You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

296 lines
7.8 KiB
Python

2 years ago
"""
wsproto/events
~~~~~~~~~~~~~~
Events that result from processing data on a WebSocket connection.
"""
from abc import ABC
from dataclasses import dataclass, field
from typing import Generic, List, Optional, Sequence, TypeVar, Union
from .extensions import Extension
from .typing import Headers
class Event(ABC):
"""
Base class for wsproto events.
"""
pass # noqa
@dataclass(frozen=True)
class Request(Event):
"""The beginning of a Websocket connection, the HTTP Upgrade request
This event is fired when a SERVER connection receives a WebSocket
handshake request (HTTP with upgrade header).
Fields:
.. attribute:: host
(Required) The hostname, or host header value.
.. attribute:: target
(Required) The request target (path and query string)
.. attribute:: extensions
The proposed extensions.
.. attribute:: extra_headers
The additional request headers, excluding extensions, host, subprotocols,
and version headers.
.. attribute:: subprotocols
A list of the subprotocols proposed in the request, as a list
of strings.
"""
host: str
target: str
extensions: Union[Sequence[Extension], Sequence[str]] = field( # type: ignore[assignment]
default_factory=list
)
extra_headers: Headers = field(default_factory=list)
subprotocols: List[str] = field(default_factory=list)
@dataclass(frozen=True)
class AcceptConnection(Event):
"""The acceptance of a Websocket upgrade request.
This event is fired when a CLIENT receives an acceptance response
from a server. It is also used to accept an upgrade request when
acting as a SERVER.
Fields:
.. attribute:: extra_headers
Any additional (non websocket related) headers present in the
acceptance response.
.. attribute:: subprotocol
The accepted subprotocol to use.
"""
subprotocol: Optional[str] = None
extensions: List[Extension] = field(default_factory=list)
extra_headers: Headers = field(default_factory=list)
@dataclass(frozen=True)
class RejectConnection(Event):
"""The rejection of a Websocket upgrade request, the HTTP response.
The ``RejectConnection`` event sends the appropriate HTTP headers to
communicate to the peer that the handshake has been rejected. You may also
send an HTTP body by setting the ``has_body`` attribute to ``True`` and then
sending one or more :class:`RejectData` events after this one. When sending
a response body, the caller should set the ``Content-Length``,
``Content-Type``, and/or ``Transfer-Encoding`` headers as appropriate.
When receiving a ``RejectConnection`` event, the ``has_body`` attribute will
in almost all cases be ``True`` (even if the server set it to ``False``) and
will be followed by at least one ``RejectData`` events, even though the data
itself might be just ``b""``. (The only scenario in which the caller
receives a ``RejectConnection`` with ``has_body == False`` is if the peer
violates sends an informational status code (1xx) other than 101.)
The ``has_body`` attribute should only be used when receiving the event. (It
has ) is False the headers must include a
content-length or transfer encoding.
Fields:
.. attribute:: headers (Headers)
The headers to send with the response.
.. attribute:: has_body
This defaults to False, but set to True if there is a body. See
also :class:`~RejectData`.
.. attribute:: status_code
The response status code.
"""
status_code: int = 400
headers: Headers = field(default_factory=list)
has_body: bool = False
@dataclass(frozen=True)
class RejectData(Event):
"""The rejection HTTP response body.
The caller may send multiple ``RejectData`` events. The final event should
have the ``body_finished`` attribute set to ``True``.
Fields:
.. attribute:: body_finished
True if this is the final chunk of the body data.
.. attribute:: data (bytes)
(Required) The raw body data.
"""
data: bytes
body_finished: bool = True
@dataclass(frozen=True)
class CloseConnection(Event):
"""The end of a Websocket connection, represents a closure frame.
**wsproto does not automatically send a response to a close event.** To
comply with the RFC you MUST send a close event back to the remote WebSocket
if you have not already sent one. The :meth:`response` method provides a
suitable event for this purpose, and you should check if a response needs
to be sent by checking :func:`wsproto.WSConnection.state`.
Fields:
.. attribute:: code
(Required) The integer close code to indicate why the connection
has closed.
.. attribute:: reason
Additional reasoning for why the connection has closed.
"""
code: int
reason: Optional[str] = None
def response(self) -> "CloseConnection":
"""Generate an RFC-compliant close frame to send back to the peer."""
return CloseConnection(code=self.code, reason=self.reason)
T = TypeVar("T", bytes, str)
@dataclass(frozen=True)
class Message(Event, Generic[T]):
"""The websocket data message.
Fields:
.. attribute:: data
(Required) The message data as byte string, can be decoded as UTF-8 for
TEXT messages. This only represents a single chunk of data and
not a full WebSocket message. You need to buffer and
reassemble these chunks to get the full message.
.. attribute:: frame_finished
This has no semantic content, but is provided just in case some
weird edge case user wants to be able to reconstruct the
fragmentation pattern of the original stream.
.. attribute:: message_finished
True if this frame is the last one of this message, False if
more frames are expected.
"""
data: T
frame_finished: bool = True
message_finished: bool = True
@dataclass(frozen=True)
class TextMessage(Message[str]): # pylint: disable=unsubscriptable-object
"""This event is fired when a data frame with TEXT payload is received.
Fields:
.. attribute:: data
The message data as string, This only represents a single chunk
of data and not a full WebSocket message. You need to buffer
and reassemble these chunks to get the full message.
"""
# https://github.com/python/mypy/issues/5744
data: str
@dataclass(frozen=True)
class BytesMessage(Message[bytes]): # pylint: disable=unsubscriptable-object
"""This event is fired when a data frame with BINARY payload is
received.
Fields:
.. attribute:: data
The message data as byte string, can be decoded as UTF-8 for
TEXT messages. This only represents a single chunk of data and
not a full WebSocket message. You need to buffer and
reassemble these chunks to get the full message.
"""
# https://github.com/python/mypy/issues/5744
data: bytes
@dataclass(frozen=True)
class Ping(Event):
"""The Ping event can be sent to trigger a ping frame and is fired
when a Ping is received.
**wsproto does not automatically send a pong response to a ping event.** To
comply with the RFC you MUST send a pong even as soon as is practical. The
:meth:`response` method provides a suitable event for this purpose.
Fields:
.. attribute:: payload
An optional payload to emit with the ping frame.
"""
payload: bytes = b""
def response(self) -> "Pong":
"""Generate an RFC-compliant :class:`Pong` response to this ping."""
return Pong(payload=self.payload)
@dataclass(frozen=True)
class Pong(Event):
"""The Pong event is fired when a Pong is received.
Fields:
.. attribute:: payload
An optional payload to emit with the pong frame.
"""
payload: bytes = b""