改为使用 proxy url

Reviewed-on: #29

konabot/common/nb/extract_image.py

@@ -8,6 +8,7 @@ import nonebot
 from nonebot.matcher import Matcher
 from nonebot.adapters import Bot, Event, Message
 from nonebot.adapters.discord import Bot as DiscordBot
+from nonebot.adapters.discord import GuildMessageCreateEvent as DiscordMessageEvent
 from nonebot.adapters.onebot.v11 import Bot as OnebotV11Bot
 from nonebot.adapters.onebot.v11 import Message as OnebotV11Message
 from nonebot.adapters.onebot.v11 import MessageEvent as OnebotV11MessageEvent
@@ -121,6 +122,14 @@ async def extract_image_from_message(
         logger.debug('获取图片的路径 Fallback 到 QQ 模块')
         return await extract_image_from_qq_message(msg, evt, bot, allow_reply)
 
+    if isinstance(evt, DiscordMessageEvent):
+        logger.debug('获取图片的路径方式走 Discord')
+        for a in evt.attachments:
+            if "image/" not in a.content_type:
+                continue
+            url = a.proxy_url
+            return (await download_image_bytes(url)).bind(bytes_to_pil)
+
     for seg in UniMessage.of(msg, bot):
         logger.info(seg)
         if isinstance(seg, Image):