Add Settings Extender (#2452)

src/Extend/Settings.php

@@ -0,0 +1,63 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Extend;
+
+use Flarum\Api\Serializer\AbstractSerializer;
+use Flarum\Api\Serializer\ForumSerializer;
+use Flarum\Extension\Extension;
+use Flarum\Foundation\ContainerUtil;
+use Flarum\Settings\SettingsRepositoryInterface;
+use Illuminate\Contracts\Container\Container;
+
+class Settings implements ExtenderInterface
+{
+    private $settings = [];
+
+    /**
+     * Serialize a setting value to the ForumSerializer attributes.
+     *
+     * @param string $attributeName: The attribute name to be used in the ForumSerializer attributes array.
+     * @param string $key: The key of the setting.
+     * @param string|callable|null $callback: Optional callback to modify the value before serialization.
+     * @return $this
+     */
+    public function serializeToForum(string $attributeName, string $key, $callback = null)
+    {
+        $this->settings[$key] = compact('attributeName', 'callback');
+
+        return $this;
+    }
+
+    public function extend(Container $container, Extension $extension = null)
+    {
+        if (! empty($this->settings)) {
+            AbstractSerializer::addMutator(
+                ForumSerializer::class,
+                function () use ($container) {
+                    $settings = $container->make(SettingsRepositoryInterface::class);
+                    $attributes = [];
+
+                    foreach ($this->settings as $key => $setting) {
+                        $value = $settings->get($key, null);
+
+                        if (isset($setting['callback'])) {
+                            $callback = ContainerUtil::wrapCallback($setting['callback'], $container);
+                            $value = $callback($value);
+                        }
+
+                        $attributes[$setting['attributeName']] = $value;
+                    }
+
+                    return $attributes;
+                }
+            );
+        }
+    }
+}