Examples for presentation.

.gitignore

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+.idea
+composer.phar
+vendor
+.phpunit.result.cache

README.md

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+Example for presentation.

composer.json

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+{
+  "name": "kukulis/readable-example",
+  "description": "Example for presentation",
+  "type": "project",
+  "authors": [
+    {
+      "name": "Giedrius Tumelis"
+    }
+  ],
+  "autoload": {
+    "psr-4": {
+      "Example\\": "sources/Example/"
+    }
+  },
+  "autoload-dev": {
+    "psr-4": {
+      "Tests\\": "tests/"
+    }
+  },
+  "require": {
+    "psr/event-dispatcher": "^1.0",
+    "symfony/uid": "^5.4",
+    "guzzlehttp/guzzle": "^7.9",
+    "ext-pdo": "*",
+    "ext-json": "*"
+  },
+  "require-dev": {
+    "phpunit/phpunit": "^9.5"
+  }
+}

phpunit.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="./vendor/phpunit/phpunit/phpunit.xsd"
+         bootstrap="vendor/autoload.php"
+         colors="true"
+         defaultTestSuite="Unit" >
+    <testsuites>
+        <testsuite name="Unit">
+            <directory suffix="Test.php">./tests/Unit</directory>
+        </testsuite>
+    </testsuites>
+</phpunit>

sources/Example/Bad/APIService.php

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+<?php
+
+namespace Example\Bad;
+
+use GuzzleHttp\Client;
+
+class APIService
+{
+    private Repository $dbService;
+
+    private Client $client;
+
+    public function __construct(Repository $dbService, Client $client)
+    {
+        $this->dbService = $dbService;
+        $this->client = $client;
+    }
+
+    public function getApiData(string $filter) : array
+    {
+        $response = $this->client->request('GET', 'api_endpoint/products', [
+            'query' => ['filter'=>$filter]
+        ]);
+
+        $json = $response->getBody()->getContents();
+
+
+        return json_decode($json, true);
+    }
+
+
+    /**
+     * @return Product[]
+     */
+    public function getProducts(string $filter) : array {
+
+        $data = $this->getApiData($filter);
+
+        $skus = [];
+        foreach ($data as $product) {
+            $skus[] = $product['sku'];
+        }
+        $products = $this->dbService->getProducts($skus);
+
+        /** @var Product[] $productsMap */
+        $productsMap = [];
+        foreach ($products as $product) {
+            $productsMap[$product->sku] = $product;
+        }
+
+        foreach ($data as $apiProduct) {
+            $productsMap[$apiProduct['sku']]->quantity = $apiProduct['amount'];
+        }
+
+        return $products;
+    }
+}

sources/Example/Bad/CalculatorService.php

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+<?php
+
+namespace Example\Bad;
+
+class CalculatorService
+{
+    private float $vatPercent;
+    private APIService  $apiService;
+
+    public function __construct(float $vatPercent, APIService $apiService)
+    {
+        $this->vatPercent = $vatPercent;
+        $this->apiService = $apiService;
+    }
+
+
+    /**
+     * @return Product[]
+     */
+    public function getProducts(string $requestData) : array {
+        $products = $this->apiService->getProducts($requestData);
+
+        foreach ($products as $product) {
+            $product->price = $product->price * ( 1 + $this->vatPercent);
+        }
+
+        return $products;
+    }
+}

sources/Example/Bad/Controller.php

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+<?php
+
+namespace Example\Bad;
+
+use Psr\Http\Message\RequestInterface;
+
+class Controller
+{
+    private CalculatorService  $calculator;
+
+    public function __construct(CalculatorService $calculator)
+    {
+        $this->calculator = $calculator;
+    }
+
+    /**
+     * @return Product[]
+     */
+    public function getProducts(RequestInterface $request) : array {
+        $params = $request->getBody();
+        return $this->calculator->getProducts($params);
+    }
+}

sources/Example/Bad/Product.php

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+<?php
+
+namespace Example\Bad;
+
+class Product
+{
+    public string $sku = '';
+    public int $quantity = 0;
+    public float $price = 0;
+
+    public function setSku(string $sku): Product
+    {
+        $this->sku = $sku;
+        return $this;
+    }
+
+    public function setQuantity(int $quantity): Product
+    {
+        $this->quantity = $quantity;
+        return $this;
+    }
+
+    public function setPrice(float $price): Product
+    {
+        $this->price = $price;
+        return $this;
+    }
+
+
+}

sources/Example/Bad/Repository.php

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+<?php
+
+namespace Example\Bad;
+
+use PDO;
+
+class Repository
+{
+    private PDO $pdo;
+
+    public function __construct(PDO $pdo)
+    {
+        $this->pdo = $pdo;
+    }
+
+    /**
+     * @return Product[]
+     */
+    public function getProducts($skus) : array{
+        $quotedSkus = [];
+        foreach($skus as $sku){
+            $quotedSkus[] = $this->pdo->quote($sku);
+        }
+        $skusStr = implode(',', $quotedSkus);
+        $sql = "SELECT * FROM products where id in ($skusStr)";
+
+        return $this->pdo->query($sql)->fetchAll(PDO::FETCH_CLASS, Product::class);
+    }
+}

sources/Example/Good/ApiClient.php

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+<?php
+
+namespace Example\Good;
+
+use GuzzleHttp\Client;
+
+class ApiClient
+{
+
+    private Client $client;
+
+    public function __construct(Client $client)
+    {
+        $this->client = $client;
+    }
+
+    /**
+     * @return Product[]
+     */
+    public function getProducts(string $filter): array
+    {
+        $response = $this->client->request('GET', 'api_endpoint/products', [
+            'query' => ['filter' => $filter]
+        ]);
+
+        $json = $response->getBody()->getContents();
+
+
+        $data = json_decode($json, true);
+
+        $products = [];
+        foreach ($data as $productArray) {
+            $products[] = (new Product())->setData($productArray);
+        }
+
+        return $products;
+    }
+}

sources/Example/Good/Controller.php

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+<?php
+
+namespace Example\Good;
+
+use Psr\Http\Message\RequestInterface;
+
+class Controller
+{
+    private ApiClient $apiClient;
+    private Repository $repository;
+    private VATCalculator $vatCalculator;
+
+    public function __construct(ApiClient $apiClient, Repository $repository, VATCalculator $vatCalculator)
+    {
+        $this->apiClient = $apiClient;
+        $this->repository = $repository;
+        $this->vatCalculator = $vatCalculator;
+    }
+
+
+    /**
+     * @return Product[]
+     */
+    public function getProducts(RequestInterface $request) : array {
+        $params = $request->getBody();
+
+        $products = $this->apiClient->getProducts($params);
+
+        $skus = [];
+        foreach ($products as $product) {
+            $skus[] = $product->sku;
+        }
+
+        $dbProducts = $this->repository->getProducts($skus);
+
+        Product::copyQuantities($dbProducts, $products);
+
+        $this->vatCalculator->applyVat($dbProducts);
+
+        return $dbProducts;
+    }
+
+}

sources/Example/Good/Product.php

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+<?php
+
+namespace Example\Good;
+
+class Product
+{
+    public string $sku = '';
+    public int $quantity = 0;
+    public float $price = 0;
+
+    public function setSku(string $sku): Product
+    {
+        $this->sku = $sku;
+        return $this;
+    }
+
+    public function setQuantity(int $quantity): Product
+    {
+        $this->quantity = $quantity;
+        return $this;
+    }
+
+    public function setPrice(float $price): Product
+    {
+        $this->price = $price;
+        return $this;
+    }
+
+
+    /**
+     * Instead of this better to use some DAO lib like JMSSerializer, or cuyz/valinor.
+     */
+    public function setData(array $data): Product {
+        $this->sku = $data['sku'] ?? '';
+        $this->quantity = $data['amount'] ?? 0;
+        $this->price = $data['price'] ?? 0;
+
+        return $this;
+    }
+
+    /**
+     * @param Product[] $destinationProducts
+     * @param Product[] $sourceProducts
+     */
+    public static function copyQuantities(array $destinationProducts, array $sourceProducts ) {
+        $indexedBySku = [];
+        foreach ($destinationProducts as $destinationProduct) {
+            $indexedBySku[$destinationProduct->sku] = $destinationProduct;
+        }
+
+        foreach ($sourceProducts as $sourceProduct) {
+            if ( !array_key_exists($sourceProduct->sku, $indexedBySku) ) {
+                continue;
+            }
+            $indexedBySku[$sourceProduct->sku]->setQuantity($sourceProduct->quantity);
+        }
+    }
+}

sources/Example/Good/Repository.php

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+<?php
+
+namespace Example\Good;
+
+use PDO;
+
+class Repository
+{
+    private PDO $pdo;
+
+    public function __construct(PDO $pdo)
+    {
+        $this->pdo = $pdo;
+    }
+
+    /**
+     * @return Product[]
+     */
+    public function getProducts($skus) : array{
+        $quotedSkus = [];
+        foreach($skus as $sku){
+            $quotedSkus[] = $this->pdo->quote($sku);
+        }
+        $skusStr = implode(',', $quotedSkus);
+        $sql = "SELECT * FROM products where id in ($skusStr)";
+
+        return $this->pdo->query($sql)->fetchAll(PDO::FETCH_CLASS, Product::class);
+    }
+}

sources/Example/Good/VATCalculator.php

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+<?php
+
+namespace Example\Good;
+
+class VATCalculator
+{
+    private float $vat;
+
+    /**
+     * @param float $vat
+     */
+    public function __construct(float $vat)
+    {
+        $this->vat = $vat;
+    }
+
+    /**
+     * @param Product[] $products
+     */
+    public function applyVat(array $products) : void {
+        foreach ($products as $product) {
+            $product->setPrice( $product->price * (1+$this->vat/100) );
+        }
+    }
+}

sources/Example/VeryGood/ApiClient.php

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+<?php
+
+namespace Example\VeryGood;
+
+use GuzzleHttp\Client;
+
+class ApiClient
+{
+
+    private Client $client;
+
+    public function __construct(Client $client)
+    {
+        $this->client = $client;
+    }
+
+    /**
+     * @return Product[]
+     */
+    public function getProducts(string $filter): array {
+        $response = $this->client->request('GET', 'api_endpoint/products', [
+            'query' => ['filter'=>$filter]
+        ]);
+
+        $json = $response->getBody()->getContents();
+        $data = json_decode($json, true);
+
+        return array_map( fn($element)=> (new Product())->setData($element), $data);
+    }
+}

sources/Example/VeryGood/Controller.php

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+<?php
+
+namespace Example\VeryGood;
+
+use Psr\Http\Message\RequestInterface;
+
+class Controller
+{
+    private ApiClient $apiClient;
+    private Repository $repository;
+
+    private float $vat;
+
+    public function __construct(ApiClient $apiClient, Repository $repository, float $vat)
+    {
+        $this->apiClient = $apiClient;
+        $this->repository = $repository;
+        $this->vat = $vat;
+    }
+
+    public function getProducts(RequestInterface $request): array
+    {
+        $params = $request->getBody();
+
+        $apiProducts = $this->apiClient->getProducts($params);
+
+        $skus = array_map(fn($product) => $product->sku, $apiProducts);
+
+        $dbProducts = $this->repository->getProducts($skus);
+
+        Indexer::applyWhenMatch(
+            $dbProducts,
+            $apiProducts,
+            fn($product) => $product->getSku(),
+            fn($product) => $product->getSku(),
+            fn(Product $dbProduct, Product $apiProduct) => $dbProduct->setQuantity($apiProduct->quantity));
+
+        return array_map(fn($product) => $product->applyVat($this->vat), $dbProducts);
+    }
+}

sources/Example/VeryGood/Indexer.php

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+<?php
+
+namespace Example\VeryGood;
+class Indexer
+{
+    public static function reindex(array $elements, callable $indexGetter)
+    {
+        $result = [];
+        foreach ($elements as $element) {
+            $index = call_user_func($indexGetter, $element);
+            $result[$index] = $element;
+        }
+
+        return $result;
+    }
+
+    public static function applyWhenMatch(
+        array    $elements,
+        array    $sourceElements,
+        callable $sourceKeyGetter,
+        callable $destinationKeyGetter,
+        callable $action
+    )
+    {
+        $indexedSources = self::reindex($sourceElements, $sourceKeyGetter);
+        foreach ($elements as $element) {
+            $destinationKey = call_user_func($destinationKeyGetter, $element);
+            if (!array_key_exists($destinationKey, $indexedSources)) {
+                continue;
+            }
+            call_user_func($action, $element, $indexedSources[$destinationKey]);
+        }
+    }
+}

sources/Example/VeryGood/Product.php

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+<?php
+
+namespace Example\VeryGood;
+
+class Product
+{
+    public string $sku = '';
+    public int $quantity = 0;
+    public float $price = 0;
+
+    public function setSku(string $sku): Product
+    {
+        $this->sku = $sku;
+        return $this;
+    }
+
+    public function setQuantity(int $quantity): Product
+    {
+        $this->quantity = $quantity;
+        return $this;
+    }
+
+    public function setPrice(float $price): Product
+    {
+        $this->price = $price;
+        return $this;
+    }
+
+    /**
+     * Instead of this better to use some DAO lib like JMSSerializer, or cuyz/valinor.
+     */
+    public function setData(array $data): Product
+    {
+        $this->sku = $data['sku'] ?? '';
+        $this->quantity = $data['amount'] ?? 0;
+        $this->price = $data['price'] ?? 0;
+
+        return $this;
+    }
+
+    public function applyVat(float $vat): Product
+    {
+        $this->price = $this->price * (1 + $vat / 100);
+
+        return $this;
+    }
+
+    public function getSku(): string
+    {
+        return $this->sku;
+    }
+
+    public function getQuantity(): int
+    {
+        return $this->quantity;
+    }
+
+    public function getPrice(): float
+    {
+        return $this->price;
+    }
+}

sources/Example/VeryGood/Repository.php

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+<?php
+
+namespace Example\VeryGood;
+
+use PDO;
+
+class Repository
+{
+    private PDO $pdo;
+
+    public function __construct(PDO $pdo)
+    {
+        $this->pdo = $pdo;
+    }
+
+    /**
+     * @return Product[]
+     */
+    public function getProducts($skus): array
+    {
+        $quotedSkus = [];
+        foreach ($skus as $sku) {
+            $quotedSkus[] = $this->pdo->quote($sku);
+        }
+        $skusStr = implode(',', $quotedSkus);
+        $sql = "SELECT * FROM products where id in ($skusStr)";
+
+        return $this->pdo->query($sql)->fetchAll(PDO::FETCH_CLASS, Product::class);
+    }
+}

tests/Unit/BadTest.php

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+<?php
+
+namespace Tests\Unit;
+
+use Example\Bad\APIService;
+use Example\Bad\CalculatorService;
+use Example\Bad\Controller;
+use Example\Bad\Repository;
+use Example\Bad\Product;
+use GuzzleHttp\Client;
+use GuzzleHttp\Psr7\Request;
+use GuzzleHttp\Psr7\Response;
+use PDO;
+use PDOStatement;
+use PHPUnit\Framework\TestCase;
+
+class BadTest extends TestCase
+{
+    public function testBad()
+    {
+        $guzzleClient = $this->createMock(Client::class);
+
+        // make call of controller from the guzzle client
+        $guzzleClient->method('request')->willReturn(
+            new Response(200, [],
+                '[
+                { "sku" : "x1234", "amount": "10" },
+                { "sku" : "x1235", "amount": "20" },
+                { "sku" : "x4567", "amount": "5" }
+            ]'
+            )
+        );
+
+        $pdo = $this->createMock(PDO::class);
+        $pdoResult = $this->createMock(PDOStatement::class);
+        $pdoResult->method('fetchAll')->willReturn([
+            (new Product())->setSku("x1234")->setPrice(10),
+            (new Product())->setSku("x1235")->setPrice(20),
+            (new Product())->setSku("x4567")->setPrice(30),
+        ]);
+        $pdo->method('query')->willReturn($pdoResult);
+
+        $dbService = new Repository($pdo);
+        $apiService = new ApiService($dbService, $guzzleClient);
+        $calculatorService = new CalculatorService(0.20, $apiService);
+        $controller = new Controller($calculatorService);
+
+        $products = $controller->getProducts(new Request('get', '/api', [], 'cosmetics'));
+
+        $expectedProducts = [
+            (new Product())->setSku("x1234")->setPrice(12)->setQuantity(10),
+            (new Product())->setSku("x1235")->setPrice(24)->setQuantity(20),
+            (new Product())->setSku("x4567")->setPrice(36)->setQuantity(5),
+        ];
+
+        $this->assertEquals($expectedProducts, $products);
+    }
+}

tests/Unit/GoodTest.php

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+<?php
+
+namespace Tests\Unit;
+
+use Example\Good\ApiClient;
+use Example\Good\Controller;
+use Example\Good\Product;
+use Example\Good\Repository;
+use Example\Good\VATCalculator;
+use GuzzleHttp\Client;
+use GuzzleHttp\Psr7\Request;
+use GuzzleHttp\Psr7\Response;
+use PDO;
+use PDOStatement;
+use PHPUnit\Framework\TestCase;
+
+class GoodTest extends TestCase
+{
+    public function testGood()
+    {
+        $guzzleClient = $this->createMock(Client::class);
+
+        // make call of controller from the guzzle client
+        $guzzleClient->method('request')->willReturnCallback(
+            function () {
+                return new Response(200, [],
+                    '[
+                { "sku" : "x1234", "amount": "10" },
+                { "sku" : "x1235", "amount": "20" },
+                { "sku" : "x4567", "amount": "5" }
+            ]'
+
+                );
+            }
+        );
+
+        $pdo = $this->createMock(PDO::class);
+        $pdoResult = $this->createMock(PDOStatement::class);
+        $pdoResult->method('fetchAll')->willReturn([
+            (new Product())->setSku("x1234")->setPrice(10),
+            (new Product())->setSku("x1235")->setPrice(20),
+            (new Product())->setSku("x4567")->setPrice(30),
+        ]);
+        $pdo->method('query')->willReturn($pdoResult);
+
+        $dbService = new Repository($pdo);
+        $apiService = new ApiClient($guzzleClient);
+
+        $vatCalculator = new VATCalculator(20);
+
+        $controller = new Controller($apiService, $dbService, $vatCalculator);
+
+        $products = $controller->getProducts(new Request('get', '/api', [], 'cosmetics'));
+
+        $expectedProducts = [
+            (new Product())->setSku("x1234")->setPrice(12)->setQuantity(10),
+            (new Product())->setSku("x1235")->setPrice(24)->setQuantity(20),
+            (new Product())->setSku("x4567")->setPrice(36)->setQuantity(5),
+        ];
+
+        $this->assertEquals($expectedProducts, $products);
+    }
+}

tests/Unit/VeryGoodTest.php

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+<?php
+
+namespace Tests\Unit;
+
+use Example\VeryGood\ApiClient;
+use Example\VeryGood\Controller;
+use Example\VeryGood\Product;
+use Example\VeryGood\Repository;
+use GuzzleHttp\Client;
+use GuzzleHttp\Psr7\Request;
+use GuzzleHttp\Psr7\Response;
+use PDO;
+use PDOStatement;
+use PHPUnit\Framework\TestCase;
+
+
+class VeryGoodTest extends TestCase
+{
+    public function testVeryGood2()
+    {
+        $guzzleClient = $this->createMock(Client::class);
+
+        // make call of controller from the guzzle client
+        $guzzleClient->method('request')->willReturnCallback(
+            function () {
+                return new Response(200, [],
+                    '[
+                { "sku" : "x1234", "amount": "10" },
+                { "sku" : "x1235", "amount": "20" },
+                { "sku" : "x4567", "amount": "5" }
+            ]'
+
+                );
+            }
+        );
+
+        $pdo = $this->createMock(PDO::class);
+        $pdoResult = $this->createMock(PDOStatement::class);
+        $pdoResult->method('fetchAll')->willReturn([
+            (new Product())->setSku("x1234")->setPrice(10),
+            (new Product())->setSku("x1235")->setPrice(20),
+            (new Product())->setSku("x4567")->setPrice(30),
+        ]);
+        $pdo->method('query')->willReturn($pdoResult);
+
+        $dbService = new Repository($pdo);
+        $apiService = new ApiClient($guzzleClient);
+
+        $controller = new Controller($apiService, $dbService, 20);
+
+        $products = $controller->getProducts(new Request('get', '/api', [], 'cosmetics'));
+
+        $expectedProducts = [
+            (new Product())->setSku("x1234")->setPrice(12)->setQuantity(10),
+            (new Product())->setSku("x1235")->setPrice(24)->setQuantity(20),
+            (new Product())->setSku("x4567")->setPrice(36)->setQuantity(5),
+        ];
+
+        $this->assertEquals($expectedProducts, $products);
+
+    }
+
+}