Issue #3094195 by mglaman: Support pagination of index results

src/Resource/IndexResource.php

@@ -3,6 +3,11 @@
 namespace Drupal\jsonapi_search_api\Resource;
 
 use Drupal\Core\Cache\CacheableMetadata;
+use Drupal\Core\Http\Exception\CacheableBadRequestHttpException;
+use Drupal\Core\Url;
+use Drupal\jsonapi\JsonApiResource\Link;
+use Drupal\jsonapi\JsonApiResource\LinkCollection;
+use Drupal\jsonapi\Query\OffsetPage;
 use Drupal\jsonapi\ResourceResponse;
 use Drupal\jsonapi_resources\Resource\EntityResourceBase;
 use Drupal\search_api\IndexInterface;
@@ -31,7 +36,18 @@ final class IndexResource extends EntityResourceBase {
    */
   public function process(Request $request, IndexInterface $index): ResourceResponse {
     $cacheability = new CacheableMetadata();
+    // Ensure that different pages will be cached separately.
+    $cacheability->addCacheContexts(['url.query_args:page']);
+
     $query = $index->query();
+
+    // Derive any pagination options from the query params or use defaults.
+    $pagination = $this->getPagination($request);
+    if ($pagination->getSize() <= 0) {
+      throw new CacheableBadRequestHttpException($cacheability, sprintf('The page size needs to be a positive integer.'));
+    }
+    $query->range($pagination->getOffset(), $pagination->getSize());
+
     // Get the results and convert to JSON:API resource object data.
     $results = $query->execute();
     $result_entities = array_map(static function (ItemInterface $item) {
@@ -39,9 +55,146 @@ final class IndexResource extends EntityResourceBase {
     }, \iterator_to_array($results));
     $primary_data = $this->createCollectionDataFromEntities(array_values($result_entities));
 
-    $response = $this->createJsonapiResponse($primary_data, $request);
+    $pager_links = $this->getPagerLinks($request, $pagination, (int) $results->getResultCount(), count($result_entities));
+
+    $response = $this->createJsonapiResponse($primary_data, $request, 200, [], $pager_links);
     $response->addCacheableDependency($cacheability);
     return $response;
   }
 
+  /**
+   * Get pagination for the request.
+   *
+   * @param \Symfony\Component\HttpFoundation\Request $request
+   *   The request.
+   *
+   * @return \Drupal\jsonapi\Query\OffsetPage
+   *   The pagination object.
+   */
+  private function getPagination(Request $request): OffsetPage {
+    return $request->query->has('page')
+      ? OffsetPage::createFromQueryParameter($request->query->get('page'))
+      : new OffsetPage(OffsetPage::DEFAULT_OFFSET, OffsetPage::SIZE_MAX);
+  }
+
+  /**
+   * Get pager links.
+   *
+   * @param \Symfony\Component\HttpFoundation\Request $request
+   *   The request.
+   * @param \Drupal\jsonapi\Query\OffsetPage $pagination
+   *   The pagination object.
+   * @param int $total_count
+   *   The total count.
+   * @param int $result_count
+   *   The result count.
+   *
+   * @return \Drupal\jsonapi\JsonApiResource\LinkCollection
+   *   The link collection.
+   */
+  protected function getPagerLinks(Request $request, OffsetPage $pagination, int $total_count, int $result_count): LinkCollection {
+    $pager_links = new LinkCollection([]);
+    $size = (int) $pagination->getSize();
+    $offset = $pagination->getOffset();
+    $query = (array) $request->query->getIterator();
+
+    // Check if this is not the last page.
+    if (($pagination->getOffset() + $result_count) < $total_count) {
+      $next_url = static::getRequestLink($request, static::getPagerQueries('next', $offset, $size, $query));
+      $pager_links = $pager_links->withLink('next', new Link(new CacheableMetadata(), $next_url, 'next'));
+      $last_url = static::getRequestLink($request, static::getPagerQueries('last', $offset, $size, $query, $total_count));
+      $pager_links = $pager_links->withLink('last', new Link(new CacheableMetadata(), $last_url, 'last'));
+    }
+    // Check if this is not the first page.
+    if ($offset > 0) {
+      $first_url = static::getRequestLink($request, static::getPagerQueries('first', $offset, $size, $query));
+      $pager_links = $pager_links->withLink('first', new Link(new CacheableMetadata(), $first_url, 'first'));
+      $prev_url = static::getRequestLink($request, static::getPagerQueries('prev', $offset, $size, $query));
+      $pager_links = $pager_links->withLink('prev', new Link(new CacheableMetadata(), $prev_url, 'prev'));
+    }
+    return $pager_links;
+  }
+
+  /**
+   * Get the query param array.
+   *
+   * @param string $link_id
+   *   The name of the pagination link requested.
+   * @param int $offset
+   *   The starting index.
+   * @param int $size
+   *   The pagination page size.
+   * @param array $query
+   *   The query parameters.
+   * @param int $total
+   *   The total size of the collection.
+   *
+   * @return array
+   *   The pagination query param array.
+   */
+  protected static function getPagerQueries($link_id, $offset, $size, array $query = [], $total = 0) {
+    $extra_query = [];
+    switch ($link_id) {
+      case 'next':
+        $extra_query = [
+          'page' => [
+            'offset' => $offset + $size,
+            'limit' => $size,
+          ],
+        ];
+        break;
+
+      case 'first':
+        $extra_query = [
+          'page' => [
+            'offset' => 0,
+            'limit' => $size,
+          ],
+        ];
+        break;
+
+      case 'last':
+        if ($total) {
+          $extra_query = [
+            'page' => [
+              'offset' => (ceil($total / $size) - 1) * $size,
+              'limit' => $size,
+            ],
+          ];
+        }
+        break;
+
+      case 'prev':
+        $extra_query = [
+          'page' => [
+            'offset' => max($offset - $size, 0),
+            'limit' => $size,
+          ],
+        ];
+        break;
+    }
+    return array_merge($query, $extra_query);
+  }
+
+  /**
+   * Get the full URL for a given request object.
+   *
+   * @param \Symfony\Component\HttpFoundation\Request $request
+   *   The request object.
+   * @param array|null $query
+   *   The query parameters to use. Leave it empty to get the query from the
+   *   request object.
+   *
+   * @return \Drupal\Core\Url
+   *   The full URL.
+   */
+  public static function getRequestLink(Request $request, $query = NULL) {
+    if ($query === NULL) {
+      return Url::fromUri($request->getUri());
+    }
+
+    $uri_without_query_string = $request->getSchemeAndHttpHost() . $request->getBaseUrl() . $request->getPathInfo();
+    return Url::fromUri($uri_without_query_string)->setOption('query', $query);
+  }
+
 }

tests/src/Functional/IndexResourceTest.php

@@ -11,7 +11,6 @@ use Drupal\Tests\jsonapi\Functional\JsonApiRequestTestTrait;
 use Drupal\Tests\jsonapi\Functional\ResourceResponseTestTrait;
 use Drupal\Tests\search_api\Functional\ExampleContentTrait;
 use Drupal\user\Entity\Role;
-use Drupal\user\RoleInterface;
 use GuzzleHttp\RequestOptions;
 
 /**
@@ -58,18 +57,17 @@ final class IndexResourceTest extends BrowserTestBase {
     $index->indexItems();
 
     $this->container->get('router.builder')->rebuildIfNeeded();
+
+    $this->grantPermissions(Role::load(Role::ANONYMOUS_ID), [
+      'view test entity',
+    ]);
   }
 
   /**
    * Tests the results contain the index values.
    */
   public function testCollection() {
-    $this->grantPermissions(Role::load(Role::ANONYMOUS_ID), [
-      'view test entity',
-    ]);
-    $url = Url::fromRoute('jsonapi_search_api.index_database_search_index', [
-      'index' => 'database_search_index',
-    ]);
+    $url = Url::fromRoute('jsonapi_search_api.index_database_search_index');
     $request_options = [];
     $request_options[RequestOptions::HEADERS]['Accept'] = 'application/vnd.api+json';
     $response = $this->request('GET', $url, $request_options);
@@ -81,4 +79,50 @@ final class IndexResourceTest extends BrowserTestBase {
     }, $response_document['data']));
   }
 
+  /**
+   * Tests the results contain the index values.
+   */
+  public function testCollectionPagination() {
+    $request_options = [];
+    $request_options[RequestOptions::HEADERS]['Accept'] = 'application/vnd.api+json';
+
+    $url = Url::fromRoute('jsonapi_search_api.index_database_search_index', [], [
+      'query' => [
+        'page' => [
+          'limit' => 2,
+          'offset' => 0,
+        ],
+      ],
+    ]);
+    $response = $this->request('GET', $url, $request_options);
+    $this->assertSame(200, $response->getStatusCode(), var_export(Json::decode((string) $response->getBody()), TRUE));
+    $response_document = Json::decode((string) $response->getBody());
+    $this->assertCount(2, $response_document['data'], var_export($response_document, TRUE));
+    $this->assertSame([1, 2], array_map(static function (array $data) {
+      return $data['attributes']['drupal_internal__id'];
+    }, $response_document['data']));
+    $this->assertArrayHasKey('next', $response_document['links']);
+    $this->assertArrayHasKey('last', $response_document['links']);
+
+    $url = Url::fromRoute('jsonapi_search_api.index_database_search_index', [], [
+      'query' => [
+        'page' => [
+          'limit' => 2,
+          'offset' => 2,
+        ],
+      ],
+    ]);
+    $response = $this->request('GET', $url, $request_options);
+    $this->assertSame(200, $response->getStatusCode(), var_export(Json::decode((string) $response->getBody()), TRUE));
+    $response_document = Json::decode((string) $response->getBody());
+    $this->assertCount(2, $response_document['data'], var_export($response_document, TRUE));
+    $this->assertSame([3, 4], array_map(static function (array $data) {
+      return $data['attributes']['drupal_internal__id'];
+    }, $response_document['data']));
+    $this->assertArrayHasKey('next', $response_document['links']);
+    $this->assertArrayHasKey('last', $response_document['links']);
+    $this->assertArrayHasKey('prev', $response_document['links']);
+    $this->assertArrayHasKey('first', $response_document['links']);
+  }
+
 }