You've seen Kris' open source libraries, but how does he tackle coding out an application? Walk through green fields with a Symfony expert as he takes his latest “next big thing” idea from the first line of code to a functional prototype. Learn design patterns and principles to guide your way in organizing your own code and take home some practical examples to kickstart your next project.

1. How Kris Writes Symfony Apps

2. Mapping Layers

3. thin

4. thin controller fat model

5. MVC

6. Is Symfony an MVC framework?

7. HTTP

8. Symfony is an HTTP framework

9. Application Land
Controller
HTTP Land

10. The controller is thin
because it maps from
HTTP-land to application-land.

11. What about the model?

12. Persistence Land
Model
Application Land

13. The model maps from
application-land to persistence-land.

14. Persistence Land
Model
Application Land
Controller
HTTP Land

15. Who lives in application land?

16. Thin controller , thin model…
Fat service layer

17. Should there be managers?

18. Application Events

19. Listen

20. /** @DIObserve(UserEvent::CREATE) */
public function onUserCreate(UserEvent $event)
{
$user = $event->getUser();
$activity = new Activity();
$activity->setActor($user);
$activity->setVerb('register');
$activity->setCreatedAt($user->getCreatedAt());
$this->dm->persist($activity);
}

21. /** @DIObserve(UserEvent::USERNAME_CHANGE) */
public function onUsernameChange(UserEvent $event)
{
$user = $event->getUser();
$dm = $event->getDocumentManager();
$dm->getRepository('Model:Widget')
->updateDenormalizedUsernames($user);
}

22. /** @DIObserve(UserEvent::FOLLOW) */
public function onFollow(UserUserEvent $event)
{
$event->getUser()
->getStats()
->incrementFollowedUsers(1);
$event->getOtherUser()
->getStats()
->incrementFollowers(1);
}

23. Dispatch

24. $event = new UserEvent($dm, $user);
$dispatcher->dispatch(UserEvent::CREATE, $event);

25. $event = new UserEvent($dm, $user);
$dispatcher->dispatch(UserEvent::UPDATE, $event);

26. $event = new UserUserEvent($dm, $user, $otherUser);
$dispatcher->dispatch(UserEvent::FOLLOW, $event);

27. preFlush

28. public function preFlush(ManagerEventArgs $event)
{
$dm = $event->getObjectManager();
$uow = $dm->getUnitOfWork();
foreach ($uow->getIdentityMap() as $class => $docs) {
if (is_a($class, 'KrisModelUser')) {
foreach ($docs as $doc) {
$this->processUserFlush($dm, $doc);
}
} elseif (is_a($class, 'KrisModelWidget')) {
foreach ($docs as $doc) {
$this->processWidgetFlush($dm, $doc);
}
}
}
}

29. Decouple your application by
delegating work to clean, concise,
single-purpose event listeners.

30. Model

31. Treat your model like a princess.

32. She gets her own wing
of the palace…

33. doctrine_mongodb:
auto_generate_hydrator_classes: %kernel.debug%
auto_generate_proxy_classes: %kernel.debug%
connections: { default: ~ }
document_managers:
default:
connection: default
database: kris
mappings:
model:
type: annotation
dir: %src%/Kris/Model
prefix: KrisModel
alias: Model

34. // repo for src/Kris/Model/User.php
$repo = $this->dm->getRepository('Model:User');

35. …doesn't do any work…

36. use KrisBundleMainBundleCanonicalizer;
public function setUsername($username)
{
$this->username = $username;
$canonicalizer = Canonicalizer::instance();
$this->usernameCanonical = $canonicalizer->canonicalize($username);
}

37. use KrisBundleMainBundleCanonicalizer;
public function setUsername($username, Canonicalizer $canonicalizer)
{
$this->username = $username;
$this->usernameCanonical = $canonicalizer->canonicalize($username);
}

38. …and is unaware of the work
being done around her.

39. public function setUsername($username)
{
// a listener will update the
// canonical username
$this->username = $username;
}

40. Cabinets don’t open themselves.

41. Contextual Configuration

42. Save your future self a headache.

43. # @MainBundle/Resources/config/widget.yml
services:
widget_twiddler:
class: KrisBundleMainBundleWidgetTwiddler
arguments:
- @event_dispatcher
- @?logger

44. JMSDiExtraBundle

45. /** @DIService("widget_twiddler") */
class Twiddler
{
/** @DIInjectParams() */
public function __construct(
EventDispatcherInterface $dispatcher,
LoggerInterface $logger = null)
{
// ...
}
}

46. services:
# aliases for auto-wiring
container: @service_container
dm: @doctrine_mongodb.odm.document_manager
doctrine: @doctrine_mongodb
dispatcher: @event_dispatcher
security: @security.context

47. require.js

48. {% block head %}
<script>
require(
[ "view/user", "model/user" ],
function(UserView, User) {
var view = new UserView({
model: new User({{ user|serialize|raw }}),
el: document.getElementById("user")
})
}
)
</script>
{% endblock %}

49. JMSSerializerBundle

50. {% block head %}
<script>
require(
[ "view/user", "model/user" ],
function(UserView, User) {
var view = new UserView({
model: new User({{ user|serialize|raw }}),
el: document.getElementById("user")
})
}
)
</script>
{% endblock %}

51. /** @ExclusionPolicy("ALL") */
class User
{
private $id;
/** @Expose() */
private $firstName;
/** @Expose() */
private $lastName;
}

52. Five more things…

53. When to create a new bundle
• Anything reusable
• A new feature
• Lots of classes relating to one feature
• Integration with a third party

54. {% include 'MainBundle:Account/Widget:sidebar.html.twig' %}

55. {% include 'AccountBundle:Widget:sidebar.html.twig' %}

56. Access Control

57. The Symfony ACL is for
arbitrary permissions

59. Encapsulate access logic in
custom voter classes

60. public function vote(TokenInterface $token, $widget, array $attributes)
{
$result = VoterInterface::ACCESS_ABSTAIN;
if (!$this->supportsClass(get_class($widget))) {
return $result;
}
foreach ($attributes as $attribute) {
if (!$this->supportsAttribute($attribute)) {
continue;
}
$result = VoterInterface::ACCESS_DENIED;
if ($token->getUser() === $widget->getUser()) {
return VoterInterface::ACCESS_GRANTED;
}
}
return $result;
}

61. JMSSecurityExtraBundle

62. /** @SecureParam(name="widget", permissions="OWNER") */
public function editAction(Widget $widget)
{
// ...
}

63. {% if is_granted('OWNER', widget) %}
{# ... #}
{% endif %}

64. No query builders
outside of repositories

65. class WidgetRepository extends DocumentRepository
{
public function findByUser(User $user)
{
return $this->createQueryBuilder()
->field('userId')->equals($user->getId())
->getQuery()
->execute();
}
public function updateDenormalizedUsernames(User $user)
{
$this->createQueryBuilder()
->update()
->multiple()
->field('userId')->equals($user->getId())
->field('userName')->set($user->getUsername())
->getQuery()
->execute();
}
}

66. Eager ID creation

67. public function __construct()
{
$this->id = (string) new MongoId();
}

68. public function __construct()
{
$this->id = (string) new MongoId();
$this->createdAt = new DateTime();
$this->widgets = new ArrayCollection();
}

69. Remember your
clone constructor

70. $foo = new Foo();
$bar = clone $foo;

71. public function __clone()
{
$this->id = (string) new MongoId();
$this->createdAt = new DateTime();
$this->widgets = new ArrayCollection(
$this->widgets->toArray()
);
}

72. public function __construct()
{
$this->id = (string) new MongoId();
$this->createdAt = new DateTime();
$this->widgets = new ArrayCollection();
}
public function __clone()
{
$this->id = (string) new MongoId();
$this->createdAt = new DateTime();
$this->widgets = new ArrayCollection(
$this->widgets->toArray()
);
}

73. Only flush from the controller

74. public function theAction(Widget $widget)
{
$this->get('widget_twiddler')
->skeedaddle($widget);
$this->flush();
}

75. Questions?