function render_example_preprocess_page in Examples for Developers 3.x
Same name and namespace in other branches
- 8 render_example/render_example.module \render_example_preprocess_page()
Implements hook_preprocess_page().
Demonstrates using a preprocess function to alter the renderable array that represents the page currently being viewed.
Related topics
File
- modules/
render_example/ render_example.module, line 95 - Demonstrates using Drupal's Render API.
Code
function render_example_preprocess_page(&$variables) {
// Only modify the 'altering' page.
if (\Drupal::routeMatch()
->getRouteName() !== 'render_example.altering') {
return;
}
$config = \Drupal::config('render_example.settings');
// Preprocess hooks are invoked by the theme layer, and are used to give
// modules a chance to manipulate the variables that are going to be made
// available to a specific template file. Since content is still defined as
// renderable arrays at this point you can do quite a bit to manipulate the
// eventual output by altering these arrays.
//
// The $page variable in this case contains the complete content of the page
// including all regions, and the blocks placed within each region.
//
// The actual process of converting a renderable array to HTML is started when
// this variable is printed out within a Twig template. Drupal's Twig
// extension provides a wrapper around the Twig code that prints out variables
// which checks to see if the variable being printed is a renderable array and
// passes it through \Drupal\Core\Render\RendererInterface::render() before
// printing it to the screen.
$page =& $variables['page'];
// Move the breadcrumbs into the content area.
if ($config
->get('move_breadcrumbs') && !empty($page['breadcrumb']) && !empty($page['content'])) {
$page['content']['breadcrumb'] = $page['breadcrumb'];
unset($page['breadcrumb']);
$page['content']['breadcrumb']['#weight'] = -99999;
// Force the content to be re-sorted.
$page['content']['#sorted'] = FALSE;
}
// Re-sort the contents of the sidebar in reverse order.
if ($config
->get('reverse_sidebar') && !empty($page['sidebar_first'])) {
$page['sidebar_first'] = array_reverse($page['sidebar_first']);
foreach (Element::children($page['sidebar_first']) as $element) {
// Reverse the weights if they exist.
if (!empty($page['sidebar_first'][$element]['#weight'])) {
$page['sidebar_first'][$element]['#weight'] *= -1;
}
}
// This forces the sidebar to be re-sorted.
$page['sidebar_first']['#sorted'] = FALSE;
}
// Show the render array used to build the current page.
// This relies on the Devel module's variable dumper service.
// https://wwww.drupal.org/project/devel
if (Drupal::moduleHandler()
->moduleExists('devel') && $config
->get('show_page')) {
$page['content']['page_render_array'] = [
'#type' => 'markup',
'#prefix' => '<h2>' . t('The page render array') . '</h2>',
// The devel.dumper service is provided by the devel module and makes for
// and easier to read var_dump(). Especially if the companion Kint module
// is enabled.
'dump' => \Drupal::service('devel.dumper')
->exportAsRenderable($page, '$page'),
'#weight' => -99999,
];
$page['content']['#sorted'] = FALSE;
}
}