Telegram机器人遇AttributeError：NoneType对象无username属性求助

问题原因 #

当用户开启消息转发隐私设置时，Telegram不会向机器人暴露转发来源用户的forward_from对象，此时update.effective_message.forward_from为None。你的代码直接访问forward_from.username，必然触发AttributeError: 'NoneType' object has no attribute 'username'。

修复方案 #

先判断forward_from是否存在，再处理后续逻辑；同时调整判断顺序，优先处理异常场景：

#!/usr/bin/python3

from telegram.ext.updater import Updater
from telegram.update import Update
from telegram.ext.callbackcontext import CallbackContext
from telegram.ext.commandhandler import CommandHandler
from telegram.ext.messagehandler import MessageHandler
from telegram.ext.filters import Filters

updater = Updater("My Token", use_context=True)

def start(update: Update, context: CallbackContext):
    update.message.reply_text(
        "Hi. I'm a bot that sniffs out this softwares scammers so you don't get exploited. Simply forward a message from the scammer to me "
        "and I'll tell you if it's the real support or not.")

def usercheck(update: Update, context: CallbackContext):
    # 优先处理隐私用户（无转发来源信息）
    if not update.effective_message.forward_from:
        update.effective_message.reply_text("🚨🚨🚨🚨🚨 If this user says they're from My softwares support - they are trying to scam you. "
            "Please report them and stop talking to them immediately. 🚨🚨🚨🚨🚨")
        return
    
    # 提取转发用户的用户名，减少重复访问
    forward_username = update.effective_message.forward_from.username
    
    if forward_username == "admin1":
        update.effective_message.reply_text("✅This message was sent from the real admin1, an authorised reseller from this group")
    elif forward_username == "dev1":
        update.effective_message.reply_text("✅This message was sent from the real dev1, an authorised developer of group")
    elif not forward_username:  # 用户本身无用户名
        update.effective_message.reply_text("🚨🚨🚨🚨🚨 If this user says they're from Gunbot support - they are trying to scam you. "
            "Please report them and stop talking to them immediately. 🚨🚨🚨🚨🚨")
    else:  # 其他有用户名的非授权用户
        update.effective_message.reply_text("🚨🚨🚨🚨🚨 If this user says they're from My softwares support - they are trying to scam you. "
            "Please report them and stop talking to them immediately. 🚨🚨🚨🚨🚨")

updater.dispatcher.add_handler(CommandHandler("start", start))
updater.dispatcher.add_handler(MessageHandler(Filters.forwarded, usercheck))
updater.start_polling()
updater.idle()

关键修改说明 #

• 新增if not update.effective_message.forward_from:判断，直接拦截隐私用户的转发请求，避免空指针错误
• 将forward_from.username提取为变量，简化代码逻辑
• 调整判断顺序：先处理无来源的异常情况，再依次匹配授权用户、无用户名用户、其他用户

内容的提问来源于stack exchange，提问作者Doomian