discord.py如何实现自定义欢迎消息变量自动转换为用户提及

我正在开发discord.py的欢迎模块，希望让自定义欢迎消息中的{member_mention}自动转换为新加入服务器用户的提及（@用户）。目前发送消息时只会保留{member_mention}文本，无法转换为实际用户提及。我需要的是自定义变量替换功能，而非直接使用member.mention，参考Dyno等热门机器人的类似功能，询问具体实现方法。

@bot.event
async def on_member_join(member):
            try:
                with open("database\\database_main\\serverdb.json", encoding="utf-8") as f:
                    data = json.load(f)
                if str(member.guild.id) in data:
                    logera = data[str(member.guild.id)]['log_joinlogs']
                    if logera == 0:
                        with open("database\\database_main\\serverdb.json", encoding="utf-8") as f:
                            data = json.load(f)
                        if str(member.guild.id) in data:
                            isenabled = data[str(member.guild.id)]['logchlID']
                            if isenabled == 0:
                                return
                            else:
                                creation = member.created_at.strftime("%a %#d %B %Y, %I:%M %p")
                                channelrs = bot.get_channel(data[str(member.guild.id)]['logchlID'])
                                embed = discord.Embed(title=f"Member Joined", color=discord.Colour.green())
                                embed.add_field(name="Account Creation Date", value=f"{creation}")
                                embed.set_footer(text=f"User ID: {member.id}")
                                embed.set_author(name=f"{member.display_name} (@{member.name})", icon_url=member.avatar)
                                await channelrs.send(embed=embed)
                    else:
                        return
            except:
                return
            with open("database\\database_main\\serverdb.json", encoding="utf-8") as f:
                datar = json.load(f)
                welcomemodule = datar[str(member.guild.id)]['welcome_module']
                if welcomemodule == 0:
                    welcomemessage = datar[str(member.guild.id)]['welcome_message']
                    if welcomemessage == "":
                        print("welcom message no?")
                        return
                    else:
                        welcoa = datar[str(member.guild.id)]['welcome_chl_id']
                        if welcoa == 0:
                            return
                        else:
                            member_mention = member.mention
                            welcomechl = bot.get_channel(datar[str(member.guild.id)]['welcome_chl_id'])
                            await welcomechl.send(f"{welcomemessage}")

{
    "1141583283403116574": {
        "level_module": 0,
        "moderation_module": 0,
        "lvlupID": 1173294414303600771,
        "xpaddition": 0,
        "logchlID": 1161019161531662466,
        "log_joinlogs": 0,
        "log_leavelogs": 0,
        "log_banlogs": 1,
        "log_deletemsglogs": 0,
        "fun_module": 0,
        "log_editedmsglogs": 0,
        "welcome_module": 0,
        "welcome_message": "hi **{member_mention}!!!**",
        "svrid": "phmouGp",
        "welcome_chl_id": 1165505902841962588,
        "welcome_dm_message": "hi"
    }
}

核心思路是将配置中的占位符替换为对应用户/服务器的实际数据，以下是三种可行实现方式：

方法1：字符串替换（基础版） #

直接用replace()方法逐个替换占位符，适合变量较少的场景：

# 定义占位符与实际值的映射
variable_map = {
    "{member_mention}": member.mention,
    "{member_name}": member.name,
    "{server_name}": member.guild.name
}

# 替换所有占位符
formatted_msg = welcomemessage
for placeholder, value in variable_map.items():
    formatted_msg = formatted_msg.replace(placeholder, value)

await welcomechl.send(formatted_msg)

方法2：str.format()（简洁扩展版） #

利用Python内置的字符串格式化功能，占位符需与format()参数名匹配，扩展性更强：

formatted_msg = welcomemessage.format(
    member_mention=member.mention,
    member_name=member.name,
    member_display_name=member.display_name,
    server_name=member.guild.name,
    member_id=member.id
)

await welcomechl.send(formatted_msg)

方法3：正则表达式替换（灵活匹配版） #

适合需要动态识别大量占位符的场景，通过正则匹配所有{xxx}格式的占位符：

import re

# 匹配所有{xxx}格式的占位符
pattern = re.compile(r"\{(\w+)\}")

def replace_match(match):
    key = match.group(1)
    # 根据占位符返回对应值
    match_dict = {
        "member_mention": member.mention,
        "member_name": member.name,
        "server_name": member.guild.name
    }
    return match_dict.get(key, match.group(0))  # 找不到则保留原占位符

formatted_msg = pattern.sub(replace_match, welcomemessage)
await welcomechl.send(formatted_msg)

以方法2为例，修改后的欢迎消息发送逻辑：

with open("database\\database_main\\serverdb.json", encoding="utf-8") as f:
    datar = json.load(f)
    welcomemodule = datar[str(member.guild.id)]['welcome_module']
    if welcomemodule == 0:
        welcomemessage = datar[str(member.guild.id)]['welcome_message']
        if welcomemessage == "":
            print("welcom message no?")
            return
        else:
            welcoa = datar[str(member.guild.id)]['welcome_chl_id']
            if welcoa == 0:
                return
            else:
                # 格式化欢迎消息
                formatted_msg = welcomemessage.format(
                    member_mention=member.mention,
                    member_name=member.name,
                    member_display_name=member.display_name,
                    server_name=member.guild.name
                )
                welcomechl = bot.get_channel(datar[str(member.guild.id)]['welcome_chl_id'])
                await welcomechl.send(formatted_msg)

• 确保JSON配置中的占位符名称与代码中format()的参数名完全一致
• 可根据需求扩展更多变量，比如用户ID、服务器成员总数等
• 建议添加异常捕获，避免因未知占位符导致的格式化错误

内容的提问来源于stack exchange，提问作者As2Bax