feat: ADRF async views (phase1) + native async serializers (phase2) + async cache infra

utils/async_cache.py

@@ -0,0 +1,114 @@
+"""
+异步 Redis 缓存封装 —— 100% 异步化基建
+========================================
+Django 的 cache 框架（django-redis）没有异步 API，本模块基于 redis.asyncio 直连，
+复用 settings 中的 REDIS 配置，提供与 django cache 对等的异步接口。
+
+用法：
+    from utils.async_cache import aget_cache, aset_cache, adelete_cache
+
+    value = await aget_cache('key')
+    await aset_cache('key', obj, timeout=3600)
+    await adelete_cache('key')
+
+序列化：msgpack（快速紧凑）+ JSON 兜底；与 django-redis 缓存池互不干扰（独立 key 前缀）。
+"""
+import asyncio
+import json
+import logging
+from django.conf import settings
+from django.core.cache import caches
+from asgiref.sync import sync_to_async
+import msgpack
+
+logger = logging.getLogger(__name__)
+
+_cache_pool = None
+_lock = asyncio.Lock()
+
+
+async def _get_pool():
+    """懒初始化 redis.asyncio 连接池（复用 settings.REDIS 配置）"""
+    global _cache_pool
+    async with _lock:
+        if _cache_pool is None:
+            import redis.asyncio as aioredis
+            _cache_pool = aioredis.Redis(
+                host=settings.REDIS_HOST,
+                port=int(settings.REDIS_PORT),
+                db=int(getattr(settings, 'REDIS_DB', 0)),
+                password=getattr(settings, 'REDIS_PASSWORD', '') or None,
+                decode_responses=False,
+                socket_connect_timeout=5,
+                socket_timeout=5,
+                max_connections=50,
+            )
+        return _cache_pool
+
+
+def _pack(value):
+    try:
+        return b'async-cache:' + msgpack.packb(value, use_bin_type=True, default=str)
+    except (TypeError, ValueError):
+        return b'async-cache-json:' + json.dumps(value, ensure_ascii=False, default=str).encode()
+
+
+def _unpack(raw):
+    if raw is None:
+        return None
+    if raw.startswith(b'async-cache-json:'):
+        return json.loads(raw[17:].decode())
+    return msgpack.unpackb(raw[12:], raw=False)
+
+
+async def aget_cache(key, default=None):
+    try:
+        pool = await _get_pool()
+        raw = await pool.get(f'async:{key}')
+        if raw is None:
+            return default
+        return _unpack(raw)
+    except Exception:
+        logger.warning('aget_cache failed for %s, falling back to sync cache', key)
+        try:
+            return await sync_to_async(caches['default'].get)(key, default)
+        except Exception:
+            return default
+
+
+async def aset_cache(key, value, timeout=300):
+    try:
+        pool = await _get_pool()
+        await pool.set(f'async:{key}', _pack(value), ex=timeout)
+        return True
+    except Exception:
+        logger.warning('aset_cache failed for %s, falling back to sync cache', key)
+        try:
+            await sync_to_async(caches['default'].set)(key, value, timeout)
+            return True
+        except Exception:
+            return False
+
+
+async def adelete_cache(key):
+    try:
+        pool = await _get_pool()
+        await pool.delete(f'async:{key}')
+        return True
+    except Exception:
+        logger.warning('adelete_cache failed for %s', key)
+        try:
+            await sync_to_async(caches['default'].delete)(key)
+            return True
+        except Exception:
+            return False
+
+
+async def aget_or_set(key, factory, timeout=300):
+    """原子性不保证（与 django cache 用法一致），value 为 await factory() 结果"""
+    v = await aget_cache(key)
+    if v is not None:
+        return v
+    v = await factory() if asyncio.iscoroutinefunction(factory) else factory()
+    await aset_cache(key, v, timeout)
+    return v