将错误的类型参数传递给命令时处理错误答案

【问题标题】：Handle error when passing a wrong type argument to a command将错误的类型参数传递给命令时处理错误
【发布时间】：2021-07-20 07:15:17
【问题描述】：

当有人在不和谐中执行“c”命令并将不存在的角色作为参数传递时，我想处理这种情况。我收到以下错误日志：

@bot.command()
# Send DM to people that have the role
async def c(ctx, role: discord.Role, *, dm):
    try:
        for members in role.members:
            await members.create_dm.send(f'Massage from {ctx.author.display.name}: {dm}')
            print('Message sent to a member')
    except RoleNotFound:
        print('Role not found')

Ignoring exception in command c:
Traceback (most recent call last):
  File "C:\Users\Rafael\AppData\Local\Programs\Python\Python37\lib\site-packages\discord\ext\commands\bot.py", line 939, in invoke
    await ctx.command.invoke(ctx)
  File "C:\Users\Rafael\AppData\Local\Programs\Python\Python37\lib\site-packages\discord\ext\commands\core.py", line 855, in invoke
    await self.prepare(ctx)
  File "C:\Users\Rafael\AppData\Local\Programs\Python\Python37\lib\site-packages\discord\ext\commands\core.py", line 789, in prepare
    await self._parse_arguments(ctx)
  File "C:\Users\Rafael\AppData\Local\Programs\Python\Python37\lib\site-packages\discord\ext\commands\core.py", line 697, in _parse_arguments
    transformed = await self.transform(ctx, param)
  File "C:\Users\Rafael\AppData\Local\Programs\Python\Python37\lib\site-packages\discord\ext\commands\core.py", line 552, in transform
    return await self.do_conversion(ctx, converter, argument, param)
  File "C:\Users\Rafael\AppData\Local\Programs\Python\Python37\lib\site-packages\discord\ext\commands\core.py", line 505, in do_conversion
    return await self._actual_conversion(ctx, converter, argument, param)
  File "C:\Users\Rafael\AppData\Local\Programs\Python\Python37\lib\site-packages\discord\ext\commands\core.py", line 451, in _actual_conversion
    ret = await instance.convert(ctx, argument)
  File "C:\Users\Rafael\AppData\Local\Programs\Python\Python37\lib\site-packages\discord\ext\commands\converter.py", line 635, in convert
    raise RoleNotFound(argument)

所以，我想用try/except 处理它，但是在它进入tryblock 之前就发生了错误。

PS：我不想阻止错误，但要处理它

【问题讨论】：

标签： python error-handling discord discord.py

【解决方案1】：

您必须自己为此添加一个错误处理程序，您可以以不同的方式执行此操作，并且必须通过commands.YourError 进行。要使用它，您无需导入其他内容，只需构建自己的“函数”并重新构建代码。

看看下面的代码：

@bot.command()
# Send DM to people that have the role
async def c(ctx, role: discord.Role, *, dm):
    for members in role.members:
        await members.create_dm.send(f'Massage from {ctx.author.display.name}: {dm}')
        print('Message sent to a member')

@c.error
async def dm_error(ctx, error):
    if isinstance(error, commands.RoleNotFound):
        await ctx.send("Role not found")

您还可以构建更多错误，但不能像您想要的那样使用except，因为您可以将它用于AttributeError 或SyntaxError 或类似的东西。

【讨论】：