制作Discord音乐机器人遇/help命令未找到错误求助

问题现象 #

执行/help命令时触发以下错误：

discord.ext.commands.bot: Ignoring exception in command None
discord.ext.commands.errors.CommandNotFound: Command "help" is not found

代码文件 #

main.py #

import discord
from discord.ext import commands
import os
from music_cog import MusicCog
from help_cog import HelpCog

intents = discord.Intents.all()
bot = commands.Bot(command_prefix="/", intents=intents)

bot.remove_command('help')


async def setup(bot):
    await bot.add_cog(HelpCog(bot))
async def set(bot):
    await bot.add_cog(MusicCog(bot))

os.environ['TOKEN'] = ''
bot.run(os.getenv('TOKEN'))

help_cog.py #

from discord.ext import commands

class HelpCog(commands.Cog):
    def __init__(self, bot):
        self.bot = bot
        self.help_message = """
'''
All Commands:
/help - Display all commands
/play - Search and play music from YouTube
/queue - View the music queue
/skip - Skip to the next song
/clear - Clear the music queue
/leave - Disconnect the bot from the voice channel
/pause - Pause the current song
/resume - Resume playing the music
'''
        """
        self.text_channel_text = []

    @commands.Cog.listener()
    async def on_ready(self):
        for guild in self.bot.guilds:
            for channel in guild.text_channels:
                self.text_channel_text.append(channel)
        await self.send_to_all(self.help_message)

    async def send_to_all(self, mess):
        for text_channel in self.text_channel_text:
            await text_channel.send(mess)

    @commands.command(name='help', help='Display all commands')
    async def help(self, ctx):
        await ctx.send(self.help_message)

music_cog.py #

import discord
from discord.ext import commands
from youtube_dl import YoutubeDL

class MusicCog(commands.Cog):
    def __init__(self, bot):
        self.bot = bot
        self.is_playing = False
        self.is_pause = False
        self.music_queue = []
        self.YDL_OPTIONS = {'format': 'bestaudio', 'noplaylist': True}
        self.FFMPEG_OPTIONS = {'before_options': '-reconnect 1 -reconnect_streamed 1 -reconnect_delay_max 5', 'options': '-vn'}
        self.vc = None

    def search_yt(self, item):
        with YoutubeDL(self.YDL_OPTIONS) as ydl:
            try:
                info = ydl.extract_info("ytsearch:%s" % item, download=False)['entries'][0]
            except Exception:
                return False
        return {'source': info['formats'][0]['url'], 'title': info['title']}

    def play_next(self):
        if len(self.music_queue) > 0:
            self.is_playing = True
            m_url = self.music_queue[0][0]['source']
            self.music_queue.pop(0)
            self.vc.play(discord.FFmpegPCMAudio(m_url, **self.FFMPEG_OPTIONS), after=lambda e: self.play_next())
        else:
            self.is_playing = False

    async def play_music(self, ctx):
        if len(self.music_queue) > 0:
            self.is_playing = True
            m_url = self.music_queue[0][0]['source']

            if self.vc is None or not self.vc.is_connected():
                self.vc = await self.music_queue[0][1].connect()

                if self.vc is None:
                    await ctx.send('Cannot connect to the voice channel')
                    return
            else:
                await self.vc.move_to(self.music_queue[0][1])

            self.music_queue.pop(0)
            self.vc.play(discord.FFmpegPCMAudio(m_url, **self.FFMPEG_OPTIONS), after=lambda e: self.play_next())

@commands.command(name='play', aliases=['p', 'P', 'playing'], help='Play song from yt')
async def play(self, ctx, *args):
    query = ' '.join(args)

    voice_channel = ctx.author.voice.channel
    if voice_channel is None:
        await ctx.send('Connect to a channel to hear music')
    elif self.is_pause:
        self.vc.resume()
    else:
        if query.startswith('https://www.youtube.com/'):
            # YouTube URL
            song_info = self.search_yt(query)
        else:
            # Search query
            song_info = self.search_yt(f'ytsearch:{query}')

        if song_info:
            await ctx.send('Song added to queue')
            self.music_queue.append([song_info, voice_channel])

            if not self.is_playing:
                await self.play_music(ctx)
        else:
            await ctx.send("Couldn't find the song, try other keywords")



    @commands.command(name='pause', help='Pause the current song')
    async def pause(self, ctx):
        if self.is_playing:
            self.is_playing = False
            self.is_pause = True
            self.vc.pause()
        elif self.is_pause:
            self.is_playing = True
            self.is_pause = False
            self.vc.resume()

    @commands.command(name='resume', aliases=['r', 'R'], help='Resume playing the music')
    async def resume(self, ctx):
        if self.is_pause:
            self.is_playing = True
            self.is_pause = False
            self.vc.resume()

    @commands.command(name='skip', aliases=['S', 'skip', 's'], help='Go to the next song')
    async def skip(self, ctx):
        if self.vc is not None and self.vc.is_playing():
            self.vc.stop()
            await self.play_music(ctx)

    @commands.command(name='queue', aliases=['q', 'Q'], help='Show all music in the queue')
    async def queue(self, ctx):
        retval = ''
        for i in range(min(len(self.music_queue), 10)):
            retval += f"{i + 1}. {self.music_queue[i][0]['title']}\n"
        if retval != '':
            await ctx.send(retval)
        else:
            await ctx.send('No music in the queue')

    @commands.command(name='clear', aliases=['c', 'C'], help='Remove all music from the queue')
    async def clear(self, ctx):
        if self.vc is not None and self.is_playing:
            self.vc.stop()
        self.music_queue = []
        await ctx.send('Queue cleared!')

    @commands.command(name='leave', aliases=['l', 'L', 'leave'], help='Remove bot from the voice channel')
    async def leave(self, ctx):
        if self.vc and self.vc.is_connected():
            self.is_playing = False
            self.is_pause = False
            await self.vc.disconnect()

问题原因及修复方案 #

1. Cog未被加载（核心问题） #

main.py中定义了setup和set函数用于添加Cog，但从未调用这些函数，导致HelpCog和MusicCog完全没有被加载到机器人中，自然找不到/help命令。

修改main.py，替换原有加载逻辑：

import discord
from discord.ext import commands
import os
import asyncio
from music_cog import MusicCog
from help_cog import HelpCog

intents = discord.Intents.all()
bot = commands.Bot(command_prefix="/", intents=intents)

bot.remove_command('help')

async def main():
    # 加载Cog
    await bot.add_cog(HelpCog(bot))
    await bot.add_cog(MusicCog(bot))
    # 启动机器人
    await bot.start(os.getenv('TOKEN'))

os.environ['TOKEN'] = '你的机器人Token'
asyncio.run(main())

2. MusicCog中play方法缩进错误 #

music_cog.py中的play方法没有缩进到MusicCog类内部，导致该命令无法被识别。将play方法整体缩进，与类内其他方法保持同级：

修改后music_cog.py中的play部分：

async def play_music(self, ctx):
        # 原有代码不变...

    @commands.command(name='play', aliases=['p', 'P', 'playing'], help='Play song from yt')
    async def play(self, ctx, *args):
        query = ' '.join(args)

        voice_channel = ctx.author.voice.channel
        if voice_channel is None:
            await ctx.send('Connect to a channel to hear music')
        elif self.is_pause:
            self.vc.resume()
        else:
            if query.startswith('https://www.youtube.com/'):
                # YouTube URL
                song_info = self.search_yt(query)
            else:
                # Search query
                song_info = self.search_yt(f'ytsearch:{query}')

            if song_info:
                await ctx.send('Song added to queue')
                self.music_queue.append([song_info, voice_channel])

                if not self.is_playing:
                    await self.play_music(ctx)
            else:
                await ctx.send("Couldn't find the song, try other keywords")

3. 可选优化：HelpCog的批量发送消息可能触发限流 #

HelpCog的on_ready方法会给所有文本频道发送帮助消息，容易触发Discord的请求限流。建议改为仅在机器人就绪后打印日志，或发送到指定频道：

@commands.Cog.listener()
async def on_ready(self):
    print(f'{self.bot.user} 已就绪！')
    # 若需要发送帮助消息，可指定频道：
    # channel = self.bot.get_channel(你的频道ID)
    # await channel.send(self.help_message)

完成以上修改后，重启机器人，/help命令即可正常使用。

内容的提问来源于stack exchange，提问作者Nguyễn Trung Kiến