SchemaExtensionPluginInterface $extension) {
+      return $extension->getBaseDefinition();
+    }, $extensions), function ($definition) {
+      return !empty($definition);
+    });
+    $schema = array_merge([$this->getSchemaDefinition()], $extensions);
+    // Event in order to alter the schema data.
+    $event = new AlterSchemaDataEvent($schema);
+    $this->dispatcher->dispatch(
+      $event,
+      AlterSchemaDataEvent::EVENT_NAME
+    );
+    $ast = Parser::parse(implode("\n\n", $event->getSchemaData()));
+    if (empty($this->inDevelopment)) {
+      $this->astCache->set($cid, $ast, CacheBackendInterface::CACHE_PERMANENT, ['graphql']);
+    }
+    return $ast;
+  }
+
+  /**
+   * Retrieves the parsed AST of the schema extension definitions.
+   *
+   * Almost copy of the original method except it
+   * provides alter schema extension event in order to manipulate data.
+   *
+   * @param array $extensions
+   *   The Drupal GraphQl extensions data.
+   *
+   * @return \GraphQL\Language\AST\DocumentNode|null
+   *   The parsed schema document.
+   *
+   * @throws \GraphQL\Error\SyntaxError
+   *
+   * @see \Drupal\graphql\Plugin\GraphQL\Schema\ComposableSchema::getSchemaDocument()
+   */
+  protected function getExtensionDocument(array $extensions = []) {
+    // Only use caching of the parsed document if we aren't in development mode.
+    $cid = "extension:{$this->getPluginId()}";
+    if (empty($this->inDevelopment) && $cache = $this->astCache->get($cid)) {
+      return $cache->data;
+    }
+
+    $extensions = array_filter(array_map(function (SchemaExtensionPluginInterface $extension) {
+      return $extension->getExtensionDefinition();
+    }, $extensions), function ($definition) {
+      return !empty($definition);
+    });
+
+    // Event in order to alter the schema extension data.
+    $event = new AlterSchemaExtensionDataEvent($extensions);
+    $this->dispatcher->dispatch(
+      $event,
+      AlterSchemaExtensionDataEvent::EVENT_NAME
+    );
+    $ast = !empty($extensions) ? Parser::parse(implode("\n\n", $event->getSchemaExtensionData())) : NULL;
+    if (empty($this->inDevelopment)) {
+      $this->astCache->set($cid, $ast, CacheBackendInterface::CACHE_PERMANENT, ['graphql']);
+    }
+
+    return $ast;
+  }
+
+}

tests/modules/graphql_alterable_schema_test/graphql_alterable_schema_test.info.yml

@@ -0,0 +1,5 @@
+type: module
+name: GraphQL Alterable Schema Test
+description: Tests if alterting schema is working.
+package: Testing
+hidden: TRUE

tests/modules/graphql_alterable_schema_test/graphql_alterable_schema_test.services.yml

@@ -0,0 +1,6 @@
+services:
+
+  graphql_alterable_schema_test.alter_data_subscriber:
+    class: Drupal\graphql_alterable_schema_test\EventSubscriber\GraphQlSubscriber
+    tags:
+      - { name: event_subscriber }

tests/modules/graphql_alterable_schema_test/src/EventSubscriber/GraphQlSubscriber.php

@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\graphql_alterable_schema_test\EventSubscriber;
+
+use Drupal\graphql\Event\AlterSchemaDataEvent;
+use Drupal\graphql\Event\AlterSchemaExtensionDataEvent;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+/**
+ * Subscribes to the graphql schema alter events.
+ */
+class GraphQlSubscriber implements EventSubscriberInterface {
+
+  /**
+   * {@inheritdoc}
+   *
+   * @return array
+   *   The event names to listen for, and the methods that should be executed.
+   */
+  public static function getSubscribedEvents() {
+    return [
+      AlterSchemaExtensionDataEvent::EVENT_NAME => ['alterSchemaExtensionData'],
+      AlterSchemaDataEvent::EVENT_NAME => ['alterSchemaData'],
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function alterSchemaExtensionData(AlterSchemaExtensionDataEvent $event): void {
+    $schemaData = $event->getSchemaExtensionData();
+    // I do not recommend direct replace, better user parsing or regex.
+    // But this is an example of what you can do.
+    $schemaData['graphql_alterable_schema_test'] = str_replace('position: Int', 'position: Int!', $schemaData['graphql_alterable_schema_test']);
+    $event->setSchemaExtensionData($schemaData);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function alterSchemaData(AlterSchemaDataEvent $event): void {
+    $schemaData = $event->getSchemaData();
+    // It is not recommended direct replacement, better user parsing or regex.
+    // But this is an example of what you can do.
+    $schemaData[0] = str_replace('alterableQuery(id: Int): Result', 'alterableQuery(id: Int!): Result', $schemaData[0]);
+    $event->setSchemaData($schemaData);
+  }
+
+}