This document compares Drupal 7 and Drupal 8. Some key differences include Drupal 8 requiring PHP 5.3.10 instead of 5.2.4, using a Composer autoloader instead of includes, and handling requests through a Symfony kernel instead of hook_bootstrapping. Drupal 8 also uses more Symfony components like events and services. The rendering process is updated with new classes like HtmlPage and HtmlFragment. Drupal 8 removes hook_menu() and replaces it with routing files and services.

1. Drupal 7 vs 8
Andy Postnikov
Freelancer
&
Alexey Gaydabura
Lead Developer at @SkillD
Lviv, 2013
http://www.skilld.fr

2. Installer makeup

3. Drupal 7 - install.php
if (version_compare(PHP_VERSION, '5.2.4') < 0) {
exit;
}
Drupal 8 - install.php
chdir('..');
require_once __DIR__ . '/vendor/autoload.php';
if (version_compare(PHP_VERSION, '5.3.10') < 0) {
exit;
}
if (ini_get('safe_mode')) {
print 'Your PHP installation has safe_mode enabled.
...';
exit;
}

4. Drupal 7 - index.php
define('DRUPAL_ROOT', getcwd());
require_once DRUPAL_ROOT . '/includes/bootstrap.inc';
drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);
menu_execute_active_handler();
Drupal 8 - index.php
require_once __DIR__ . '/core/vendor/autoload.php';
require_once __DIR__ . '/core/includes/bootstrap.inc';
try {
drupal_handle_request();
}
catch (Exception $e) {
print 'If you have ... read http://drupal.org/documentation/rebuild';
throw $e;
}

5. Drupal 7 - Bootstrap
1. DRUPAL_BOOTSTRAP_CONFIGURATION
2. DRUPAL_BOOTSTRAP_PAGE_CACHE
3. DRUPAL_BOOTSTRAP_DATABASE
4. DRUPAL_BOOTSTRAP_VARIABLES
5. DRUPAL_BOOTSTRAP_SESSION
6. DRUPAL_BOOTSTRAP_PAGE_HEADER
7. DRUPAL_BOOTSTRAP_LANGUAGE
8. DRUPAL_BOOTSTRAP_FULL

6. Drupal 8 - Bootstrap
1. DRUPAL_BOOTSTRAP_CONFIGURATION
+ DRUPAL_BOOTSTRAP_KERNEL
2. DRUPAL_BOOTSTRAP_PAGE_CACHE
3. DRUPAL_BOOTSTRAP_DATABASE
DRUPAL_BOOTSTRAP_VARIABLES
- DRUPAL_BOOTSTRAP_SESSION
- DRUPAL_BOOTSTRAP_PAGE_HEADER
- DRUPAL_BOOTSTRAP_LANGUAGE
+ DRUPAL_BOOTSTRAP_CODE
DRUPAL_BOOTSTRAP_FULL (language + theme)
Should be 3 steps - https://drupal.org/node/2023495

7. Drupal 7: Menu page callback
$result = _menu_site_is_offline()
? MENU_SITE_OFFLINE :
MENU_SITE_ONLINE;
drupal_alter('menu_site_status', $result, ...);
$result = call_user_func_array( $router['page_callback'],
$router['page_arguments']);
drupal_alter('page_delivery_callback',
$delivery_callback);
drupal_deliver_html_page()
drupal_render_page() - hook_page_build() + hook_page()
drupal_page_footer()

8. Drupal 8: Symfony drupal_handle_request()
// Initialize the environment, load settings.php, and activate a PSR-0 class
// autoloader with required namespaces registered.
drupal_bootstrap(DRUPAL_BOOTSTRAP_CONFIGURATION);
$kernel = new DrupalKernel('prod', drupal_classloader(),
!$test_only);
// @todo Remove this once everything in the bootstrap has been
//
converted to services in the DIC.
$kernel->boot();
drupal_bootstrap(DRUPAL_BOOTSTRAP_CODE);
// Create a request object from the HttpFoundation.
$request = Request::createFromGlobals();
$response = $kernel->handle($request)
->prepare($request)->send();
$kernel->terminate($request, $response);

9. D7: Hook, alter, preprocess!
●
●
●
●
●
Core hooks
Custom hooks
Alter everything
Preprocess anything
Theme suggestions
You are the King!

10. D8: Hook, alter, preprocess!
+ Subscribe
●
●
●
●
●
●
Kernel & Routing events
Core hooks
Custom hooks
Alter everything
Preprocess anything
Theme suggestions ++
You are the King!

11. D8: Subscribe kernel
namespace SymfonyComponentHttpKernel;
final class KernelEvents
●
●
●
●
●
●
REQUEST - hook_boot()
CONTROLLER - menu “page callback”
VIEW - hook_page_build()
RESPONSE - hook_page_alter()
TERMINATE - hook_exit()
EXCEPTION

12. D8: Subscribe routing
namespace DrupalCoreRouting;
final class RoutingEvents {
const ALTER = 'routing.route_alter';
const DYNAMIC = 'routing.route_dynamic';
}

13. D8: Subscribe and alter
namespace DrupalCoreEventSubscriber;
class AccessSubscriber implements EventSubscriberInterface {
static function getSubscribedEvents() {
$events[KernelEvents::REQUEST][] = array
('onKernelRequestAccessCheck', 30);
// Setting very low priority to ensure access checks are run after alters.
$events[RoutingEvents::ALTER][] = array
('onRoutingRouteAlterSetAccessCheck', -50);
return $events;
}
}

14. D8: Subscribe

15. D8: Hook, alter, preprocess
function telephone_field_info_alter(&$info) {
if (Drupal::moduleHandler()->moduleExists('text')) {
$info['telephone']['default_formatter'] = 'text_plain';
}
}
function telephone_field_formatter_info_alter(&$info) {
if (isset($info['text_plain'])) {
$info['text_plain']['field_types'][] = 'telephone';
}
}

16. D7: My.module vs altering
●
hook_menu()
$items['mypath'] = array(
'page callback' => 'mypath_page_view'
'theme callback' => 'theme_mypath_page_view'
'delivery callback' => 'deliver_mypath_page_view'
●
●
hook_theme()
mypath_page_view($arg);
VS
●
●
●
●
hook_menu_alter()
hook_theme_registry_alter()
mycore_page_view()
mycore_page_theme()

17. D7: My.module hook_menu()
1.
2.
3.
4.
5.
6.
Routing
Menu links
Local actions
Local tasks
Breadcrumbs
Contextual links

18. D8: My.module NO hook_menu()
1.
my.routing.yml
2.
my_default_menu_links()
3.
my.local_actions.yml
4.
my.local_tasks.yml
5.
class MyBreadcrumbBuilder
6.
my.contextual_links.yml
7.
my.services.yml

19. D8: My.module vs altering
hook_”world”_alter() - THE SAME!
class MyEventSubscriber implements
EventSubscriberInterface
{ public static function getSubscribedEvents(); }
class MyServiceProvider implements
ServiceProviderInterface, ServiceModifierInterface
{
public function register(ContainerBuilder $container) {}
public function alter(ContainerBuilder $container) {}
}

20. D8: Services & Managers

21. D7 vs D8: render
Render array (‘#theme’ => ‘item_list’,‘#items’ => array())
https://drupal.org/node/2068471
+
$events[KernelEvents::VIEW][] = array('onHtmlFragment', 100);
+
$events[KernelEvents::VIEW][] = array('onHtmlPage', 50);
class Link extends HeadElement
class Metatag extends HeadElement
class HeadElement
class HtmlPage extends HtmlFragment
class HtmlFragment

22. When it’s ready™?
https://drupal.org/node/2107085
http://xjm.drupalgardens.com/blog/when-its-ready
no more hook_menu()
no more variable_get()
complete language negotiation
complete entity field api

23. Questions?

24. Drupal 7 vs 8
Anderey Postnikov
Alexey Gaydabura
Freelance Developer
Skype: andypost
E-mail: apostnikov@gmail.com
Lead Developer at @SkillD
Skype: alexey.gaydabura
E-mail: gaydabura@gmail.com
http://www.skilld.fr