PHPで学ぶプログラミングの教訓 / Lessons in Programming Learned through PHP

PHP Conference Japan 2024 のトークです
二本立てになってます

プロポーザル：https://fortee.jp/phpcon-2024/proposal/6567eb24-ac3e-4ce6-aefe-db33fdf61643

【前半】PHPで学ぶプログラミングの教訓

プログラミングには様々な原理原則が存在します
また開発者は開発をしていく上で色々な教訓を得ます
そういった生の知見には一定以上の関心があります（https://x.com/nrslib/status/1819699023713828936）

本セッションではこれまで培ってきた教訓を実例ベースで解説いたします

【後半】PHPで学ぶバックエンドソフトウェアアーキテクチャ選定の勘所

ソフトウェア開発とアーキテクチャは切っても切れない関係です
しかしながら、日進月歩のシステム開発の世界ではトレンドが刻一刻と変化します
そこで本セッションでは各種アーキテクチャの解説と、どのアーキテクチャを選択するかについてお話します

# URL
YouTube: https://www.youtube.com/c/narusemi
HomePage: https://nrslib.com
Twitter: https://twitter.com/nrslib
Instagram: https://www.instagram.com/nrslib/

Transcript

10. $counter = 1; $counter = $counter + 1; $counter = $counter * 2; $initialCounter = 1; $incrementedCounter = $initialCounter + 1; $doubledCounter = $incrementedCounter * 2;
13. $intUserAge = 25; $strUserName = "John Doe"; $userAge = 25; $userName = "John Doe";
15. $mmLength = 25; $cmLength = 250; $jpyPrice = 0; $usdPrice = 0;
17. if (!($userAge < 18 || $userName === "")) { echo "Valid user"; } if ($userAge >= 18 && $userName !== "") { echo "Valid user"; }
18. ($a || $b) == (!$a && !$b)
20. $isUserLoggedIn = true; if (!$isUserLoggedIn) { echo "This will never be executed"; }
23. // file1.php function calculateTax($amount) { return $amount * 0.1; } // file2.php function calculateTax($amount) { return $amount * 0.1; }
24. // tax_utils.php function calculateTax($amount) { return $amount * 0.1; } // file1.php require_once 'tax_utils.php'; echo calculateTax(100); // file2.php require_once 'tax_utils.php'; echo calculateTax(200);
30. $taxRate = 0.1; function calculateTax($price) { return $price * 0.1; // ハードコードされた値 } echo calculateTax(100); $taxRate = 0.1; function calculateTax($price, $taxRate) { return $price * $taxRate; } echo calculateTax(100, $taxRate);
35. $numberOfRecords = (int)readline("Enter the number of records: "); $data = []; for ($i = 0; $i < $numberOfRecords; $i++) { // 入力と処理が混在 $id = (int)readline("Enter ID for record $i: "); $name = readline("Enter name for record $i: "); $score = (int)readline("Enter score for record $i: "); $status = $score >= 50 ? 'Passed' : 'Failed'; $adjustedScore = $score + 5; $date = readline("Enter date for record $i (YYYY-MM-DD): "); $data[] = [ "id" => $id, "name" => $name, "score" => $score, "status" => $status, "adjusted_score" => $adjustedScore, "date" => $date ]; echo "ID: $id, Name: $name, Status: $status, Adjusted Score: $adjustedScore, Date: $date¥n"; }
36. $data = []; $numberOfRecords = (int)readline("Enter the number of records: "); for ($i = 0; $i < $numberOfRecords; $i++) { $id = (int)readline("Enter ID for record $i: "); $name = readline("Enter name for record $i: "); $score = (int)readline("Enter score for record $i: "); $date = readline("Enter date for record $i (YYYY-MM-DD): "); $data[] = [ "id" => $id, "name" => $name, "score" => $score, "date" => $date ]; } // 処理フェーズ foreach ($data as $record) { $record['status'] = $record['score'] >= 50 ? 'Passed' : 'Failed'; $record['adjusted_score'] = $record['score'] + 5; } // 出力フェーズ foreach ($data as $record) { echo "ID: {$record['id']}, Name: {$record['name']}, Status: {$record['status']}, Adjusted Score: {$record }
39. class A { public $b; public function __construct($b) { $this->b = $b; } } class B { public $a; public function __construct($a) { $this->a = $a; } } $a = new A(null); $b = new B($a); $a->b = $b; // 相互参照
48. class BankAccount { private $balance; public function __construct($balance) { $this->balance = $balance; } public function getBalance() { return $this->balance; } public function setBalance($balance) { $this->balance = $balance; } } $account = new BankAccount(100); if ($account->getBalance() >= 50) { $account->setBalance($account->getBalance() - 50); }
49. class BankAccount { private $balance; public function __construct($balance) { $this->balance = $balance; } public function withdraw($amount) { if ($this->balance >= $amount) { $this->balance -= $amount; } else { throw new Exception("Insufficient funds"); } } } $account = new BankAccount(100); $account->withdraw(50);
55. class SafeFileHandler { private $filePath; private $isReadOnly = true; public function __construct(string $filePath) { if (!file_exists($filePath)) { throw new Exception("File does not exist: $filePath"); } $this->filePath = $filePath; } public function setWritable(): void { $this->isReadOnly = false; } public function write(string $data): void { if ($this->isReadOnly) { throw new Exception("File is in read-only mode. Enable write mode explicitly using setWritable()."); } file_put_contents($this->filePath, $data, FILE_APPEND); } public function read(): string { return file_get_contents($this->filePath); } }
56. try { $fileHandler = new SafeFileHandler("example.txt"); echo "File content:¥n" . $fileHandler->read(); // 書き込みモードを明示的に設定しない限り、書き込みは失敗 $fileHandler->write("New data¥n"); // 例外をスロー } catch (Exception $e) { echo "Error: " . $e->getMessage() . "¥n"; } try { $fileHandler->setWritable(); $fileHandler->write("New data¥n"); // 成功 echo "Data written successfully.¥n"; } catch (Exception $e) { echo "Error: " . $e->getMessage() . "¥n"; }
59. class Logger { public function log($message) { echo "[Log]: $message¥n"; } } // データベースサービスが Logger を継承 class DatabaseService extends Logger { public function query($sql) { $this->log("Executing query: $sql"); // 実際のクエリ実行（疑似コード） echo "Query result for: $sql¥n"; } } // 使用例 $dbService = new DatabaseService(); $dbService->query("SELECT * FROM users");
60. interface LoggerInterface { public function log($message); } class ConsoleLogger implements LoggerInterface { public function log($message) { echo "[Console Log]: $message¥n"; } } class DatabaseService { private $logger; public function __construct(LoggerInterface $logger) { $this->logger = $logger; } public function query($sql) { $this->logger->log("Executing query: $sql"); // 実際のクエリ実行（疑似コード） echo "Query result for: $sql¥n"; } }
63. class User { public function saveToDatabase() { // Save user to database } public function sendWelcomeEmail() { // Send email to user } }
64. class User { public $name; public function __construct($name) { $this->name = $name; } } class UserRepository { public function save(User $user) { // Save user to database } } class EmailService { public function sendWelcomeEmail(User $user) { // Send email to user } }
67. class DiscountService { public function calculateDiscount($customerType, $amount) { if ($customerType === 'Regular') { return $amount * 0.9; // 10% 割引 } elseif ($customerType === 'VIP') { return $amount * 0.8; // 20% 割引 } else { return $amount; // 割引なし } } }
68. interface DiscountStrategy { public function calculate($amount); } class RegularDiscount implements DiscountStrategy { public function calculate($amount) { return $amount * 0.9; // 10% 割引 } } class VIPDiscount implements DiscountStrategy { public function calculate($amount) { return $amount * 0.8; // 20% 割引 } } class NoDiscount implements DiscountStrategy { public function calculate($amount) { return $amount; // 割引なし } } // 割引サービスクラス class DiscountService { private $strategy; public function __construct(DiscountStrategy $strategy) { $this->strategy = $strategy; } public function calculateDiscount($amount) { return $this->strategy->calculate($amount); } }
72. // データが複数箇所に重複して管理されている $userName = "John Doe"; // 1箇所目 $firstName = "John"; // 2箇所目 $lastName = "Doe"; // 3箇所目 echo "User: $userName¥n"; echo "Full Name: $firstName $lastName¥n"; // 名前の変更が一貫しない $firstName = "Jane"; // 更新漏れ echo "User: $userName¥n"; // 出力が不整合になる echo "Full Name: $firstName $lastName¥n";
73. class User { private $firstName; private $lastName; public function __construct($firstName, $lastName) { $this->firstName = $firstName; $this->lastName = $lastName; } public function getFullName() { return $this->firstName . ' ' . $this->lastName; } public function getFirstName() { return $this->firstName; } public function getLastName() { return $this->lastName; } public function setFirstName($firstName) { $this->firstName = $firstName; } public function setLastName($lastName) // 使用例 $user = new User("John", "Doe"); // データは一箇所で管理 echo "User: " . $user->getFullName() . "¥n"; // 名前を変更するとすべてが一貫性を保つ $user->setFirstName("Jane"); echo "User: " . $user->getFullName() . "¥n";
82. <?php spl_autoload_register(function ($class) { echo "Hello world!"; eval("class $class {}"); // クラスが未定義の場合に動的に作成 }); new SomeClass(); // Hello world!
88. class Email { private $to; private $from; private $subject; private $message; private $headers; public function __construct($to, $message, $from = 'noreply@example.com', $subject = 'No Subject', $headers = []) { $this->to = $to; $this->from = $from; $this->subject = $subject; $this->message = $message; $this->headers = $headers; } public function send() { // ヘッダーを構築 $formattedHeaders = "From: {$this->from}¥r¥n"; foreach ($this->headers as $key => $value) { $formattedHeaders .= "$key: $value¥r¥n"; } // デフォルト値が設定されているため、最小限の情報でメールを送信可能 mail($this->to, $this->subject, $this->message, $formattedHeaders); echo "Email sent to {$this->to} with subject '{$this->subject}'¥n"; } }
89. // 最小限の情報で使う場合（簡単なデフォルト設定が有効） $email = new Email( to: 'user@example.com', message: 'Welcome to our service!' ); $email->send(); // 必要な部分だけ上書きする場合 $email = new Email( to: 'user@example.com', message: 'Here is your daily update!', subject: 'Daily Update', headers: ['CC' => 'admin@example.com'] ); $email->send();
134. 136 class UserController { private UserService $userService; public function __construct(UserService $userService) { $this->userService = $userService; } public function createUser(string $id, string $name): void { $this->userService->createUser($id, $name); echo "User created successfully!¥n"; } public function getUser(string $id): void { $user = $this->userService->getUser($id); if ($user) { echo "User ID: " . $user->getId() . ", Name: " . $user->getName() . "¥n"; } else { echo "User not found.¥n"; } } }
136. 138 class UserService { private UserRepository $userRepository; public function __construct(UserRepository $userRepository) { $this->userRepository = $userRepository; } public function getUser(string $id): ?User { return $this->userRepository->findById($id); } public function createUser(string $id, string $name): void { $user = new User($id, $name); $this->userRepository->save($user); } }
138. 140 interface UserRepository { public function findById(string $id): ?User; public function save(User $user): void; }
140. 142 class InMemoryUserRepository implements UserRepository { private array $users = []; public function findById(string $id): ?User { return $this->users[$id] ?? null; } public function save(User $user): void { $this->users[$user->getId()] = $user; } }
152. 154 ビジネスロジックを中心に見据える
153. 155 ビジネスロジックを中心に見据える ヘキサゴナルアーキテクチャ と同じ
154. 156 ヘキサゴナルの外側の具体的な実装について 詳細に記載されているのが クリーンアーキテクチャ
157. 159 Enterprise Business Rules Entities
158. 160 Enterprise Business Rules Entities いわゆるドメインモデルを実装した ドメインオブジェクト ドメインの概念を表現する
160. 162 Application Business Rules Use Cases
161. 163 Application Business Rules Use Cases アプリケーションレイヤー
162. 164 Application Business Rules Use Cases アプリケーションレイヤー アプリケーションの目的である ドメインにおける問題を解決するため ドメインオブジェクトを束ねあげ ユースケースを実現する
164. 166 Interface Adapters
165. 167 Controllers Presenters Gateways Interface Adapters
166. 168 Controllers Presenters Gateways Interface Adapters
167. 169 Controllers Presenters Gateways Interface Adapters
168. 170 Controllers Presenters Gateways Interface Adapters
169. 171 Controllers Presenters Gateways Interface Adapters Mock
171. 173 Controller Presenter
172. 174 Controller Presenter
173. 175 Controller Presenter
174. 176 Controller Presenter
175. 177 Controller Presenter Use Case Interactor
176. 178 Controller Presenter Use Case Interactor Use Case Input Port Use Case Output Port
177. 179 Controller Presenter Use Case Interactor Use Case Input Port Use Case Output Port < I > < I >
178. 180 Controller Presenter Use Case Interactor Use Case Input Port Use Case Output Port < I > < I >
179. 181 Controller Presenter Use Case Interactor Use Case Input Port Use Case Output Port < I > < I >
180. 182 Controller Presenter Use Case Interactor Use Case Input Port Use Case Output Port < I > < I >
181. 183 Controller Presenter Use Case Interactor Use Case Input Port Use Case Output Port < I > < I >
182. 184 Frameworks & Drivers
183. 185 Frameworks & Drivers 詳細なコード ギークなコード ビジネスロジックが これに依存しないようにする
184. 186 Frameworks & Drivers 詳細なコード ギークなコード ビジネスロジックが これに依存しないようにする DIP
185. 187 依存の方向
186. 188 依存の方向は内向き 内側の変更は外に影響する 内側は外側を知らない 依存の方向
187. 189 依存の方向は内向き 内側の変更は外に影響する 内側は外側を知らない ドメインロジックで Web とか DB とか UI とかを 扱わない 依存の方向
190. 192 Controller Presenter Use Case Interactor Use Case Input Port Use Case Output Port < I > < I >
191. 193 Controller Presenter Use Case Interactor Use Case Input Port Use Case Output Port < I > < I > もっと細かく
192. 194 図 22-2 「Clean Architecture 達人に学ぶソフトウェアの構造と設計」（Robert C. Martin）より
193. 195 図 22-2 「Clean Architecture 達人に学ぶソフトウェアの構造と設計」（Robert C. Martin）より
194. 196 図 22-2 「Clean Architecture 達人に学ぶソフトウェアの構造と設計」（Robert C. Martin）より
195. 197 図 22-2 「Clean Architecture 達人に学ぶソフトウェアの構造と設計」（Robert C. Martin）より 上下は逆で 用語も少し違うけど 同じ
196. 198 図 22-2 「Clean Architecture 達人に学ぶソフトウェアの構造と設計」（Robert C. Martin）より 上下は逆で 用語も少し違うけど 同じ これに従って実装
200. 202 class UserController extends BaseController { public function index(UserGetListUseCaseInterface $interactor) { $request = new UserGetListRequest(1, 10); $interactor->handle($request); } public function create(UserCreateUseCaseInterface $interactor, Request $request) { $name = $request->input('name'); $request = new UserCreateRequest($name); $interactor->handle($request); } }
201. 203 class UserController extends BaseController { public function index(UserGetListUseCaseInterface $interactor) { $request = new UserGetListRequest(1, 10); $interactor->handle($request); } public function create(UserCreateUseCaseInterface $interactor, Request $request) { $name = $request->input('name'); $request = new UserCreateRequest($name); $interactor->handle($request); } } アプリケーションが要求するデータに入力を変換
202. 204 class UserController extends BaseController { public function index(UserGetListUseCaseInterface $interactor) { $request = new UserGetListRequest(1, 10); $interactor->handle($request); } public function create(UserCreateUseCaseInterface $interactor, Request $request) { $name = $request->input('name'); $request = new UserCreateRequest($name); $interactor->handle($request); } } アプリケーションが要求するデータに入力を変換
205. 207 DS : Data Structure
206. 208 DS : Data Structure class UserCreateRequest { /** * @var string */ private $name; /** * UserCreateRequest constructor. * @param string $name */ public function __construct(string $name) { $this->name = $name; } /** * @return string */ public function getName(): string { return $this->name; } }
209. 211 interface UserCreateUseCaseInterface { /** * @param UserCreateRequest $request * @return UserCreateResponse */ public function handle(UserCreateRequest $request); } 名称は好みで InputPort, UseCase, InputBoundary などのバリエーションがあるイメージ
212. 214 class UserCreateInteractor implements UserCreateUseCaseInterface { /** * @var UserRepositoryInterface */ private $userRepository; /** * @var UserCreatePresenter */ private $presenter; /** * UserCreateInteractor constructor. * @param UserRepositoryInterface $userRepository * @param UserCreatePresenterInterface $presenter */ public function __construct(UserRepositoryInterface $userRepository, UserCreatePresenterInterface $presenter) { $this->userRepository = $userRepository; $this->presenter = $presenter; } /** * @param UserCreateRequest $request * @return void */ public function handle(UserCreateRequest $request) { $userId = new UserId(uniqid()); $userName = $request->getName(); $createdUser = new User($userId, $userName); $this->userRepository->save($createdUser); $response = new UserCreateResponse($userId->getValue(), $userName); $this->presenter->output($response); } }
215. 217 interface UserRepositoryInterface { /** * @param User $user * @return mixed */ public function save(User $user); /** * @param UserId $id * @return User */ public function find(UserId $id); /** * @param int $page * @param int $size * @return mixed */ public function findByPage($page, $size); }
216. 218 interface UserRepositoryInterface { /** * @param User $user * @return mixed */ public function save(User $user); /** * @param UserId $id * @return User */ public function find(UserId $id); /** * @param int $page * @param int $size * @return mixed */ public function findByPage($page, $size); }
217. 219 interface UserRepositoryInterface { /** * @param User $user * @return mixed */ public function save(User $user); /** * @param UserId $id * @return User */ public function find(UserId $id); /** * @param int $page * @param int $size * @return mixed */ public function findByPage($page, $size); } Gateway
220. 222 実装は SQL 直打ちでも Entity の再構築が できれば なんでも OK class UserRepository implements UserRepositoryInterface { /** * @param User $user * @return mixed */ public function save(User $user) { DB::table('users') ->updateOrInsert( ['id' => $user->getId()], ['name' => $user->getName()] ); } /** * @param UserId $id * @return User */ public function find(UserId $id) { $user = DB::table('users')->where('id', $id->getValue())->first(); return new User($id, $user->name); } /** * @param int $page * @param int $size * @return mixed */ public function findByPage($page, $size) { // TODO: Implement findByPage() method. } }
223. 225 class User { /** * @var UserId */ private $id; /** * @var string */ private $name; /** * User constructor. * @param UserId $id * @param string $name */ public function __construct(UserId $id, string $name) { $this->id = $id; $this->name = $name; } /** * @return UserId */ public function getId(): UserId { return $this->id; } /** * @return string */ public function getName(): string { return $this->name; } }
226. 228 class UserCreateResponse { /** * @var string */ private $createdUserId; /** * @var string */ private $userName; /** * UserCreateResponse constructor. * @param string $createdUserId * @param string $userName */ public function __construct(string $createdUserId, string $userName) { $this->createdUserId = $createdUserId; $this->userName = $userName; } /** * @return string */ public function getCreatedUserId(): string { return $this->createdUserId; } /** * @return string */ public function getUserName(): string { return $this->userName; } }
229. 231 interface UserCreatePresenterInterface { /** * @param UserCreateResponse $outputData * @return mixed */ public function output(UserCreateResponse $outputData); }
232. 234 class UserCreatePresenter implements UserCreatePresenterInterface { /** * @var CleanArchitectureMiddleware */ private $middleware; /** * UserCreatePresenter constructor. * @param CleanArchitectureMiddleware $middleware */ public function __construct(CleanArchitectureMiddleware $middleware) { $this->middleware = $middleware; } public function output(UserCreateResponse $outputData) { $viewModel = new UserCreateViewModel($outputData->getCreatedUserId(), $outputData->getUserName()); $this->middleware->setData(view('user.create', compact('viewModel'))); } }
235. 237 class UserCreateViewModel { /** * @var string */ private $id; /** * @var string */ private $name; /** * UserCreateViewModel constructor. * @param string $id * @param string $name */ public function __construct(string $id, string $name) { $this->id = $id; $this->name = $name; } /** * @return string */ public function getId(): string { return $this->id; } /** * @return string */ public function getName(): string { return $this->name; } }