如何为 discord.py 创建自定义装饰器?

问题描述

我正在开发一个机器人.对于某个 cog，我希望创建一个自定义检查装饰器来检查运行命令的人是否具有特定角色.角色作为实例变量存储为角色类.当我尝试运行它时，它不起作用.装饰器是怎么做的?

I am working on a bot. For a certain cog, I wish to create a custom check decorator that checks to see if the person running the command has a certain role. The role is stored as a role class as an instance variable. When I tried running it, it doesn't work. How do you make the decorator?

class Moderation(commands.Cog):
    def __init__(self, bot: commands.Bot):
        self.bot = bot
        self.mod_role = None  # Assume there's already a role here

    class Decorator:
        @classmethod
        def requires_mod(cls, func):
            async def decorator(self, ctx: commands.Context, *args, **kwargs):
                if self.mod_role not in ctx.author.roles:
                    await ctx.send("You do not have permission to use this command")
                func(ctx, *args, **kwargs)
            return decorator

    @commands.command()
    @Decorator.requires_mod
    async def purge(self, ctx: commands.Context, amt: int):
        await ctx.channel.purge(limit=amt+1)
        await ctx.send(f":white_check_mark: | Deleted {amt} messages.")

推荐答案

这个概念被内置到 commands 扩展中作为 检查

This concept is built into the commands extension as Checks

即使是特定于 cog 的检查，例如 cog_check 不知道 cog 本身:它们都不接收 self 作为参数.

Even the cog-specific checks like cog_check aren't aware of the cog itself: none of them receive self as an argument.

您需要重写您的支票，使其不依赖于self.如果您现在知道角色名称或 ID，或者在创建 Moderation 类时，可以使用内置的 has_any_role 检查.

You need to rewrite your check such that it doesn't rely on self. If you know the role names or ids now, or when creating the Moderation class, you can use the built-in has_any_role check.

否则最简单的方法可能是使用 Moderation 的类属性或全局值来存储角色:

Otherwise the easiest way is probably to use either a class attribute of Moderation or a global value to store the role:

from discord.ext import commands

def predicate(ctx):
    return Moderation.mod_role in ctx.author.roles

has_mod_role = commands.check(predicate)


class Moderation(commands.Cog):
    mod_role = None 

    def __init__(bot):
        self.bot = bot
        Moderation.mod_role = ... 

    @commands.command()
    @has_mod_role
    async def yourcommand(ctx, ...):
        ...