Class PayloadTooBig

src/websockets/exceptions.py:381–432

Raised when parsing a frame with a payload that exceeds the maximum size. The Sans-I/O layer uses this exception internally. It doesn't bubble up to the I/O layer. The :meth:`~websockets.extensions.Extension.decode` method of extensions must raise :exc:`PayloadTooBig` if decod

class PayloadTooBig(WebSocketException):
    """
    Raised when parsing a frame with a payload that exceeds the maximum size.

    The Sans-I/O layer uses this exception internally. It doesn't bubble up to
    the I/O layer.

    The :meth:`~websockets.extensions.Extension.decode` method of extensions
    must raise :exc:`PayloadTooBig` if decoding a frame would exceed the limit.

    """

    def __init__(
        self,
        size_or_message: int | None | str,
        max_size: int | None = None,
        current_size: int | None = None,
    ) -> None:
        if isinstance(size_or_message, str):
            assert max_size is None
            assert current_size is None
            warnings.warn(  # deprecated in 14.0 - 2024-11-09
                "PayloadTooBig(message) is deprecated; "
                "change to PayloadTooBig(size, max_size)",
                DeprecationWarning,
            )
            self.message: str | None = size_or_message
        else:
            self.message = None
            self.size: int | None = size_or_message
            assert max_size is not None
            self.max_size: int = max_size
            self.current_size: int | None = None
            self.set_current_size(current_size)

    def __str__(self) -> str:
        if self.message is not None:
            return self.message
        else:
            message = "frame "
            if self.size is not None:
                message += f"with {self.size} bytes "
            if self.current_size is not None:
                message += f"after reading {self.current_size} bytes "
            message += f"exceeds limit of {self.max_size} bytes"
            return message

    def set_current_size(self, current_size: int | None) -> None:
        assert self.current_size is None
        if current_size is not None:
            self.max_size += current_size
            self.current_size = current_size


class InvalidState(WebSocketException, AssertionError):