Securing a Python Application

ZTrust integrates with Python using OpenID Connect (OIDC) to handle authentication and authorization. This setup enables secure login and role-based access for your applications.

Prerequisites

Before integrating your Spring Boot application with ZTrust, ensure the following are in place:

• ZTrust SSO – A running ZTrust instance that will act as the identity and access management provider.

• Configured Realm and Client – A realm and client must already be created in ZTrust, with the client configured for OIDC. These settings will be used by your Python app to authenticate users and validate tokens.

With these prerequisites, your application will be ready to establish a secure connection with ZTrust using OpenID Connect.

Set up ZTrust

1. Log in to ZTrust Admin Console.

   

2. Click on Manage Realms in the sidebar to view the list of realms available in your ZTrust.

   

3. From the list of realms, select the realm where you want to integrate the Python Application.

   

4. From the left sidebar, navigate to the Clients section.

   

5. You will see a list of clients (applications). Choose/ Create the client for which you want to secure Python Application.

   

6. After select your client, it will take you to the settings page

   

7. Enter your application’s redirect URL in the Valid Redirect URIs field.

   

8. Then under Capability config turn on Client authentication and save

   

9. You will now see a new tab enabled, called Credentials.

   

10. Navigate to the Credentials tab, where you can view and copy the Client Secret.

    

11. With the ZTrust configuration complete, we can now move on to the Python side of the setup.

Set up Python

1. Load ZTrust Configuration

The application reads ZTrust authentication details (URL, realm, client ID, secret) from environment variables.

ZTRUST_AUTH_URL = os.getenv("ZTRUST_AUTH_URL")
ZTRUST_REALM = os.getenv("ZTRUST_REALM")
ZTRUST_CLIENT_ID = os.getenv("ZTRUST_CLIENT_ID")
ZTRUST_CLIENT_SECRET = os.getenv("ZTRUST_CLIENT_SECRET")

2. Fetch ZTrust Public Keys (JWKS)

Python application retrieves ZTrust’s official public keys to validate tokens.

JWKS_URL = f"{ZTRUST_AUTH_URL}/realms/{ZTRUST_REALM}/protocol/openid-connect/certs"
jwks_data = requests.get(JWKS_URL).json()

3. Validate User Token

When a user logs in, ZTrust issues a JWT (JSON Web Token).The app verifies the token and extracts user identity details.

def get_current_user(token: str = Depends(OAUTH2_SCHEME)) -> dict:
    payload = jwt.decode(
        token,
        key=get_public_key(token),
        algorithms=['RS256']
    )

4. Enforce Role-Based Access

User roles (e.g., Admin, SuperAdmin, User) are checked before allowing actions.

def role_checker(required_role: list[str]):
    def wrapper(user: dict = Depends(get_current_user)):
        roles = user.get("realm_access", {}).get("roles", [])
        if not any(role in roles for role in required_role):
            raise HTTPException(status_code=403, detail="Missing required role")
        return user
    return wrapper

5. Authentication & Security Dependencies

To implement secure authentication and integration with ZTrust, the following Python libraries were used:

• python-jose (3.5.0) – For handling JWT (JSON Web Token) encoding, decoding, and validation.

• python-multipart (0.0.9) – For managing form data and file uploads in FastAPI requests.

• requests (2.32.3) – For making HTTP requests, such as retrieving ZTrust’s public keys (JWKS).

• python-dotenv (1.0.1) – For securely loading environment variables (authentication URLs, client IDs, secrets) without hardcoding them in the codebase.