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| from abc import ABC, abstractmethod | |
| from contextlib import asynccontextmanager | |
| from typing import AsyncGenerator | |
| import redis.asyncio as redis | |
| class AsyncCacheBackend(ABC): | |
| @abstractmethod | |
| async def get(self, key: str | bytes) -> bytes: | |
| ... | |
| @abstractmethod | |
| async def set(self, key: str | bytes, value: bytes, ttl: int | None = None) -> None: | |
| ... | |
| @abstractmethod | |
| async def delete(self, key: str | bytes) -> None: | |
| ... | |
| class RedisAsyncCache(AsyncCacheBackend): | |
| def __init__(self, conn: redis.Redis): | |
| self._redis = conn | |
| async def get(self, key: str | bytes) -> bytes: | |
| data = await self._redis.get(key) | |
| if data is None: | |
| raise KeyError(key) | |
| return data | |
| async def set(self, key: str | bytes, value: bytes, ttl: int | None = None) -> None: | |
| await self._redis.set(key, value, ex=ttl) | |
| async def delete(self, key: str | bytes) -> None: | |
| await self._redis.delete(key) | |
| class InMemoryAsyncCache(AsyncCacheBackend): | |
| def __init__(self): | |
| self._cache = {} | |
| @staticmethod | |
| def _build_key(key: str | bytes) -> bytes: | |
| if isinstance(key, str): | |
| return key.encode() | |
| return key | |
| async def get(self, key: str | bytes) -> bytes: | |
| return self._cache[self._build_key(key)] | |
| async def set(self, key: str | bytes, value: bytes, _: int | None = None) -> None: | |
| self._cache[self._build_key(key)] = value | |
| async def delete(self, key: str | bytes) -> None: | |
| try: | |
| del self._cache[self._build_key(key)] | |
| except KeyError: | |
| pass | |
| class AsyncCache: | |
| def __init__(self, backend: AsyncCacheBackend, /) -> None: | |
| self._cache = backend | |
| async def get(self, key: str | bytes) -> bytes: | |
| return await self._cache.get(key) | |
| async def set(self, key: str | bytes, value: bytes, ttl: int | None = None) -> None: | |
| await self._cache.set(key, value, ttl) | |
| async def delete(self, key: str | bytes) -> None: | |
| await self._cache.delete(key) | |
| @asynccontextmanager | |
| async def async_redis_connection(host: str, *, port: int = 6379, db: int = 0, **kwargs: Any) -> AsyncGenerator[redis.Redis, None]: | |
| params = { | |
| "auto_close_connection_pool": True, | |
| } | |
| params.update(kwargs) | |
| conn = redis.Redis(host=host, port=port, db=db, **params) | |
| try: | |
| yield conn | |
| finally: | |
| await conn.close() | |
| @asynccontextmanager | |
| async def async_cache(host: str | None = None, **kwargs: Any) -> AsyncGenerator[AsyncCache, None]: | |
| if not host: | |
| cache = AsyncCache(InMemoryAsyncCache()) | |
| yield cache | |
| return | |
| async with async_redis_connection(host, **kwargs) as conn: | |
| cache = AsyncCache(RedisAsyncCache(conn)) | |
| yield cache |
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