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399 lines
9.8 KiB
399 lines
9.8 KiB
"""
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:mod:`websockets.exceptions` defines the following exception hierarchy:
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* :exc:`WebSocketException`
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* :exc:`ConnectionClosed`
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* :exc:`ConnectionClosedError`
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* :exc:`ConnectionClosedOK`
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* :exc:`InvalidHandshake`
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* :exc:`SecurityError`
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* :exc:`InvalidMessage`
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* :exc:`InvalidHeader`
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* :exc:`InvalidHeaderFormat`
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* :exc:`InvalidHeaderValue`
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* :exc:`InvalidOrigin`
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* :exc:`InvalidUpgrade`
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* :exc:`InvalidStatus`
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* :exc:`InvalidStatusCode` (legacy)
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* :exc:`NegotiationError`
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* :exc:`DuplicateParameter`
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* :exc:`InvalidParameterName`
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* :exc:`InvalidParameterValue`
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* :exc:`AbortHandshake`
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* :exc:`RedirectHandshake`
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* :exc:`InvalidState`
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* :exc:`InvalidURI`
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* :exc:`PayloadTooBig`
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* :exc:`ProtocolError`
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"""
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from __future__ import annotations
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import http
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from typing import Optional
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from . import datastructures, frames, http11
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__all__ = [
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"WebSocketException",
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"ConnectionClosed",
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"ConnectionClosedError",
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"ConnectionClosedOK",
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"InvalidHandshake",
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"SecurityError",
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"InvalidMessage",
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"InvalidHeader",
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"InvalidHeaderFormat",
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"InvalidHeaderValue",
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"InvalidOrigin",
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"InvalidUpgrade",
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"InvalidStatus",
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"InvalidStatusCode",
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"NegotiationError",
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"DuplicateParameter",
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"InvalidParameterName",
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"InvalidParameterValue",
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"AbortHandshake",
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"RedirectHandshake",
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"InvalidState",
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"InvalidURI",
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"PayloadTooBig",
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"ProtocolError",
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"WebSocketProtocolError",
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]
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class WebSocketException(Exception):
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"""
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Base class for all exceptions defined by websockets.
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"""
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class ConnectionClosed(WebSocketException):
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"""
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Raised when trying to interact with a closed connection.
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Attributes:
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rcvd (Optional[Close]): if a close frame was received, its code and
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reason are available in ``rcvd.code`` and ``rcvd.reason``.
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sent (Optional[Close]): if a close frame was sent, its code and reason
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are available in ``sent.code`` and ``sent.reason``.
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rcvd_then_sent (Optional[bool]): if close frames were received and
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sent, this attribute tells in which order this happened, from the
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perspective of this side of the connection.
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"""
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def __init__(
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self,
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rcvd: Optional[frames.Close],
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sent: Optional[frames.Close],
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rcvd_then_sent: Optional[bool] = None,
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) -> None:
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self.rcvd = rcvd
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self.sent = sent
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self.rcvd_then_sent = rcvd_then_sent
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def __str__(self) -> str:
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if self.rcvd is None:
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if self.sent is None:
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assert self.rcvd_then_sent is None
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return "no close frame received or sent"
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else:
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assert self.rcvd_then_sent is None
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return f"sent {self.sent}; no close frame received"
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else:
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if self.sent is None:
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assert self.rcvd_then_sent is None
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return f"received {self.rcvd}; no close frame sent"
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else:
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assert self.rcvd_then_sent is not None
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if self.rcvd_then_sent:
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return f"received {self.rcvd}; then sent {self.sent}"
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else:
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return f"sent {self.sent}; then received {self.rcvd}"
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# code and reason attributes are provided for backwards-compatibility
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@property
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def code(self) -> int:
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return 1006 if self.rcvd is None else self.rcvd.code
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@property
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def reason(self) -> str:
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return "" if self.rcvd is None else self.rcvd.reason
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class ConnectionClosedError(ConnectionClosed):
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"""
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Like :exc:`ConnectionClosed`, when the connection terminated with an error.
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A close code other than 1000 (OK) or 1001 (going away) was received or
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sent, or the closing handshake didn't complete properly.
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"""
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class ConnectionClosedOK(ConnectionClosed):
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"""
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Like :exc:`ConnectionClosed`, when the connection terminated properly.
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A close code 1000 (OK) or 1001 (going away) was received and sent.
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"""
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class InvalidHandshake(WebSocketException):
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"""
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Raised during the handshake when the WebSocket connection fails.
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"""
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class SecurityError(InvalidHandshake):
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"""
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Raised when a handshake request or response breaks a security rule.
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Security limits are hard coded.
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"""
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class InvalidMessage(InvalidHandshake):
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"""
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Raised when a handshake request or response is malformed.
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"""
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class InvalidHeader(InvalidHandshake):
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"""
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Raised when a HTTP header doesn't have a valid format or value.
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"""
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def __init__(self, name: str, value: Optional[str] = None) -> None:
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self.name = name
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self.value = value
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def __str__(self) -> str:
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if self.value is None:
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return f"missing {self.name} header"
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elif self.value == "":
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return f"empty {self.name} header"
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else:
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return f"invalid {self.name} header: {self.value}"
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class InvalidHeaderFormat(InvalidHeader):
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"""
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Raised when a HTTP header cannot be parsed.
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The format of the header doesn't match the grammar for that header.
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"""
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def __init__(self, name: str, error: str, header: str, pos: int) -> None:
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super().__init__(name, f"{error} at {pos} in {header}")
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class InvalidHeaderValue(InvalidHeader):
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"""
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Raised when a HTTP header has a wrong value.
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The format of the header is correct but a value isn't acceptable.
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"""
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class InvalidOrigin(InvalidHeader):
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"""
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Raised when the Origin header in a request isn't allowed.
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"""
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def __init__(self, origin: Optional[str]) -> None:
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super().__init__("Origin", origin)
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class InvalidUpgrade(InvalidHeader):
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"""
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Raised when the Upgrade or Connection header isn't correct.
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"""
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class InvalidStatus(InvalidHandshake):
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"""
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Raised when a handshake response rejects the WebSocket upgrade.
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"""
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def __init__(self, response: http11.Response) -> None:
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self.response = response
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def __str__(self) -> str:
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return (
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"server rejected WebSocket connection: "
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f"HTTP {self.response.status_code:d}"
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)
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class InvalidStatusCode(InvalidHandshake):
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"""
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Raised when a handshake response status code is invalid.
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"""
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def __init__(self, status_code: int, headers: datastructures.Headers) -> None:
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self.status_code = status_code
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self.headers = headers
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def __str__(self) -> str:
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return f"server rejected WebSocket connection: HTTP {self.status_code}"
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class NegotiationError(InvalidHandshake):
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"""
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Raised when negotiating an extension fails.
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"""
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class DuplicateParameter(NegotiationError):
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"""
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Raised when a parameter name is repeated in an extension header.
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"""
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def __init__(self, name: str) -> None:
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self.name = name
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def __str__(self) -> str:
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return f"duplicate parameter: {self.name}"
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class InvalidParameterName(NegotiationError):
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"""
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Raised when a parameter name in an extension header is invalid.
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"""
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def __init__(self, name: str) -> None:
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self.name = name
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def __str__(self) -> str:
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return f"invalid parameter name: {self.name}"
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class InvalidParameterValue(NegotiationError):
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"""
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Raised when a parameter value in an extension header is invalid.
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"""
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def __init__(self, name: str, value: Optional[str]) -> None:
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self.name = name
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self.value = value
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def __str__(self) -> str:
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if self.value is None:
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return f"missing value for parameter {self.name}"
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elif self.value == "":
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return f"empty value for parameter {self.name}"
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else:
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return f"invalid value for parameter {self.name}: {self.value}"
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class AbortHandshake(InvalidHandshake):
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"""
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Raised to abort the handshake on purpose and return a HTTP response.
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This exception is an implementation detail.
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The public API
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is :meth:`~websockets.server.WebSocketServerProtocol.process_request`.
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Attributes:
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status (~http.HTTPStatus): HTTP status code.
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headers (Headers): HTTP response headers.
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body (bytes): HTTP response body.
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"""
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def __init__(
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self,
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status: http.HTTPStatus,
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headers: datastructures.HeadersLike,
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body: bytes = b"",
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) -> None:
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self.status = status
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self.headers = datastructures.Headers(headers)
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self.body = body
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def __str__(self) -> str:
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return (
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f"HTTP {self.status:d}, "
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f"{len(self.headers)} headers, "
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f"{len(self.body)} bytes"
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)
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class RedirectHandshake(InvalidHandshake):
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"""
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Raised when a handshake gets redirected.
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This exception is an implementation detail.
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"""
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def __init__(self, uri: str) -> None:
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self.uri = uri
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def __str__(self) -> str:
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return f"redirect to {self.uri}"
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class InvalidState(WebSocketException, AssertionError):
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"""
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Raised when an operation is forbidden in the current state.
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This exception is an implementation detail.
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It should never be raised in normal circumstances.
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"""
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class InvalidURI(WebSocketException):
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"""
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Raised when connecting to an URI that isn't a valid WebSocket URI.
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"""
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def __init__(self, uri: str, msg: str) -> None:
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self.uri = uri
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self.msg = msg
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def __str__(self) -> str:
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return f"{self.uri} isn't a valid URI: {self.msg}"
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class PayloadTooBig(WebSocketException):
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"""
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Raised when receiving a frame with a payload exceeding the maximum size.
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"""
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class ProtocolError(WebSocketException):
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"""
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Raised when a frame breaks the protocol.
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"""
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WebSocketProtocolError = ProtocolError # for backwards compatibility
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