pyssb/ssb/muxrpc.py

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# SPDX-License-Identifier: MIT
#
# Copyright (c) 2017 PySSB contributors (see AUTHORS for more details)
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
"""MuxRPC"""
from typing import Any, AsyncIterator, Callable, Dict, List, Literal, Optional, Union
from typing_extensions import Self
from .packet_stream import PacketStream, PSMessage, PSMessageType, PSRequestHandler, PSStreamHandler
MuxRPCJSON = Dict[str, Any]
MuxRPCCallType = Literal["async", "duplex", "sink", "source", "sync"]
MuxRPCRequestHandlerType = Callable[[PacketStream, "MuxRPCRequest"], None]
MuxRPCRequestParam = Union[bytes, str, MuxRPCJSON] # pylint: disable=invalid-name
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class MuxRPCAPIException(Exception):
"""Exception to raise on MuxRPC API errors"""
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class MuxRPCHandler: # pylint: disable=too-few-public-methods
"""Base MuxRPC handler class"""
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def check_message(self, msg: PSMessage) -> None:
"""Check message validity"""
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body = msg.body
if isinstance(body, dict) and "name" in body and body["name"] == "Error":
raise MuxRPCAPIException(body["message"])
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def __aiter__(self) -> AsyncIterator[Optional[PSMessage]]:
raise NotImplementedError()
async def __anext__(self) -> Optional[PSMessage]:
raise NotImplementedError()
def send(self, msg: Any, msg_type: PSMessageType = PSMessageType.JSON, end: bool = False) -> None:
"""Send a message through the stream"""
raise NotImplementedError()
async def get_response(self) -> PSMessage:
"""Get the response for an RPC request"""
raise NotImplementedError()
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class MuxRPCRequestHandler(MuxRPCHandler): # pylint: disable=abstract-method
"""MuxRPC handler for incoming RPC requests"""
def __init__(self, ps_handler: PSRequestHandler):
self.ps_handler = ps_handler
async def get_response(self) -> PSMessage:
"""Get the response data"""
msg = await self.ps_handler.__anext__()
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self.check_message(msg)
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return msg
class MuxRPCSourceHandler(MuxRPCHandler): # pylint: disable=abstract-method
"""MuxRPC handler for source-type RPC requests"""
def __init__(self, ps_handler: PSStreamHandler):
self.ps_handler = ps_handler
def __aiter__(self) -> AsyncIterator[Optional[PSMessage]]:
return self
async def __anext__(self) -> Optional[PSMessage]:
msg = await self.ps_handler.__anext__()
assert msg
self.check_message(msg)
return msg
class MuxRPCSinkHandlerMixin: # pylint: disable=too-few-public-methods
"""Mixin for sink-type MuxRPC handlers"""
connection: PacketStream
req: int
def send(self, msg: Any, msg_type: PSMessageType = PSMessageType.JSON, end: bool = False) -> None:
"""Send a message through the stream"""
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self.connection.send(msg, stream=True, msg_type=msg_type, req=self.req, end_err=end)
class MuxRPCDuplexHandler(MuxRPCSinkHandlerMixin, MuxRPCSourceHandler): # pylint: disable=abstract-method
"""MuxRPC handler for duplex streams"""
def __init__(self, ps_handler: PSStreamHandler, connection: PacketStream, req: int):
super().__init__(ps_handler)
self.connection = connection
self.req = req
class MuxRPCSinkHandler(MuxRPCHandler, MuxRPCSinkHandlerMixin): # pylint: disable=abstract-method
"""MuxRPC handler for sinks"""
def __init__(self, connection: PacketStream, req: int):
self.connection = connection
self.req = req
def _get_appropriate_api_handler(
type_: MuxRPCCallType, connection: PacketStream, ps_handler: Union[PSRequestHandler, PSStreamHandler], req: int
) -> MuxRPCHandler:
"""Find the appropriate MuxRPC handler"""
if type_ in {"sync", "async"}:
assert isinstance(ps_handler, PSRequestHandler)
return MuxRPCRequestHandler(ps_handler)
if type_ == "source":
assert isinstance(ps_handler, PSStreamHandler)
return MuxRPCSourceHandler(ps_handler)
if type_ == "sink":
return MuxRPCSinkHandler(connection, req)
if type_ == "duplex":
assert isinstance(ps_handler, PSStreamHandler)
return MuxRPCDuplexHandler(ps_handler, connection, req)
raise TypeError(f"Unknown request type {type_}")
class MuxRPCRequest:
"""MuxRPC request"""
@classmethod
def from_message(cls, message: PSMessage) -> Self:
"""Initialise a request from a raw packet stream message"""
body = message.body
assert isinstance(body, dict)
return cls(".".join(body["name"]), body["args"])
def __init__(self, name: str, args: List[MuxRPCRequestParam]):
self.name = name
self.args = args
def __repr__(self) -> str:
return f"<MuxRPCRequest {self.name} {self.args}>"
class MuxRPCMessage:
"""MuxRPC message"""
@classmethod
def from_message(cls, message: PSMessage) -> Self:
"""Initialise a MuxRPC message from a raw packet stream message"""
return cls(message.body)
def __init__(self, body: Union[bytes, str, Dict[str, Any]]):
self.body = body
def __repr__(self) -> str:
return f"<MuxRPCMessage {self.body!r}>"
class MuxRPCAPI:
"""Generic MuxRPC API"""
def __init__(self) -> None:
self.handlers: Dict[str, MuxRPCRequestHandlerType] = {}
self.connection: Optional[PacketStream] = None
async def process_messages(self) -> None:
"""Continuously process incoming messages"""
assert self.connection
async for req_message in self.connection:
if req_message is None:
return
body = req_message.body
if isinstance(body, dict) and body.get("name"):
self.process(self.connection, MuxRPCRequest.from_message(req_message))
def add_connection(self, connection: PacketStream) -> None:
"""Set the packet stream connection of this RPC API"""
self.connection = connection
def define(self, name: str) -> Callable[[MuxRPCRequestHandlerType], MuxRPCRequestHandlerType]:
"""Decorator to define an RPC method handler"""
def _handle(f: MuxRPCRequestHandlerType) -> MuxRPCRequestHandlerType:
self.handlers[name] = f
return f
return _handle
def process(self, connection: PacketStream, request: MuxRPCRequest) -> None:
"""Process an incoming request"""
handler = self.handlers.get(request.name)
if not handler:
raise MuxRPCAPIException(f"Method {request.name} not found!")
handler(connection, request)
def call(self, name: str, args: List[MuxRPCRequestParam], type_: MuxRPCCallType = "sync") -> MuxRPCHandler:
"""Call an RPC method"""
assert self.connection
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if not self.connection.is_connected:
raise Exception("not connected") # pylint: disable=broad-exception-raised
old_counter = self.connection.req_counter
ps_handler = self.connection.send(
{"name": name.split("."), "args": args, "type": type_},
stream=type_ in {"sink", "source", "duplex"},
)
return _get_appropriate_api_handler(type_, self.connection, ps_handler, old_counter)