CODE EXAMPLE FOR PYTHON

flask-login

def login():
    if request.method == 'GET':
        return '''
<form action='login' method='POST'>
    <input type='text' name='name' id='name' placeholder='name'></input>
    <input type='password' name='pw' id='pw' placeholder='password'></input>
    <input type='submit' name='submit'></input>
</form>
               '''

    name = request.form.get('name')
    if request.form.get('pw') == password:
        user = User.query.filter_by(name=name).first()
        if not user:
            user = User(name=name)
            db.session.add(user)
            db.session.commit()
        flask_login.login_user(user)
        return redirect(url_for('protected'))

    return 'Bad login'