Bernhard Schussek gave a presentation on leveraging Symfony2 forms at the Symfony Live conference in March 2011. He discussed the evolution of the Symfony form component, its service-oriented architecture, and how forms are decoupled from business logic. He provided an example of an online sausage shop order form to demonstrate how form data is bound to objects and submitted. The presentation covered the form configuration class, form processing, field types, validation, embedding forms, and form themes.

1. Bernhard Schussek
Leveraging Symfony2 Forms
Symfony Live Conference, March 03rd 2011

2. About myself
Software Architect in Vienna
Student of Software
Engineering
Symfony since 2006
Outdoor and music junkie

3. Agenda
Introductory example
The Form Config class
Form processing
Fields
Useful features

4. The Symfony2 Form
component

5. The Symfony2 Form component
Evolution of symfony1 sfForm
2.5 years development
Fixes most of its problems
Reusable widgets
Embedded forms

6. Why 2.5 years?

7. "It takes a long time to make somthing
complicated simple, but if you do, it will work
without problems for a long time."
– F. Andy Seidl, http://faseidl.com

8. Service Oriented Architecture
Applications provide services
Services are exchangable
These services can be consumed by different actors
Humans
Machines

9. Forms don't contain
business logic

10. Services do

11. Example:
Online sausage shop

12. Example: Online sausage shop
You
Request
Response

13. Example: Online sausage shop
Consumer Service
You
Request
Response

14. Example: Online sausage shop
Consumer Service
Request
Response

15. Example: Online sausage shop
Consumer Service
Request
Response

16. Service implementation
class Order
{
function setName($name);
function setAddress($address);
function setSausage($sausage);
function setAmount($amount);
}

17. Flow of information
I am Max!

18. Flow of information
I am Max!
$order->setName('Max')

19. Flow of information
Order form
Name: Max
Address: Sensio Labs,
Paris
Sausage: Bratwurst
Amount: 5

20. Flow of information
Order form
$order
Name: Max ->setName('Max')
Address: Sensio Labs, ->setAddress(
'Sensio Labs,
Paris
Paris')
Sausage: Bratwurst ->setSausage(
'Bratwurst')
Amount: 5 ->setAmount(5);

21. Flow of information
Existing order
$order
->getName() Name: Bob
->getAddress() Address: Liip Office
Zurich
->getSausage() Sausage: Cervelat
->getAmount(); Amount: 10

22. The Form Config class

23. Form definition
PHP class
class OrderFormConfig extends AbstractConfig
{
public function configure(
FieldInterface $form, array $options)
{
}
}

24. Form definition
PHP class
class OrderFormConfig extends AbstractConfig
{
public function configure(
FieldInterface $form, array $options)
{
$form->add('text', 'name')
->add('text', 'address')
->add('text', 'sausage')
->add('integer', 'amount');
}
}

25. Form definition
PHP class
class OrderFormConfig extends AbstractConfig
{
...
public function getIdentifier()
{
return 'form.order';
}
}

26. Why not a simple
OrderForm class?

27. Why we need Config classes
OrderForm cannot be put into the Dependency
Injection Container ...
... but OrderFormConfig can!

28. Dependency Injection Container
<service id="form.order" class="OrderFormConfig">
<tag name="form.config" alias="form.order" />
<argument type="service" id="form.factory" />
</service>
Tag alias == form identifier
public function getIdentifier()
{
return 'form.order';
}

29. Form processing

30. Form processing Form identifier
$factory = $this->get('form.factory');
$form = $factory->getInstance('form.order');
$form->setData($order);
if ($request->getMethod() === 'POST') {
$form->bindRequest($request);
if ($form->isValid()) {
$order->send();
return new RedirectResponse(...);
}
}

31. Form processing
$factory = $this->get('form.factory');
$form = $factory->getInstance('form.order');
$form->setData($order); Service object
if ($request->getMethod() === 'POST') {
$form->bindRequest($request);
if ($form->isValid()) {
$order->send();
return new RedirectResponse(...);
}
}

32. Form processing
$factory = $this->get('form.factory');
$form = $factory->getInstance('form.order');
$form->setData($order);
if ($request->getMethod() === 'POST') {
$form->bindRequest($request);
if ($form->isValid()) { Calls setters
$order->send();
return new RedirectResponse(...);
}
}

33. Form processing
$factory = $this->get('form.factory');
$form = $factory->getInstance('form.order');
$form->setData($order);
if ($request->getMethod() === 'POST') {
$form->bindRequest($request);
if ($form->isValid()) {
$order->send();
return new RedirectResponse(...);
}
} $order now contains submitted data!

34. Form rendering
In the action
return $this->render(
'HelloBundle:Hello:index.twig.html',
array('form' => $form->getRenderer()));
Contains view variables and methods

35. Form rendering
In the template
<form action="#" method="post">
{{ form.widget }}
</form>
"widget" is a view method

36. Form rendering
"fields" is a view variable
<form action="#" method="post">
{{ form.errors }}
{% for field in form.vars.fields %}
{{ field.errors }}
{{ field.label }}
{{ field.widget }}
{% endfor %}
{{ form.rest }}
</form>

37. Form rendering
<form action="#" method="post">
{{ form.errors }}
{{ form.name.errors }}
{{ form.name.label }}
{{ form.name.widget }}
{{ form.rest }}
</form>

38. Form rendering
{{ form.rest }}
Renders all fields that weren't rendered before
... fields that you forgot to render manually
... hidden fields

39. What about validation?

40. Form validation
uses the Symfony2 Validator
"Constraints" are put onto your PHP classes
(services, entities etc.)

41. Validation constraints
class Order
{
/**
* @check:NotNull
* @check:AssertType("string")
* @check:MaxLength(50, message=
* "Long name, dude...")
*/
private $name;
}

42. Fields

43. Text input
Title:
$form->add('text', 'title');

44. Textarea
Content:
$form->add('textarea', 'content');

45. Date selector
Mmmh localized!
Publish at:
$form->add('date', 'publishAt');

46. Country selector
Localized too! Yummy!
Nationality:
$form->add('country', 'nationality');

47. File upload
Profile picture:
$form->add('file', 'profilePicture');
Remembers uploaded files on errors!

48. Repeated input
Email:
Email (again):
$form->add('repeated', 'email');

49. Core fields
entity
birthday password
file
checkbox percent
hidden
choice repeated
integer
collection textarea
language
country text
locale
date timezone
money
datetime url
number

50. Field architecture
Filters
Value transformers

51. Filters
modify a value
uni­directional
Example: FixUrlProtocolFilter
symfony-project.com http://symfony-project.com

52. Value Transformers
convert values between two representations
bi­directional
Example: DateTimeToArrayTransformer
array(
'year' => 2011,
object(DateTime) 'month' => 5,
'day' => 1,
)

53. Example: Entity field
The user sees:
Symfony sees:
Entity field
Checkbox Checkbox Checkbox Checkbox
"0" "1" "2" "3"
Tag IDs

54. Tag IDs
array("0" => "0", "1" => "1", "2" => "1", ...)
"0" "1" "0" "0"
Checkbox Checkbox Checkbox Checkbox
"0" "1" "2" "3"

55. Tag IDs
array("0" => "0", "1" => "1", "2" => "1", ...)
"0" "1" "0" "0"
Checkbox Checkbox Checkbox Checkbox
"0" "1" "2" "3"

56. Checkbox Checkbox Checkbox Checkbox
"0" "1" "2" "3"
false true true false
array("0" => false, "1" => true, "2" => true, ...)
ArrayCollection($securityTag, $validatorTag)

57. Checkbox Checkbox Checkbox Checkbox
"0" "1" "2" "3"
false true true false
ChoicesToArrayTransformer
array("0" => false, "1" => true, "2" => true, ...)
ArrayCollection($securityTag, $validatorTag)

58. Checkbox Checkbox Checkbox Checkbox
"0" "1" "2" "3"
false true true false
array("0" => false, "1" => true, "2" => true, ...)
ArrayToEntitiesTransformer
ArrayCollection($securityTag, $validatorTag)

59. CSRF protection
Cross­Site Request Forgery
A form is submitted using the session of another
person
All kinds of misuse
Built­in protection in Symfony2

60. CSRF protection
app/config/config.yml
framework:
csrf_protection:
enabled: true
secret: 30665e19ef0010d5620553

61. Field creation
Manual
Automatic
Symfony2 looks at metadata of the domain class to
"guess" the correct field type and settings
E.g. Validator metadata, Doctrine2 metadata

62. Manual field creation
public function configure(
FieldInterface $form, array $options)
{
$form->add('entity', 'sausage', array(
'class' => 'Sausage',
));
}
but Doctrine already knows, that "sausage" is a
To­One relationship to the Sausage class!

63. Automatic field creation
public function configure(
FieldInterface $form, array $options)
{
$form->setDataClass('Order');
$form->add('sausage');
}

64. Automatic with options overriding
public function configure(
FieldInterface $form, array $options)
{
$form->setDataClass('Order')
->add('sausage', array(
'required' => false,
));
}

65. Embedded forms
Symfony2 allows to embed forms into another very
easily
Fields and forms implement FieldInterface
"A form is a field"

66. Embedded to­one forms
public function configure(
FieldInterface $form, array $options)
{
$form->add('form.sausage', 'sausage');
}
Identifier of SausageFormConfig

67. Embedded to­many forms
public function configure(
FieldInterface $form, array $options)
{
$form->add('collection', 'sausages', array(
'identifier' => 'form.sausage'
));
}
Identifier of SausageFormConfig

68. Config options
Options for influencing the field's/form's creation
class ConcealedFieldConfig extends Abstract..
{
public function getDefaultOptions($options)
{
return array(
'concealed' => true,
);
}
}

69. Config inheritance
Dynamic inheritance from other forms/fields
class ConcealedFieldConfig extends Abstract..
{
public function getParent(array $options)
{
return $options['concealed']
? 'password' : 'text';
}
}

70. Form themes
Are normal Twig templates
Blocks for each field type
{% block textarea__widget %}
<textarea {{ block('attributes') }}>
{{ value }}
</textarea>
{% endblock textarea__widget %}

71. Form themes
Can specify widget, errors, label and row
templates for specific field types
{% block textarea__row %}
<tr><td colspan="2">
{{ this.errors }}
{{ this.widget }}
</td></tr>
{% endblock textarea__row %}

72. Form themes
Core themes:
TwigBundle::div_layout.html.twig
TwigBundle::table_layout.html.twig
Configuration in the DI parameter
"form.theme.template"
More flexible configuration options coming soon

73. Questions?
Thanks for listening!
Code can currently be found on
https://github.com/bschussek/symfony/tree/experimental
Bernhard Schussek
Twitter: @webmozart

74. The End
Copyright
"dog window" by Larry Wentzel
http://www.flickr.com/photos/wentzelepsy
"Symfony Live 2011 Logo" by Sensio Labs
http://www.sensiolabs.com