public ThemeManager::render($hook, array $variables)
Generates themed output.
See the Default theme implementations topic for details.
Parameters
string $hook: The name of the theme hook to call.
array $variables: An associative array of theme variables.
Return value
string|\Drupal\Component\Render\MarkupInterface The rendered output, or a Markup object.
Overrides ThemeManagerInterface::render
File
- core/lib/Drupal/Core/Theme/ThemeManager.php, line 130
Class
- ThemeManager
- Provides the default implementation of a theme manager.
Namespace
Drupal\Core\Theme
Code
public function render($hook, array $variables) { static $default_attributes; $active_theme = $this->getActiveTheme(); // If called before all modules are loaded, we do not necessarily have a // full theme registry to work with, and therefore cannot process the theme // request properly. See also \Drupal\Core\Theme\Registry::get(). if (!$this->moduleHandler->isLoaded() && !defined('MAINTENANCE_MODE')) { throw new \Exception('The theme implementations may not be rendered until all modules are loaded.'); } $theme_registry = $this->themeRegistry->getRuntime(); // If an array of hook candidates were passed, use the first one that has an // implementation. if (is_array($hook)) { foreach ($hook as $candidate) { if ($theme_registry->has($candidate)) { break; } } $hook = $candidate; } // Save the original theme hook, so it can be supplied to theme variable // preprocess callbacks. $original_hook = $hook; // If there's no implementation, check for more generic fallbacks. // If there's still no implementation, log an error and return an empty // string. if (!$theme_registry->has($hook)) { // Iteratively strip everything after the last '__' delimiter, until an // implementation is found. while ($pos = strrpos($hook, '__')) { $hook = substr($hook, 0, $pos); if ($theme_registry->has($hook)) { break; } } if (!$theme_registry->has($hook)) { // Only log a message when not trying theme suggestions ($hook being an // array). if (!isset($candidate)) { \Drupal::logger('theme')->warning('Theme hook %hook not found.', array('%hook' => $hook)); } // There is no theme implementation for the hook passed. Return FALSE so // the function calling // \Drupal\Core\Theme\ThemeManagerInterface::render() can differentiate // between a hook that exists and renders an empty string, and a hook // that is not implemented. return FALSE; } } $info = $theme_registry->get($hook); // If a renderable array is passed as $variables, then set $variables to // the arguments expected by the theme function. if (isset($variables['#theme']) || isset($variables['#theme_wrappers'])) { $element = $variables; $variables = array(); if (isset($info['variables'])) { foreach (array_keys($info['variables']) as $name) { if (isset($element["#$name"]) || array_key_exists("#$name", $element)) { $variables[$name] = $element["#$name"]; } } } else { $variables[$info['render element']] = $element; // Give a hint to render engines to prevent infinite recursion. $variables[$info['render element']]['#render_children'] = TRUE; } } // Merge in argument defaults. if (!empty($info['variables'])) { $variables += $info['variables']; } elseif (!empty($info['render element'])) { $variables += array($info['render element'] => array()); } // Supply original caller info. $variables += array( 'theme_hook_original' => $original_hook, ); // Set base hook for later use. For example if '#theme' => 'node__article' // is called, we run hook_theme_suggestions_node_alter() rather than // hook_theme_suggestions_node__article_alter(), and also pass in the base // hook as the last parameter to the suggestions alter hooks. if (isset($info['base hook'])) { $base_theme_hook = $info['base hook']; } else { $base_theme_hook = $hook; } // Invoke hook_theme_suggestions_HOOK(). $suggestions = $this->moduleHandler->invokeAll('theme_suggestions_' . $base_theme_hook, array($variables)); // If the theme implementation was invoked with a direct theme suggestion // like '#theme' => 'node__article', add it to the suggestions array before // invoking suggestion alter hooks. if (isset($info['base hook'])) { $suggestions[] = $hook; } // Invoke hook_theme_suggestions_alter() and // hook_theme_suggestions_HOOK_alter(). $hooks = array( 'theme_suggestions', 'theme_suggestions_' . $base_theme_hook, ); $this->moduleHandler->alter($hooks, $suggestions, $variables, $base_theme_hook); $this->alter($hooks, $suggestions, $variables, $base_theme_hook); // Check if each suggestion exists in the theme registry, and if so, // use it instead of the base hook. For example, a function may use // '#theme' => 'node', but a module can add 'node__article' as a suggestion // via hook_theme_suggestions_HOOK_alter(), enabling a theme to have // an alternate template file for article nodes. foreach (array_reverse($suggestions) as $suggestion) { if ($theme_registry->has($suggestion)) { $info = $theme_registry->get($suggestion); break; } } // Include a file if the theme function or variable preprocessor is held // elsewhere. if (!empty($info['includes'])) { foreach ($info['includes'] as $include_file) { include_once $this->root . '/' . $include_file; } } // Invoke the variable preprocessors, if any. if (isset($info['base hook'])) { $base_hook = $info['base hook']; $base_hook_info = $theme_registry->get($base_hook); // Include files required by the base hook, since its variable // preprocessors might reside there. if (!empty($base_hook_info['includes'])) { foreach ($base_hook_info['includes'] as $include_file) { include_once $this->root . '/' . $include_file; } } if (isset($base_hook_info['preprocess functions'])) { // Set a variable for the 'theme_hook_suggestion'. This is used to // maintain backwards compatibility with template engines. $theme_hook_suggestion = $hook; } } if (isset($info['preprocess functions'])) { foreach ($info['preprocess functions'] as $preprocessor_function) { if (function_exists($preprocessor_function)) { $preprocessor_function($variables, $hook, $info); } } // Allow theme preprocess functions to set $variables['#attached'] and // $variables['#cache'] and use them like the corresponding element // properties on render arrays. In Drupal 8, this is the (only) officially // supported method of attaching bubbleable metadata from preprocess // functions. Assets attached here should be associated with the template // that we are preprocessing variables for. $preprocess_bubbleable = []; foreach (['#attached', '#cache'] as $key) { if (isset($variables[$key])) { $preprocess_bubbleable[$key] = $variables[$key]; } } // We do not allow preprocess functions to define cacheable elements. unset($preprocess_bubbleable['#cache']['keys']); if ($preprocess_bubbleable) { // @todo Inject the Renderer in https://www.drupal.org/node/2529438. drupal_render($preprocess_bubbleable); } } // Generate the output using either a function or a template. $output = ''; if (isset($info['function'])) { if (function_exists($info['function'])) { // Theme functions do not render via the theme engine, so the output is // not autoescaped. However, we can only presume that the theme function // has been written correctly and that the markup is safe. $output = Markup::create($info['function']($variables)); } } else { $render_function = 'twig_render_template'; $extension = '.html.twig'; // The theme engine may use a different extension and a different // renderer. $theme_engine = $active_theme->getEngine(); if (isset($theme_engine)) { if ($info['type'] != 'module') { if (function_exists($theme_engine . '_render_template')) { $render_function = $theme_engine . '_render_template'; } $extension_function = $theme_engine . '_extension'; if (function_exists($extension_function)) { $extension = $extension_function(); } } } // In some cases, a template implementation may not have had // template_preprocess() run (for example, if the default implementation // is a function, but a template overrides that default implementation). // In these cases, a template should still be able to expect to have // access to the variables provided by template_preprocess(), so we add // them here if they don't already exist. We don't want the overhead of // running template_preprocess() twice, so we use the 'directory' variable // to determine if it has already run, which while not completely // intuitive, is reasonably safe, and allows us to save on the overhead of // adding some new variable to track that. if (!isset($variables['directory'])) { $default_template_variables = array(); template_preprocess($default_template_variables, $hook, $info); $variables += $default_template_variables; } if (!isset($default_attributes)) { $default_attributes = new Attribute(); } foreach (array('attributes', 'title_attributes', 'content_attributes') as $key) { if (isset($variables[$key]) && !($variables[$key] instanceof Attribute)) { if ($variables[$key]) { $variables[$key] = new Attribute($variables[$key]); } else { // Create empty attributes. $variables[$key] = clone $default_attributes; } } } // Render the output using the template file. $template_file = $info['template'] . $extension; if (isset($info['path'])) { $template_file = $info['path'] . '/' . $template_file; } // Add the theme suggestions to the variables array just before rendering // the template for backwards compatibility with template engines. $variables['theme_hook_suggestions'] = $suggestions; // For backwards compatibility, pass 'theme_hook_suggestion' on to the // template engine. This is only set when calling a direct suggestion like // '#theme' => 'menu__shortcut_default' when the template exists in the // current theme. if (isset($theme_hook_suggestion)) { $variables['theme_hook_suggestion'] = $theme_hook_suggestion; } $output = $render_function($template_file, $variables); } return ($output instanceof MarkupInterface) ? $output : (string) $output; }
Please login to continue.