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- """
- :mod:`websockets.exceptions` defines the following hierarchy of exceptions.
- * :exc:`WebSocketException`
- * :exc:`ConnectionClosed`
- * :exc:`ConnectionClosedOK`
- * :exc:`ConnectionClosedError`
- * :exc:`InvalidURI`
- * :exc:`InvalidProxy`
- * :exc:`InvalidHandshake`
- * :exc:`SecurityError`
- * :exc:`ProxyError`
- * :exc:`InvalidProxyMessage`
- * :exc:`InvalidProxyStatus`
- * :exc:`InvalidMessage`
- * :exc:`InvalidStatus`
- * :exc:`InvalidStatusCode` (legacy)
- * :exc:`InvalidHeader`
- * :exc:`InvalidHeaderFormat`
- * :exc:`InvalidHeaderValue`
- * :exc:`InvalidOrigin`
- * :exc:`InvalidUpgrade`
- * :exc:`NegotiationError`
- * :exc:`DuplicateParameter`
- * :exc:`InvalidParameterName`
- * :exc:`InvalidParameterValue`
- * :exc:`AbortHandshake` (legacy)
- * :exc:`RedirectHandshake` (legacy)
- * :exc:`ProtocolError` (Sans-I/O)
- * :exc:`PayloadTooBig` (Sans-I/O)
- * :exc:`InvalidState` (Sans-I/O)
- * :exc:`ConcurrencyError`
- """
- from __future__ import annotations
- import warnings
- from .imports import lazy_import
- __all__ = [
- "WebSocketException",
- "ConnectionClosed",
- "ConnectionClosedOK",
- "ConnectionClosedError",
- "InvalidURI",
- "InvalidProxy",
- "InvalidHandshake",
- "SecurityError",
- "ProxyError",
- "InvalidProxyMessage",
- "InvalidProxyStatus",
- "InvalidMessage",
- "InvalidStatus",
- "InvalidHeader",
- "InvalidHeaderFormat",
- "InvalidHeaderValue",
- "InvalidOrigin",
- "InvalidUpgrade",
- "NegotiationError",
- "DuplicateParameter",
- "InvalidParameterName",
- "InvalidParameterValue",
- "ProtocolError",
- "PayloadTooBig",
- "InvalidState",
- "ConcurrencyError",
- ]
- class WebSocketException(Exception):
- """
- Base class for all exceptions defined by websockets.
- """
- class ConnectionClosed(WebSocketException):
- """
- Raised when trying to interact with a closed connection.
- Attributes:
- rcvd: If a close frame was received, its code and reason are available
- in ``rcvd.code`` and ``rcvd.reason``.
- sent: If a close frame was sent, its code and reason are available
- in ``sent.code`` and ``sent.reason``.
- rcvd_then_sent: If close frames were received and sent, this attribute
- tells in which order this happened, from the perspective of this
- side of the connection.
- """
- def __init__(
- self,
- rcvd: frames.Close | None,
- sent: frames.Close | None,
- rcvd_then_sent: bool | None = None,
- ) -> None:
- self.rcvd = rcvd
- self.sent = sent
- self.rcvd_then_sent = rcvd_then_sent
- assert (self.rcvd_then_sent is None) == (self.rcvd is None or self.sent is None)
- def __str__(self) -> str:
- if self.rcvd is None:
- if self.sent is None:
- return "no close frame received or sent"
- else:
- return f"sent {self.sent}; no close frame received"
- else:
- if self.sent is None:
- return f"received {self.rcvd}; no close frame sent"
- else:
- if self.rcvd_then_sent:
- return f"received {self.rcvd}; then sent {self.sent}"
- else:
- return f"sent {self.sent}; then received {self.rcvd}"
- # code and reason attributes are provided for backwards-compatibility
- @property
- def code(self) -> int:
- warnings.warn( # deprecated in 13.1 - 2024-09-21
- "ConnectionClosed.code is deprecated; "
- "use Protocol.close_code or ConnectionClosed.rcvd.code",
- DeprecationWarning,
- )
- if self.rcvd is None:
- return frames.CloseCode.ABNORMAL_CLOSURE
- return self.rcvd.code
- @property
- def reason(self) -> str:
- warnings.warn( # deprecated in 13.1 - 2024-09-21
- "ConnectionClosed.reason is deprecated; "
- "use Protocol.close_reason or ConnectionClosed.rcvd.reason",
- DeprecationWarning,
- )
- if self.rcvd is None:
- return ""
- return self.rcvd.reason
- class ConnectionClosedOK(ConnectionClosed):
- """
- Like :exc:`ConnectionClosed`, when the connection terminated properly.
- A close code with code 1000 (OK) or 1001 (going away) or without a code was
- received and sent.
- """
- class ConnectionClosedError(ConnectionClosed):
- """
- Like :exc:`ConnectionClosed`, when the connection terminated with an error.
- A close frame with a code other than 1000 (OK) or 1001 (going away) was
- received or sent, or the closing handshake didn't complete properly.
- """
- class InvalidURI(WebSocketException):
- """
- Raised when connecting to a URI that isn't a valid WebSocket URI.
- """
- def __init__(self, uri: str, msg: str) -> None:
- self.uri = uri
- self.msg = msg
- def __str__(self) -> str:
- return f"{self.uri} isn't a valid URI: {self.msg}"
- class InvalidProxy(WebSocketException):
- """
- Raised when connecting via a proxy that isn't valid.
- """
- def __init__(self, proxy: str, msg: str) -> None:
- self.proxy = proxy
- self.msg = msg
- def __str__(self) -> str:
- return f"{self.proxy} isn't a valid proxy: {self.msg}"
- class InvalidHandshake(WebSocketException):
- """
- Base class for exceptions raised when the opening handshake fails.
- """
- class SecurityError(InvalidHandshake):
- """
- Raised when a handshake request or response breaks a security rule.
- Security limits can be configured with :doc:`environment variables
- <../reference/variables>`.
- """
- class ProxyError(InvalidHandshake):
- """
- Raised when failing to connect to a proxy.
- """
- class InvalidProxyMessage(ProxyError):
- """
- Raised when an HTTP proxy response is malformed.
- """
- class InvalidProxyStatus(ProxyError):
- """
- Raised when an HTTP proxy rejects the connection.
- """
- def __init__(self, response: http11.Response) -> None:
- self.response = response
- def __str__(self) -> str:
- return f"proxy rejected connection: HTTP {self.response.status_code:d}"
- class InvalidMessage(InvalidHandshake):
- """
- Raised when a handshake request or response is malformed.
- """
- class InvalidStatus(InvalidHandshake):
- """
- Raised when a handshake response rejects the WebSocket upgrade.
- """
- def __init__(self, response: http11.Response) -> None:
- self.response = response
- def __str__(self) -> str:
- return (
- f"server rejected WebSocket connection: HTTP {self.response.status_code:d}"
- )
- class InvalidHeader(InvalidHandshake):
- """
- Raised when an HTTP header doesn't have a valid format or value.
- """
- def __init__(self, name: str, value: str | None = None) -> None:
- self.name = name
- self.value = value
- def __str__(self) -> str:
- if self.value is None:
- return f"missing {self.name} header"
- elif self.value == "":
- return f"empty {self.name} header"
- else:
- return f"invalid {self.name} header: {self.value}"
- class InvalidHeaderFormat(InvalidHeader):
- """
- Raised when an HTTP header cannot be parsed.
- The format of the header doesn't match the grammar for that header.
- """
- def __init__(self, name: str, error: str, header: str, pos: int) -> None:
- super().__init__(name, f"{error} at {pos} in {header}")
- class InvalidHeaderValue(InvalidHeader):
- """
- Raised when an HTTP header has a wrong value.
- The format of the header is correct but the value isn't acceptable.
- """
- class InvalidOrigin(InvalidHeader):
- """
- Raised when the Origin header in a request isn't allowed.
- """
- def __init__(self, origin: str | None) -> None:
- super().__init__("Origin", origin)
- class InvalidUpgrade(InvalidHeader):
- """
- Raised when the Upgrade or Connection header isn't correct.
- """
- class NegotiationError(InvalidHandshake):
- """
- Raised when negotiating an extension or a subprotocol fails.
- """
- class DuplicateParameter(NegotiationError):
- """
- Raised when a parameter name is repeated in an extension header.
- """
- def __init__(self, name: str) -> None:
- self.name = name
- def __str__(self) -> str:
- return f"duplicate parameter: {self.name}"
- class InvalidParameterName(NegotiationError):
- """
- Raised when a parameter name in an extension header is invalid.
- """
- def __init__(self, name: str) -> None:
- self.name = name
- def __str__(self) -> str:
- return f"invalid parameter name: {self.name}"
- class InvalidParameterValue(NegotiationError):
- """
- Raised when a parameter value in an extension header is invalid.
- """
- def __init__(self, name: str, value: str | None) -> None:
- self.name = name
- self.value = value
- def __str__(self) -> str:
- if self.value is None:
- return f"missing value for parameter {self.name}"
- elif self.value == "":
- return f"empty value for parameter {self.name}"
- else:
- return f"invalid value for parameter {self.name}: {self.value}"
- class ProtocolError(WebSocketException):
- """
- Raised when receiving or sending a frame that breaks the protocol.
- The Sans-I/O implementation raises this exception when:
- * receiving or sending a frame that contains invalid data;
- * receiving or sending an invalid sequence of frames.
- """
- 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,
- cur_size: int | None = None,
- ) -> None:
- if isinstance(size_or_message, str):
- assert max_size is None
- assert cur_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.cur_size: int | None = None
- self.set_current_size(cur_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.cur_size is not None:
- message += f"after reading {self.cur_size} bytes "
- message += f"exceeds limit of {self.max_size} bytes"
- return message
- def set_current_size(self, cur_size: int | None) -> None:
- assert self.cur_size is None
- if cur_size is not None:
- self.max_size += cur_size
- self.cur_size = cur_size
- class InvalidState(WebSocketException, AssertionError):
- """
- Raised when sending a frame is forbidden in the current state.
- Specifically, the Sans-I/O layer raises this exception when:
- * sending a data frame to a connection in a state other
- :attr:`~websockets.protocol.State.OPEN`;
- * sending a control frame to a connection in a state other than
- :attr:`~websockets.protocol.State.OPEN` or
- :attr:`~websockets.protocol.State.CLOSING`.
- """
- class ConcurrencyError(WebSocketException, RuntimeError):
- """
- Raised when receiving or sending messages concurrently.
- WebSocket is a connection-oriented protocol. Reads must be serialized; so
- must be writes. However, reading and writing concurrently is possible.
- """
- # At the bottom to break import cycles created by type annotations.
- from . import frames, http11 # noqa: E402
- lazy_import(
- globals(),
- deprecated_aliases={
- # deprecated in 14.0 - 2024-11-09
- "AbortHandshake": ".legacy.exceptions",
- "InvalidStatusCode": ".legacy.exceptions",
- "RedirectHandshake": ".legacy.exceptions",
- "WebSocketProtocolError": ".legacy.exceptions",
- },
- )
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