Magento 2 Dependency Injection, Interceptors, and You - php[world] 2015

Magento 2 introduces dependency injection and interceptors, two approaches to creating a more flexible, extendable architecture. These concepts are new to many PHP developers, but they are critical to understanding and taking advantage of the power and flexibility of Magento 2. Let's take a high-level look at these concepts, and then dive into some real examples of how to utilize these techniques in your development work with Magento 2.

Transcript

1. PRESENTED BY JOSHUA WARREN PRESENTED AT PHPWORLD 2015 Magento 2 DEPENDENCY INJECTION, INTERCEPTORS AND YOU
2. JoshuaWarren.com #phpworld
3. JoshuaWarren.com Magento 2 officially released yesterday! #phpworld
4. JoshuaWarren.com 100 slides in ~45 minutes lots of code focus on the concepts, download the slides later #phpworld
5. MY EXPERIENCE
6. JoshuaWarren.com My Experience PHP Developer Since 1999 Founded Creatuity in 2008 Focused on the Magento platform #phpworld
7. JoshuaWarren.com early adopter of both Magento 1 and Magento 2 #phpworld
8. JoshuaWarren.com Frequent Magento presenter #phpworld
9. JoshuaWarren.com Led the Creatuity team in building 3 Magento 2 extensions (more on the way!) #phpworld
10. JoshuaWarren.com Already migrating a few merchants from Magento 1 to Magento 2 #phpworld
11. JoshuaWarren.com Wrote Writing the book on Magento 2 #phpworld
12. JoshuaWarren.com Not a Magento employee, but working closely with the development, documentation & product teams on Magento 2 #phpworld
13. JoshuaWarren.com A quick note for any Magento 1 developers in the audience… #phpworld
14. JoshuaWarren.com #phpworld
15. JoshuaWarren.com …for PHP developers new to Magento. #phpworld
16. JoshuaWarren.com PHP developers are learning Magento 2 faster than many Magento 1 developers. #phpworld
17. JoshuaWarren.com Approach Magento 2 with a desire to learn and understand the underlying patterns. #phpworld
18. JoshuaWarren.com Don’t approach Magento 2 with the thought “how do I make my Magento 1 code work here” #phpworld
19. JoshuaWarren.com #phpworld
20. JoshuaWarren.com Shoshin is a Zen concept meaning “beginner’s mind” #phpworld
21. JoshuaWarren.com An attitude of openness, eagerness and lack of preconceptions. #phpworld
22. JoshuaWarren.com No matter your level of Magento 1 experience, approach Magento 2 with a beginner’s mind #phpworld
23. JoshuaWarren.com With that mind, let’s dive into Magento 2… #phpworld
24. MAGENTO 2 github.com/magento/magento2
25. JoshuaWarren.com Technologies #phpworld
26. JoshuaWarren.com #phpworld Composer composer create-project magento/product-community-edition -- stability="beta" <installation directory name>
27. JoshuaWarren.com Each Magento 2 module is a separate Composer package #phpworld
28. JoshuaWarren.com PSR-0 thru PSR-4 #phpworld
29. JoshuaWarren.com Testing built in from the start. phpunit, selenium, JMeter, Jasmine #phpworld
30. JoshuaWarren.com HTML5, CSS3, LESS CSS Preprocessor, JQuery, RequireJS #phpworld
31. JoshuaWarren.com Components from Zend Framework 1, Zend Framework 2, Symfony #phpworld
32. JoshuaWarren.com Technical Architecture #phpworld
33. JoshuaWarren.com Presentation Layer, Service Layer, Domain Layer, Persistence Layer #phpworld
34. JoshuaWarren.com #phpworld
35. JoshuaWarren.com Presentation Layer - views, literally and figuratively #phpworld
36. JoshuaWarren.com Service Layer - an intermediary between the presentation and model layers #phpworld
37. JoshuaWarren.com Service layer provides a stable, backwards-compatible interface and forms the foundation for dependency injection. #phpworld
38. JoshuaWarren.com Domain layer - business logic, including models. Contains the implementation of service contracts. #phpworld
39. JoshuaWarren.com Persistence Layer - resource models that perform CRUD operations on database tables. #phpworld
40. JoshuaWarren.com Some models use a single table, others continue to use the Entity-Attribute-Value design pattern used in Magento 1. #phpworld
41. JoshuaWarren.com Design Patterns #phpworld
42. JoshuaWarren.com Loose Coupling #phpworld
43. JoshuaWarren.com Dependency Injection #phpworld
44. JoshuaWarren.com Service Contracts #phpworld
45. JoshuaWarren.com Interceptors #phpworld
46. JoshuaWarren.com Semantic Versioning #phpworld
47. JoshuaWarren.com Start your Magento 2 journey learning the basics of these design patterns #phpworld
48. JoshuaWarren.com We are going to take a closer look at two patterns today: dependency injection and interceptors #phpworld
49. DEPENDENCY INJECTION Sorry - no cool photo here, because I don’t like needles…
50. JoshuaWarren.com DI is exactly what it sounds like - injecting dependencies into the objects that need them. #phpworld
51. JoshuaWarren.com It sounds complicated, but it’s not. #phpworld
52. JoshuaWarren.com Hollywood Principle: “Don’t call us, we’ll call you” #phpworld
53. JoshuaWarren.com With DI, instead of building an object in your class, it’s passed in via your constructor. #phpworld
54. JoshuaWarren.com DI is designed to reduce dependencies and promote loose coupling #phpworld
55. JoshuaWarren.com DI makes unit testing much easier #phpworld
56. JoshuaWarren.com DI allows for mocking - replacing things like the MySQL adapter with a mock object during testing #phpworld
57. JoshuaWarren.com Magento 2 uses the Constructor Injection pattern of DI #phpworld
58. JoshuaWarren.com This replaces the usage of the Mage class from Magento 1. #phpworld
59. JoshuaWarren.com DI in Magento 2 is Automatic Dependency Injection #phpworld
60. JoshuaWarren.com Objects do not need to locate the object or value in which it depends - it’s automatic. #phpworld
61. JoshuaWarren.com Magento’s object manager uses PHP’s reflection features to automatically instantiate needed objects #phpworld
62. JoshuaWarren.com DI in Magento 2 is handled via XML files #phpworld
63. JoshuaWarren.com #phpworld di.xml <config xmlns:xsi=“[…]” xsi:noNamespaceSchemaLocation=“[…]”>
 <virtualType name="Magento\SamplePaymentProvider\Block\Form\Payinstore" type="Magento\Payment\Block\Form" shared="false"> <arguments>
 <argument name="data" xsi:type="array">
 <item name="template" xsi:type=“string"> Magento_SamplePaymentProvider::form/payinstore.phtml </item>
 </argument>
 </arguments>
 </virtualType>
 </config>
64. JoshuaWarren.com I highly recommend Alan Storm’s article “Magento 2’s Automatic Dependency Injection” #phpworld
65. JoshuaWarren.com #phpworld Without Dependency Injection public function getFormattedPrice($sku)
 {
 $db = new DBHandler;
 $row = $db->query('SELECT price FROM products WHERE sku = ?', $sku);
 $formatter = new PriceFormatter;
 return $formatter->asDollars($row['price']);
 }
66. JoshuaWarren.com #phpworld With Dependency Injection public function getFormattedPrice($sku, $db, $formatter)
 {
 $row = $db->query('SELECT price FROM products WHERE sku = ?', $sku);
 return $formatter->asDollars($row['price']);
 }
67. JoshuaWarren.com DI simplifies testing, maintenance and readability #phpworld
68. JoshuaWarren.com DI.XML is also where plugins following our next pattern to discuss are declared. #phpworld
69. INTERCEPTORS
70. JoshuaWarren.com Plugin system based on the interceptor pattern #phpworld
71. JoshuaWarren.com Calls to almost any module can be intercepted and altered #phpworld
72. JoshuaWarren.com Vast improvement over the rewrite pattern in Magento 1 - no more rewrite conflicts #phpworld
73. JoshuaWarren.com #phpworld di.xml <config>
 <type name="{ObservedType}">
 <plugin name="{pluginName}" type="{PluginClassName}" sortOrder="1" disabled="false"/>
 </type>
 </config>
74. JoshuaWarren.com Sort order defines order if multiple plugins intercept the same item #phpworld
75. JoshuaWarren.com Possible to intercept before, after and around a function #phpworld
76. JoshuaWarren.com #phpworld ‘Before’ Interceptor class Plugin
 {
 public function beforeSetName(\Magento\Catalog\Model\Product $subject, $name)
 {
 return array('(' . $name . ')');
 }
 }
77. JoshuaWarren.com #phpworld ‘After’ Interceptor class Plugin
 {
 public function afterGetName(\Magento\Catalog\Model\Product $subject, $result)
 {
 return '|' . $result . '|';
 }
 }
78. JoshuaWarren.com #phpworld ‘Around’ Interceptor class Plugin
 {
 public function aroundSave(\Magento\Catalog\Model\Product $subject, \Closure $proceed)
 {
 $this->doSomethingBeforeProductIsSaved();
 $returnValue = $proceed();
 if ($returnValue) {
 $this->postProductToFacebook();
 }
 return $returnValue;
 }
 }
79. JoshuaWarren.com Check out the magento 2 sample modules repo for a module that demonstrates interception #phpworld
80. JoshuaWarren.com #phpworld DI.xml <type name="Magento\SampleInterception\Model\Intercepted\ChildBefore">
 <plugin name="Magento_SampleInterception::demoPluginBefore" type="Magento\SampleInterception\Plugin\PluginBefore" />
 </type>
 <type name="Magento\SampleInterception\Model\Intercepted\ChildAfter">
 <plugin name="Magento_SampleInterception::demoPluginAfter" type="Magento\SampleInterception\Plugin\PluginAfter" />
 </type>
 <type name="Magento\SampleInterception\Model\Intercepted\ChildAround">
 <plugin name="Magento_SampleInterception::demoPluginAround" type="Magento\SampleInterception\Plugin\PluginAround" />
 </type>
 <type name="Magento\SampleInterception\Model\Intercepted\ChildInherit">
 <plugin name="Magento_SampleInterception::demoPluginInheritance" type="Magento\SampleInterception\Plugin\ParentPlugin" />
 </type>

81. JoshuaWarren.com #phpworld Plugin/PluginBefore.php public function beforeBaseMethodUppercase(ChildBefore $subject, $interceptedInput)
 {
 return ["(before) $interceptedInput (/before)"];
 }
82. JoshuaWarren.com #phpworld Plugin/PluginAfter.php public function afterBaseMethodUppercase(ChildAfter $subject, $interceptedOutput)
 {
 return "(after) $interceptedOutput (/after)";
 }
83. JoshuaWarren.com #phpworld Plugin/PluginAround.php public function aroundBaseMethodUppercase(ChildAround $subject, \Closure $proceed, $interceptedInput)
 {
 $argument = "(around: before base method) $interceptedInput (/around: before base method)";
 $result = $proceed($argument);
 return "(around: after base method) $result (/around: after base method)";
 }
84. JoshuaWarren.com Interceptors are a replacement for rewrites #phpworld
85. JoshuaWarren.com Interceptors supplement, but not replace, events and observers #phpworld
86. JoshuaWarren.com Sort order conflicts #phpworld
87. JoshuaWarren.com Please don’t define a sort order of 1 unless you really need it #phpworld
88. JoshuaWarren.com We’re all waiting to see what happens with sort order conflicts in real world usage #phpworld
89. JoshuaWarren.com Ideally, the largest extension authors will coordinate their sort order for common conflicts #phpworld
90. JoshuaWarren.com If not, when installing extensions, developers will need to modify their sort order to resolve conflicts. #phpworld
91. LEARNING MORE Don’t end up like this guy ->
92. JoshuaWarren.com devdocs.magento.com - ‘How Do I?’ magento.stackexchange.com/questions/tagged/ magento2 https://github.com/magento/magento2-samples #phpworld
93. JoshuaWarren.com Read through the sample modules. #phpworld
94. JoshuaWarren.com The sample modules don’t currently work (see issue #42) #phpworld
95. JoshuaWarren.com In order to run the sample modules, you will have to add a registration.php file. #phpworld
96. JoshuaWarren.com Otherwise, they’re still a great resource to see dependency injection and interceptors in action. #phpworld
97. Dev Docs Team Team of hard-working technical writers (not developers) Writing documentation for a system that has yet to be used ‘in the wild’ Very eager for feedback and input - they don’t know what documentation you need Very open to pull requests of documentation or just open an issue on Github with feedback + requests JoshuaWarren.com #phpworld
98. Dev Docs Team JoshuaWarren.com #phpworld
99. JoshuaWarren.com Magento U Courses Fundamentals of Magento 2 Development Front-end Course #phpworld
100. JoshuaWarren.com AlanStorm.com AlanKent.me CoderOnCode.com github.com/creatuity/LearningMagento2 #phpworld
101. JoshuaWarren.com Upcoming events: Magento Imagine - April 2016 #phpworld
102. JoshuaWarren.com As a freelancer… Learning Magento 2 Set aside time in your week to learn the design patterns Magento 2 uses Work through the sample code the Magento 2 team has provided Begin experimenting with developing with Magento 2 Do not try to learn ‘on the job’ - be careful accepting M2 work before you’re ready #phpworld
103. JoshuaWarren.com As an in-house developer for a merchant… Learning Magento 2 Determine when your business is likely to migrate to Magento 2 First 2-4 weeks of your Magento 2 migration schedule should be learning Magento 2 Learn the patterns before you start! #phpworld
104. JoshuaWarren.com As an agency or industry partner… Learning Magento 2 Create a tiger team of developers focused on Magento 2 Allow those developers time in the day to learn Magento 2 Those developers should implement your first Magento 2 projects That team then helps the rest of your team through the learning curve #phpworld
105. JoshuaWarren.com When do I need to be Magento 2 ready? Learning Magento 2 Magento 2 will be released late enough in the year that most merchants won’t begin using it immediately. Merchants will also wait until their mission-critical extensions are available on Magento 2. Start learning it now - but don’t panic! #phpworld
106. JoshuaWarren.com Programming With Magento 2 coming to amazon.com & phparch.com #phpworld
107. Keep in Touch! @JoshuaSWarren JoshuaWarren.com Mage2DevBook.com joind.in/14790
108. JoshuaWarren.com #phpworld