TASK: add migration to convert all node uriPathSegment to lowercase

Classes/Migration/Transformation/PropertyValueToLowercase.php

@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Flowpack\SeoRouting\Migration\Transformation;
+
+use Neos\ContentRepository\Domain\Model\NodeData;
+use Neos\ContentRepository\Migration\Transformations\AbstractTransformation;
+
+class PropertyValueToLowercase extends AbstractTransformation
+{
+    private string $propertyName;
+
+    public function setProperty(string $propertyName): void
+    {
+        $this->propertyName = $propertyName;
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function isTransformable(NodeData $node)
+    {
+        return $node->hasProperty($this->propertyName);
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function execute(NodeData $node)
+    {
+        $currentPropertyValue = $node->getProperty($this->propertyName);
+        if (! is_string($currentPropertyValue)) {
+            return $node;
+        }
+        $newPropertyValue = strtolower($currentPropertyValue);
+        $node->setProperty($this->propertyName, $newPropertyValue);
+
+        return $node;
+    }
+}

Migrations/ContentRepository/Version20250124153030.yaml

@@ -0,0 +1,16 @@
+up:
+  comments: 'Transforms all uriPathSegment values to lowercase'
+  warnings: 'As this migration removes the distinction between uppercase and lowercase it might not be cleanly undone by the down migration.'
+  migration:
+    - filters:
+        - type: 'NodeType'
+          settings:
+            nodeType: 'Neos.Neos:Document'
+            withSubTypes: TRUE
+      transformations:
+        - type: 'Flowpack\SeoRouting\Migration\Transformation\PropertyValueToLowercase'
+          settings:
+            property: 'uriPathSegment'
+
+down:
+  comments: 'No down migration available'

README.md

@@ -43,6 +43,12 @@ Just require it via composer:
 
 `composer require flowpack/seo-routing`
 
+If you want to use the *toLowerCase* feature you should execute the migration that comes with this package:
+
+`./flow node:migrate 20250124153030 --confirmation true`
+
+This migration transforms all the URLs of all your nodes to lowercase. It's irreversible.
+
 ## Configuration
 
 ### Standard Configuration
@@ -52,7 +58,8 @@ with / at the end) and do all redirects with a 301 http status.
 
 *Note: The lowercase redirect is deactivated by default, because you have to make sure, that there is
 no Neos page with an `uriPathSegment` with camelCase or upperspace letters - this would lead to redirects in the
-neverland.*
+neverland. You can achieve this by running the migration that ships with this package,
+see [installation](#installation).*
 
 ```
 Flowpack: