Added an ORM adapter which allows fetch joins (#121)

Author: jbtronics

src/Adapter/Doctrine/FetchJoinORMAdapter.php

@@ -0,0 +1,135 @@
+<?php
+/*
+ * Symfony DataTables Bundle
+ * (c) Jan Böhmer 2020
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace Omines\DataTablesBundle\Adapter\Doctrine;
+
+use Doctrine\ORM\Query;
+use Doctrine\ORM\QueryBuilder;
+use Doctrine\ORM\Tools\Pagination\Paginator;
+use Omines\DataTablesBundle\Adapter\AdapterQuery;
+use Omines\DataTablesBundle\Adapter\Doctrine\Event\ORMAdapterQueryEvent;
+use Omines\DataTablesBundle\Adapter\Doctrine\ORMAdapterEvents;
+use Omines\DataTablesBundle\Column\AbstractColumn;
+use Symfony\Component\OptionsResolver\OptionsResolver;
+
+/**
+ * Similar to ORMAdapter this class allows to access objects from the doctrine ORM.
+ * Unlike the default ORMAdapter supports Fetch Joins (additional entites are fetched from DB via joins) using
+ * the Doctrine Paginator.
+ * @author Jan Böhmer
+ */
+class FetchJoinORMAdapter extends ORMAdapter
+{
+    protected $use_simple_total;
+
+    public function configure(array $options)
+    {
+        parent::configure($options);
+        $this->use_simple_total = $options['simple_total_query'];
+    }
+
+    protected function configureOptions(OptionsResolver $resolver)
+    {
+        parent::configureOptions($resolver);
+
+        //Enforce object hydration mode (fetch join only works for objects)
+        $resolver->addAllowedValues('hydrate', Query::HYDRATE_OBJECT);
+
+        /**
+         * Add the possibility to replace the query for total entity count through a very simple one, to improve performance.
+         * You can only use this option, if you did not apply any criteria to your total count.
+         */
+        $resolver->setDefault('simple_total_query', false);
+
+        return $resolver;
+    }
+
+    protected function prepareQuery(AdapterQuery $query)
+    {
+        $state = $query->getState();
+        $query->set('qb', $builder = $this->createQueryBuilder($state));
+        $query->set('rootAlias', $rootAlias = $builder->getDQLPart('from')[0]->getAlias());
+
+        // Provide default field mappings if needed
+        foreach ($state->getDataTable()->getColumns() as $column) {
+            if (null === $column->getField() && isset($this->metadata->fieldMappings[$name = $column->getName()])) {
+                $column->setOption('field', "{$rootAlias}.{$name}");
+            }
+        }
+
+        /** @var Query\Expr\From $fromClause */
+        $fromClause = $builder->getDQLPart('from')[0];
+        $identifier = "{$fromClause->getAlias()}.{$this->metadata->getSingleIdentifierFieldName()}";
+
+        //Use simpler (faster) total count query if the user wanted so...
+        if ($this->use_simple_total) {
+            $query->setTotalRows($this->getSimpleTotalCount($builder));
+        } else {
+            $query->setTotalRows($this->getCount($builder, $identifier));
+        }
+
+        // Get record count after filtering
+        $this->buildCriteria($builder, $state);
+        $query->setFilteredRows($this->getCount($builder, $identifier));
+
+        // Perform mapping of all referred fields and implied fields
+        $aliases = $this->getAliases($query);
+        $query->set('aliases', $aliases);
+        $query->setIdentifierPropertyPath($this->mapFieldToPropertyPath($identifier, $aliases));
+    }
+
+    public function getResults(AdapterQuery $query): \Traversable
+    {
+        $builder = $query->get('qb');
+        $state = $query->getState();
+
+        // Apply definitive view state for current 'page' of the table
+        foreach ($state->getOrderBy() as list($column, $direction)) {
+            /** @var AbstractColumn $column */
+            if ($column->isOrderable()) {
+                $builder->addOrderBy($column->getOrderField(), $direction);
+            }
+        }
+        if ($state->getLength() > 0) {
+            $builder
+                ->setFirstResult($state->getStart())
+                ->setMaxResults($state->getLength());
+        }
+
+        $query = $builder->getQuery();
+        $event = new ORMAdapterQueryEvent($query);
+        $state->getDataTable()->getEventDispatcher()->dispatch($event, ORMAdapterEvents::PRE_QUERY);
+
+        //Use Doctrine paginator for result iteration
+        $paginator = new Paginator($query);
+
+        foreach ($paginator->getIterator() as $result) {
+            yield $result;
+            $this->manager->detach($result);
+        }
+    }
+
+    public function getCount(QueryBuilder $queryBuilder, $identifier)
+    {
+        $paginator = new Paginator($queryBuilder);
+        return $paginator->count();
+    }
+
+    protected function getSimpleTotalCount(QueryBuilder $queryBuilder)
+    {
+        /** The paginator count queries can be rather slow, so when query for total count (100ms or longer),
+         * just return the entity count.
+         */
+        /** @var Query\Expr\From $from_expr */
+        $from_expr = $queryBuilder->getDQLPart('from')[0];
+        return $this->manager->getRepository($from_expr->getFrom())->count([]);
+    }
+}

src/Adapter/Doctrine/ORMAdapter.php

@@ -41,10 +41,10 @@ class ORMAdapter extends AbstractAdapter
     private $registry;
 
     /** @var EntityManager */
-    private $manager;
+    protected $manager;
 
     /** @var \Doctrine\ORM\Mapping\ClassMetadata */
-    private $metadata;
+    protected $metadata;
 
     /** @var int */
     private $hydrationMode;
@@ -262,7 +262,7 @@ protected function hasGroupByPart($identifier, array $gbList)
      * @param string $field
      * @return string
      */
-    private function mapFieldToPropertyPath($field, array $aliases = [])
+    protected function mapFieldToPropertyPath($field, array $aliases = [])
     {
         $parts = explode('.', $field);
         if (count($parts) < 2) {

src/Resources/config/services.xml

@@ -12,6 +12,9 @@
         <service id="Omines\DataTablesBundle\Adapter\Doctrine\ORMAdapter">
             <argument type="service" id="doctrine" on-invalid="null" />
         </service>
+        <service id="Omines\DataTablesBundle\Adapter\Doctrine\FetchJoinORMAdapter">
+            <argument type="service" id="doctrine" on-invalid="null" />
+        </service>
 
         <!-- Columns -->
         <service id="Omines\DataTablesBundle\Column\TwigColumn">