zulip/zerver/lib/exceptions.py

from enum import Enum, auto
from typing import Any, Dict, List, Optional, Tuple

from django.core.exceptions import ValidationError
from django.utils.translation import gettext as _


class ErrorCode(Enum):
    BAD_REQUEST = auto()  # Generic name, from the name of HTTP 400.
    REQUEST_VARIABLE_MISSING = auto()
    REQUEST_VARIABLE_INVALID = auto()
    INVALID_JSON = auto()
    BAD_IMAGE = auto()
    REALM_UPLOAD_QUOTA = auto()
    BAD_NARROW = auto()
    CANNOT_DEACTIVATE_LAST_USER = auto()
    MISSING_HTTP_EVENT_HEADER = auto()
    STREAM_DOES_NOT_EXIST = auto()
    UNAUTHORIZED_PRINCIPAL = auto()
    UNSUPPORTED_WEBHOOK_EVENT_TYPE = auto()
    ANOMALOUS_WEBHOOK_PAYLOAD = auto()
    BAD_EVENT_QUEUE_ID = auto()
    CSRF_FAILED = auto()
    INVITATION_FAILED = auto()
    INVALID_ZULIP_SERVER = auto()
    INVALID_MARKDOWN_INCLUDE_STATEMENT = auto()
    REQUEST_CONFUSING_VAR = auto()
    INVALID_API_KEY = auto()
    INVALID_ZOOM_TOKEN = auto()
    UNAUTHENTICATED_USER = auto()
    NONEXISTENT_SUBDOMAIN = auto()
    RATE_LIMIT_HIT = auto()
    USER_DEACTIVATED = auto()
    REALM_DEACTIVATED = auto()
    REMOTE_SERVER_DEACTIVATED = auto()
    PASSWORD_AUTH_DISABLED = auto()
    PASSWORD_RESET_REQUIRED = auto()
    AUTHENTICATION_FAILED = auto()
    UNAUTHORIZED = auto()


class JsonableError(Exception):
    """A standardized error format we can turn into a nice JSON HTTP response.

    This class can be invoked in a couple ways.

     * Easiest, but completely machine-unreadable:

         raise JsonableError(_("No such widget: {}").format(widget_name))

       The message may be passed through to clients and shown to a user,
       so translation is required.  Because the text will vary depending
       on the user's language, it's not possible for code to distinguish
       this error from others in a non-buggy way.

     * Fully machine-readable, with an error code and structured data:

         class NoSuchWidgetError(JsonableError):
             code = ErrorCode.NO_SUCH_WIDGET
             data_fields = ['widget_name']

             def __init__(self, widget_name: str) -> None:
                 self.widget_name: str = widget_name

             @staticmethod
             def msg_format() -> str:
                 return _("No such widget: {widget_name}")

         raise NoSuchWidgetError(widget_name)

       Now both server and client code see a `widget_name` attribute
       and an error code.

    Subclasses may also override `http_status_code`.
    """

    # Override this in subclasses, as needed.
    code: ErrorCode = ErrorCode.BAD_REQUEST

    # Override this in subclasses if providing structured data.
    data_fields: List[str] = []

    # Optionally override this in subclasses to return a different HTTP status,
    # like 403 or 404.
    http_status_code: int = 400

    def __init__(self, msg: str) -> None:
        # `_msg` is an implementation detail of `JsonableError` itself.
        self._msg: str = msg

    @staticmethod
    def msg_format() -> str:
        """Override in subclasses.  Gets the items in `data_fields` as format args.

        This should return (a translation of) a string literal.
        The reason it's not simply a class attribute is to allow
        translation to work.
        """
        # Secretly this gets one more format arg not in `data_fields`: `_msg`.
        # That's for the sake of the `JsonableError` base logic itself, for
        # the simplest form of use where we just get a plain message string
        # at construction time.
        return "{_msg}"

    @property
    def extra_headers(self) -> Dict[str, Any]:
        return {}

    #
    # Infrastructure -- not intended to be overridden in subclasses.
    #

    @property
    def msg(self) -> str:
        format_data = dict(
            ((f, getattr(self, f)) for f in self.data_fields), _msg=getattr(self, "_msg", None)
        )
        return self.msg_format().format(**format_data)

    @property
    def data(self) -> Dict[str, Any]:
        return dict(((f, getattr(self, f)) for f in self.data_fields), code=self.code.name)

    def __str__(self) -> str:
        return self.msg


class UnauthorizedError(JsonableError):
    code: ErrorCode = ErrorCode.UNAUTHORIZED
    http_status_code: int = 401

    def __init__(self, msg: Optional[str] = None, www_authenticate: Optional[str] = None) -> None:
        if msg is None:
            msg = _("Not logged in: API authentication or user session required")
        super().__init__(msg)
        if www_authenticate is None:
            self.www_authenticate = 'Basic realm="zulip"'
        elif www_authenticate == "session":
            self.www_authenticate = 'Session realm="zulip"'
        else:
            raise AssertionError("Invalid www_authenticate value!")

    @property
    def extra_headers(self) -> Dict[str, Any]:
        extra_headers_dict = super().extra_headers
        extra_headers_dict["WWW-Authenticate"] = self.www_authenticate
        return extra_headers_dict


class StreamDoesNotExistError(JsonableError):
    code = ErrorCode.STREAM_DOES_NOT_EXIST
    data_fields = ["stream"]

    def __init__(self, stream: str) -> None:
        self.stream = stream

    @staticmethod
    def msg_format() -> str:
        return _("Stream '{stream}' does not exist")


class StreamWithIDDoesNotExistError(JsonableError):
    code = ErrorCode.STREAM_DOES_NOT_EXIST
    data_fields = ["stream_id"]

    def __init__(self, stream_id: int) -> None:
        self.stream_id = stream_id

    @staticmethod
    def msg_format() -> str:
        return _("Stream with ID '{stream_id}' does not exist")


class CannotDeactivateLastUserError(JsonableError):
    code = ErrorCode.CANNOT_DEACTIVATE_LAST_USER
    data_fields = ["is_last_owner", "entity"]

    def __init__(self, is_last_owner: bool) -> None:
        self.is_last_owner = is_last_owner
        self.entity = _("organization owner") if is_last_owner else _("user")

    @staticmethod
    def msg_format() -> str:
        return _("Cannot deactivate the only {entity}.")


class InvalidMarkdownIncludeStatement(JsonableError):
    code = ErrorCode.INVALID_MARKDOWN_INCLUDE_STATEMENT
    data_fields = ["include_statement"]

    def __init__(self, include_statement: str) -> None:
        self.include_statement = include_statement

    @staticmethod
    def msg_format() -> str:
        return _("Invalid Markdown include statement: {include_statement}")


class RateLimited(JsonableError):
    code = ErrorCode.RATE_LIMIT_HIT
    http_status_code = 429

    def __init__(self, secs_to_freedom: Optional[float] = None) -> None:
        self.secs_to_freedom = secs_to_freedom

    @staticmethod
    def msg_format() -> str:
        return _("API usage exceeded rate limit")

    @property
    def extra_headers(self) -> Dict[str, Any]:
        extra_headers_dict = super().extra_headers
        if self.secs_to_freedom is not None:
            extra_headers_dict["Retry-After"] = self.secs_to_freedom

        return extra_headers_dict

    @property
    def data(self) -> Dict[str, Any]:
        data_dict = super().data
        data_dict["retry-after"] = self.secs_to_freedom

        return data_dict


class InvalidJSONError(JsonableError):
    code = ErrorCode.INVALID_JSON

    @staticmethod
    def msg_format() -> str:
        return _("Malformed JSON")


class OrganizationMemberRequired(JsonableError):
    code: ErrorCode = ErrorCode.UNAUTHORIZED_PRINCIPAL

    def __init__(self) -> None:
        pass

    @staticmethod
    def msg_format() -> str:
        return _("Must be an organization member")


class OrganizationAdministratorRequired(JsonableError):
    code: ErrorCode = ErrorCode.UNAUTHORIZED_PRINCIPAL

    def __init__(self) -> None:
        pass

    @staticmethod
    def msg_format() -> str:
        return _("Must be an organization administrator")


class OrganizationOwnerRequired(JsonableError):
    code: ErrorCode = ErrorCode.UNAUTHORIZED_PRINCIPAL

    def __init__(self) -> None:
        pass

    @staticmethod
    def msg_format() -> str:
        return _("Must be an organization owner")


class AuthenticationFailedError(JsonableError):
    # Generic class for authentication failures
    code: ErrorCode = ErrorCode.AUTHENTICATION_FAILED
    http_status_code = 401

    def __init__(self) -> None:
        pass

    @staticmethod
    def msg_format() -> str:
        return _("Your username or password is incorrect")


class UserDeactivatedError(AuthenticationFailedError):
    code: ErrorCode = ErrorCode.USER_DEACTIVATED

    @staticmethod
    def msg_format() -> str:
        return _("Account is deactivated")


class RealmDeactivatedError(AuthenticationFailedError):
    code: ErrorCode = ErrorCode.REALM_DEACTIVATED

    @staticmethod
    def msg_format() -> str:
        return _("This organization has been deactivated")


class RemoteServerDeactivatedError(AuthenticationFailedError):
    code: ErrorCode = ErrorCode.REALM_DEACTIVATED

    @staticmethod
    def msg_format() -> str:
        return _(
            "The mobile push notification service registration for your server has been deactivated"
        )


class PasswordAuthDisabledError(AuthenticationFailedError):
    code: ErrorCode = ErrorCode.PASSWORD_AUTH_DISABLED

    @staticmethod
    def msg_format() -> str:
        return _("Password authentication is disabled in this organization")


class PasswordResetRequiredError(AuthenticationFailedError):
    code: ErrorCode = ErrorCode.PASSWORD_RESET_REQUIRED

    @staticmethod
    def msg_format() -> str:
        return _("Your password has been disabled and needs to be reset")


class MarkdownRenderingException(Exception):
    pass


class InvalidAPIKeyError(JsonableError):
    code = ErrorCode.INVALID_API_KEY
    http_status_code = 401

    def __init__(self) -> None:
        pass

    @staticmethod
    def msg_format() -> str:
        return _("Invalid API key")


class InvalidAPIKeyFormatError(InvalidAPIKeyError):
    @staticmethod
    def msg_format() -> str:
        return _("Malformed API key")


class WebhookError(JsonableError):
    """
    Intended as a generic exception raised by specific webhook
    integrations. This class is subclassed by more specific exceptions
    such as UnsupportedWebhookEventType and AnomalousWebhookPayload.
    """

    data_fields = ["webhook_name"]

    def __init__(self) -> None:
        # webhook_name is often set by decorators such as webhook_view
        # in zerver/decorator.py
        self.webhook_name = "(unknown)"


class UnsupportedWebhookEventType(WebhookError):
    """Intended as an exception for event formats that we know the
    third-party service generates but which Zulip doesn't support /
    generate a message for.

    Exceptions where we cannot parse the event type, possibly because
    the event isn't actually from the service in question, should
    raise AnomalousWebhookPayload.
    """

    code = ErrorCode.UNSUPPORTED_WEBHOOK_EVENT_TYPE
    data_fields = ["webhook_name", "event_type"]

    def __init__(self, event_type: Optional[str]) -> None:
        super().__init__()
        self.event_type = event_type

    @staticmethod
    def msg_format() -> str:
        return _("The '{event_type}' event isn't currently supported by the {webhook_name} webhook")


class AnomalousWebhookPayload(WebhookError):
    """Intended as an exception for incoming webhook requests that we
    cannot recognize as having been generated by the service in
    question. (E.g. because someone pointed a Jira server at the
    GitHub integration URL).

    If we can parse the event but don't support it, use
    UnsupportedWebhookEventType.

    """

    code = ErrorCode.ANOMALOUS_WEBHOOK_PAYLOAD

    @staticmethod
    def msg_format() -> str:
        return _("Unable to parse request: Did {webhook_name} generate this event?")


class MissingAuthenticationError(JsonableError):
    code = ErrorCode.UNAUTHENTICATED_USER
    http_status_code = 401

    def __init__(self) -> None:
        pass

    # No msg_format is defined since this exception is caught and
    # converted into json_unauthorized in Zulip's middleware.


class InvalidSubdomainError(JsonableError):
    code = ErrorCode.NONEXISTENT_SUBDOMAIN
    http_status_code = 404

    def __init__(self) -> None:
        pass

    @staticmethod
    def msg_format() -> str:
        return _("Invalid subdomain")


class ZephyrMessageAlreadySentException(Exception):
    def __init__(self, message_id: int) -> None:
        self.message_id = message_id


class InvitationError(JsonableError):
    code = ErrorCode.INVITATION_FAILED
    data_fields = [
        "errors",
        "sent_invitations",
        "license_limit_reached",
        "daily_limit_reached",
    ]

    def __init__(
        self,
        msg: str,
        errors: List[Tuple[str, str, bool]],
        sent_invitations: bool,
        license_limit_reached: bool = False,
        daily_limit_reached: bool = False,
    ) -> None:
        self._msg: str = msg
        self.errors: List[Tuple[str, str, bool]] = errors
        self.sent_invitations: bool = sent_invitations
        self.license_limit_reached: bool = license_limit_reached
        self.daily_limit_reached: bool = daily_limit_reached


class AccessDeniedError(JsonableError):
    http_status_code = 403

    def __init__(self) -> None:
        pass

    @staticmethod
    def msg_format() -> str:
        return _("Access denied")


class ResourceNotFoundError(JsonableError):
    http_status_code = 404


class ValidationFailureError(JsonableError):
    # This class translations a Django ValidationError into a
    # Zulip-style JsonableError, sending back just the first error for
    # consistency of API.
    data_fields = ["errors"]

    def __init__(self, error: ValidationError) -> None:
        super().__init__(error.messages[0])
        self.errors = dict(error)