Discord.py Python 经济机器人与 mongodb“NoneType”错误答案

【问题标题】：Discord.py Python economy bot with mongodb "NoneType" errorDiscord.py Python 经济机器人与 mongodb“NoneType”错误
【发布时间】：2021-08-11 07:24:28
【问题描述】：

（英语不好）我想用 mongodb 创建一个经济型机器人，它在 2 天前运行良好，但现在出现“NoneType”错误

main.py中的源代码（在数据库中添加用户）：

@client.event
async def on_ready():
    print(f'''
[*]BOT: ON
[*]BOT NAME : {client.user}
[*]BOT ID: {client.user.id}
        ''')
    for guild in client.guilds:
        for member in guild.members:
            post = {
                "_id": member.id,
                "balance": 10000000,
                "xp": 0,
                "level": 1
            }
            if collection.count_documents({"_id": member.id}) == 0:
                collection.insert_one(post)

该代码正在运行，因为我在 db 上看到了该代码

来自有问题的cog的源代码：

class Economic(commands.Cog):
    def __init__(self, client):
        self.client = client
        self.cluster  = MongoClient(f"mongodb+srv://discord:{secret}@cluster403.xn9cm.mongodb.net/discord1?retryWrites=true&w=majority")
        cluster  = MongoClient(f"mongodb+srv://discord:{secret}@cluster403.xn9cm.mongodb.net/users?retryWrites=true&w=majority")
        self.collection = cluster.users.tutu
    @commands.command(
        name = "balance",
        aliases = ["ball","money"],
        brief = "User balance",
        usage = "balance <@user>",
        description = "none....."
    )
    async def user_balace(self, ctx, member: discord.Member = None):
        if member is None:
            embed = discord.Embed(
                title = f"__{ctx.author}__'s balance",
                description = f"Money: {self.collection.find_one({'_id': ctx.author.id})['balance']}"
            )
            await ctx.send(embed=embed)

当我在控制台中输入“平衡”命令时，我得到了那个错误：

Ignoring exception in command balance:
Traceback (most recent call last):
  File "D:\lib\site-packages\discord\ext\commands\core.py", line 85, in wrapped
    ret = await coro(*args, **kwargs)
  File "C:\Users\Nick403\Desktop\Apps\PROJECTS\BOT\cogs\eco.py", line 22, in user_balace
    description = f"Money: {self.collection.find_one({'_id': ctx.author.id})['balance']}"
TypeError: 'NoneType' object is not subscriptable

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

Traceback (most recent call last):
  File "D:\lib\site-packages\discord\ext\commands\bot.py", line 939, in invoke
    await ctx.command.invoke(ctx)
  File "D:\lib\site-packages\discord\ext\commands\core.py", line 863, in invoke
    await injected(*ctx.args, **ctx.kwargs)
  File "D:\lib\site-packages\discord\ext\commands\core.py", line 94, in wrapped
    raise CommandInvokeError(exc) from exc
discord.ext.commands.errors.CommandInvokeError: Command raised an exception: TypeError: 'NoneType' object is not subscriptable

有人可以帮助我吗？（对不起我的英语不好）

【问题讨论】：

标签： python-3.x mongodb discord.py pymongo

【解决方案1】：

错误消息本质上是说self.collection.find_one({'_id': ctx.author.id}) 正在以None 的形式返回。在PyMongo Documentation 中，我们可以看到find_one() 将在集合中找不到此类项目时返回None。如果您的数据库中没有特定用户，我会重写您的代码以确保安全。

if self.collection.find({'_id': ctx.author.id}).count() == 0:
    self.collection.insert_one({USER OBJECT})

user = self.collection.find_one({'_id': ctx.author.id})

【讨论】：