Basic short-úrl import implementation

module/Core/src/Util/DoctrineBatchIterator.php

@@ -0,0 +1,67 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shlinkio\Shlink\Core\Util;
+
+use Doctrine\ORM\EntityManagerInterface;
+use IteratorAggregate;
+use Throwable;
+
+/**
+ * Inspired by ocramius/doctrine-batch-utils https://github.com/Ocramius/DoctrineBatchUtils
+ */
+class DoctrineBatchIterator implements IteratorAggregate
+{
+    private iterable $resultSet;
+    private EntityManagerInterface $em;
+    private int $batchSize;
+
+    public function __construct(iterable $resultSet, EntityManagerInterface $em, int $batchSize)
+    {
+        $this->resultSet = $resultSet;
+        $this->em = $em;
+        $this->batchSize = $batchSize;
+    }
+
+    /**
+     * @throws Throwable
+     */
+    public function getIterator(): iterable
+    {
+        $iteration = 0;
+        $resultSet = $this->resultSet;
+
+        $this->em->beginTransaction();
+
+        try {
+            foreach ($resultSet as $key => $value) {
+                $iteration++;
+                yield $key => $value;
+                $this->flushAndClearBatch($iteration);
+            }
+        } catch (Throwable $e) {
+            $this->em->rollback();
+
+            throw $e;
+        }
+
+        $this->flushAndClearEntityManager();
+        $this->em->commit();
+    }
+
+    private function flushAndClearBatch(int $iteration): void
+    {
+        if ($iteration % $this->batchSize) {
+            return;
+        }
+
+        $this->flushAndClearEntityManager();
+    }
+
+    private function flushAndClearEntityManager(): void
+    {
+        $this->em->flush();
+        $this->em->clear();
+    }
+}