图片内容，将图片地址缓存到redis，然后通过随机redis快速提取路径。减少等待时间

plugins/xiuren_image/images_cache.py

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+import os
+import time
+import random
+import asyncio
+from typing import Optional, List
+
+import logging
+
+from db.connection import DBConnectionManager
+
+logger = logging.getLogger(__name__)
+
+
+class ImageCacheManager:
+    IMAGE_KEY_PREFIX = "group:images:"
+    LAST_UPDATE_TIME_KEY = "group:images:last_update_time"
+    BATCH_SIZE = 500
+
+    def __init__(self, image_folder: str):
+        self.image_folder = image_folder
+        self.redis = DBConnectionManager.get_instance().get_redis_connection()
+        self.image_extensions = {'.jpg', '.jpeg', '.png', '.gif', '.bmp', '.tiff', '.webp'}
+
+    def _get_last_update_time(self) -> float:
+        ts = self.redis.get(self.LAST_UPDATE_TIME_KEY)
+        if ts:
+            try:
+                return float(ts)
+            except Exception as e:
+                logger.warning(f"解析最后更新时间失败: {e}")
+        return 0.0
+
+    def _set_last_update_time(self, ts: float) -> None:
+        self.redis.set(self.LAST_UPDATE_TIME_KEY, ts)
+
+    def should_update_index(self) -> bool:
+        try:
+            folder_mtime = os.path.getmtime(self.image_folder)
+            last_ts = self._get_last_update_time()
+            if folder_mtime <= last_ts:
+                logger.info("图片目录未更新，无需重新索引")
+                return False
+            return True
+        except Exception as e:
+            logger.error(f"判断图片目录更新时间失败: {e}")
+            return True  # 出错则默认更新
+
+    def _scan_new_images(self, last_update_ts: float) -> List[str]:
+        """扫描目录获取新增图片文件路径"""
+        new_images = []
+        for root, _, files in os.walk(self.image_folder):
+            for file in files:
+                try:
+                    _, ext = os.path.splitext(file)
+                    if ext.lower() in self.image_extensions:
+                        full_path = os.path.join(root, file)
+                        # 只收录修改时间大于上次更新的文件
+                        if os.path.getmtime(full_path) > last_update_ts:
+                            if os.access(full_path, os.R_OK):
+                                new_images.append(full_path)
+                except Exception as e:
+                    logger.warning(f"处理文件时异常 {file}: {e}")
+        return new_images
+
+    def _redis_batch_write(self, keys_values: List[tuple]):
+        pipeline = self.redis.pipeline()
+        for key, value in keys_values:
+            pipeline.sadd(key, value)
+        pipeline.execute()
+
+    async def update_image_cache(self):
+        """异步更新Redis图片缓存，分批写入，避免一次写入压力过大"""
+        if not self.should_update_index():
+            return
+
+        last_update_ts = self._get_last_update_time()
+        new_images = self._scan_new_images(last_update_ts)
+
+        if not new_images:
+            logger.info("无新增图片，无需更新缓存")
+            # 也更新时间戳防止重复扫描
+            self._set_last_update_time(time.time())
+            return
+
+        logger.info(f"新增图片数量: {len(new_images)}, 开始写入 Redis 分批")
+
+        total = len(new_images)
+        batch_size = self.BATCH_SIZE
+        # Redis key 固定为 set，方便随机取成员
+        redis_key = self.IMAGE_KEY_PREFIX + "all"
+
+        for i in range(0, total, batch_size):
+            batch = new_images[i:i + batch_size]
+            kvs = [(redis_key, path) for path in batch]
+            try:
+                self._redis_batch_write(kvs)
+                logger.info(f"写入 Redis 批次 {i // batch_size + 1} 成功，数量: {len(batch)}")
+            except Exception as e:
+                logger.error(f"Redis 写入失败: {e}")
+                # 这里可选择是否继续或退出，暂继续
+
+        # 更新最后更新时间戳
+        self._set_last_update_time(time.time())
+
+    def get_random_image(self) -> Optional[str]:
+        redis_key = self.IMAGE_KEY_PREFIX + "all"
+        try:
+            img = self.redis.srandmember(redis_key)
+            if img:
+                # redis 返回字节，转字符串
+                return img.decode('utf-8') if isinstance(img, bytes) else img
+        except Exception as e:
+            logger.error(f"获取随机图片失败: {e}")
+        return None