Reference for ultralytics/hub/auth.py

class Auth:
    """Manages authentication processes including API key handling, cookie-based authentication, and header generation.

    The class supports different methods of authentication:
    1. Directly using an API key.
    2. Authenticating using browser cookies (specifically in Google Colab).
    3. Prompting the user to enter an API key.

    Attributes:
        id_token (str | bool): Token used for identity verification, initialized as False.
        api_key (str | bool): API key for authentication, initialized as False.
        model_key (bool): Placeholder for model key, initialized as False.

    Methods:
        authenticate: Attempt to authenticate with the server using either id_token or API key.
        auth_with_cookies: Attempt to fetch authentication via cookies and set id_token.
        get_auth_header: Get the authentication header for making API requests.
        request_api_key: Prompt the user to input their API key.

    Examples:
        Initialize Auth with an API key
        >>> auth = Auth(api_key="your_api_key_here")

        Initialize Auth without API key (will prompt for input)
        >>> auth = Auth()
    """

    id_token = api_key = model_key = False

    def __init__(self, api_key: str = "", verbose: bool = False):
        """Initialize Auth class and authenticate user.

        Handles API key validation, Google Colab authentication, and new key requests. Updates SETTINGS upon successful
        authentication.

        Args:
            api_key (str): API key or combined key_id format.
            verbose (bool): Enable verbose logging.
        """
        # Split the input API key in case it contains a combined key_model and keep only the API key part
        api_key = api_key.split("_", 1)[0]

        # Set API key attribute as value passed or SETTINGS API key if none passed
        self.api_key = api_key or SETTINGS.get("api_key", "")

        # If an API key is provided
        if self.api_key:
            # If the provided API key matches the API key in the SETTINGS
            if self.api_key == SETTINGS.get("api_key"):
                # Log that the user is already logged in
                if verbose:
                    LOGGER.info(f"{PREFIX}Authenticated ✅")
                return
            else:
                # Attempt to authenticate with the provided API key
                success = self.authenticate()
        # If the API key is not provided and the environment is a Google Colab notebook
        elif IS_COLAB:
            # Attempt to authenticate using browser cookies
            success = self.auth_with_cookies()
        else:
            # Request an API key
            success = self.request_api_key()

        # Update SETTINGS with the new API key after successful authentication
        if success:
            SETTINGS.update({"api_key": self.api_key})
            # Log that the new login was successful
            if verbose:
                LOGGER.info(f"{PREFIX}New authentication successful ✅")
        elif verbose:
            LOGGER.info(f"{PREFIX}Get API key from {API_KEY_URL} and then run 'yolo login API_KEY'")

def auth_with_cookies(self) -> bool:
    """Attempt to fetch authentication via cookies and set id_token.

    User must be logged in to HUB and running in a supported browser.

    Returns:
        (bool): True if authentication is successful, False otherwise.
    """
    if not IS_COLAB:
        return False  # Currently only works with Colab
    try:
        authn = request_with_credentials(f"{HUB_API_ROOT}/v1/auth/auto")
        if authn.get("success", False):
            self.id_token = authn.get("data", {}).get("idToken", None)
            self.authenticate()
            return True
        raise ConnectionError("Unable to fetch browser authentication details.")
    except ConnectionError:
        self.id_token = False  # reset invalid
        return False

def authenticate(self) -> bool:
    """Attempt to authenticate with the server using either id_token or API key.

    Returns:
        (bool): True if authentication is successful, False otherwise.
    """
    import requests  # scoped as slow import

    try:
        if header := self.get_auth_header():
            r = requests.post(f"{HUB_API_ROOT}/v1/auth", headers=header)
            if not r.json().get("success", False):
                raise ConnectionError("Unable to authenticate.")
            return True
        raise ConnectionError("User has not authenticated locally.")
    except ConnectionError:
        self.id_token = self.api_key = False  # reset invalid
        LOGGER.warning(f"{PREFIX}Invalid API key")
        return False

def get_auth_header(self):
    """Get the authentication header for making API requests.

    Returns:
        (dict | None): The authentication header if id_token or API key is set, None otherwise.
    """
    if self.id_token:
        return {"authorization": f"Bearer {self.id_token}"}
    elif self.api_key:
        return {"x-api-key": self.api_key}

def request_api_key(self, max_attempts: int = 3) -> bool:
    """Prompt the user to input their API key.

    Args:
        max_attempts (int): Maximum number of authentication attempts.

    Returns:
        (bool): True if authentication is successful, False otherwise.
    """
    import getpass

    for attempts in range(max_attempts):
        LOGGER.info(f"{PREFIX}Login. Attempt {attempts + 1} of {max_attempts}")
        input_key = getpass.getpass(f"Enter API key from {API_KEY_URL} ")
        self.api_key = input_key.split("_", 1)[0]  # remove model id if present
        if self.authenticate():
            return True
    raise ConnectionError(emojis(f"{PREFIX}Failed to authenticate ❌"))