Auth client

HTTP client used by user-service to call auth-service.

This module is intentionally free of any Pact dependency, it is production code. The Pact dependency only appears in test_consumer_auth, which exercises this client against a Pact mock server to define the contract between user_service (consumer) and auth-service (provider).

This also demonstrates the consumer-driven philosophy: the client only requests and parses the fields it actually needs (valid), even though auth-service may return additional information in its response.

Classes

AuthClient(base_url: str)

HTTP client for credential validation against auth-service.

This client is used by user_service to verify user credentials before creating accounts. It satisfies the CredentialsVerifier protocol and is the real implementation that would run in production.

The matching Pact consumer tests live in test_consumer_auth.

PARAMETER	DESCRIPTION
base_url	Base URL of auth-service, e.g. http://auth-service. Trailing slashes are stripped automatically. TYPE: str

Source code in examples/http/service_consumer_provider/auth_client.py

def __init__(self, base_url: str) -> None:
    """
    Initialise the auth client.

    Args:
        base_url:
            Base URL of `auth-service`, e.g. `http://auth-service`. Trailing
            slashes are stripped automatically.
    """
    self._base_url = base_url.rstrip("/")
    self._session = requests.Session()

Functions

validate_credentials(username: str, password: str) -> bool

Validate credentials against auth-service.

Sends a POST /auth/validate request with the supplied credentials and returns whether auth-service considers them valid. This is the only field the client reads from the response: an example of how consumer-driven contracts focus on what the consumer actually uses.

PARAMETER	DESCRIPTION
username	Username to validate. TYPE: str
password	Password to validate. TYPE: str

RETURNS	DESCRIPTION
bool	True when credentials are valid; otherwise False.

RAISES	DESCRIPTION
HTTPError	If auth-service responds with a non-2xx status.

Source code in examples/http/service_consumer_provider/auth_client.py

def validate_credentials(self, username: str, password: str) -> bool:
    """
    Validate credentials against `auth-service`.

    Sends a `POST /auth/validate` request with the supplied credentials and
    returns whether `auth-service` considers them valid. This is the only
    field the client reads from the response: an example of how
    consumer-driven contracts focus on what the consumer *actually uses*.

    Args:
        username:
            Username to validate.

        password:
            Password to validate.

    Returns:
        `True` when credentials are valid; otherwise `False`.

    Raises:
        requests.HTTPError:
            If `auth-service` responds with a non-2xx status.
    """
    response = self._session.post(
        f"{self._base_url}/auth/validate",
        json={"username": username, "password": password},
    )
    response.raise_for_status()
    body = response.json()
    return bool(body.get("valid", False))