Eric Froemling 02399815ed
v1.6.10
2022-03-18 22:02:10 -05:00

131 lines
4.7 KiB
Python

# Released under the MIT License. See LICENSE for details.
#
"""Functionality for sending and responding to messages.
Supports static typing for message types and possible return types.
"""
from __future__ import annotations
from typing import TYPE_CHECKING, TypeVar
from efro.message._message import Response
if TYPE_CHECKING:
from typing import Any, Callable, Optional, Awaitable
from efro.message._message import Message
from efro.message._protocol import MessageProtocol
TM = TypeVar('TM', bound='MessageSender')
class MessageSender:
"""Facilitates sending messages to a target and receiving responses.
This is instantiated at the class level and used to register unbound
class methods to handle raw message sending.
Example:
class MyClass:
msg = MyMessageSender(some_protocol)
@msg.send_method
def send_raw_message(self, message: str) -> str:
# Actually send the message here.
# MyMessageSender class should provide overloads for send(), send_bg(),
# etc. to ensure all sending happens with valid types.
obj = MyClass()
obj.msg.send(SomeMessageType())
"""
def __init__(self, protocol: MessageProtocol) -> None:
self.protocol = protocol
self._send_raw_message_call: Optional[Callable[[Any, str], str]] = None
self._send_async_raw_message_call: Optional[Callable[
[Any, str], Awaitable[str]]] = None
def send_method(
self, call: Callable[[Any, str],
str]) -> Callable[[Any, str], str]:
"""Function decorator for setting raw send method."""
assert self._send_raw_message_call is None
self._send_raw_message_call = call
return call
def send_async_method(
self, call: Callable[[Any, str], Awaitable[str]]
) -> Callable[[Any, str], Awaitable[str]]:
"""Function decorator for setting raw send-async method."""
assert self._send_async_raw_message_call is None
self._send_async_raw_message_call = call
return call
def send(self, bound_obj: Any, message: Message) -> Optional[Response]:
"""Send a message and receive a response.
Will encode the message for transport and call dispatch_raw_message()
"""
if self._send_raw_message_call is None:
raise RuntimeError('send() is unimplemented for this type.')
msg_encoded = self.protocol.encode_message(message)
response_encoded = self._send_raw_message_call(bound_obj, msg_encoded)
response = self.protocol.decode_response(response_encoded)
assert isinstance(response, (Response, type(None)))
assert (response is None
or type(response) in type(message).get_response_types())
return response
async def send_async(self, bound_obj: Any,
message: Message) -> Optional[Response]:
"""Send a message asynchronously using asyncio.
The message will be encoded for transport and passed to
dispatch_raw_message_async.
"""
if self._send_async_raw_message_call is None:
raise RuntimeError('send_async() is unimplemented for this type.')
msg_encoded = self.protocol.encode_message(message)
response_encoded = await self._send_async_raw_message_call(
bound_obj, msg_encoded)
response = self.protocol.decode_response(response_encoded)
assert isinstance(response, (Response, type(None)))
assert (response is None
or type(response) in type(message).get_response_types())
return response
class BoundMessageSender:
"""Base class for bound senders."""
def __init__(self, obj: Any, sender: MessageSender) -> None:
# Note: not checking obj here since we want to support
# at least our protocol property when accessed via type.
self._obj = obj
self._sender = sender
@property
def protocol(self) -> MessageProtocol:
"""Protocol associated with this sender."""
return self._sender.protocol
def send_untyped(self, message: Message) -> Optional[Response]:
"""Send a message synchronously.
Whenever possible, use the send() call provided by generated
subclasses instead of this; it will provide better type safety.
"""
assert self._obj is not None
return self._sender.send(self._obj, message)
async def send_async_untyped(self, message: Message) -> Optional[Response]:
"""Send a message asynchronously.
Whenever possible, use the send_async() call provided by generated
subclasses instead of this; it will provide better type safety.
"""
assert self._obj is not None
return await self._sender.send_async(self._obj, message)