authn_z

Backend_ppt/authn_z/services.tex

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+\section{Service Layer}
+
+\begin{frame}[shrink=15]{Mi az a Service Layer?}
+  \begin{block}{Definíció}
+    Tervezési minta - üzleti logika elválasztása controller-ektől és data layer-től.
+  \end{block}
+  \begin{itemize}
+    \item Separation of Concerns
+    \item Reusability (újrafelhasználható logika)
+    \item Testability (könnyebb tesztelés)
+    \item Maintainability
+  \end{itemize}
+  \begin{exampleblock}{Architektúra}
+    Controller → Service → Repository → Database
+  \end{exampleblock}
+\end{frame}
+
+\begin{frame}[shrink=15]{Háromrétegű architektúra}
+  \begin{columns}
+    \begin{column}{0.32\textwidth}
+      \begin{block}{Presentation}
+        \begin{small}
+        Controllers, Routes\\
+        HTTP req/res\\
+        Validáció
+        \end{small}
+      \end{block}
+    \end{column}
+    \begin{column}{0.32\textwidth}
+      \begin{block}{Business Logic}
+        \begin{small}
+        \textbf{Services}\\
+        Üzleti szabályok\\
+        Orchestration
+        \end{small}
+      \end{block}
+    \end{column}
+    \begin{column}{0.32\textwidth}
+      \begin{block}{Data Access}
+        \begin{small}
+        Repository\\
+        ORM\\
+        Database
+        \end{small}
+      \end{block}
+    \end{column}
+  \end{columns}
+  \begin{alertblock}{Fontos}
+    Controller \textbf{NEM} tartalmaz üzleti logikát, csak delegál!
+  \end{alertblock}
+\end{frame}
+
+\begin{frame}[shrink=15]{Service Layer előnyei}
+  \begin{enumerate}
+    \item \textbf{Separation}: Tiszta felelősségi körök
+    \item \textbf{Reusability}: Több controller használhatja
+    \item \textbf{Testability}: Könnyen unit tesztelhető
+    \item \textbf{Maintainability}: Változások izoláltak
+  \end{enumerate}
+\end{frame}
+
+\begin{frame}[fragile,shrink=20]{AuthService - Interface}
+  \begin{verbatim}
+class AuthService {
+  async register(userData) { ... }
+  async login(email, password) { ... }
+  async logout(userId) { ... }
+  async refreshToken(refreshToken) { ... }
+  async verifyToken(token) { ... }
+  async resetPassword(email) { ... }
+}
+  \end{verbatim}
+\end{frame}
+
+\begin{frame}[fragile,shrink=20]{AuthService - Register}
+  \begin{verbatim}
+class AuthService {
+  async register(userData) {
+    const exists = await this.userRepo.findByEmail(userData.email);
+    if (exists) throw new Error('User exists');
+    
+    const hashed = await bcrypt.hash(userData.password, 10);
+    const user = await this.userRepo.create({
+      ...userData,
+      password: hashed
+    });
+    
+    return { id: user.id, email: user.email };
+  }
+}
+  \end{verbatim}
+\end{frame}
+
+\begin{frame}[fragile,shrink=20]{AuthService - Login}
+  \begin{verbatim}
+async login(email, password) {
+  const user = await this.userRepo.findByEmail(email);
+  if (!user) throw new Error('Invalid credentials');
+  
+  const valid = await bcrypt.compare(password, user.password);
+  if (!valid) throw new Error('Invalid credentials');
+  
+  const token = jwt.sign(
+    { userId: user.id, role: user.role },
+    process.env.JWT_SECRET,
+    { expiresIn: '1h' }
+  );
+  
+  return { token, user: { id: user.id, email: user.email } };
+}
+  \end{verbatim}
+\end{frame}
+
+\begin{frame}[fragile,shrink=20]{Controller használja Service-t}
+  \begin{verbatim}
+class AuthController {
+  constructor(authService) {
+    this.authService = authService;
+  }
+  
+  async register(req, res) {
+    try {
+      const user = await this.authService.register(req.body);
+      res.status(201).json(user);
+    } catch (err) {
+      res.status(400).json({ error: err.message });
+    }
+  }
+  
+  async login(req, res) {
+    try {
+      const result = await this.authService.login(req.body.email, req.body.password);
+      res.json(result);
+    } catch (err) {
+      res.status(401).json({ error: err.message });
+    }
+  }
+}
+  \end{verbatim}
+\end{frame}
+
+\begin{frame}[fragile,shrink=20]{UserService példa}
+  \begin{verbatim}
+class UserService {
+  constructor(userRepo) {
+    this.userRepo = userRepo;
+  }
+  
+  async getById(id) {
+    const user = await this.userRepo.findById(id);
+    if (!user) throw new Error('User not found');
+    return user;
+  }
+  
+  async update(id, data) {
+    const user = await this.getById(id);
+    return await this.userRepo.update(id, data);
+  }
+  
+  async delete(id) {
+    await this.getById(id);
+    return await this.userRepo.delete(id);
+  }
+}
+  \end{verbatim}
+\end{frame}
+
+\begin{frame}[fragile,shrink=20]{Dependency Injection}
+  \begin{verbatim}
+// Repository
+class UserRepository {
+  async findById(id) { /* DB query */ }
+  async create(data) { /* DB insert */ }
+}
+
+// Service
+class UserService {
+  constructor(userRepository) {
+    this.userRepo = userRepository;
+  }
+  // ...
+}
+
+// DI container
+const userRepo = new UserRepository();
+const userService = new UserService(userRepo);
+const userController = new UserController(userService);
+  \end{verbatim}
+\end{frame}
+
+\begin{frame}[shrink=15]{Service Layer Best Practices}
+  \begin{enumerate}
+    \item Service-ek ne dependáljanak controller-ektől
+    \item Egy service = egy domain (User, Auth, Order)
+    \item Dependency Injection használata
+    \item Service-ek ne ismerjék HTTP-t (req, res)
+    \item Hibakezelés service-ben (throw Error)
+    \item Transaction logika service-ben
+    \item Async/await következetes használata
+  \end{enumerate}
+\end{frame}
+
+\begin{frame}[fragile,shrink=20]{Transaction példa Service-ben}
+  \begin{verbatim}
+class OrderService {
+  async createOrder(userId, items) {
+    const transaction = await db.transaction();
+    
+    try {
+      const order = await this.orderRepo.create({ userId }, transaction);
+      
+      for (const item of items) {
+        await this.orderItemRepo.create({ orderId: order.id, ...item }, transaction);
+      }
+      
+      await transaction.commit();
+      return order;
+    } catch (err) {
+      await transaction.rollback();
+      throw err;
+    }
+  }
+}
+  \end{verbatim}
+\end{frame}
+
+\begin{frame}[shrink=15]{Testing Service Layer}
+  \begin{itemize}
+    \item Service-ek unit tesztelése mock repository-val
+    \item Ne kelljen DB a unit teszthez
+    \item Integration teszt valódi DB-vel
+  \end{itemize}
+\end{frame}