How do I implement user login in Python, Java, and JavaScript?

How do I implement user login in Python, Java, and JavaScript?

In Python, you can use Flask with Flask-Login. In Java, consider using Spring Security. For JavaScript, you can use Node.js with Express and Passport.

Can you provide a code example for each language?

Sure! Here's a simple example for each:

Python (Flask):

from flask import Flask, request, redirect, url_for
app = Flask(__name__)

@app.route('/login', methods=['GET', 'POST'])
def login():
    if request.method == 'POST':
        # handle login logic
        return redirect(url_for('home'))
    return 'Login Form'

Java (Spring Security):

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {
    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .authorizeRequests()
            .antMatchers('/login').permitAll()
            .anyRequest().authenticated();
    }
}

JavaScript (Node.js with Express):

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

app.post('/login', passport.authenticate('local', {
    successRedirect: '/home',
    failureRedirect: '/login'
}));

What libraries or frameworks do I need to use for these examples?

For Python, you'll need Flask and Flask-Login. For Java, use Spring Boot and Spring Security. For JavaScript, install Express and Passport.