Issue #3254011 by Luke.Leber: Allow more granular activation of module decorator

config/install/inline_all_css.settings.yml

+enabled: false
+enabled_themes: {  }

config/schema/inline_all_css.schema.yml

+inline_all_css.settings:
+  type: config_object
+  mapping:
+    enabled:
+      type: boolean
+      label: 'Transform external stylesheets into inline styles'
+    enabled_themes:
+      type: sequence
+      label: 'Enabled themes'
+      sequence:
+        type: string
+        label: 'Enabled theme'

inline_all_css.links.menu.yml

+inline_all_css.config:
+  title: Inline all css configuration
+  description: 'Configure inline all css.'
+  parent: system.admin_config_system
+  route_name: inline_all_css.config

inline_all_css.permissions.yml

+'administer inline all css':
+  title: 'Administer inline all css'
+  description: 'Administer inline all css settings.'
+  restrict access: true

inline_all_css.routing.yml

+inline_all_css.config:
+  path: '/admin/config/system/inline_all_css'
+  defaults:
+    _form: '\Drupal\inline_all_css\Form\SettingsForm'
+    _title: 'Inline all css configuration'
+  requirements:
+    _permission: 'administer inline all css'

inline_all_css.services.yml

@@ -4,5 +4,8 @@ services:
     class: Drupal\inline_all_css\Asset\CriticalCssCollectionRenderer
     decorates: asset.css.collection_renderer
     arguments:
+      - '@asset.css.collection_renderer.inline_all_css.inner'
+      - '@config.factory'
+      - '@theme.manager'
       - '@file_system'
       - '@event_dispatcher'

src/Asset/CriticalCssCollectionRenderer.php

@@ -3,8 +3,10 @@
 namespace Drupal\inline_all_css\Asset;
 
 use Drupal\Core\Asset\AssetCollectionRendererInterface;
+use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\File\FileSystemInterface;
 use Drupal\Core\Render\Markup;
+use Drupal\Core\Theme\ThemeManagerInterface;
 use Drupal\inline_all_css\Event\CssPreRenderEvent;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 use function file_get_contents;
@@ -16,6 +18,27 @@ use function file_get_contents;
  */
 class CriticalCssCollectionRenderer implements AssetCollectionRendererInterface {
 
+  /**
+   * The decorated collection renderer service.
+   *
+   * @var \Drupal\Core\Asset\AssetCollectionRendererInterface
+   */
+  protected $cssCollectionRenderer;
+
+  /**
+   * The module configuration.
+   *
+   * @var \Drupal\Core\Config\ImmutableConfig
+   */
+  protected $config;
+
+  /**
+   * The theme manager service.
+   *
+   * @var \Drupal\Core\Theme\ThemeManagerInterface
+   */
+  protected $themeManager;
+
   /**
    * The filesystem service.
    *
@@ -33,20 +56,35 @@ class CriticalCssCollectionRenderer implements AssetCollectionRendererInterface
   /**
    * Constructs a CriticalCssCollectionRenderer.
    *
+   * @param \Drupal\Core\Asset\AssetCollectionRendererInterface $css_collection_renderer
+   *   The decorated asset renderer service.
+   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
+   *   The config factory service.
+   * @param \Drupal\Core\Theme\ThemeManagerInterface $theme_manager
+   *   The theme manager service.
    * @param \Drupal\Core\File\FileSystemInterface $file_system
    *   The file system service.
    * @param \Symfony\Component\EventDispatcher\EventDispatcherInterface $event_dispatcher
    *   The event dispatcher service.
    */
-  public function __construct(FileSystemInterface $file_system, EventDispatcherInterface $event_dispatcher) {
+  public function __construct(AssetCollectionRendererInterface $css_collection_renderer, ConfigFactoryInterface $config_factory, ThemeManagerInterface $theme_manager, FileSystemInterface $file_system, EventDispatcherInterface $event_dispatcher) {
+    $this->cssCollectionRenderer = $css_collection_renderer;
+    $this->config = $config_factory->get('inline_all_css.settings');
+    $this->themeManager = $theme_manager;
     $this->fileSystem = $file_system;
     $this->eventDispatcher = $event_dispatcher;
   }
 
   /**
-   * {@inheritdoc}
+   * Generates an inline style element from the provided assets.
+   *
+   * @param array $assets
+   *   An asset collection.
+   *
+   * @return array
+   *   An inline style tag element.
    */
-  public function render(array $assets) {
+  protected function getInlineCss(array $assets) {
     $css = '';
     foreach ($assets as $asset) {
       $file = $this->fileSystem->realpath($asset['data']);
@@ -59,12 +97,33 @@ class CriticalCssCollectionRenderer implements AssetCollectionRendererInterface
     $css = $event->getCss();
 
     return [
-      [
-        '#type' => 'html_tag',
-        '#tag' => 'style',
-        '#value' => Markup::create($css),
-      ],
+      '#type' => 'html_tag',
+      '#tag' => 'style',
+      '#value' => Markup::create($css),
     ];
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function render(array $assets) {
+    $elements = [];
+
+    if ($this->config->get('enabled') === TRUE) {
+      $enabled_themes = $this->config->get('enabled_themes');
+      $active_theme = $this->themeManager->getActiveTheme()->getName();
+      if (empty($enabled_themes) || in_array($active_theme, $enabled_themes, TRUE)) {
+        $elements[] = $this->getInlineCss($assets);
+      }
+      else {
+        $elements = $this->cssCollectionRenderer->render($assets);
+      }
+    }
+    else {
+      $elements = $this->cssCollectionRenderer->render($assets);
+    }
+
+    return $elements;
+  }
+
 }

src/Form/SettingsForm.php

+<?php
+
+namespace Drupal\inline_all_css\Form;
+
+use Drupal\Core\Form\ConfigFormBase;
+use Drupal\Core\Form\FormStateInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Settings form for the inline all css module.
+ */
+class SettingsForm extends ConfigFormBase {
+
+  /**
+   * The theme handler service.
+   *
+   * @var \Drupal\Core\Extension\ThemeHandlerInterface
+   */
+  protected $themeHandler;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    $instance = parent::create($container);
+    $instance->themeHandler = $container->get('theme_handler');
+    return $instance;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getEditableConfigNames() {
+    return ['inline_all_css.settings'];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'inline_all_css_settings';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+    $config = $this->config('inline_all_css.settings');
+
+    $form['warning'] = [
+      '#type' => 'markup',
+      '#markup' => <<<HTML
+<p class="messages messages--warning">{$this->t('If there is a content security policy in place, please be sure to test this setting before enabling on production!')}</p>
+HTML,
+    ];
+
+    $form['enabled'] = [
+      '#type' => 'checkbox',
+      '#title' => $this->t('Enable'),
+      '#default_value' => $config->get('enabled'),
+    ];
+
+    $themes = $this->themeHandler->listInfo();
+    foreach ($themes as $k => $theme) {
+      $themes[$k] = $theme->getName();
+    }
+
+    $form['enabled_themes'] = [
+      '#type' => 'checkboxes',
+      '#title' => $this->t('Enabled themes'),
+      '#description' => $this->t('If no themes are selected, css will be inlined on all themes'),
+      '#options' => $themes,
+      '#multiple' => TRUE,
+      '#default_value' => $config->get('enabled_themes'),
+      '#states' => [
+        'visible' => [
+          ':input[name="enabled"]' => ['checked' => TRUE],
+        ],
+      ],
+    ];
+
+    return parent::buildForm($form, $form_state);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+    $config = $this->config('inline_all_css.settings');
+    $config->set('enabled', $form_state->getValue('enabled'));
+
+    $enabled_themes = $form_state->getValue('enabled_themes');
+
+    // Only take the values.
+    $enabled_themes = array_values($enabled_themes);
+
+    // Filter out any empties.
+    $enabled_themes = array_filter($enabled_themes);
+
+    $config->set('enabled_themes', $enabled_themes);
+    $config->save();
+    parent::submitForm($form, $form_state);
+  }
+
+}

tests/src/Functional/SettingsFormTest.php

+<?php
+
+namespace Drupal\Tests\inline_all_css\Functional;
+
+use Drupal\Core\Url;
+use Drupal\Tests\BrowserTestBase;
+
+/**
+ * Test cases for the settings form.
+ *
+ * @group inline_all_css
+ */
+class SettingsFormTest extends BrowserTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = [
+    'inline_all_css',
+  ];
+
+  /**
+   * Test case for the settings form.
+   */
+  public function testSettingsForm() {
+    $session = $this->getSession();
+
+    // Ensure that access is denied by default.
+    $this->drupalGet(Url::fromRoute('inline_all_css.config'));
+    static::assertEquals(403, $session->getStatusCode());
+
+    // Ensure that access is granted with the proper permission.
+    $this->drupalLogin($this->drupalCreateUser(['administer inline all css']));
+    $this->drupalGet(Url::fromRoute('inline_all_css.config'));
+    static::assertEquals(200, $session->getStatusCode());
+
+    $page = $session->getPage();
+    $assert = $this->assertSession();
+
+    // Ensure the proper initial form state.
+    $assert->pageTextContains('If there is a content security policy in place, please be sure to test this setting before enabling on production!');
+    $enabled = $page->findField('Enable');
+    static::assertFalse($enabled->isChecked());
+
+    // Save some settings.
+    $enabled->check();
+    $page->findField('stark')->check();
+    $page->findButton('Save configuration')->press();
+    $assert->pageTextContains('The configuration options have been saved.');
+
+    // Ensure that the new form state matches expectations.
+    $enabled = $page->findField('Enable');
+    $stark = $page->findField('stark');
+
+    static::assertTrue($enabled->isChecked());
+    static::assertTrue($stark->isChecked());
+
+    // Ensure that the configuration itself is in the right state.
+    $config = \Drupal::config('inline_all_css.settings');
+    static::assertTrue($config->get('enabled'));
+    static::assertEquals(['stark'], $config->get('enabled_themes'));
+  }
+
+}

tests/src/Unit/CssCollectionRendererTest.php

@@ -2,8 +2,13 @@
 
 namespace Drupal\Tests\inline_all_css\Unit;
 
+use Drupal\Core\Asset\AssetCollectionRendererInterface;
+use Drupal\Core\Config\Config;
+use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\File\FileSystemInterface;
 use Drupal\Core\Render\Markup;
+use Drupal\Core\Theme\ActiveTheme;
+use Drupal\Core\Theme\ThemeManagerInterface;
 use Drupal\inline_all_css\Asset\CriticalCssCollectionRenderer;
 use Drupal\inline_all_css\Event\CssPreRenderEvent;
 use Drupal\Tests\UnitTestCase;
@@ -16,6 +21,12 @@ use Symfony\Component\EventDispatcher\EventDispatcherInterface;
  */
 class CssCollectionRendererTest extends UnitTestCase {
 
+  protected const ASSETS = [
+    ['data' => 'public://test-1.css'],
+    ['data' => 'public://test-2.css'],
+    ['data' => 'public://test-3.css'],
+  ];
+
   /**
    * The subject under test.
    *
@@ -23,6 +34,27 @@ class CssCollectionRendererTest extends UnitTestCase {
    */
   protected $instance;
 
+  /**
+   * The mocked css collection renderer.
+   *
+   * @var \Drupal\Core\Asset\AssetCollectionRendererInterface|\PHPUnit\Framework\MockObject\MockObject
+   */
+  protected $cssCollectionRenderer;
+
+  /**
+   * The mocked theme manager service.
+   *
+   * @var \Drupal\Core\Theme\ThemeManagerInterface|\PHPUnit\Framework\MockObject\MockObject
+   */
+  protected $themeManager;
+
+  /**
+   * The mock config.
+   *
+   * @var \Drupal\Core\Config\Config
+   */
+  protected $config;
+
   /**
    * {@inheritdoc}
    */
@@ -48,25 +80,131 @@ class CssCollectionRendererTest extends UnitTestCase {
       ->willReturnCallback(static function (CssPreRenderEvent $event) {
         $css = $event->getCss();
         $css .= <<<CSS
-.event {
+p {
   color: gray;
 }
 CSS;
         $event->setCss($css);
       });
 
-    $this->instance = new CriticalCssCollectionRenderer($filesystem, $eventDispatcher);
+    $this->cssCollectionRenderer = $this->getMockBuilder(AssetCollectionRendererInterface::class)
+      ->disableOriginalConstructor()
+      ->getMock();
+
+    $this->themeManager = $this->getMockBuilder(ThemeManagerInterface::class)
+      ->disableOriginalConstructor()
+      ->getMock();
+
+    $config_factory = $this->getMockBuilder(ConfigFactoryInterface::class)
+      ->disableOriginalConstructor()
+      ->getMock();
+
+    $this->config = $this->getMockBuilder(Config::class)
+      ->disableOriginalConstructor()
+      ->getMock();
+
+    $config_factory
+      ->method('get')
+      ->willReturn($this->config);
+
+    $this->instance = new CriticalCssCollectionRenderer($this->cssCollectionRenderer, $config_factory, $this->themeManager, $filesystem, $eventDispatcher);
+  }
+
+  /**
+   * Sets the mock module configuration.
+   *
+   * @param bool $enabled
+   *   Should inlining be enabled?
+   * @param string[] $enabled_themes
+   *   An array of themes to enable inlining for.
+   */
+  protected function setConfig($enabled, array $enabled_themes) {
+    $this->config
+      ->method('get')
+      ->willReturnMap([
+        ['enabled', $enabled],
+        ['enabled_themes', $enabled_themes],
+      ]);
+  }
+
+  /**
+   * Sets the current active theme.
+   *
+   * @param string $theme
+   *   The theme to set.
+   */
+  protected function setActiveTheme($theme) {
+    $active_theme = $this->getMockBuilder(ActiveTheme::class)
+      ->disableOriginalConstructor()
+      ->getMock();
+
+    $active_theme
+      ->method('getName')
+      ->willReturn($theme);
+
+    $this->themeManager
+      ->method('getActiveTheme')
+      ->willReturn($active_theme);
+  }
+
+  /**
+   * Test case for when the enabled flag is not set.
+   */
+  public function testCssCollectionRendererDisabled() {
+    $this->setConfig(FALSE, []);
+
+    // The decorated service should be called.
+    $this->cssCollectionRenderer
+      ->expects(static::once())
+      ->method('render');
+
+    $this->instance->render(static::ASSETS);
+  }
+
+  /**
+   * Test case for when the enabled flag is set, but the theme is wrong.
+   */
+  public function testCssCollectionRendererWrongTheme() {
+    $this->setConfig(TRUE, ['some_theme']);
+
+    $this->setActiveTheme('a_different_theme');
+
+    // The decorated service should be called.
+    $this->cssCollectionRenderer
+      ->expects(static::once())
+      ->method('render');
+
+    $this->instance->render(static::ASSETS);
+  }
+
+  /**
+   * Test case for when the enabled flag is set and all themes are enabled.
+   */
+  public function testCssCollectionRendererAllThemes() {
+    $this->setConfig(TRUE, []);
+
+    $this->setActiveTheme('should_not_matter');
+
+    // The decorated service should be called.
+    $this->cssCollectionRenderer
+      ->expects(static::never())
+      ->method('render');
+
+    $this->instance->render(static::ASSETS);
   }
 
   /**
    * Test case for inline CSS rendering.
    */
-  public function testCssCollectionRenderer() {
-    $assets = [
-      ['data' => 'public://test-1.css'],
-      ['data' => 'public://test-2.css'],
-      ['data' => 'public://test-3.css'],
-    ];
+  public function testCssCollectionRendererEnabled() {
+
+    $this->setConfig(TRUE, ['my_theme']);
+    $this->setActiveTheme('my_theme');
+
+    // The decorated service should not be called.
+    $this->cssCollectionRenderer
+      ->expects(static::never())
+      ->method('render');
 
     $expected = [
       [
@@ -82,13 +220,13 @@ html {
 body {
   color: blue;
 }
-.event {
+p {
   color: gray;
 }
 CSS),
       ],
     ];
-    $actual = $this->instance->render($assets);
+    $actual = $this->instance->render(static::ASSETS);
 
     static::assertEquals($expected, $actual);
   }