Securing Your Pylons App: A Beginner's Guide to User Authentication with AuthKit and SQLAlchemy

Solution:

Setting Up AuthKit:

• Install authkit: pip install authkit
• Configure AuthKit in development.ini:

[app:main]
authkit.data.provider = config_dict
authkit.data = {
    'users': {'admin': {'password': 'secret', 'roles': ['admin']}},
    'groups': {},
    'permissions': {},
}

• This defines a single user "admin" with password "secret" and "admin" role.

Creating User Model (using SQLAlchemy):

from sqlalchemy import create_engine, Column, String, Integer
from sqlalchemy.orm import sessionmaker

engine = create_engine('sqlite:///users.db')
Session = sessionmaker(bind=engine)

class User(Base):
    __tablename__ = 'users'
    id = Column(Integer, primary_key=True)
    username = Column(String(80), unique=True, nullable=False)
    password = Column(String(80), nullable=False)
    role = Column(String(80), nullable=False)

# Create tables using SQLAlchemy commands

session = Session()
user = User(username='john', password='john123', role='user')
session.add(user)
session.commit()
session.close()

• This code defines a User model with username, password, and role stored in a database.

Integrating AuthKit with SQLAlchemy:

• Install authkit.declarative: pip install authkit.declarative
• Use authkit.declarative.DeclarativeProvider for user data:

from authkit.declarative import DeclarativeProvider

provider = DeclarativeProvider(
    session_factory=Session,
    user_cls=User,
    username_col='username',
    password_col='password',
    role_col='role'
)

# Update development.ini with provider settings
authkit.data.provider = 'your_package.provider'

• This replaces the hardcoded user data with the DeclarativeProvider accessing users from the database.

Login and Authorization:

• Create login form template with username and password fields.
• Use authkit.authorize to check user roles before accessing protected views:

@authkit.authorize('admin')
def admin_page():
    # Accessible only to users with "admin" role
    pass

@view_config(action='login')
def login():
    form = ...  # Your login form
    if form.validate():
        username = form.get('username')
        password = form.get('password')
        user = provider.authenticate(username, password)
        if user:
            authkit.login(user)
            return redirect_to('/admin')
        else:
            flash('Invalid login credentials')
    return render_template('login.html', form=form)

• authkit.authorize decorator restricts access based on user roles.
• authkit.login stores user information in session for subsequent requests.

Logout and Session Management:

• Add a logout button or link to your application.
• Use authkit.logout to remove user information from the session.

Related Issues and Solutions:

• Password security: Hash and salt passwords before storing them in the database.
• Session security: Use secure cookies with HTTPS and appropriate HTTPOnly flags.
• Multiple authentication methods: Consider using OpenID or social login providers with additional libraries.
• Role-based access control: Implement granular permission checks based on roles or other attributes.

Remember: This is a simplified example. Real-world applications require careful security considerations and further customization based on your specific needs.

I hope this explanation helps you understand the basics of user authentication in Pylons + AuthKit!