pincer.core.gateway.Dispatcher.__dispatcher() - Code Metrics - Inspection of ":sparkles: Support Discord Gateway Event Compressi..." - Pincer-org/Pincer - Measure and Improve Code Quality continuously with Scrutinizer

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Pull Request — main (#160)

unknown

created 2021-10-24 18:27 UTC

pincer.core.gateway.Dispatcher.__dispatcher() C

↳ Parent: pincer.core.gateway

Complexity

Conditions

Size

Total Lines	72
Code Lines	39

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
eloc	39
dl	0
loc	72
rs	5.9999
c	0
b	0
f	0
cc	10
nop	2

How to fix Long Method Complexity

# Copyright Pincer 2021-Present

# Full MIT License can be found in `LICENSE` at the project root.


from __future__ import annotations

import logging
import zlib
from asyncio import get_event_loop, AbstractEventLoop, ensure_future
from platform import system
from typing import Dict, Callable, Awaitable, Optional

from websockets import connect
from websockets.exceptions import ConnectionClosedError, ConnectionClosedOK
from websockets.legacy.client import WebSocketClientProtocol

from . import __package__
from .._config import GatewayConfig
from ..core.dispatch import GatewayDispatch
from ..core.heartbeat import Heartbeat
from ..exceptions import (
    PincerError, InvalidTokenError, UnhandledException,
    _InternalPerformReconnectError, DisallowedIntentsError
)
from ..objects import Intents

ZLIB_SUFFIX = b'\x00\x00\xff\xff'

Handler = Callable[[WebSocketClientProtocol, GatewayDispatch], Awaitable[None]]
_log = logging.getLogger(__package__)


class Dispatcher:
    """
    The Dispatcher handles all interactions with discord websocket API.
    This also contains the main event loop, and handles the heartbeat.

    Running the dispatcher will create a connection with the
    Discord WebSocket API on behalf of the provided token.

    This token must be a bot token.
    (Which can be found on
    `<https://discord.com/developers/applications/<bot_id>/bot>`_)
    """

    # TODO: Implement compression

    def __init__(
            self, token: str, *,
            handlers: Dict[int, Handler],
            intents: Intents
    ) -> None:
        """
        :param token:
            Bot token for discord's API.

        :param intents:
            Represents the discord bot intents.

        :param handlers:
            A hashmap of coroutines with as key the gateway opcode.

        :raises InvalidTokenError:
            Discord Token length is not 59 characters.
        """

        if len(token) != 59:
            raise InvalidTokenError(
                "Discord Token must have exactly 59 characters."
            )

        self.__token = token
        self.__keep_alive = True
        self.__socket: Optional[WebSocketClientProtocol] = None
        self.__intents = intents

        async def identify_and_handle_hello(
                socket: WebSocketClientProtocol,
                payload: GatewayDispatch
        ):
            """
            Identifies the client to the Discord Websocket API, this
            gets done when the client receives the ``hello`` (opcode 10)
            message from discord. Right after we send our identification
            the heartbeat starts.

            :param socket:
                The current socket, which can be used to interact
                with the Discord API.

            :param payload:
                The received payload from Discord.
            """
            _log.debug("Sending authentication/identification message.")

            await socket.send(self.__hello_socket)
            await Heartbeat.handle_hello(socket, payload)

        async def handle_reconnect(_, payload: GatewayDispatch):
            """
            Closes the client and then reconnects it.
            """
            _log.debug("Reconnecting client...")
            await self.close()

            Heartbeat.update_sequence(payload.seq)
            self.start_loop()

        self.__dispatch_handlers: Dict[int, Handler] = {
            **handlers,
            7: handle_reconnect,
            9: handle_reconnect,
            10: identify_and_handle_hello,
            11: Heartbeat.handle_heartbeat
        }

        self.__dispatch_errors: Dict[int, PincerError] = {
            4000: _InternalPerformReconnectError(),
            4004: InvalidTokenError(),
            4007: _InternalPerformReconnectError(),
            4009: _InternalPerformReconnectError(),
            4014: DisallowedIntentsError()
        }

    @property
    def intents(self):

        return self.__intents

    @property
    def __hello_socket(self) -> str:
        return str(
            GatewayDispatch(
                2, {
                    "token": self.__token,
                    "intents": self.__intents,
                    "properties": {
                        "$os": system(),
                        "$browser": __package__,
                        "$device": __package__
                    },
                    "compress": GatewayConfig.compressed()
                }
            )
        )

    async def __handler_manager(
            self,
            socket: WebSocketClientProtocol,
            payload: GatewayDispatch,
            loop: AbstractEventLoop
    ):
        """
        This manages all handles for given OP codes.
        This method gets invoked for every message that is received from
        Discord.

        :meta public:

        :param socket:
            The current socket, which can be used to interact with
            the Discord API.

        :param payload:
            The received payload from Discord.

        :param loop:
            The current async loop on which the future is bound.
        """
        _log.debug(
            "New event received, checking if handler exists for opcode: %i",
            payload.op
        )

        handler: Handler = self.__dispatch_handlers.get(payload.op)
        all_handler: Handler = self.__dispatch_handlers.get(-1)

        if not handler:
            _log.error(
                "No handler was found for opcode %i, please report this to the "
                "pincer dev team!", payload.op
            )

            if not all_handler:
                raise UnhandledException(f"Unhandled payload: {payload}")

        _log.debug(
            "Event handler found, ensuring async future in current loop."
        )

        def execute_handler(event_handler: Handler):
            if event_handler:
                ensure_future(event_handler(socket, payload), loop=loop)

        execute_handler(handler)
        execute_handler(all_handler)

    async def __dispatcher(self, loop: AbstractEventLoop):
        """
        The main event loop.
        This handles all interactions with the websocket API.

        :meta public:

        :param loop:
            The loop in which the dispatcher is running.
        """
        _log.debug(
            "Establishing websocket connection with `%s`", GatewayConfig.uri()
        )

        async with connect(GatewayConfig.uri()) as socket:
            self.__socket = socket

            # Removing the limit of the received socket.
            # Having the default limit can cause an issue
            # with first payload of bigger bots.
            socket.max_size = None

            _log.debug(
                "Successfully established websocket connection with `%s`",
                GatewayConfig.uri()
            )

            if GatewayConfig.compression == "zlib-stream":
                # Create an inflator for compressed data as defined in
                # https://discord.com/developers/docs/topics/gateway
                inflator = zlib.decompressobj()

            while self.__keep_alive:
                try:
                    _log.debug("Waiting for new event.")
                    msg = await socket.recv()

                    if isinstance(msg, bytes):
                        if GatewayConfig.compression == "zlib-payload":
                            msg = zlib.decompress(msg)
                        else:
                            buffer = bytearray(msg)

                            while not buffer.endswith(ZLIB_SUFFIX):
                                buffer.extend(await socket.recv())

                            msg = inflator.decompress(buffer).decode('utf-8')


                    await self.__handler_manager(
                        socket,
                        GatewayDispatch.from_string(msg),
                        loop
                    )

                except ConnectionClosedError as exc:
                    _log.debug(
                        "The connection with `%s` has been broken unexpectedly."
                        " (%i, %s)", GatewayConfig.uri(), exc.code, exc.reason
                    )

                    await self.close()
                    exception = self.__dispatch_errors.get(exc.code)

                    if isinstance(exception, _InternalPerformReconnectError):
                        Heartbeat.update_sequence(0)
                        return self.start_loop()

                    raise exception or UnhandledException(
                        f"Dispatch error ({exc.code}): {exc.reason}"
                    )
                except ConnectionClosedOK:
                    _log.debug("Connection closed successfully.")

    def start_loop(self, *, loop: AbstractEventLoop = None):
        """
        Instantiate the dispatcher, this will create a connection to the
        Discord websocket API on behalf of the client who's token has
        been passed.

        Keyword Arguments:

        :param loop:
            The loop in which the Dispatcher will run. If no loop is
            provided it will get a new one.
        """
        _log.debug("Starting GatewayDispatcher")
        loop = loop or get_event_loop()
        loop.run_until_complete(self.__dispatcher(loop))
        loop.close()

    async def close(self):
        """
        Stop the dispatcher from listening and responding to gateway
        events. This should let the client close on itself.
        """
        if not self.__socket:
            _log.error("Cannot close non existing socket socket connection.")
            raise RuntimeError("Please open the connection before closing.")

        _log.debug(
            "Setting keep_alive to False, this will terminate the heartbeat."
        )

        self.__keep_alive = False
        await self.__socket.close()


1			# Copyright Pincer 2021-Present
			0 ignored issues – show introduced 2021-09-02 11:34 UTC by Report Bug Copy Issue Report Missing module docstring Loading history...
2			# Full MIT License can be found in `LICENSE` at the project root.
3
4
5			from __future__ import annotations
6
7			import logging
8			import zlib
9			from asyncio import get_event_loop, AbstractEventLoop, ensure_future
10			from platform import system
11			from typing import Dict, Callable, Awaitable, Optional
12
13			from websockets import connect
14			from websockets.exceptions import ConnectionClosedError, ConnectionClosedOK
15			from websockets.legacy.client import WebSocketClientProtocol
16
17			from . import __package__
18			from .._config import GatewayConfig
19			from ..core.dispatch import GatewayDispatch
20			from ..core.heartbeat import Heartbeat
21			from ..exceptions import (
22			PincerError, InvalidTokenError, UnhandledException,
23			_InternalPerformReconnectError, DisallowedIntentsError
24			)
25			from ..objects import Intents
26
27			ZLIB_SUFFIX = b'\x00\x00\xff\xff'
28
29			Handler = Callable[[WebSocketClientProtocol, GatewayDispatch], Awaitable[None]]
30			_log = logging.getLogger(__package__)
31
32
33			class Dispatcher:
34			"""
35			The Dispatcher handles all interactions with discord websocket API.
36			This also contains the main event loop, and handles the heartbeat.
37
38			Running the dispatcher will create a connection with the
39			Discord WebSocket API on behalf of the provided token.
40
41			This token must be a bot token.
42			(Which can be found on
43			`<https://discord.com/developers/applications/<bot_id>/bot>`_)
44			"""
45
46			# TODO: Implement compression
			0 ignored issues – show Coding Style introduced 2021-09-01 20:09 UTC by Report Bug Copy Issue Report `TODO` and `FIXME` comments should generally be avoided. Loading history...
47			def __init__(
48			self, token: str, *,
49			handlers: Dict[int, Handler],
50			intents: Intents
51			) -> None:
52			"""
53			:param token:
54			Bot token for discord's API.
55
56			:param intents:
57			Represents the discord bot intents.
58
59			:param handlers:
60			A hashmap of coroutines with as key the gateway opcode.
61
62			:raises InvalidTokenError:
63			Discord Token length is not 59 characters.
64			"""
65
66			if len(token) != 59:
67			raise InvalidTokenError(
68			"Discord Token must have exactly 59 characters."
69			)
70
71			self.__token = token
72			self.__keep_alive = True
73			self.__socket: Optional[WebSocketClientProtocol] = None
74			self.__intents = intents
75
76			async def identify_and_handle_hello(
77			socket: WebSocketClientProtocol,
78			payload: GatewayDispatch
79			):
80			"""
81			Identifies the client to the Discord Websocket API, this
82			gets done when the client receives the ``hello`` (opcode 10)
83			message from discord. Right after we send our identification
84			the heartbeat starts.
85
86			:param socket:
87			The current socket, which can be used to interact
88			with the Discord API.
89
90			:param payload:
91			The received payload from Discord.
92			"""
93			_log.debug("Sending authentication/identification message.")
94
95			await socket.send(self.__hello_socket)
96			await Heartbeat.handle_hello(socket, payload)
97
98			async def handle_reconnect(_, payload: GatewayDispatch):
99			"""
100			Closes the client and then reconnects it.
101			"""
102			_log.debug("Reconnecting client...")
103			await self.close()
104
105			Heartbeat.update_sequence(payload.seq)
106			self.start_loop()
107
108			self.__dispatch_handlers: Dict[int, Handler] = {
109			**handlers,
110			7: handle_reconnect,
111			9: handle_reconnect,
112			10: identify_and_handle_hello,
113			11: Heartbeat.handle_heartbeat
114			}
115
116			self.__dispatch_errors: Dict[int, PincerError] = {
117			4000: _InternalPerformReconnectError(),
118			4004: InvalidTokenError(),
119			4007: _InternalPerformReconnectError(),
120			4009: _InternalPerformReconnectError(),
121			4014: DisallowedIntentsError()
122			}
123
124			@property
125			def intents(self):
			0 ignored issues – show introduced 2021-09-13 13:25 UTC by Report Bug Copy Issue Report Missing function or method docstring Loading history...
126			return self.__intents
127
128			@property
129			def __hello_socket(self) -> str:
130			return str(
131			GatewayDispatch(
132			2, {
133			"token": self.__token,
134			"intents": self.__intents,
135			"properties": {
136			"$os": system(),
137			"$browser": __package__,
138			"$device": __package__
139			},
140			"compress": GatewayConfig.compressed()
141			}
142			)
143			)
144
145			async def __handler_manager(
146			self,
147			socket: WebSocketClientProtocol,
148			payload: GatewayDispatch,
149			loop: AbstractEventLoop
150			):
151			"""
152			This manages all handles for given OP codes.
153			This method gets invoked for every message that is received from
154			Discord.
155
156			:meta public:
157
158			:param socket:
159			The current socket, which can be used to interact with
160			the Discord API.
161
162			:param payload:
163			The received payload from Discord.
164
165			:param loop:
166			The current async loop on which the future is bound.
167			"""
168			_log.debug(
169			"New event received, checking if handler exists for opcode: %i",
170			payload.op
171			)
172
173			handler: Handler = self.__dispatch_handlers.get(payload.op)
174			all_handler: Handler = self.__dispatch_handlers.get(-1)
175
176			if not handler:
177			_log.error(
178			"No handler was found for opcode %i, please report this to the "
179			"pincer dev team!", payload.op
180			)
181
182			if not all_handler:
183			raise UnhandledException(f"Unhandled payload: {payload}")
184
185			_log.debug(
186			"Event handler found, ensuring async future in current loop."
187			)
188
189			def execute_handler(event_handler: Handler):
190			if event_handler:
191			ensure_future(event_handler(socket, payload), loop=loop)
192
193			execute_handler(handler)
194			execute_handler(all_handler)
195
196			async def __dispatcher(self, loop: AbstractEventLoop):
197			"""
198			The main event loop.
199			This handles all interactions with the websocket API.
200
201			:meta public:
202
203			:param loop:
204			The loop in which the dispatcher is running.
205			"""
206			_log.debug(
207			"Establishing websocket connection with `%s`", GatewayConfig.uri()
208			)
209
210			async with connect(GatewayConfig.uri()) as socket:
211			self.__socket = socket
212
213			# Removing the limit of the received socket.
214			# Having the default limit can cause an issue
215			# with first payload of bigger bots.
216			socket.max_size = None
217
218			_log.debug(
219			"Successfully established websocket connection with `%s`",
220			GatewayConfig.uri()
221			)
222
223			if GatewayConfig.compression == "zlib-stream":
224			# Create an inflator for compressed data as defined in
225			# https://discord.com/developers/docs/topics/gateway
226			inflator = zlib.decompressobj()
227
228			while self.__keep_alive:
229			try:
230			_log.debug("Waiting for new event.")
231			msg = await socket.recv()
232
233			if isinstance(msg, bytes):
234			if GatewayConfig.compression == "zlib-payload":
235			msg = zlib.decompress(msg)
236			else:
237			buffer = bytearray(msg)
238
239			while not buffer.endswith(ZLIB_SUFFIX):
240			buffer.extend(await socket.recv())
241
242			msg = inflator.decompress(buffer).decode('utf-8')
			0 ignored issues – show introduced 2021-10-24 14:09 UTC by Report Bug Copy Issue Report The variable `inflator` does not seem to be defined in case `GatewayConfig.compression == "zlib-stream"` on line `223` is `False`. Are you sure this can never be the case? Loading history...
243
244			await self.__handler_manager(
245			socket,
246			GatewayDispatch.from_string(msg),
247			loop
248			)
249
250			except ConnectionClosedError as exc:
251			_log.debug(
252			"The connection with `%s` has been broken unexpectedly."
253			" (%i, %s)", GatewayConfig.uri(), exc.code, exc.reason
254			)
255
256			await self.close()
257			exception = self.__dispatch_errors.get(exc.code)
258
259			if isinstance(exception, _InternalPerformReconnectError):
260			Heartbeat.update_sequence(0)
261			return self.start_loop()
262
263			raise exception or UnhandledException(
264			f"Dispatch error ({exc.code}): {exc.reason}"
265			)
266			except ConnectionClosedOK:
267			_log.debug("Connection closed successfully.")
268
269			def start_loop(self, *, loop: AbstractEventLoop = None):
270			"""
271			Instantiate the dispatcher, this will create a connection to the
272			Discord websocket API on behalf of the client who's token has
273			been passed.
274
275			Keyword Arguments:
276
277			:param loop:
278			The loop in which the Dispatcher will run. If no loop is
279			provided it will get a new one.
280			"""
281			_log.debug("Starting GatewayDispatcher")
282			loop = loop or get_event_loop()
283			loop.run_until_complete(self.__dispatcher(loop))
284			loop.close()
285
286			async def close(self):
287			"""
288			Stop the dispatcher from listening and responding to gateway
289			events. This should let the client close on itself.
290			"""
291			if not self.__socket:
292			_log.error("Cannot close non existing socket socket connection.")
293			raise RuntimeError("Please open the connection before closing.")
294
295			_log.debug(
296			"Setting keep_alive to False, this will terminate the heartbeat."
297			)
298
299			self.__keep_alive = False
300			await self.__socket.close()
301

Pincer-org / Pincer

Pull Request — main (#160)

pincer.core.gateway.Dispatcher.__dispatcher() C

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