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|
"""Helpers for setting a cooldown on commands."""
from __future__ import annotations
import asyncio
import math
import random
import time
import typing
from collections.abc import Awaitable, Hashable
from contextlib import suppress
from dataclasses import dataclass
from typing import Callable # sphinx-autodoc-typehints breaks with collections.abc.Callable
import discord
from discord.ext.commands import CommandError, Context
from botcore.utils import scheduling
from botcore.utils.function import command_wraps
__all__ = ["CommandOnCooldown", "block_duplicate_invocations", "P", "R"]
_ArgsTuple = tuple[object]
if typing.TYPE_CHECKING:
from botcore import BotBase
import typing_extensions
P = typing_extensions.ParamSpec("P")
P.__constraints__ = ()
else:
P = typing.TypeVar("P")
"""The command's signature."""
R = typing.TypeVar("R")
"""The command's return value."""
class CommandOnCooldown(CommandError, typing.Generic[P, R]):
"""Raised when a command is invoked while on cooldown."""
def __init__(
self,
message: str | None,
function: Callable[P, Awaitable[R]],
*args: object,
**kwargs: object,
):
super().__init__(message, function, args, kwargs)
self._function = function
self._args = args
self._kwargs = kwargs
async def call_without_cooldown(self) -> R:
"""
Run the command this cooldown blocked.
Returns:
The command's return value.
"""
return await self._function(*self._args, **self._kwargs)
@dataclass
class _CooldownItem:
call_arguments: _ArgsTuple
timeout_timestamp: float
class _CommandCooldownManager:
"""
Manage invocation cooldowns for a command through the arguments the command is called with.
Use `set_cooldown` to set a cooldown,
and `is_on_cooldown` to check for a cooldown for a channel with the given arguments.
A cooldown lasts for `cooldown_duration` seconds.
"""
def __init__(self, *, cooldown_duration: float):
self._cooldowns = dict[tuple[Hashable, _ArgsTuple], float]()
self._cooldowns_non_hashable = dict[Hashable, list[_CooldownItem]]()
self._cooldown_duration = cooldown_duration
self.cleanup_task = scheduling.create_task(
self._periodical_cleanup(random.uniform(0, 10)),
name="CooldownManager cleanup",
)
def set_cooldown(self, channel: Hashable, call_arguments: _ArgsTuple) -> None:
"""Set `call_arguments` arguments on cooldown in `channel`."""
timeout_timestamp = time.monotonic() + self._cooldown_duration
try:
self._cooldowns[(channel, call_arguments)] = timeout_timestamp
except TypeError:
cooldowns_list = self._cooldowns_non_hashable.setdefault(channel, [])
for item in cooldowns_list:
if item.call_arguments == call_arguments:
item.timeout_timestamp = timeout_timestamp
else:
cooldowns_list.append(_CooldownItem(call_arguments, timeout_timestamp))
def is_on_cooldown(self, channel: Hashable, call_arguments: _ArgsTuple) -> bool:
"""Check whether `call_arguments` is on cooldown in `channel`."""
current_time = time.monotonic()
try:
return self._cooldowns.get((channel, call_arguments), -math.inf) > current_time
except TypeError:
cooldowns_list = self._cooldowns_non_hashable.get(channel, None)
if cooldowns_list is None:
return False
for item in cooldowns_list:
if item.call_arguments == call_arguments:
return item.timeout_timestamp > current_time
return False
async def _periodical_cleanup(self, initial_delay: float) -> None:
"""
Delete stale items every hour after waiting for `initial_delay`.
The `initial_delay` ensures cleanups are not running for every command at the same time.
"""
await asyncio.sleep(initial_delay)
while True:
await asyncio.sleep(60 * 60)
self._delete_stale_items()
def _delete_stale_items(self) -> None:
"""Remove expired items from internal collections."""
current_time = time.monotonic()
for key, timeout_timestamp in self._cooldowns.copy().items():
if timeout_timestamp < current_time:
del self._cooldowns[key]
for key, cooldowns_list in self._cooldowns_non_hashable.copy().items():
filtered_cooldowns = [
cooldown_item for cooldown_item in cooldowns_list if cooldown_item.timeout_timestamp < current_time
]
if not filtered_cooldowns:
del self._cooldowns_non_hashable[key]
else:
self._cooldowns_non_hashable[key] = filtered_cooldowns
def block_duplicate_invocations(
*, cooldown_duration: float = 5, send_notice: bool = False
) -> Callable[[Callable[P, Awaitable[R]]], Callable[P, Awaitable[R]]]:
"""
Prevent duplicate invocations of a command with the same arguments in a channel for ``cooldown_duration`` seconds.
Args:
cooldown_duration: Length of the cooldown in seconds.
send_notice: If :obj:`True`, notify the user about the cooldown with a reply.
Returns:
A decorator that adds a wrapper which applies the cooldowns.
Warning:
The created wrapper raises :exc:`CommandOnCooldown` when the command is on cooldown.
"""
def decorator(func: Callable[P, Awaitable[R]]) -> Callable[P, Awaitable[R]]:
mgr = _CommandCooldownManager(cooldown_duration=cooldown_duration)
@command_wraps(func)
async def wrapper(*args: P.args, **kwargs: P.kwargs) -> R:
arg_tuple = (*args[2:], *kwargs.items())
ctx = typing.cast("Context[BotBase]", args[1])
channel = ctx.channel
if not isinstance(channel, discord.DMChannel):
if mgr.is_on_cooldown(ctx.channel, arg_tuple):
if send_notice:
with suppress(discord.NotFound):
await ctx.reply("The command is on cooldown with the given arguments.")
raise CommandOnCooldown(ctx.message.content, func, *args, **kwargs)
mgr.set_cooldown(ctx.channel, arg_tuple)
return await func(*args, **kwargs)
return wrapper
return decorator
|
