Vinai Kopp - MM15NL

Meet-Magento NL, 28. May 2015

Vinai Kopp

About Vinai

2 The beautiful Magento Module November, 1st 2014

„Coding and Magento are obviously important parts of my life. But there is more then that. When I am not diving into the code or giving trainings, I like to spend time with my family, to run, to swim and to tend to my bees.”

3 Modern Module Architecture Meet-Magento NL, 28. May 2015

Why Architecture?

Motivation


„We want our applications to contain two attributes: 1. High Maintainability 2. Low Technical Debt”

Chris Fidao Author of Implementing Laravel


The Story

A Startup Delivery Service

Headline Georgia 28. Introduction


Copy Georgia 20. Hi. I’m Vinai. This talk is about Magento 1. I think it is important to understand as much as possible about Magento 1, as it is the basis for Magento 2, where the framework has received …

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Customer Groups

9 Modern Module Architecture

Guest (NOT LOGGED IN) + General:

Delivery only to specified postcodes


Wholesale:

Approved at registration, no postcode check

THINK BIG


Franchise


Countries

Postcode Filter Rules


Rule Field Example Rule 1

Country AT

Customer Groups NOT LOGGED IN, General

Postcodes 1, 2, 13, 12

Rule Field Example Rule 2

Country NL

Customer Groups NOT LOGGED IN, General

Postcodes 3500, 3521, 3527, ...

Wholesaler


No matching rule ===

delivery allowed



Implementation #1

A Magento Module

Typical Magento Module


1.  Create app/code/local/FoodInJar/PostCodeFilter/

2.  Create postcodefilter_rule table with setup script

3.  Create Rule model, resource model and collection

4.  Create admin grid and form and controller

5.  Create Observer for checkout integration

6.  Create Ajax controller for additional frontend integration




What does this code tell you?


„ I am a Magento Module.”



How reusable is it?


„Well … not really.”



Are there any tests?


„Why bother, it's boilerplate!”



Does it work well with other extensions? Does it work with a new version of Magento 1.x? How fast can changes to the filter rules be implemented? How quickly can a new developer start to work on the code? How long to deployment after a bug was fixed? Can I use it in Magento 2?




„Okay, I admit it. Tests do add value.”


Implementation #2

A Decoupled Architecture

Implementation #2


A PHP Library

Decoupling


My PostCodeFilter Code

Decoupling


My PostCodeFilter Code 2

Decoupling



Flow of Information



Storage

User Interface

ApplicaHon

Domain

Infrastructure

Implementation as a Library


Layered Architecture


User Interface (Delivery)

ApplicaHon (Use Cases)

Domain (Problem Space)

Infrastructure (DB)



Layered Architecture




Ports & Adapters

Hexagonical Architecture


Alistair Cockburn

http://alistair.cockburn.us/Hexagonal+architecture

„ Allow an application to equally be driven by users, programs, automated test or batch scripts, and to be developed and tested in isolation from its eventual run-time devices and databases.”



UI

Storage

Application +

Domain



Web

Tests

Mock DB

CSV MySQL

SOAP API

Tests

Application +

Domain

Email



Postcode Filter Rules

Magento Admin Tests

Magento Frontend

Magento DB



Well... where do I start…?



class CustomerSpecifiesShippingAddressTest extends \PHPUnit_Framework_TestCase { /** * @test */ public function itShouldReturnFalseIfTheCustomerMayNotOrder() { $this->assertFalse( $customerSpecifiesShippingAddress->isAllowedDestination( $customerGroupId, $country, $postCode ) ); } }

Test First



class CustomerSpecifiesShippingAddress { public function isAllowedDestination( $customerGroupId, $iso2country, $postCode ) { return false; } }

Test First




Use Case Orientated Design




Value Objects




„ Architecture exposes usage”

Uncle Bob Martin


Plugging the Library into Magento



Storage

Using the Library in a Magento Module


Checking Customer Postcodes




use \Varien_Event_Observer as Event; use VinaiKopp\PostCodeFilter\CustomerSpecifiesShippingAddress; class VinaiKopp_PostCodeFilter_Model_Observer { // ... public function checkPostCodeIsAllowedIfNextStepIsShippingMethod( Event $event ) { /** @var Mage_Core_Controller_Response_Http $response */ $response = $event->getData('controller_action')->getResponse(); if ($this->isNextStepShippingMethod($response)) { $quote = $this->getCurrentCustomerQuote(); if (!$this->quoteMayBeOrdered($quote, $quote->getShippingAddress())) { $this->setErrorJsonResponse( $response, $quote->getShippingAddress() ); } } }

Query Postcode Filter Rules



use \Varien_Event_Observer as Event; use VinaiKopp\PostCodeFilter\CustomerSpecifiesShippingAddress; class VinaiKopp_PostCodeFilter_Model_Observer { // ... private function quoteMayBeOrdered( Mage_Sales_Model_Quote $quote, Mage_Sales_Model_Quote_Address $shippingAddress ) { $useCase = $this->getCustomerSpecifiesPostCodeUseCase(); return $useCase->isAllowedDestination( (int)$quote->getCustomerGroupId(), $shippingAddress->getCountry(), $shippingAddress->getPostcode() ); }

Query Postcode Filter Rules




Storing Postcode Filter Rules in the Magento DB





Storage


namespace VinaiKopp\PostCodeFilter; interface RuleStorage { public function findPostCodesByCountryAndGroupId( $iso2country, $customerGroupId ); public function findRulesByCountryAndGroupIds( $iso2country, array $customerGroupIds ); public function findAllRules(); public function create($iso2country, $customerGroupId, array $postCodes); public function delete($iso2country, $customerGroupId); public function beginTransaction(); public function commitTransaction(); public function rollbackTransaction(); }

Storage Interface (Library Side)



use VinaiKopp\PostCodeFilter\RuleStorage; class VinaiKopp_PostCodeFilter_Model_Resource_RuleStorage implements RuleStorage { public function findPostCodesByCountryAndGroupId( $iso2country, $customerGroupId ) { $query = $this->readConnection->select() ->from($this->tableName, 'post_codes') ->where('country=?', $iso2country) ->where('customer_group_id=?', $customerGroupId); $result = $this->readConnection->fetchOne($query); if (! $result) { return []; } return $this->splitPostCodes($result); // ... }

Storage Implementation (Magento Side)


Instantiation of Library Classes


Creating Something from Nothing


use VinaiKopp\PostCodeFilter\CustomerSpecifiesShippingAddress; class VinaiKopp_PostCodeFilter_Helper_Factory extends Mage_Core_Helper_Abstract { // ... public function createCustomerChecksPostCodeUseCase() { $this->registerPostCodeFilterAutoloader(); $class = 'vinaikopp_postcodefilter/ruleStorage' $storage = Mage::getResourceModel($class); return new CustomerSpecifiesShippingAddress( new RuleRepositoryReader($storage) ); }




class VinaiKopp_PostCodeFilter_Helper_Factory extends Mage_Core_Helper_Abstract { private $autoloaderRegistered = false; private function registerPostCodeFilterAutoloader() { if ($this->autoloaderRegistered) { return; } $this->autoloaderRegistered = true; spl_autoload_register(function ($class) { $prefix = 'VinaiKopp\\PostCodeFilter\\'; if (strncmp($prefix, $class, strlen($prefix)) !== 0) { return; } $this->buildPathToFileAndIncludeIfFileExists(); }, false, true); }





Grid uses Adapter Collection



use VinaiKopp\PostCodeFilter\Rule\Rule; use VinaiKopp\PostCodeFilter\AdminViewsRuleList; class VinaiKopp_PostCodeFilter_Model_RuleCollection extends Varien_Data_Collection_Db { // ... public function load($printQuery = false, $logQuery = false) { $rules = $this->getUseCase()->fetchRules(); $this->_items = array_map([$this, 'convertRuleToVarienObject'], $rules); $this->_setIsLoaded(true); return $this; }

Collection adapts Postcode Filter Rules



use VinaiKopp\PostCodeFilter\Rule\Rule; use VinaiKopp\PostCodeFilter\AdminViewsRuleList; class VinaiKopp_PostCodeFilter_Model_RuleCollection extends Varien_Data_Collection_Db { // ... private function convertRuleToVarienObject(Rule $rule) { return new Varien_Object([ 'country' => $rule->getCountryValue(), 'customer_groups' => $rule->getCustomerGroupIdValues(), 'post_codes' => $rule->getPostCodeValues() ]); }

Collection adapts the Postcode Filter Rules


(GoF Adapter Pattern: Convert the interface of a class into another interface the clients expect.)

Dependencies


OOP means Managing Dependencies

Visualizing Code Dependencies


https://github.com/mamuz/PhpDependencyAnalysis

PhpDependencyAnalysis

Visualizing Code Dependencies: Call, Usage and Inheritance Graphs


https://github.com/mamuz/PhpDependencyAnalysis

Does the Postcode Filter comply with the DIP?


Dependency Inversion Principle


•  High-level modules should not depend on low-level modules. Both should depend on abstractions.

•  Abstractions should not depend on details.

•  Details should depend on abstractions.

Summary


Costs vs. Benefits


- More code (Library + Magento Adapter)

Complexity

Summary


Costs vs. Benefits


- Increased development cost (the first few times)

Complexity

Summary


Costs vs. Benefits


- Development has to be more thoughtful

Complexity

Summary


Costs vs. Benefits


Freedom

Summary


Costs vs. Benefits


+ Lower maintenance costs (Domain code independent of framework, test coverage)

Freedom

Summary


Costs vs. Benefits


+ Developers unfamiliar with Magento more productive

Freedom

Summary


Costs vs. Benefits


+ Real reusability (on component and class level)

Freedom

Summary


Costs vs. Benefits


+ Better upgradability (only one side of the adapter affected)

Freedom

Summary


Costs vs. Benefits


+ Easier to reason about domain

Freedom

Summary


Costs vs. Benefits


+ Usable with other platforms or frameworks (are you ready for Magento 2?)

Freedom

Summary


Costs vs. Benefits


+ Developer Satisfaction (able to choose testing, design, methodology, dicipline)

Freedom

Thank you!


Please, Ask questions Share thoughts Now :)


Vinai Kopp | @VinaiKopp | [email protected] https://github.com/Vinai/VinaiKopp_PostCodeFilter

Vinai Kopp - MM15NL

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