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403 lines
9.9 KiB
403 lines
9.9 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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if self.rcvd is None: |
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return 1006 |
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return self.rcvd.code |
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@property |
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def reason(self) -> str: |
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if self.rcvd is None: |
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return "" |
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return 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 frame with a code other than 1000 (OK) or 1001 (going away) was |
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received or 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 with code 1000 (OK) or 1001 (going away) or without a code was |
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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 an 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 an 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 an 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 an 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 a 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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