Implement Regex on SQLite platform using a callback to PHP.

src/Doctrine/SQLiteRegexExtension.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace App\Doctrine;
+
+use Doctrine\Bundle\DoctrineBundle\EventSubscriber\EventSubscriberInterface;
+use Doctrine\DBAL\Event\ConnectionEventArgs;
+use Doctrine\DBAL\Events;
+use Doctrine\DBAL\Platforms\SqlitePlatform;
+
+/**
+ * This subscriber is used to add the regexp operator to the SQLite platform.
+ * As a PHP callback is called for every entry to compare it is most likely much slower than using regex on MySQL.
+ * But as regex is not often used, this should be fine for most use cases, also it is almost impossible to implement a better solution.
+ */
+class SQLiteRegexExtension implements EventSubscriberInterface
+{
+    public function postConnect(ConnectionEventArgs $eventArgs): void
+    {
+        $connection = $eventArgs->getConnection();
+
+        //We only execute this on SQLite databases
+        if ($connection->getDatabasePlatform() instanceof SqlitePlatform) {
+            $native_connection = $connection->getNativeConnection();
+
+            //Ensure that the function really exists on the connection, as it is marked as experimental according to PHP documentation
+            if($native_connection instanceof \PDO && method_exists($native_connection, 'sqliteCreateFunction' )) {
+                $native_connection->sqliteCreateFunction('REGEXP', function ($pattern, $value) {
+                    return (false !== mb_ereg($pattern, $value)) ? 1 : 0;
+                });
+            }
+        }
+    }
+
+    public function getSubscribedEvents()
+    {
+        return[
+            Events::postConnect
+        ];
+    }
+}