alapok modosit

2026-01-28 02:29:38 +01:00
parent 3866a62feb
commit dc1ac19907
10 changed files with 2013 additions and 17 deletions
@@ -0,0 +1,339 @@
+% Express.js REST API
+
+\section{Express.js REST API}
+
+\begin{frame}{Mi az Express.js?}
+  \begin{block}{Express}
+    Gyors, minimalista web framework Node.js-hez.
+  \end{block}
+  
+  \begin{exampleblock}{Jellemzők}
+    \begin{itemize}
+      \item Egyszerű API
+      \item Middleware-alapú
+      \item Routing támogatás
+      \item Template engine-ek
+      \item Nagy közösség és sok plugin
+    \end{itemize}
+  \end{exampleblock}
+\end{frame}
+
+\begin{frame}[fragile,shrink=10]{Express telepítése}
+  \begin{exampleblock}{NPM inicializálás és telepítés}
+    \tiny
+    \begin{verbatim}
+npm init -y
+npm install express
+    \end{verbatim}
+  \end{exampleblock}
+  
+  \begin{exampleblock}{package.json}
+    \tiny
+    \begin{verbatim}
+{
+  "name": "my-api",
+  "version": "1.0.0",
+  "main": "server.js",
+  "scripts": {
+    "start": "node server.js",
+    "dev": "nodemon server.js"
+  },
+  "dependencies": {
+    "express": "^4.18.2"
+  }
+}
+    \end{verbatim}
+  \end{exampleblock}
+\end{frame}
+
+\begin{frame}[fragile,shrink=10]{Első Express szerver}
+  \begin{exampleblock}{server.js}
+    \tiny
+    \begin{verbatim}
+const express = require('express');
+const app = express();
+const PORT = 3000;
+
+// Middleware
+app.use(express.json());
+
+// Egyszerű route
+app.get('/', (req, res) => {
+  res.json({ message: 'Hello, Express!' });
+});
+
+// Szerver indítása
+app.listen(PORT, () => {
+  console.log(`Server running on http://localhost:${PORT}`);
+});
+    \end{verbatim}
+  \end{exampleblock}
+\end{frame}
+
+\begin{frame}[fragile,shrink=10]{GET végpont}
+  \begin{exampleblock}{Összes elem lekérdezése}
+    \tiny
+    \begin{verbatim}
+let users = [
+  {id: 1, name: 'Alice', email: 'alice@example.com'},
+  {id: 2, name: 'Bob', email: 'bob@example.com'}
+];
+
+app.get('/api/users', (req, res) => {
+  res.json(users);
+});
+    \end{verbatim}
+  \end{exampleblock}
+  
+  \begin{exampleblock}{Egy elem lekérdezése}
+    \tiny
+    \begin{verbatim}
+app.get('/api/users/:id', (req, res) => {
+  const user = users.find(u => u.id === parseInt(req.params.id));
+  if (!user) {
+    return res.status(404).json({ error: 'User not found' });
+  }
+  res.json(user);
+});
+    \end{verbatim}
+  \end{exampleblock}
+\end{frame}
+
+\begin{frame}[fragile,shrink=10]{POST végpont}
+  \begin{exampleblock}{Új elem létrehozása}
+    \tiny
+    \begin{verbatim}
+app.post('/api/users', (req, res) => {
+  const { name, email } = req.body;
+  
+  if (!name || !email) {
+    return res.status(400).json({ error: 'Name and email required' });
+  }
+  
+  const newUser = {
+    id: users.length + 1,
+    name,
+    email
+  };
+  
+  users.push(newUser);
+  res.status(201).json(newUser);
+});
+    \end{verbatim}
+  \end{exampleblock}
+\end{frame}
+
+\begin{frame}[fragile,shrink=10]{PUT és PATCH végpontok}
+  \begin{exampleblock}{PUT - Teljes frissítés}
+    \tiny
+    \begin{verbatim}
+app.put('/api/users/:id', (req, res) => {
+  const idx = users.findIndex(u => u.id === parseInt(req.params.id));
+  if (idx === -1) return res.status(404).json({ error: 'Not found' });
+  
+  users[idx] = { id: parseInt(req.params.id), ...req.body };
+  res.json(users[idx]);
+});
+    \end{verbatim}
+  \end{exampleblock}
+  
+  \begin{exampleblock}{PATCH - Részleges frissítés}
+    \tiny
+    \begin{verbatim}
+app.patch('/api/users/:id', (req, res) => {
+  const user = users.find(u => u.id === parseInt(req.params.id));
+  if (!user) return res.status(404).json({ error: 'Not found' });
+  
+  Object.assign(user, req.body);
+  res.json(user);
+});
+    \end{verbatim}
+  \end{exampleblock}
+\end{frame}
+
+\begin{frame}[fragile,shrink=10]{DELETE végpont}
+  \begin{exampleblock}{Elem törlése}
+    \tiny
+    \begin{verbatim}
+app.delete('/api/users/:id', (req, res) => {
+  const idx = users.findIndex(u => u.id === parseInt(req.params.id));
+  
+  if (idx === -1) {
+    return res.status(404).json({ error: 'User not found' });
+  }
+  
+  users.splice(idx, 1);
+  res.status(204).send();
+});
+    \end{verbatim}
+  \end{exampleblock}
+  
+  \begin{alertblock}{204 No Content}
+    Sikeres törlés esetén nem kell response body.
+  \end{alertblock}
+\end{frame}
+
+\begin{frame}[fragile,shrink=10]{Middleware-ek}
+  \begin{block}{Mi a Middleware?}
+    Függvények, amelyek hozzáférnek a request és response objektumokhoz, és a \texttt{next()} függvényhez.
+  \end{block}
+  
+  \begin{exampleblock}{Logger middleware}
+    \tiny
+    \begin{verbatim}
+app.use((req, res, next) => {
+  console.log(`${req.method} ${req.url}`);
+  next();
+});
+    \end{verbatim}
+  \end{exampleblock}
+  
+  \begin{exampleblock}{Auth middleware}
+    \tiny
+    \begin{verbatim}
+const authMiddleware = (req, res, next) => {
+  const token = req.headers.authorization;
+  if (!token) return res.status(401).json({ error: 'Unauthorized' });
+  next();
+};
+
+app.get('/api/protected', authMiddleware, (req, res) => {
+  res.json({ data: 'Protected data' });
+});
+    \end{verbatim}
+  \end{exampleblock}
+\end{frame}
+
+\begin{frame}[fragile,shrink=10]{Error Handling}
+  \begin{exampleblock}{Error handling middleware}
+    \tiny
+    \begin{verbatim}
+app.use((err, req, res, next) => {
+  console.error(err.stack);
+  res.status(500).json({
+    error: {
+      message: err.message,
+      code: 'INTERNAL_ERROR'
+    }
+  });
+});
+    \end{verbatim}
+  \end{exampleblock}
+  
+  \begin{exampleblock}{Try-catch async}
+    \tiny
+    \begin{verbatim}
+app.get('/api/users/:id', async (req, res, next) => {
+  try {
+    const user = await getUserById(req.params.id);
+    if (!user) throw new Error('User not found');
+    res.json(user);
+  } catch (error) {
+    next(error);
+  }
+});
+    \end{verbatim}
+  \end{exampleblock}
+\end{frame}
+
+\begin{frame}[fragile,shrink=10]{Validáció Joi-val (1/2)}
+  \begin{exampleblock}{Joi telepítése}
+    \tiny
+    \begin{verbatim}
+npm install joi
+    \end{verbatim}
+  \end{exampleblock}
+  
+  \begin{exampleblock}{Schema definiálás}
+    \tiny
+    \begin{verbatim}
+const Joi = require('joi');
+
+const userSchema = Joi.object({
+  name: Joi.string().min(3).max(50).required(),
+  email: Joi.string().email().required(),
+  age: Joi.number().integer().min(0).max(120)
+});
+    \end{verbatim}
+  \end{exampleblock}
+\end{frame}
+
+\begin{frame}[fragile,shrink=10]{Validáció Joi-val (2/2)}
+  \begin{exampleblock}{Validáció használata}
+    \tiny
+    \begin{verbatim}
+app.post('/api/users', (req, res) => {
+  const { error, value } = userSchema.validate(req.body);
+  
+  if (error) {
+    return res.status(400).json({
+      error: error.details[0].message
+    });
+  }
+  
+  // value a validált adat
+  const newUser = { id: users.length + 1, ...value };
+  users.push(newUser);
+  res.status(201).json(newUser);
+});
+    \end{verbatim}
+  \end{exampleblock}
+\end{frame}
+
+\begin{frame}[fragile,shrink=15]{Express Router - Moduláris routing (1/2)}
+  \begin{exampleblock}{routes/users.js}
+    \tiny
+    \begin{verbatim}
+const express = require('express');
+const router = express.Router();
+
+router.get('/', (req, res) => {
+  res.json({ message: 'Get all users' });
+});
+
+router.get('/:id', (req, res) => {
+  res.json({ message: `Get user ${req.params.id}` });
+});
+
+router.post('/', (req, res) => {
+  res.json({ message: 'Create user' });
+});
+
+module.exports = router;
+    \end{verbatim}
+  \end{exampleblock}
+\end{frame}
+
+\begin{frame}[fragile,shrink=10]{Express Router - Moduláris routing (2/2)}
+  \begin{exampleblock}{app.js - Router használata}
+    \tiny
+    \begin{verbatim}
+const express = require('express');
+const app = express();
+const userRoutes = require('./routes/users');
+
+app.use(express.json());
+app.use('/api/users', userRoutes);
+
+app.listen(3000);
+    \end{verbatim}
+  \end{exampleblock}
+  
+  \begin{alertblock}{Prefix}
+    Az \texttt{app.use('/api/users', userRoutes)} prefix-szel látja el az összes route-ot.
+  \end{alertblock}
+\end{frame}
+
+\begin{frame}{Összefoglalás - Express}
+  \begin{itemize}
+    \item Express = minimalista web framework
+    \item Routing: GET, POST, PUT, PATCH, DELETE
+    \item Middleware-ek: kérések feldolgozása
+    \item Error handling: hibakezelő middleware
+    \item Validáció: Joi vagy más library
+    \item Router: moduláris útvonalkezelés
+  \end{itemize}
+  
+  \vspace{0.5cm}
+  
+\end{frame}