功能细节优化

backend/redis_cache.py

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+"""Redis 缓存层，替代内存缓存，支持持久化和跨进程共享。"""
+import json
+import redis
+from typing import Any, Optional
+from config import REDIS_HOST, REDIS_PORT, REDIS_DB, REDIS_PASSWORD
+
+class RedisCache:
+    def __init__(self):
+        self.client: Optional[redis.Redis] = None
+        self.enabled = False
+        self._connect()
+    
+    def _connect(self):
+        """连接 Redis，失败时降级为禁用状态"""
+        try:
+            self.client = redis.Redis(
+                host=REDIS_HOST,
+                port=REDIS_PORT,
+                db=REDIS_DB,
+                password=REDIS_PASSWORD if REDIS_PASSWORD else None,
+                decode_responses=True,
+                socket_connect_timeout=2,
+                socket_timeout=2
+            )
+            self.client.ping()
+            self.enabled = True
+            print(f"✓ Redis 已连接: {REDIS_HOST}:{REDIS_PORT}")
+        except Exception as e:
+            self.enabled = False
+            print(f"✗ Redis 连接失败，缓存已禁用: {e}")
+    
+    def get(self, key: str) -> Optional[Any]:
+        """获取缓存，自动反序列化 JSON"""
+        if not self.enabled:
+            return None
+        try:
+            value = self.client.get(key)
+            if value:
+                return json.loads(value)
+            return None
+        except Exception as e:
+            print(f"Redis get error: {e}")
+            return None
+    
+    def set(self, key: str, value: Any, expire: int = 3600):
+        """设置缓存，自动序列化为 JSON
+        
+        Args:
+            key: 缓存键
+            value: 缓存值（可序列化为JSON的对象）
+            expire: 过期时间（秒），默认1小时
+        """
+        if not self.enabled:
+            return False
+        try:
+            serialized = json.dumps(value, ensure_ascii=False, default=str)
+            self.client.setex(key, expire, serialized)
+            return True
+        except Exception as e:
+            print(f"Redis set error: {e}")
+            return False
+    
+    def delete(self, key: str):
+        """删除缓存"""
+        if not self.enabled:
+            return False
+        try:
+            self.client.delete(key)
+            return True
+        except Exception as e:
+            print(f"Redis delete error: {e}")
+            return False
+    
+    def clear_pattern(self, pattern: str):
+        """批量删除匹配模式的键"""
+        if not self.enabled:
+            return 0
+        try:
+            keys = self.client.keys(pattern)
+            if keys:
+                return self.client.delete(*keys)
+            return 0
+        except Exception as e:
+            print(f"Redis clear_pattern error: {e}")
+            return 0
+
+# 全局单例
+cache = RedisCache()