Discord机器人/play命令报错：AttributeError 'str'对象无author属性

错误信息 #

2023-12-01 21:25:11 ERROR discord.ext.commands.bot Ignoring exception in command pusti
Traceback (most recent call last):
File "C:\Users\x\AppData\Roaming\Python\Python312\site-packages\discord\ext\commands\core.py", line 235, in wrapped
ret = await coro(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "E:\discord-bot\main.py", line 149, in pusti
voice_channel = ctx.author.voice.channel
^^^^^^^^^^
AttributeError: 'str' object has no attribute 'author'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File "C:\Users\x\AppData\Roaming\Python\Python312\site-packages\discord\ext\commands\bot.py", line 1350, in invoke
await ctx.command.invoke(ctx)
File "C:\Users\x\AppData\Roaming\Python\Python312\site-packages\discord\ext\commands\core.py", line 1029, in invoke
await injected(*ctx.args, **ctx.kwargs) # type: ignore
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Users\x\AppData\Roaming\Python\Python312\site-packages\discord\ext\commands\core.py", line 244, in wrapped
raise CommandInvokeError(exc) from exc
discord.ext.commands.errors.CommandInvokeError: Command raised an exception: AttributeError: 'str' object has no attribute 'author'

问题代码 #

@client.command(name = "pusti", aliases = ["p", "play", "playing"], help = "播放你提供链接的歌曲。🎵")    
async def pusti(self, ctx, *args):
    query = " ".join(args)
    voice_channel = ctx.author.voice.channel
    if voice_channel is None:
        await ctx.send("➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖\n请先加入语音频道！🎵\n➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖")
    elif self.is_paused:
        self.vc.resume()
    else:
        song = self.search_yt(query)
        if type(song) == type(True):
            await ctx.send("➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖\n你的歌曲已加入等待队列。🎵\n➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖")
            self.music_queue.append([song, voice_channel])
            if self.is_playing == False:
                await self.play_music(ctx)

错误原因 #

1. 参数定义错误：代码中命令函数用了self作为第一个参数，但该函数并非commands.Cog类的成员方法，导致参数顺序混乱。实际调用时，Discord传入的上下文对象ctx被赋值给self，歌曲查询字符串被赋值给ctx，最终引发'str' object has no attribute 'author'错误。
2. 命令类型不匹配：你使用的是Discord斜杠命令（/pusti），但代码中用的@client.command装饰器仅支持前缀式命令（比如!pusti），不兼容斜杠命令。

修正方案 #

方案1：保留前缀式命令（比如!pusti） #

去掉多余的self参数，调整相关属性调用：

@client.command(name = "pusti", aliases = ["p", "play", "playing"], help = "播放你提供链接的歌曲。🎵")    
async def pusti(ctx, *args):
    query = " ".join(args)
    # 先判断用户是否在语音频道
    if not ctx.author.voice:
        await ctx.send("➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖\n请先加入语音频道！🎵\n➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖")
        return
    voice_channel = ctx.author.voice.channel
    
    if client.is_paused:
        client.vc.resume()
    else:
        song = search_yt(query)  # 若search_yt是全局函数，去掉self.
        if isinstance(song, bool):  # 替代type(song) == type(True)的更规范写法
            await ctx.send("➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖\n你的歌曲已加入等待队列。🎵\n➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖")
            client.music_queue.append([song, voice_channel])
            if client.is_playing == False:
                await play_music(ctx)  # 若play_music是全局函数，去掉self.

方案2：适配斜杠命令（/pusti） #

使用Discord应用命令装饰器@client.tree.command，调整参数和上下文对象：

import discord

@client.tree.command(name="pusti", description="播放你提供链接的歌曲。🎵")
async def pusti(interaction: discord.Interaction, query: str):
    # 判断用户是否在语音频道
    if not interaction.user.voice:
        await interaction.response.send_message("➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖\n请先加入语音频道！🎵\n➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖")
        return
    voice_channel = interaction.user.voice.channel
    
    if client.is_paused:
        client.vc.resume()
    else:
        song = search_yt(query)
        if isinstance(song, bool):
            await interaction.response.send_message("➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖\n你的歌曲已加入等待队列。🎵\n➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖➖")
            client.music_queue.append([song, voice_channel])
            if client.is_playing == False:
                await play_music(interaction)  # 注意play_music需适配Interaction对象

# 启动机器人时同步斜杠命令到Discord
@client.event
async def on_ready():
    await client.tree.sync()
    print(f"Logged in as {client.user}")

注意事项 #

• 如果search_yt、play_music以及is_paused、music_queue等是类成员，需确保命令函数属于对应的commands.Cog类，此时self参数才合法，且装饰器应使用@commands.command而非@client.command。
• 斜杠命令需在机器人启动时调用await client.tree.sync()完成同步，否则Discord端不会显示该命令。

内容的提问来源于stack exchange，提问作者exibo