app.py

from flask import Flask, jsonify, request, render_template
from flask_sqlalchemy import SQLAlchemy
from flask_bcrypt import Bcrypt
from flask_jwt_extended import JWTManager, create_access_token, jwt_required, get_jwt_identity
from flask_cors import CORS

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///myapp.db'
app.config['SECRET_KEY'] = 'your_secret_key_here'
app.config['JWT_SECRET_KEY'] = 'your_jwt_secret_key_here'
db = SQLAlchemy(app)
bcrypt = Bcrypt(app)
jwt = JWTManager(app)
CORS(app)

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(50), unique=True, nullable=False)
    password = db.Column(db.String(60), nullable=False)

# Sign up route
@app.route('/register', methods=['GET', 'POST'])
def register():
    if request.method == 'POST':
        username = request.form.get('username')
        password = request.form.get('password')
        
        existing_user = User.query.filter_by(username=username).first()
        if existing_user:
            return jsonify({"message": "Username already exists"}), 400
        
        hashed_password = bcrypt.generate_password_hash(password).decode('utf-8')
        new_user = User(username=username, password=hashed_password)
        
        db.session.add(new_user)
        db.session.commit()
        
        return jsonify({"message": "User registered successfully"}), 201

    return render_template('register.html')

# Authentication and token generation endpoint
@app.route('/login', methods=['POST'])
def login():
    data = request.get_json()
    username = data.get('username')
    password = data.get('password')

    user = User.query.filter_by(username=username).first()

    if user and bcrypt.check_password_hash(user.password, password):
        access_token = create_access_token(identity=user.username)
        return jsonify({"access_token": access_token}), 200
    else:
        return jsonify({"message": "Invalid credentials"}), 401

# Protected endpoint
@app.route('/protected', methods=['GET'])
@jwt_required()
def protected():
    current_user = get_jwt_identity()
    return jsonify({"message": f"Hello, {current_user}!"}), 200

@app.route('/')
def index():
    return render_template('index.html')

if __name__ == '__main__':
    with app.app_context():
        db.create_all()
    app.run(debug=True)