feat: Allow registering settings as Less config vars through Settings Extender (#3011)

Co-authored-by: Alexander Skvortsov <38059171+askvortsov1@users.noreply.github.com>

framework/core/src/Extend/Settings.php

@@ -21,6 +21,7 @@ class Settings implements ExtenderInterface
 {
     private $settings = [];
     private $defaults = [];
+    private $lessConfigs = [];
 
     /**
      * Serialize a setting value to the ForumSerializer attributes.
@@ -61,6 +62,28 @@ class Settings implements ExtenderInterface
         return $this;
     }
 
+    /**
+     * Register a setting as a LESS configuration variable.
+     *
+     * @param string $configName: The name of the configuration variable, in hyphen case.
+     * @param string $key: The key of the setting.
+     * @param string|callable|null $callback: Optional callback to modify the value.
+     *
+     * The callback can be a closure or an invokable class, and should accept:
+     * - mixed $value: The value of the setting.
+     *
+     * The callable should return:
+     * - mixed $value: The modified value.
+     *
+     * @return self
+     */
+    public function registerLessConfigVar(string $configName, string $key, $callback = null): self
+    {
+        $this->lessConfigs[$configName] = compact('key', 'callback');
+
+        return $this;
+    }
+
     public function extend(Container $container, Extension $extension = null)
     {
         if (! empty($this->defaults)) {
@@ -97,5 +120,19 @@ class Settings implements ExtenderInterface
                 }
             );
         }
+
+        if (! empty($this->lessConfigs)) {
+            $container->extend('flarum.less.config', function (array $existingConfig, Container $container) {
+                $config = $this->lessConfigs;
+
+                foreach ($config as $var => $data) {
+                    if (isset($data['callback'])) {
+                        $config[$var]['callback'] = ContainerUtil::wrapCallback($data['callback'], $container);
+                    }
+                }
+
+                return array_merge($existingConfig, $config);
+            });
+        }
     }
 }

framework/core/src/Forum/ForumServiceProvider.php

@@ -163,7 +163,8 @@ class ForumServiceProvider extends AbstractServiceProvider
                 $validator = new ValidateCustomLess(
                     $container->make('flarum.assets.forum'),
                     $container->make('flarum.locales'),
-                    $container
+                    $container,
+                    $container->make('flarum.less.config')
                 );
                 $validator->whenSettingsSaved($event);
             }
@@ -175,7 +176,8 @@ class ForumServiceProvider extends AbstractServiceProvider
                 $validator = new ValidateCustomLess(
                     $container->make('flarum.assets.forum'),
                     $container->make('flarum.locales'),
-                    $container
+                    $container,
+                    $container->make('flarum.less.config')
                 );
                 $validator->whenSettingsSaving($event);
             }

framework/core/src/Forum/ValidateCustomLess.php

@@ -43,20 +43,21 @@ class ValidateCustomLess
     protected $container;
 
     /**
-     * @param Assets $assets
+     * @var array
-     * @param LocaleManager $locales
-     * @param Container $container
      */
-    public function __construct(Assets $assets, LocaleManager $locales, Container $container)
+    protected $customLessSettings;
+
+    public function __construct(Assets $assets, LocaleManager $locales, Container $container, array $customLessSettings = [])
     {
         $this->assets = $assets;
         $this->locales = $locales;
         $this->container = $container;
+        $this->customLessSettings = $customLessSettings;
     }
 
     public function whenSettingsSaving(Saving $event)
     {
-        if (! isset($event->settings['custom_less'])) {
+        if (! isset($event->settings['custom_less']) && ! $this->hasDirtyCustomLessSettings($event)) {
             return;
         }
 
@@ -95,7 +96,7 @@ class ValidateCustomLess
 
     public function whenSettingsSaved(Saved $event)
     {
-        if (! isset($event->settings['custom_less'])) {
+        if (! isset($event->settings['custom_less']) && ! $this->hasDirtyCustomLessSettings($event)) {
             return;
         }
 
@@ -105,4 +106,24 @@ class ValidateCustomLess
             $this->assets->makeLocaleCss($locale)->flush();
         }
     }
+
+    /**
+     * @param Saved|Saving $event
+     * @return bool
+     */
+    protected function hasDirtyCustomLessSettings($event): bool
+    {
+        if (empty($this->customLessSettings)) {
+            return false;
+        }
+
+        $dirtySettings = array_intersect(
+            array_keys($event->settings),
+            array_map(function ($setting) {
+                return $setting['key'];
+            }, $this->customLessSettings)
+        );
+
+        return ! empty($dirtySettings);
+    }
 }

framework/core/src/Frontend/FrontendServiceProvider.php

@@ -106,6 +106,29 @@ class FrontendServiceProvider extends AbstractServiceProvider
                 ];
             }
         );
+
+        $this->container->singleton('flarum.less.config', function (Container $container) {
+            return [
+                'config-primary-color'   => [
+                    'key' => 'theme_primary_color',
+                ],
+                'config-secondary-color' => [
+                    'key' => 'theme_secondary_color',
+                ],
+                'config-dark-mode'       => [
+                    'key' => 'theme_dark_mode',
+                    'callback' => function ($value) {
+                        return $value ? 'true' : 'false';
+                    },
+                ],
+                'config-colored-header'  => [
+                    'key' => 'theme_colored_header',
+                    'callback' => function ($value) {
+                        return $value ? 'true' : 'false';
+                    },
+                ],
+            ];
+        });
     }
 
     /**
@@ -132,17 +155,18 @@ class FrontendServiceProvider extends AbstractServiceProvider
     private function addLessVariables(SourceCollector $sources)
     {
         $sources->addString(function () {
+            $vars = $this->container->make('flarum.less.config');
             $settings = $this->container->make(SettingsRepositoryInterface::class);
 
-            $vars = [
+            return array_reduce(array_keys($vars), function ($string, $name) use ($vars, $settings) {
-                'config-primary-color'   => $settings->get('theme_primary_color', '#000'),
+                $var = $vars[$name];
-                'config-secondary-color' => $settings->get('theme_secondary_color', '#000'),
+                $value = $settings->get($var['key'], $var['default'] ?? null);
-                'config-dark-mode'       => $settings->get('theme_dark_mode') ? 'true' : 'false',
-                'config-colored-header'  => $settings->get('theme_colored_header') ? 'true' : 'false'
-            ];
 
-            return array_reduce(array_keys($vars), function ($string, $name) use ($vars) {
+                if (isset($var['callback'])) {
-                return $string."@$name: {$vars[$name]};";
+                    $value = $var['callback']($value);
+                }
+
+                return $string."@$name: {$value};";
             }, '');
         });
     }

framework/core/src/Frontend/RecompileFrontendAssets.php

@@ -39,6 +39,7 @@ class RecompileFrontendAssets
 
     public function whenSettingsSaved(Saved $event)
     {
+        // @deprecated 'theme_' check, to be removed in 2.0
         if (preg_grep('/^theme_/i', array_keys($event->settings))) {
             $this->flushCss();
         }

framework/core/src/Settings/SettingsServiceProvider.php

@@ -22,7 +22,10 @@ class SettingsServiceProvider extends AbstractServiceProvider
     public function register()
     {
         $this->container->singleton('flarum.settings.default', function () {
-            return new Collection();
+            return new Collection([
+                'theme_primary_color' => '#4D698E',
+                'theme_secondary_color' => '#4D698E',
+            ]);
         });
 
         $this->container->singleton(SettingsRepositoryInterface::class, function (Container $container) {

framework/core/tests/fixtures/less/config.less

@@ -0,0 +1,3 @@
+body {
+  --custom-config-setting: @custom-config-setting;
+}

framework/core/tests/integration/extenders/SettingsTest.php

@@ -220,6 +220,61 @@ class SettingsTest extends TestCase
 
         $this->assertEquals(null, $value);
     }
+
+    /**
+     * @test
+     */
+    public function custom_less_var_does_not_work_by_default()
+    {
+        $this->extend(
+            (new Extend\Frontend('forum'))
+                ->css(__DIR__.'/../../fixtures/less/config.less'),
+        );
+
+        $response = $this->send($this->request('GET', '/'));
+
+        $this->assertEquals(500, $response->getStatusCode());
+    }
+
+    /**
+     * @test
+     */
+    public function custom_less_var_works_if_registered()
+    {
+        $this->extend(
+            (new Extend\Frontend('forum'))
+                ->css(__DIR__.'/../../fixtures/less/config.less'),
+            (new Extend\Settings())
+                ->registerLessConfigVar('custom-config-setting', 'custom-prefix.custom_setting')
+        );
+
+        $response = $this->send($this->request('GET', '/'));
+
+        $cssFilePath = $this->app()->getContainer()->make('filesystem')->disk('flarum-assets')->path('forum.css');
+        $this->assertStringContainsString('--custom-config-setting:customValue', file_get_contents($cssFilePath));
+
+        $this->assertEquals(200, $response->getStatusCode());
+    }
+
+    /**
+     * @test
+     */
+    public function cant_save_setting_if_invalid_less_var()
+    {
+        $this->extend(
+            (new Extend\Settings())
+                ->registerLessConfigVar('custom-config-setting2', 'custom-prefix.custom_setting2')
+        );
+
+        $response = $this->send($this->request('POST', '/api/settings', [
+            'authenticatedAs' => 1,
+            'json' => [
+                'custom-prefix.custom_setting2' => '@muralf'
+            ],
+        ]));
+
+        $this->assertEquals(422, $response->getStatusCode());
+    }
 }
 
 class CustomInvokableClass