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
@kriswallsmith • February 9, 2013

2. About Me

3. @kriswallsmith.net
• Born, raised, & live in Portland
• 10+ years of experience
• Lead Architect at OpenSky
• Open source fanboy

8. brewcycleportland.com

12. assetic

13. Buzz

14. Spork

16. Go big or go home.

17. Getting Started

18. composer create-project
symfony/framework-standard-edition
opti-grab/ 2.2.x-dev

20. - "doctrine/orm": "~2.2,>=2.2.3",
- "doctrine/doctrine-bundle": "1.2.*",
+ "doctrine/mongodb-odm-bundle": "3.0.*",
+ "jms/serializer-bundle": "1.0.*",

21. ./app/console generate:bundle
--namespace=OptiGrab/Bundle/MainBundle

22. assetic:
debug: %kernel.debug%
use_controller: false
bundles: [ MainBundle ]
filters:
cssrewrite: ~
uglifyjs2: { compress: true, mangle: true }
uglifycss: ~

23. jms_di_extra:
locations:
bundles:
- MainBundle

24. public function registerContainerConfiguration(LoaderInterface $loader)
{
$loader->load(__DIR__.'/config/config_'.$this->getEnvironment().'.yml');
// load local_*.yml or local.yml
if (
file_exists($file = __DIR__.'/config/local_'.$this->getEnvironment().'.yml')
||
file_exists($file = __DIR__.'/config/local.yml')
) {
$loader->load($file);
}
}

25. MongoDB

26. Treat your model like a princess.

27. She gets her own wing
of the palace…

28. doctrine_mongodb:
auto_generate_hydrator_classes: %kernel.debug%
auto_generate_proxy_classes: %kernel.debug%
connections: { default: ~ }
document_managers:
default:
connection: default
database: optiGrab
mappings:
model:
type: annotation
dir: %src_dir%/OptiGrab/Model
prefix: OptiGrabModel
alias: Model

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

30. …doesn't do any work…

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

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

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

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

35. No query builders
outside of repositories

36. 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();
}
}

37. Eager id creation

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

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

40. Remember your
clone constructor

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

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

43. 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()
);
}

44. Only flush from the controller

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

46. Save space on field names

47. /** @ODMString(name="u") */
private $username;
/** @ODMString(name="uc") @ODMUniqueIndex */
private $usernameCanonical;

48. public function getUsername()
{
return $this->username ?: $this->usernameCanonical;
}
public function setUsername($username)
{
if ($username) {
$this->usernameCanonical = strtolower($username);
$this->username = $username === $this->usernameCanonical ? null : $username;
} else {
$this->usernameCanonical = null;
$this->username = null;
}
}

49. No proxy objects

50. /** @ODMReferenceOne(targetDocument="User") */
private $user;

51. public function getUser()
{
if ($this->userId && !$this->user) {
throw new UninitializedReferenceException('user');
}
return $this->user;
}

52. Mapping Layers

53. What is a mapping layer?

54. A mapping layer is thin

55. Thin controller, fat model…

56. Is Symfony an MVC framework?

57. Symfony is an HTTP framework

58. Application Land
Controller
HTTP Land

59. The controller maps from
HTTP-land to application-land.

60. What about the model?

63. public function registerAction()
{
// ...
$user->sendWelcomeEmail();
// ...
}

64. public function registerAction()
{
// ...
$mailer->sendWelcomeEmail($user);
// ...
}

65. Persistence Land
Model
Application Land

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

67. Persistence Land
Model
Application Land
Controller
HTTP Land

68. Who lives in application land?

69. Thin controller, thin model…
Fat service layer!

70. Application Events

71. Use lots of them

72. That happened.

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

74. Unit of Work

75. public function onFlush(OnFlushEventArgs $event)
{
$dm = $event->getDocumentManager();
$uow = $dm->getUnitOfWork();
foreach ($uow->getIdentityMap() as $class => $docs) {
if (self::checkClass('OptiGrabModelUser', $class)) {
foreach ($docs as $doc) {
$this->processUserFlush($dm, $doc);
}
} elseif (self::checkClass('OptiGrabModelWidget', $class)) {
foreach ($docs as $doc) {
$this->processWidgetFlush($dm, $doc);
}
}
}
}

76. private function processUserFlush(DocumentManager $dm, User $user)
{
$uow = $dm->getUnitOfWork();
$meta = $dm->getClassMetadata('Model:User');
$changes = $uow->getDocumentChangeSet($user);
if (isset($changes['id'][1])) {
$this->dispatcher->dispatch(UserEvents::CREATE, new UserEvent($dm, $user));
}
if (isset($changes['usernameCanonical'][0]) && null !== $changes['usernameCanonical'][0]) {
$this->dispatcher->dispatch(UserEvents::USERNAME_CHANGE, new UserEvent($dm, $user));
}
if ($followedUsers = $meta->getFieldValue($user, 'followedUsers')) {
foreach ($followedUsers->getInsertDiff() as $otherUser) {
$this->dispatcher->dispatch(
UserEvents::FOLLOW_USER,
new UserUserEvent($dm, $user, $otherUser)
);
}
foreach ($followedUsers->getDeleteDiff() as $otherUser) {
// ...
}
}
}

77. /** @DIObserve("user.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);
}

78. /** @DIObserve("user.create") */
public function onUserCreate(UserEvent $event)
{
$dm = $event->getDocumentManager();
$user = $event->getUser();
$widget = new Widget();
$widget->setUser($user);
$dm->persist($widget);
// manually notify the event
$event->getDispatcher()->dispatch(
WidgetEvents::CREATE,
new WidgetEvent($dm, $widget)
);
}

79. /** @DIObserve("user.follow_user") */
public function onFollowUser(UserUserEvent $event)
{
$event->getUser()
->getStats()
->incrementFollowedUsers(1);
$event->getOtherUser()
->getStats()
->incrementFollowers(1);
}

80. Two event classes per model
• @MainBundleUserEvents: encapsulates event name constants
such as UserEvents::CREATE and
UserEvents::CHANGE_USERNAME
• @MainBundleEventUserEvent: base event object, accepts
$dm and $user arguments
• @MainBundleWidgetEvents…
• @MainBundleEventWidgetEvent…

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

82. Delegate work to clean, concise,
single-purpose event listeners

83. Contextual Configuration

84. Save your future self a headache

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

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

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

88. JMSDiExtraBundle

89. require.js

91. <script src="{{ asset('js/lib/require.js') }}"></script>
<script>
require.config({
baseUrl: "{{ asset('js') }}",
paths: {
"jquery": "//ajax.googleapis.com/.../jquery.min",
"underscore": "lib/underscore",
"backbone": "lib/backbone"
},
shim: {
"jquery": { exports: "jQuery" },
"underscore": { exports: "_" },
"backbone": {
deps: [ "jquery", "underscore" ],
exports: "Backbone"
}
}
})
require([ "main" ])
</script>

92. // web/js/model/user.js
define(
[ "underscore", "backbone" ],
function(_, Backbone) {
var tmpl = _.template("<%- first %> <%- last %>")
return Backbone.Model.extend({
name: function() {
return tmpl({
first: this.get("first_name"),
last: this.get("last_name")
})
}
})
}
)

93. {% 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 %}

94. Dependencies
• model: backbone, underscore
• view: backbone, jquery
• template: model, view

95. {% javascripts
"js/lib/jquery.js" "js/lib/underscore.js"
"js/lib/backbone.js" "js/model/user.js"
"js/view/user.js"
filter="?uglifyjs2" output="js/packed/user.js" %}
<script src="{{ asset_url }}"></script>
{% endjavascripts %}
<script>
var view = new UserView({
model: new User({{ user|serialize|raw }}),
el: document.getElementById("user")
})
</script>

96. Unused dependencies
naturally slough off

97. JMSSerializerBundle

98. {% 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 %}

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

100. Miscellaneous

101. When to create a new bundle

102. Lots of classes pertaining to
one feature

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

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

105. Access Control

106. The Symfony ACL is for
arbitrary permissions

107. Encapsulate access logic in
custom voter classes

108. /** @DIService(public=false) @DITag("security.voter") */
class WidgetVoter implements VoterInterface
{
public function supportsAttribute($attribute)
{
return 'OWNER' === $attribute;
}
public function supportsClass($class)
{
return 'OptiGrabModelWidget' === $class
|| is_subclass_of($class, 'OptiGrabModelWidget');
}
public function vote(TokenInterface $token, $widget, array $attributes)
{
// ...
}
}

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

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

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

112. Only mock interfaces

113. interface FacebookInterface
{
function getUser();
function api();
}
/** @DIService("facebook") */
class Facebook extends BaseFacebook implements FacebookInterface
{
// ...
}

114. $facebook = $this->getMock('OptiGrabBundleMainBundleFacebookFacebookInterface');
$facebook->expects($this->any())
->method('getUser')
->will($this->returnValue(123));

115. Questions?

116. @kriswallsmith.net
joind.in/8024
Thank You!