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 @xabbuh && @el_stoffel
6. @xabbuh && @el_stoffel Forms
7. @xabbuh && @el_stoffel @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 Standard Forms 1. Solution
11. @xabbuh && @el_stoffel Implementation
12. @xabbuh && @el_stoffel Controller src/Controller/ProductController.php @xabbuh && @el_stoffel
13. @xabbuh && @el_stoffel FormType @xabbuh && @el_stoffel src/Form/ProductType.php
14. @xabbuh && @el_stoffel class Product { private $id; /** * @Assert\Length(min=3) */ private $name; /** * @Assert\NotNull */ private $category; /** * @Assert\GreaterThan(0) */ private $priceAmount; /** * @Assert\GreaterThanOrEqual(0) */ private $priceTax; /** * @Assert\Currency */ private $priceCurrency; public function getId(): ?int { Model @xabbuh && @el_stoffel src/Entity/Product.php
15. @xabbuh && @el_stoffel * @Assert\Currency */ private $priceCurrency; public function getId(): ?int { return $this->id; } public function getName(): ?string { return $this->name; } public function setName(?string $name): void { $this->name = $name; } public function getCategory(): ?Category { return $this->category; } public function setCategory(?Category $category): void { $this->category = $category; } public function getPriceAmount(): ?int { return $this->priceAmount; } public function setPriceAmount(?int $priceAmount): void { $this->priceAmount = $priceAmount; } Model @xabbuh && @el_stoffel src/Entity/Product.php
16. @xabbuh && @el_stoffel Data Flow
17. @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 @xabbuh && @el_stoffel
18. @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 @xabbuh && @el_stoffel
19. @xabbuh && @el_stoffel HttpFoundation Controller Controller @xabbuh && @el_stoffel
20. @xabbuh && @el_stoffel HttpFoundation Controller Controller @xabbuh && @el_stoffel
21. @xabbuh && @el_stoffel Controller FormType Request Handler @xabbuh && @el_stoffel
22. @xabbuh && @el_stoffel Code
23. @xabbuh && @el_stoffel Symfony Front Controller HttpFoundation Form Validator Glue Code Controller FormType Domain Product Category Price
24. @xabbuh && @el_stoffel FormType Model HTTP Request Front Controller Controller Form Glue Code Domain Symfony Model
25. @xabbuh && @el_stoffel Anemic Domain Model
26. @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
27. @xabbuh && @el_stoffel Rich Domain Model
28. @xabbuh && @el_stoffel Rich Domain Model combines data and logic valid by design easy to test defined state transitions
29. @xabbuh && @el_stoffel Anemic vs. Rich Model
30. @xabbuh && @el_stoffel @xabbuh && @el_stoffel
31. @xabbuh && @el_stoffel @xabbuh && @el_stoffel
32. @xabbuh && @el_stoffel @xabbuh && @el_stoffel
33. @xabbuh && @el_stoffel @xabbuh && @el_stoffel
34. @xabbuh && @el_stoffel @xabbuh && @el_stoffel
35. @xabbuh && @el_stoffel @xabbuh && @el_stoffel
36. @xabbuh && @el_stoffel @xabbuh && @el_stoffel
37. @xabbuh && @el_stoffel @xabbuh && @el_stoffel
38. @xabbuh && @el_stoffel @xabbuh && @el_stoffel
39. @xabbuh && @el_stoffel "how not to agree about software design" - sp00m on stackoverflow - @xabbuh && @el_stoffel
40. @xabbuh && @el_stoffel Anemic Models Prototyping Ease of use Easily generated Rich Models Clean Code Testability Truly OOP Your Choice!
41. @xabbuh && @el_stoffel Let's use Rich Domain Models with Symfony Forms
42. @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; } public function getName(): string { return $this->name; } public function rename(string $name): void { $this->validateName($name); Model src/Entity/Product.php @xabbuh && @el_stoffel
43. @xabbuh && @el_stoffel public function getId(): int { return $this->id; } 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 { return $this->price; } public function costs(Price $price): void { $this->price = $price; } Model src/Entity/Product.php @xabbuh && @el_stoffel
44. @xabbuh && @el_stoffel $this->name = $name; } public function getCategory(): Category { return $this->category; } public function moveToCategory(Category $category): void { $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
45. @xabbuh && @el_stoffel Model src/Entity/Price.php @xabbuh && @el_stoffel
46. @xabbuh && @el_stoffel Model src/Entity/Category.php @xabbuh && @el_stoffel
47. @xabbuh && @el_stoffel @xabbuh && @el_stoffel
48. @xabbuh && @el_stoffel 2. Solution Easy: Data ransfer bject T O s
49. @xabbuh && @el_stoffel Implementation
50. @xabbuh && @el_stoffel final class Product { public $id; /** * @Assert\Length(min=3) */ public $name; /** * @Assert\NotNull */ public $category; /** * @Assert\GreaterThan(0) */ public $priceAmount; /** * @Assert\GreaterThanOrEqual(0) */ public $priceTax; /** * @Assert\Currency */ public $priceCurrency; public static function fromEntity(ProductEntity $product = null): self DTO src/Form/DTO/Product.php @xabbuh && @el_stoffel
51. @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
52. @xabbuh && @el_stoffel $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); 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
53. @xabbuh && @el_stoffel FormType src/Form/ProductType.php @xabbuh && @el_stoffel
54. @xabbuh && @el_stoffel Controller src/Controller/ProductController.php @xabbuh && @el_stoffel
55. @xabbuh && @el_stoffel Data Flow
56. @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 @xabbuh && @el_stoffel
57. @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 @xabbuh && @el_stoffel
58. @xabbuh && @el_stoffel HttpFoundation Controller Controller @xabbuh && @el_stoffel
59. @xabbuh && @el_stoffel HttpFoundation Controller Controller @xabbuh && @el_stoffel
60. @xabbuh && @el_stoffel Controller FormType Request Handler ProductDto ProductDto:: @xabbuh && @el_stoffel
61. @xabbuh && @el_stoffel HttpFoundation Controller Controller @xabbuh && @el_stoffel
62. @xabbuh && @el_stoffel Code
63. @xabbuh && @el_stoffel Symfony Front Controller HttpFoundation Form Validator Glue Code Controller FormType DTO Domain Product Category Price
64. @xabbuh && @el_stoffel FormType HTTP Request Front Controller Controller Form Glue Code Domain Symfony DTO Model Model DTO
65. @xabbuh && @el_stoffel DTO Solution enables us to use Rich Domain Models easy to implement and maintain additional Glue Code redundant validation rules
66. @xabbuh && @el_stoffel Hard: DataMapper 3. Solution
67. @xabbuh && @el_stoffel Implementation
68. @xabbuh && @el_stoffel Controller src/Controller/ProductController.php @xabbuh && @el_stoffel same as first solution
69. @xabbuh && @el_stoffel FormType src/Form/ProductType.php @xabbuh && @el_stoffel
70. @xabbuh && @el_stoffel FormType src/Form/ProductType.php @xabbuh && @el_stoffel
71. @xabbuh && @el_stoffel FormType src/Form/ProductType.php @xabbuh && @el_stoffel
72. @xabbuh && @el_stoffel FormType src/Form/ProductType.php @xabbuh && @el_stoffel
73. @xabbuh && @el_stoffel Data Flow
74. @xabbuh && @el_stoffel HTML Formular Form Submit 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 @xabbuh && @el_stoffel
75. @xabbuh && @el_stoffel Front Controller 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 @xabbuh && @el_stoffel
76. @xabbuh && @el_stoffel HttpFoundation Controller Controller @xabbuh && @el_stoffel
77. @xabbuh && @el_stoffel HttpFoundation Controller Controller @xabbuh && @el_stoffel
78. @xabbuh && @el_stoffel Request Handler Controller FormType DataMapper @xabbuh && @el_stoffel
79. @xabbuh && @el_stoffel Code
80. @xabbuh && @el_stoffel Symfony Front Controller HttpFoundation Form Validator Glue Code Controller FormType DataMapper Domain Product Category Price
81. @xabbuh && @el_stoffel Form Type Model HTTP Request Front Controller Controller Form Glue Code Domain Symfony Model Data Mapper Data Mapper
82. @xabbuh && @el_stoffel DataMapper Solution enables us to use Rich Domain Models requires advanced knowledge about Forms additional Glue Code hard to test
83. @xabbuh && @el_stoffel Still not satisfied?
84. @xabbuh && @el_stoffel We feel you …
85. @xabbuh && @el_stoffel Introducing …
86. @xabbuh && @el_stoffel New: RichModelFormsBundle 4. Solution
87. @xabbuh && @el_stoffel sensiolabs-de/rich-model-forms-bundle Disclaimer: Still Experimental
88. @xabbuh && @el_stoffel Installation
89. @xabbuh && @el_stoffel composer require \ sensiolabs-de/rich-model-forms-bundle
90. @xabbuh && @el_stoffel Features
91. @xabbuh && @el_stoffel Different read/write property paths
92. @xabbuh && @el_stoffel Different read/write property paths
93. @xabbuh && @el_stoffel Exception Handling
94. @xabbuh && @el_stoffel Exception Handling
95. @xabbuh && @el_stoffel Mandatory Constructor Arguments
96. @xabbuh && @el_stoffel Mandatory Constructor Arguments
97. @xabbuh && @el_stoffel Immutable Value Object
98. @xabbuh && @el_stoffel Immutable Value Object
99. @xabbuh && @el_stoffel Implementation
100. @xabbuh && @el_stoffel Controller src/Controller/ProductController.php still same as first solution @xabbuh && @el_stoffel
101. @xabbuh && @el_stoffel FormType src/Form/ProductType.php @xabbuh && @el_stoffel
102. @xabbuh && @el_stoffel FormType src/Form/ProductType.php @xabbuh && @el_stoffel
103. @xabbuh && @el_stoffel Data Flow
104. @xabbuh && @el_stoffel HTML Formular Form Submit 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
105. @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
106. @xabbuh && @el_stoffel HttpFoundation Controller Controller @xabbuh && @el_stoffel
107. @xabbuh && @el_stoffel HttpFoundation Controller Controller @xabbuh && @el_stoffel
108. @xabbuh && @el_stoffel Request Handler Controller FormType RichModelFormsBundle @xabbuh && @el_stoffel
109. @xabbuh && @el_stoffel Code
110. @xabbuh && @el_stoffel Symfony Front Controller HttpFoundation Form New Bundle Glue Code Controller FormType Domain Model
111. @xabbuh && @el_stoffel FormType Model HTTP Request Front Controller Controller Form Glue Code Domain Symfony Model
112. @xabbuh && @el_stoffel RichModelFormsBundle to the rescue! generalizes the previous approach additional form config options tailored for rich model form needs released, but still in development
113. @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
114. @xabbuh && @el_stoffel Your turn! Help us make it stable!
115. @xabbuh && @el_stoffel DTOs New Bundle DataMapper hard to implement hard to test additional glue code easy to implement duplicated validation additional glue code no glue code needed experimental future core feature? Using Symfony Forms with Rich Domain Models
116. @xabbuh && @el_stoffel Thank you! Questions?