Drupal8 modernization (new object-oriented base) and adoption of many Symfony components is a huge step in connecting these two amazing communities and amazing projects. Drupal8 is not powered by full-stack Symfony and there is still many differences between these two relatives, but still, Symfony developers should master it easily.
This talk is for Symfony developers who don't have experience with Drupal8. It will guide you through routing, controllers, hooks, events, Drupal Console, DI and many other interesting elements that power Drupal8 under the hood. It will also show how to build custom modules Symfony way.
2. @antonioperic
About me
• Antonio Perić-Mažar, mag. ing. comp.
• CEO, Co-Founder @ Locastic
• Co-Founder @ Shift Conference
• Software developer, Symfony2
• Open Source Contributor
• SFUGCRO
• www.locastic.com
• antonio@locastic.com
• @antonioperic
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Locastic
• We help clients create amazing web and mobile apps (since 2011)
• design and development agency
• mobile development
• web development
• UX/UI
• Training and Consulting
• Shift Conference, Symfony Croatia
• www.locastic.com
• @locastic
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What this means
• Drupal8 doesn’t use full stack Symfony, it uses components (maybe in future)
• Moving Drupal to modern stack
• Building powerful CMS on top of Symfony components
• More learning for Drupal developers (OOP, Symfony, new concepts)
• Connecting two big communities
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Who is it for?
• Content strategist
• Site Administrators
• Content editors
• “Build stuff without writing code”
• v8.3.2
• Professional developers
• Bespoke applications
• “Make writing code easier”
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In Drupal 8 there's three different types of
knowledge that you're going to be using in
order to work with it effectively.
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Lets use composer
• drupal/drupal.
• This uses Drupal itself as a template for the new site. It is the simplest
solution but lacks additional configuration that can be helpful.
• drupal-composer/drupal-project.
• This open source project acts as a kickstarter for Composer-based Drupal
sites. It provides default configuration that otherwise needs to be added
manually.
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What happens when request
enters Drupal
1. Bootstrap configuration:
◦Read the settings.php file, generate some other settings dynamically, and store
them both in global variables and the DrupalComponentUtilitySettings singleton
object.
◦Start the class loader, that takes care of loading classes.
◦Set the Drupal error handler.
◦Detect if Drupal is actually installed. If it is not, redirect to the installer script.
2. Create the Drupal kernel.
3. Initialize the service container (either from cache or from rebuild).
4. Add the container to the Drupal static class.
5. Attempt to serve page from static page cache (just like Drupal 7).
6. Load all variables (variable_get).
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What happens when request
enters Drupal
7. Load other necessary (procedural) include files.
8. Register stream wrappers (public://, private://, temp:// and custom
wrappers).
9. Create the HTTP Request object (using the Symfony HttpFoundation
component).
10. Let the DrupalKernel handle it and return a response.
11. Send the response.
12. Terminate the request (modules can act upon this event).
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Pipeline
1. After the controller returned a render array, the VIEW will be triggered by the HttpKernel, because
the controller result is not a Response, but a render array.
2. MainContentViewSubscriber is subscribed to the VIEW event. It checks whether the controller
result is an array, and if so, it guarantees to generate a Response.
3. Next, MainContentViewSubscriber checks whether the negotiated request format is supported:
1. Any format for which a main content renderer service exists (an implementation of
MainContentRendererInterface is supported.
2. If the negotiated request format is not supported, a 406 JSON response is generated, which lists
the supported formats in a machine-readable way (as per RFC 2616, section 10.4.7).
4. Otherwise, when the negotiated request format is supported, the corresponding main content
renderer service is initialized. A response is generated by calling
MainContentRendererInterface::renderResponse() on the service. That's it
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Available “defaults” keys
• _controller
The specified method is simply called with the specified route parameters, and is
expected to return a response.
• _content
If specified, the _controller is set based on the request's mime type, and fills the
content of the response with the result of the specified method (usually a string or
render array).
• _form
If specified, the _controller is set to HtmlFormController::content, which responds with
the specified form. This form must be a fully qualified class name (or service id) that
implements FormInterface and usually extends FormBase. Indeed, form building has
also become object oriented!
• _entity_form
If specified, the _controller is set to HtmlEntityFormController::content, which
responds with the specified entity form (specified as {entity_type}.{add|edit|delete}).
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Available “defaults” keys
• _controller
The specified method is simply called with the specified route parameters, and is
expected to return a response.
• _content
If specified, the _controller is set based on the request's mime type, and fills the
content of the response with the result of the specified method (usually a string or
render array).
• _form
If specified, the _controller is set to HtmlFormController::content, which responds with
the specified form. This form must be a fully qualified class name (or service id) that
implements FormInterface and usually extends FormBase. Indeed, form building has
also become object oriented!
• _entity_form
If specified, the _controller is set to HtmlEntityFormController::content, which
responds with the specified entity form (specified as {entity_type}.{add|edit|delete}).
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Available “requirements” keys
• _permission
The current user must have the specified permission.
• _role
The current user must have the specified role.
• _method
The allowed HTTP methods (GET, POST, etc).
• _scheme
Set to https or http. The request scheme must be the same as the specified scheme. This
property is also taken into account when generating urls (Drupal::url(..)) rather than routing.
If set, urls will have this scheme set fixed.
• _node_add_access
A custom access check for adding new nodes of some node type.
• _entity_access
A generic access checker for entities.
• _format
Mime type formats
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Registering event subscribers
Here are the steps to register an event subscriber:
Define a service in your module, tagged with 'event_subscriber' (see the Services topic for instructions).
Define a class for your subscriber service that implements SymfonyComponentEventDispatcherEventSubscriberInterface
In your class, the getSubscribedEvents method returns a list of the events this class is subscribed to, and which methods on the class
should be called for each one. Example:
public static function getSubscribedEvents() {
// Subscribe to kernel terminate with priority 100.
$events[KernelEvents::TERMINATE][] = array('onTerminate', 100);
// Subscribe to kernel request with default priority of 0.
$events[KernelEvents::REQUEST][] = array('onRequest');
return $events;
}
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Recap
• Symfony components are main building tool for D8
• DIC is backbone of Drupal
• DI for controllers is very easy
• Events are replacing hooks
• Building custom module is easy
• Hardest thing is to start
• This is just beginning there is a lot to learn about and from D8