Chapter 4Node.js & Express~1 min read

Routing आणि Parameters

Dynamic Routes बनवा

Real-world APIs मध्ये dynamic routes लागतात — `/users/123`, `/products/laptop`. Express मध्ये route parameters आणि query strings handle करता येतात.

Route parameters (:param)

javascript

// :id हा route parameter आहे
app.get('/users/:id', (req, res) => {
  const userId = req.params.id;
  res.json({ message: `User ${userId} मिळाला` });
});
// GET /users/42 → { message: "User 42 मिळाला" }

// Multiple params
app.get('/courses/:courseId/chapters/:chapterId', (req, res) => {
  const { courseId, chapterId } = req.params;
  res.json({ courseId, chapterId });
});

Query strings (?key=value)

javascript

// GET /products?category=laptop&sort=price
app.get('/products', (req, res) => {
  const { category, sort, page = 1, limit = 10 } = req.query;

  res.json({
    category,
    sort,
    page: Number(page),
    limit: Number(limit),
    message: `${category} products fetched`
  });
});

Express Router — routes organize करा

javascript

// routes/userRoutes.js
const router = require('express').Router();

router.get('/', (req, res) => res.json({ users: [] }));
router.get('/:id', (req, res) => res.json({ id: req.params.id }));
router.post('/', (req, res) => res.json({ created: req.body }));
router.delete('/:id', (req, res) => res.json({ deleted: req.params.id }));

module.exports = router;

// app.js मध्ये
const userRoutes = require('./routes/userRoutes');
app.use('/users', userRoutes);
// आता: GET /users, GET /users/1, POST /users, DELETE /users/1

✅ Key Points — लक्षात ठेवा

▸req.params — route parameters (:id)
▸req.query — query string (?key=val)
▸req.body — POST request body
▸Express Router — routes organize करा
▸app.use('/prefix', router) — mount router

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Express.js — पहिला Server

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Middleware