Using Symfony Forms with Rich Domain Models

With the popularisation of DDD people started shifting from anemic models with only getters and setters to a rich model describing the state changes in specific methods. This way of designing models does not play well with Symfony forms. User provided input is inherently invalid while we want to maintain certain invariants in our domain model. A common approach to overcome these limitations is to create data transfer objects our forms are then bound to. This can lead to lots of mapping & glue code that might be cumbersome to write and maintain. But couldn’t we do better? In this talk we will discuss the different aspects of a rich domain model that makes it hard to use it in conjunction with the Form component. We will then look at the possibilities to hook into the data flow of the form handling and discover how we can modify it to interact seamlessly with our model.

Bundle: https://github.com/sensiolabs-de/rich-model-forms-bundle
Demo App: https://github.com/sensiolabs-de/rich-model-forms-demo

Transcript

1. @xabbuh && @el_stoffel
2. @xabbuh && @el_stoffel Christopher Hertel Consultant & Trainer @ SensioLabs Symfony User Group Berlin Christian Flothmann Software Developer @ SensioLabs Symfony Core & Docs Member
3. @xabbuh && @el_stoffel Our Use Case
4. @xabbuh && @el_stoffel Simple Product CRUD
5. @xabbuh && @el_stoffel
6. @xabbuh && @el_stoffel Forms
7. @xabbuh && @el_stoffel
8. @xabbuh && @el_stoffel Domain
9. @xabbuh && @el_stoffel Product Name Category Price Category Name Parent Price Amount Taxrate Currency Category
10. @xabbuh && @el_stoffel Focus on product form today
11. @xabbuh && @el_stoffel Standard Forms 1. Solution
12. @xabbuh && @el_stoffel Implementation
13. @xabbuh && @el_stoffel Controller src/Controller/ProductController.php @xabbuh && @el_stoffel
14. @xabbuh && @el_stoffel FormType @xabbuh && @el_stoffel src/Form/ProductType.php
15. @xabbuh && @el_stoffel class Product { private $id; /** * @Assert\Length(min=3) */ private $name; /** * @Assert\NotNull */ private $category; /** * @Assert\GreaterThan(0) */ private $priceAmount; /** Model @xabbuh && @el_stoffel src/Entity/Product.php
16. @xabbuh && @el_stoffel public function setPriceTax(?int $priceTax): void { $this->priceTax = $priceTax; } public function getPriceCurrency(): ?string { return $this->priceCurrency; } public function setPriceCurrency(?string $priceCurrency): void { $this->priceCurrency = $priceCurrency; } } Model @xabbuh && @el_stoffel src/Entity/Product.php
17. @xabbuh && @el_stoffel Data Flow
18. @xabbuh && @el_stoffel HTML Form POST /product HTTP/1.1 Host: localhost:8000 Connection: keep-alive Content-Length: 133 Cache-Control: max-age=0 [...] Accept-Language: en;q=0.9 product[name]: rocket product[category]: 18 product[priceAmount]: 0.59 product[priceTax]: 7 product[priceCurrency]: EUR HTTP Request Form Submit
19. @xabbuh && @el_stoffel POST /product HTTP/1.1 Host: localhost:8000 Connection: keep-alive Content-Length: 133 Cache-Control: max-age=0 [...] Accept-Language: en;q=0.9 product[name]: rocket product[category]: 18 product[priceAmount]: 0.59 product[priceTax]: 7 product[priceCurrency]: EUR HTTP Request HttpFoundation Front Controller
20. @xabbuh && @el_stoffel HttpFoundation Controller Controller
21. @xabbuh && @el_stoffel HttpFoundation Controller Controller
22. @xabbuh && @el_stoffel Controller FormType Request Handler
23. @xabbuh && @el_stoffel Code
24. @xabbuh && @el_stoffel Symfony Front Controller HttpFoundation Form Validator Glue Code Controller FormType Domain Model
25. @xabbuh && @el_stoffel FormType Model HTTP Request Front Controller Controller Form Glue Code Domain Symfony Model
26. @xabbuh && @el_stoffel Anemic Domain Model
27. @xabbuh && @el_stoffel Anemic Domain Model focus on data structured easy to implement and to maintain contains little or no logic no guarantee to be valid or consistent
28. @xabbuh && @el_stoffel Rich Domain Model
29. @xabbuh && @el_stoffel Rich Domain Model combines data and logic valid by design easy to test defined state transitions
30. @xabbuh && @el_stoffel Anemic vs. Rich Model
31. @xabbuh && @el_stoffel
32. @xabbuh && @el_stoffel
33. @xabbuh && @el_stoffel
34. @xabbuh && @el_stoffel
35. @xabbuh && @el_stoffel
36. @xabbuh && @el_stoffel
37. @xabbuh && @el_stoffel
38. @xabbuh && @el_stoffel
39. @xabbuh && @el_stoffel
40. @xabbuh && @el_stoffel "how not to agree about software design" - sp00m on stackoverflow -
41. @xabbuh && @el_stoffel Anemic Models Prototyping Ease of use Easily generated Rich Models Clean Code Testability Truly OOP Your Choice!
42. @xabbuh && @el_stoffel Let's use Rich Domain Models with Symfony Forms
43. @xabbuh && @el_stoffel class Product { private $id; private $name; private $category; private $price; public function __construct(string $name, Category $category, Price $price) { $this->validateName($name); $this->name = $name; $this->category = $category; $this->price = $price; } public function getId(): int { return $this->id; } Model src/Entity/Product.php @xabbuh && @el_stoffel
44. @xabbuh && @el_stoffel } public function getName(): string { return $this->name; } public function rename(string $name): void { $this->validateName($name); $this->name = $name; } public function getCategory(): Category { return $this->category; } public function moveToCategory(Category $category): void { $this->category = $category; } public function getPrice(): Price Model src/Entity/Product.php @xabbuh && @el_stoffel
45. @xabbuh && @el_stoffel { $this->category = $category; } public function getPrice(): Price { return $this->price; } public function costs(Price $price): void { $this->price = $price; } private function validateName(string $name): void { if (strlen($name) < 3) { throw ProductException::invalidName($name); } } } Model src/Entity/Product.php @xabbuh && @el_stoffel
46. @xabbuh && @el_stoffel Model src/Entity/Price.php @xabbuh && @el_stoffel
47. @xabbuh && @el_stoffel Model src/Entity/Category.php @xabbuh && @el_stoffel
48. @xabbuh && @el_stoffel
49. @xabbuh && @el_stoffel
50. @xabbuh && @el_stoffel
51. @xabbuh && @el_stoffel 2. Solution Easy: Data ransfer bject T O s
52. @xabbuh && @el_stoffel Implementation
53. @xabbuh && @el_stoffel final class Product { public $id; /** * @Assert\Length(min=3) */ public $name; /** * @Assert\NotNull */ public $category; /** * @Assert\GreaterThan(0) */ public $priceAmount; /** DTO src/Form/DTO/Product.php @xabbuh && @el_stoffel
54. @xabbuh && @el_stoffel * @Assert\Currency */ public $priceCurrency; public static function fromEntity(ProductEntity $product = null): self { $self = new self(); if (null === $product) { return $self; } $self->id = $product->getId(); $self->name = $product->getName(); $self->category = $product->getCategory(); $self->priceAmount = $product->getPrice()->getAmount(); $self->priceTax = $product->getPrice()->getTax(); $self->priceCurrency = $product->getPrice()->getCurrency(); return $self; } public function toEntity(ProductEntity $product = null): ProductEntity { $price = new Price((int) $this->priceAmount, $this->priceTax, $this->priceCurrency); DTO src/Form/DTO/Product.php @xabbuh && @el_stoffel
55. @xabbuh && @el_stoffel return $self; } public function toEntity(ProductEntity $product = null): ProductEntity { $price = new Price((int) $this->priceAmount, $this->priceTax, $this->priceCurrency); if (null === $product) { return new ProductEntity($this->name, $this->category, $price); } if ($product->getName() !== $this->name) { $product->rename($this->name); } if ($product->getCategory() !== $this->category) { $product->moveToCategory($this->category); } if (!$price->equals($product->getPrice())) { $product->costs($price); } return $product; } } DTO src/Form/DTO/Product.php @xabbuh && @el_stoffel
56. @xabbuh && @el_stoffel FormType src/Form/ProductType.php @xabbuh && @el_stoffel
57. @xabbuh && @el_stoffel Controller src/Controller/ProductController.php @xabbuh && @el_stoffel
58. @xabbuh && @el_stoffel Data Flow
59. @xabbuh && @el_stoffel HTML Formular POST /product HTTP/1.1 Host: localhost:8000 Connection: keep-alive Content-Length: 133 Cache-Control: max-age=0 [...] Accept-Language: en;q=0.9 product[name]: rocket product[category]: 18 product[priceAmount]: 0.59 product[priceTax]: 7 product[priceCurrency]: EUR HTTP Request Form Submit
60. @xabbuh && @el_stoffel POST /product HTTP/1.1 Host: localhost:8000 Connection: keep-alive Content-Length: 133 Cache-Control: max-age=0 [...] Accept-Language: en;q=0.9 product[name]: rocket product[category]: 18 product[priceAmount]: 0.59 product[priceTax]: 7 product[priceCurrency]: EUR HTTP Request HttpFoundation Front Controller
61. @xabbuh && @el_stoffel HttpFoundation Controller Controller
62. @xabbuh && @el_stoffel HttpFoundation Controller Controller
63. @xabbuh && @el_stoffel Controller FormType Request Handler ProductDto ProductDto::
64. @xabbuh && @el_stoffel HttpFoundation Controller Controller
65. @xabbuh && @el_stoffel Code
66. @xabbuh && @el_stoffel Symfony Front Controller HttpFoundation Form Validator Glue Code Controller FormType Domain Model DTO
67. @xabbuh && @el_stoffel FormType HTTP Request Front Controller Controller Form Glue Code Domain Symfony DTO Model Model DTO
68. @xabbuh && @el_stoffel DTO Solution enables us to use Rich Domain Models easy to implement and maintain additional Glue Code redundant validation rules
69. @xabbuh && @el_stoffel Hard: DataMapper 3. Solution
70. @xabbuh && @el_stoffel Implementation
71. @xabbuh && @el_stoffel Controller src/Controller/ProductController.php same as first solution @xabbuh && @el_stoffel
72. @xabbuh && @el_stoffel FormType src/Form/ProductType.php @xabbuh && @el_stoffel
73. @xabbuh && @el_stoffel FormType src/Form/ProductType.php @xabbuh && @el_stoffel
74. @xabbuh && @el_stoffel FormType src/Form/ProductType.php @xabbuh && @el_stoffel
75. @xabbuh && @el_stoffel FormType src/Form/ProductType.php @xabbuh && @el_stoffel
76. @xabbuh && @el_stoffel Data Flow
77. @xabbuh && @el_stoffel HTML Formular POST /product HTTP/1.1 Host: localhost:8000 Connection: keep-alive Content-Length: 133 Cache-Control: max-age=0 [...] Accept-Language: en;q=0.9 product[name]: rocket product[category]: 18 product[price][amount]: 0.59 product[price][tax]: 7 product[price][currency]: EUR HTTP Request Form Submit
78. @xabbuh && @el_stoffel POST /product HTTP/1.1 Host: localhost:8000 Connection: keep-alive Content-Length: 133 Cache-Control: max-age=0 [...] Accept-Language: en;q=0.9 product[name]: rocket product[category]: 18 product[price][amount]: 0.59 product[price][tax]: 7 product[price][currency]: EUR HTTP Request HttpFoundation Front Controller
79. @xabbuh && @el_stoffel HttpFoundation Controller Controller
80. @xabbuh && @el_stoffel HttpFoundation Controller Controller
81. @xabbuh && @el_stoffel Controller FormType Request Handler DataMapper
82. @xabbuh && @el_stoffel Code
83. @xabbuh && @el_stoffel Symfony Front Controller HttpFoundation Form Validator Glue Code Controller FormType Domain Model DataMapper
84. @xabbuh && @el_stoffel Form Type Model HTTP Request Front Controller Controller Form Glue Code Domain Symfony Model Data Mapper Data Mapper
85. @xabbuh && @el_stoffel DataMapper Solution enables us to use Rich Domain Models requires advanced knowledge about Forms additional Glue Code hard to test
86. @xabbuh && @el_stoffel Still not satisfied?
87. @xabbuh && @el_stoffel We feel you …
88. @xabbuh && @el_stoffel Introducing …
89. @xabbuh && @el_stoffel New: RichModelFormsBundle 4. Solution
90. @xabbuh && @el_stoffel sensiolabs-de/rich-model-forms-bundle Disclaimer: Still Experimental
91. @xabbuh && @el_stoffel Installation
92. @xabbuh && @el_stoffel composer require \ sensiolabs-de/rich-model-forms-bundle:dev-master
93. @xabbuh && @el_stoffel Features
94. @xabbuh && @el_stoffel Different read/write property paths
95. @xabbuh && @el_stoffel Different read/write property paths
96. @xabbuh && @el_stoffel Exception Handling
97. @xabbuh && @el_stoffel Exception Handling
98. @xabbuh && @el_stoffel Mandatory Constructor Arguments
99. @xabbuh && @el_stoffel Mandatory Constructor Arguments
100. @xabbuh && @el_stoffel Immutable Value Object
101. @xabbuh && @el_stoffel Immutable Value Object
102. @xabbuh && @el_stoffel Implementation
103. @xabbuh && @el_stoffel Controller src/Controller/ProductController.php still same as first solution @xabbuh && @el_stoffel
104. @xabbuh && @el_stoffel FormType src/Form/ProductType.php @xabbuh && @el_stoffel
105. @xabbuh && @el_stoffel FormType src/Form/ProductType.php @xabbuh && @el_stoffel
106. @xabbuh && @el_stoffel Data Flow
107. @xabbuh && @el_stoffel HTML Formular POST /product HTTP/1.1 Host: localhost:8000 Connection: keep-alive Content-Length: 133 Cache-Control: max-age=0 [...] Accept-Language: en;q=0.9 product[name]: rocket product[category]: 18 product[price][amount]: 0.59 product[price][tax]: 7 product[price][currency]: EUR HTTP Request Form Submit
108. @xabbuh && @el_stoffel POST /product HTTP/1.1 Host: localhost:8000 Connection: keep-alive Content-Length: 133 Cache-Control: max-age=0 [...] Accept-Language: en;q=0.9 product[name]: rocket product[category]: 18 product[price][amount]: 0.59 product[price][tax]: 7 product[price][currency]: EUR HTTP Request HttpFoundation Front Controller
109. @xabbuh && @el_stoffel HttpFoundation Controller Controller
110. @xabbuh && @el_stoffel HttpFoundation Controller Controller
111. @xabbuh && @el_stoffel Controller FormType Request Handler RichModelFormsBundle
112. @xabbuh && @el_stoffel Code
113. @xabbuh && @el_stoffel Symfony Front Controller HttpFoundation Form Validator Glue Code Controller FormType Domain Model
114. @xabbuh && @el_stoffel FormType Model HTTP Request Front Controller Controller Form Glue Code Domain Symfony Model
115. @xabbuh && @el_stoffel RichModelFormsBundle to the rescue! generalizes the previous approach additional form config options tailored for rich model form needs released today
116. @xabbuh && @el_stoffel Final Disclaimer not feature complete covers common use cases we discovered needs input for more use cases no, not yet in production
117. @xabbuh && @el_stoffel Your turn! Help us make it stable!
118. @xabbuh && @el_stoffel Thank you! Questions?
119. @xabbuh && @el_stoffel Please give us feedback on joind.in/talk/c0228