优化IO问题，使用异步方案进行视频下载等操作。

plugins/dify/main.py

@@ -1,10 +1,10 @@
 import os
-
 import cv2
 import requests
 import json
 import time
 import re  # 添加re模块导入
+import asyncio
 from typing import Dict, Any, List, Optional, Tuple
 
 from pathlib import Path
@@ -209,7 +209,7 @@ class DifyPlugin(MessagePluginInterface):
                 if file_type == 1:
                     await bot.send_image_message(target, Path(response))
                 elif file_type == 2:
-                    first_frame = self._get_first_frame(response, f"dify_frame_{int(time.time())}.jpg")
+                    first_frame = await self._get_first_frame(response, f"dify_frame_{int(time.time())}.jpg")
                     await bot.send_video_message(target, Path(response), Path(first_frame))
                 else:
                     return False, "获取媒资失败"
@@ -321,12 +321,12 @@ class DifyPlugin(MessagePluginInterface):
                         if outputs["type"] == "image":
                             downloader = MediaDownloader()
                             image_url = outputs["result"]
-                            image_path = downloader.download_media(image_url)
+                            image_path = await downloader.download_media(image_url)
                             answer = image_path
                         if outputs["type"] == "video":
                             downloader = MediaDownloader()
                             image_url = outputs["result"]
-                            image_path = downloader.download_media(image_url)
+                            image_path = await downloader.download_media(image_url)
                             answer = image_path
                     # 处理文本类型返回
                     elif "text" in outputs and isinstance(outputs["text"], str):
@@ -446,40 +446,43 @@ class DifyPlugin(MessagePluginInterface):
         else:
             return 0
 
-    def _get_first_frame(self, video_path, output_path):
+    async def _get_first_frame(self, video_path: str, output_path: str) -> Optional[str]:
         """
-        提取视频的第一帧并保存为图片
+        异步提取视频的第一帧并保存为图片
         :param video_path: 视频文件路径
         :param output_path: 输出图片路径
         :return: 输出图片的绝对路径，如果失败则返回None
         """
         try:
             self.LOG.info(f"开始提取视频首帧: {video_path}")
-            # 打开视频文件
-            cap = cv2.VideoCapture(video_path)
-            if not cap.isOpened():
-                self.LOG.error(f"无法打开视频: {video_path}")
-                return None
+            
+            # 使用线程池执行OpenCV操作
+            def extract_frame():
+                cap = cv2.VideoCapture(video_path)
+                if not cap.isOpened():
+                    self.LOG.error(f"无法打开视频: {video_path}")
+                    return None
+
+                ret, frame = cap.read()
+                if not ret:
+                    self.LOG.error("无法读取视频帧")
+                    cap.release()
+                    return None
+
+                try:
+                    cv2.imwrite(output_path, frame)
+                    self.LOG.info(f"首帧已保存为: {output_path}")
+                except Exception as e:
+                    self.LOG.error(f"保存首帧图片失败: {e}")
+                    cap.release()
+                    return None
 
-            # 读取首帧
-            ret, frame = cap.read()
-            if not ret:
-                self.LOG.error("无法读取视频帧")
                 cap.release()
-                return None
+                return os.path.abspath(output_path)
 
-            # 保存首帧为图片
-            try:
-                cv2.imwrite(output_path, frame)
-                self.LOG.info(f"首帧已保存为: {output_path}")
-            except Exception as e:
-                self.LOG.error(f"保存首帧图片失败: {e}")
-                cap.release()
-                return None
-
-            # 释放资源
-            cap.release()
-            return os.path.abspath(output_path)
+            # 在线程池中执行OpenCV操作
+            result = await asyncio.to_thread(extract_frame)
+            return result
 
         except Exception as e:
             self.LOG.error(f"提取视频首帧时出错: {e}")