? ?? Node.js? Express.js? ???? ????? ???? ??? ??? ??? ????. Express.js? Node.js? ???? ???? ?? ??? ? ??????? ??? ? ???? ????????. ??? ???, ????, ??? ?? ? ?? ??.

?? ?????:

app.use(??)
app.use(??, ??)
GET, POST, PUT, DELETE
????? ????
???? ?? ???? ??
????? ??? ??
?? ?? ?? ????
??? ??
EJS

1. app.use(??)

Express.js? app.use(callback) ???? ???? ??? ???? ? ?????. ? ????? HTTP ???? URL? ???? ??????? ?? ?? ??? ???? ?????.

?) ? ??? ????? ???? ?? ??? ???? ???? ??? ???? ?????.

const express = require('express'); 
const app = express();

app.use((req, res, next) => {
  console.log('Middleware running for every request.');
  next();
});

2. app.use(??, ??)

? ??? ???? ?? ??? ????? ???? ? ????. ????? ??? ??? ??? ???? ???? ?????.

?) ? ???? /users? ???? ??? ???? ????? ??????.

app.use('/users', (req, res, next) => {
  console.log('Middleware only for /users route.');
  next();
});

3. ??, ????, ??, ????

??? ???? ???? ?? ???? ?? HTTP ???(GET, POST, PUT, DELETE ?)? ??? ? ????. ???? ? ??????? ??? ?????.

?) ? ???? ??? ??? ?? CRUD ??(??, ??, ????, ??)? ?? ??? ?????.

app.get('/users', (req, ress) => {
  res.send('Fetching all users');
});

app.post('/users', (req, res) => {
  res.send('Creating a new user');
});

app.put('/users/:id', (req, res) => {
  res.send(`Updating user with ID: ${req.params.id}`);
});

app.delete('/users/:id', (req, res) => {
  res.send('Deleting user with ID: ${req.params.id}`);
});

4. ????? ????

Express.js? ???? ??? ??(req) ? ??(res) ??? ???? ? ??? ??? ????? ????? ??-?? ??? ??? ? ????.

?? ??:

• ?? ??: ?? ??? ??? ??? ? ????.
• ??/?? ??: ????? ??? ???????, req? ???? ?????, res ??? ??? ? ????.
• ??-?? ?? ??: ????? ???? ?????? ?? ??? ??? ??? ? ????.

?) ? ??? ????? ?? ??? ??? ?? ???? ???? ?? ???? ?? ??????.

app.use((req, res, next) => {
  req.customData = 'Some custom data';
  next();
});

app.get('/', (req, res) => {
  res.send(`Data from middleware: ${req.customData}`);
});

5. ?? ???? ??

?? ???? next()? ???? ?? ????? ?? ???? ???? ??????. next()? ???? ??? ??? ??? ???? ?? ??? ??? ?????.

?) ??? ?? ? ???? ??? ??? ?? ???? ???? ??? ? ????.

const express = require('express'); 
const app = express();

app.use((req, res, next) => {
  console.log('Middleware running for every request.');
  next();
});

6. ????? ??? ????

Express Router? ??? ???????? ??? ???? ? ??? ?????. ??? ? ?? ?? ??? ???? ??? ? ??? ???.

?) ? ??? ???? /users? ????? /users/profile? ?? ??? ???? ??? ?? ?????.

app.use('/users', (req, res, next) => {
  console.log('Middleware only for /users route.');
  next();
});

7. ?? ?? ?? ????

??? ?? ? ??? ????? ??? ??? ???? ?? ?????. Express.js? ?? ???? ???? ?? ????? ?????.

?) express-session? ???? ??? ????? ?? ???? ?????, ?? ??? ?? ??? ?? ?? ?????.

app.get('/users', (req, ress) => {
  res.send('Fetching all users');
});

app.post('/users', (req, res) => {
  res.send('Creating a new user');
});

app.put('/users/:id', (req, res) => {
  res.send(`Updating user with ID: ${req.params.id}`);
});

app.delete('/users/:id', (req, res) => {
  res.send('Deleting user with ID: ${req.params.id}`);
});

8. ??? ??

??? ??? ???? ?? ???? ? ??? ???? ???? ???? ??? ? ????. ?? ?? EJS??? ???? ?? ?? ??? ??? ? ????.

?) ? ???? ??? ??? ??? EJS ???? ?????.

app.use((req, res, next) => {
  req.customData = 'Some custom data';
  next();
});

app.get('/', (req, res) => {
  res.send(`Data from middleware: ${req.customData}`);
});

9. EJS(???? ??????)

EJS? HTML? ???? HTML ?? ?? ?? JavaScript? ??? ? ?? ?? ?? ??? ?????. ????? ???? Express.js? ? ???? ?? ????? ?????.

?) <%= %> ??? JavaScript ???? HTML? ???? ? ?????.

app.use((req, res, next) => {
  console.log('First middleware');
  next();
});

app.use((req, res, next) => {
  console.log('Second middlware');
});

? ??? Node.js? Express.js? ???? ????? ?? ?????. ??? ??? PHP ??? ????? ?? ?? ??? ?????!