如何使用Discord Bot复制并重新发送Embed消息？

问题描述 #

• 需求：通过自有Discord Bot转发指定ID的Discohook Embed消息，已知来源频道ID、目标频道ID和消息ID
• 尝试代码：

def runDiscordBot():
    TOKEN = ""
    client = commands.Bot(command_prefix="$", intents = discord.Intents.all())

    @client.event
    async def on_ready():
        channel = client.get_channel(1094649315810611202)
        message = await channel.fetch_message(1096173976688001134)
        await channel.send(message.content)
        print(f'{client.user} is now running!')

    client.run(TOKEN)

• 报错信息：

2023-04-13 23:30:58 ERROR    discord.client Ignoring exception in on_ready
Traceback (most recent call last):
  File "C:\Users\birea\AppData\Local\Programs\Python\Python311\Lib\site-packages\discord\client.py", line 441, in _run_event
    await coro(*args, **kwargs)
  File "c:\Users\birea\Desktop\Programi\FARKBot\tempCodeRunnerFile.python", line 12, in on_ready
    await channel.send(message.content)
  File "C:\Users\birea\AppData\Local\Programs\Python\Python311\Lib\site-packages\discord\abc.py", line 1561, in send
    data = await state.http.send_message(channel.id, params=params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\birea\AppData\Local\Programs\Python\Python311\Lib\site-packages\discord\http.py", line 744, in request
    raise HTTPException(response, data)
discord.errors.HTTPException: 400 Bad Request (error code: 50006): Cannot send an empty message

• 额外信息：打印message.content为空行，打印message输出：

<Message id=1096173976688001134 channel=<TextChannel id=1094649315810611202 name='general' position=0 nsfw=False news=False category_id=1094649315810611200> type=<MessageType.default: 0> author=<User id=1096121542745788426 name='FARKBot' discriminator='0000' bot=True> flags=<MessageFlags value=0>>

问题原因 #

Discohook发送的Embed消息没有普通文本内容，message.content自然为空。Embed数据存储在message.embeds属性中（这是一个包含所有Embed对象的列表），直接发送空内容会触发Discord API的"不能发送空消息"错误。

解决方法 #

修改代码，在发送消息时传入embeds参数传递原消息的Embed列表，如需转发附件也可一并处理。

修改后的代码 #

def runDiscordBot():
    TOKEN = ""
    client = commands.Bot(command_prefix="$", intents = discord.Intents.all())

    @client.event
    async def on_ready():
        # 获取来源频道
        source_channel = client.get_channel(1094649315810611202)
        # 获取目标频道（需转发到其他频道时替换为对应ID）
        target_channel = client.get_channel(1094649315810611202)
        # 获取指定消息
        message = await source_channel.fetch_message(1096173976688001134)
        
        # 转发消息，包含文本、Embed和附件
        await target_channel.send(
            content=message.content,
            embeds=message.embeds,
            files=[await attachment.to_file() for attachment in message.attachments]
        )
        
        print(f'{client.user} 已启动运行！')

    client.run(TOKEN)

代码说明 #

• embeds=message.embeds：将原消息中的所有Embed对象传递给发送方法，确保转发内容包含原Embed
• files参数：通过列表推导式将原消息的附件转换为可发送的文件对象，实现附件同步转发
• 来源/目标频道分离：如需转发到不同频道，单独修改target_channel的ID即可

内容的提问来源于stack exchange，提问作者Ryoschin Lot