Make backends store bytes instead of strings

This is, for the majority of backends, the native format anyway, and so
we save encoding and decoding when using the PickleCodec or if (in future)
a orjson Coder was to be added.

For the JsonCodec, the only thing that changed is the location where the
JSON data is encoded to bytes and decoded back again to a string.

README.md

@@ -78,7 +78,7 @@ async def index():
 
 @app.on_event("startup")
 async def startup():
-    redis = aioredis.from_url("redis://localhost", encoding="utf8", decode_responses=True)
+    redis = aioredis.from_url("redis://localhost")
     FastAPICache.init(RedisBackend(redis), prefix="fastapi-cache")
 
 ```
@@ -180,6 +180,13 @@ async def index():
 `InMemoryBackend` store cache data in memory and use lazy delete, which mean if you don't access it after cached, it
 will not delete automatically.
 
+
+### RedisBackend
+
+When using the redis backend, please make sure you pass in a redis client that does [_not_ decode responses][redis-decode] (`decode_responses` **must** be `False`, which is the default). Cached data is stored as `bytes` (binary), decoding these i the redis client would break caching.
+
+[redis-decode]: https://redis-py.readthedocs.io/en/latest/examples/connection_examples.html#by-default-Redis-return-binary-responses,-to-decode-them-use-decode_responses=True
+
 ## Tests and coverage
 
 ```shell

fastapi_cache/backends/__init__.py

@@ -4,15 +4,15 @@ from typing import Optional, Tuple
 
 class Backend:
     @abc.abstractmethod
-    async def get_with_ttl(self, key: str) -> Tuple[int, Optional[str]]:
+    async def get_with_ttl(self, key: str) -> Tuple[int, Optional[bytes]]:
         raise NotImplementedError
 
     @abc.abstractmethod
-    async def get(self, key: str) -> Optional[str]:
+    async def get(self, key: str) -> Optional[bytes]:
         raise NotImplementedError
 
     @abc.abstractmethod
-    async def set(self, key: str, value: str, expire: Optional[int] = None) -> None:
+    async def set(self, key: str, value: bytes, expire: Optional[int] = None) -> None:
         raise NotImplementedError
 
     @abc.abstractmethod

fastapi_cache/backends/dynamodb.py

@@ -39,11 +39,11 @@ class DynamoBackend(Backend):
     async def close(self) -> None:
         self.client = await self.client.__aexit__(None, None, None)
 
-    async def get_with_ttl(self, key: str) -> Tuple[int, str]:
+    async def get_with_ttl(self, key: str) -> Tuple[int, Optional[bytes]]:
         response = await self.client.get_item(TableName=self.table_name, Key={"key": {"S": key}})
 
         if "Item" in response:
-            value = response["Item"].get("value", {}).get("S")
+            value = response["Item"].get("value", {}).get("B")
             ttl = response["Item"].get("ttl", {}).get("N")
 
             if not ttl:
@@ -56,12 +56,12 @@ class DynamoBackend(Backend):
 
         return 0, None
 
-    async def get(self, key: str) -> str:
+    async def get(self, key: str) -> Optional[bytes]:
         response = await self.client.get_item(TableName=self.table_name, Key={"key": {"S": key}})
         if "Item" in response:
-            return response["Item"].get("value", {}).get("S")
+            return response["Item"].get("value", {}).get("B")
 
-    async def set(self, key: str, value: str, expire: Optional[int] = None) -> None:
+    async def set(self, key: str, value: bytes, expire: Optional[int] = None) -> None:
         ttl = (
             {
                 "ttl": {
@@ -83,7 +83,7 @@ class DynamoBackend(Backend):
             Item={
                 **{
                     "key": {"S": key},
-                    "value": {"S": value},
+                    "value": {"B": value},
                 },
                 **ttl,
             },

fastapi_cache/backends/inmemory.py

@@ -8,7 +8,7 @@ from fastapi_cache.backends import Backend
 
 @dataclass
 class Value:
-    data: str
+    data: bytes
     ttl_ts: int
 
 
@@ -29,21 +29,21 @@ class InMemoryBackend(Backend):
                 return v
         return None
 
-    async def get_with_ttl(self, key: str) -> Tuple[int, Optional[str]]:
+    async def get_with_ttl(self, key: str) -> Tuple[int, Optional[bytes]]:
         async with self._lock:
             v = self._get(key)
             if v:
                 return v.ttl_ts - self._now, v.data
             return 0, None
 
-    async def get(self, key: str) -> Optional[str]:
+    async def get(self, key: str) -> Optional[bytes]:
         async with self._lock:
             v = self._get(key)
             if v:
                 return v.data
             return None
 
-    async def set(self, key: str, value: str, expire: Optional[int] = None) -> None:
+    async def set(self, key: str, value: bytes, expire: Optional[int] = None) -> None:
         async with self._lock:
             self._store[key] = Value(value, self._now + (expire or 0))
 

fastapi_cache/backends/memcached.py

@@ -9,14 +9,14 @@ class MemcachedBackend(Backend):
     def __init__(self, mcache: Client):
         self.mcache = mcache
 
-    async def get_with_ttl(self, key: str) -> Tuple[int, Optional[str]]:
-        return 3600, await self.mcache.get(key.encode())
+    async def get_with_ttl(self, key: str) -> Tuple[int, Optional[bytes]]:
+        return 3600, await self.get(key)
 
-    async def get(self, key: str) -> Optional[str]:
-        return await self.mcache.get(key, key.encode())
+    async def get(self, key: str) -> Optional[bytes]:
+        return await self.mcache.get(key.encode())
 
-    async def set(self, key: str, value: str, expire: Optional[int] = None) -> None:
-        await self.mcache.set(key.encode(), value.encode(), exptime=expire or 0)
+    async def set(self, key: str, value: bytes, expire: Optional[int] = None) -> None:
+        await self.mcache.set(key.encode(), value, exptime=expire or 0)
 
     async def clear(self, namespace: Optional[str] = None, key: Optional[str] = None) -> int:
         raise NotImplementedError

fastapi_cache/backends/redis.py

@@ -1,4 +1,4 @@
-from typing import Optional, Tuple
+from typing import Optional, Tuple, Union
 
 from redis.asyncio.client import Redis
 from redis.asyncio.cluster import RedisCluster
@@ -7,18 +7,18 @@ from fastapi_cache.backends import Backend
 
 
 class RedisBackend(Backend):
-    def __init__(self, redis: Redis[str] | RedisCluster[str]):
+    def __init__(self, redis: Union[Redis[bytes], RedisCluster[bytes]]):
         self.redis = redis
         self.is_cluster: bool = isinstance(redis, RedisCluster)
 
-    async def get_with_ttl(self, key: str) -> Tuple[int, str]:
+    async def get_with_ttl(self, key: str) -> Tuple[int, Optional[bytes]]:
         async with self.redis.pipeline(transaction=not self.is_cluster) as pipe:
             return await pipe.ttl(key).get(key).execute()
 
-    async def get(self, key: str) -> Optional[str]:
+    async def get(self, key: str) -> Optional[bytes]:
         return await self.redis.get(key)
 
-    async def set(self, key: str, value: str, expire: Optional[int] = None) -> None:
+    async def set(self, key: str, value: bytes, expire: Optional[int] = None) -> None:
         return await self.redis.set(key, value, ex=expire)
 
     async def clear(self, namespace: Optional[str] = None, key: Optional[str] = None) -> int:

fastapi_cache/coder.py

@@ -1,9 +1,8 @@
-import codecs
 import datetime
 import json
 import pickle  # nosec:B403
 from decimal import Decimal
-from typing import Any, Callable, ClassVar, Dict, TypeVar, overload
+from typing import Any, Callable, ClassVar, Dict, Optional, TypeVar, Union, overload
 
 import pendulum
 from fastapi.encoders import jsonable_encoder
@@ -46,11 +45,11 @@ def object_hook(obj: Any) -> Any:
 
 class Coder:
     @classmethod
-    def encode(cls, value: Any) -> str:
+    def encode(cls, value: Any) -> bytes:
         raise NotImplementedError
 
     @classmethod
-    def decode(cls, value: str) -> Any:
+    def decode(cls, value: bytes) -> Any:
         raise NotImplementedError
 
     # (Shared) cache for endpoint return types to Pydantic model fields.
@@ -62,16 +61,16 @@ class Coder:
 
     @overload
     @classmethod
-    def decode_as_type(cls, value: str, type_: _T) -> _T:
+    def decode_as_type(cls, value: bytes, *, type_: _T) -> _T:
         ...
 
     @overload
     @classmethod
-    def decode_as_type(cls, value: str, *, type_: None) -> Any:
+    def decode_as_type(cls, value: bytes, *, type_: None) -> Any:
         ...
 
     @classmethod
-    def decode_as_type(cls, value: str, *, type_: _T | None) -> _T | Any:
+    def decode_as_type(cls, value: bytes, *, type_: Optional[_T]) -> Union[_T, Any]:
         """Decode value to the specific given type
 
         The default implementation uses the Pydantic model system to convert the value.
@@ -95,29 +94,32 @@ class Coder:
 
 class JsonCoder(Coder):
     @classmethod
-    def encode(cls, value: Any) -> str:
+    def encode(cls, value: Any) -> bytes:
         if isinstance(value, JSONResponse):
-            return value.body.decode()
-        return json.dumps(value, cls=JsonEncoder)
+            return value.body
+        return json.dumps(value, cls=JsonEncoder).encode()
 
     @classmethod
-    def decode(cls, value: str) -> str:
-        return json.loads(value, object_hook=object_hook)
+    def decode(cls, value: bytes) -> Any:
+        # explicitly decode from UTF-8 bytes first, as otherwise
+        # json.loads() will first have to detect the correct UTF-
+        # encoding used.
+        return json.loads(value.decode(), object_hook=object_hook)
 
 
 class PickleCoder(Coder):
     @classmethod
-    def encode(cls, value: Any) -> str:
+    def encode(cls, value: Any) -> bytes:
         if isinstance(value, TemplateResponse):
             value = value.body
-        return codecs.encode(pickle.dumps(value), "base64").decode()
+        return pickle.dumps(value)
 
     @classmethod
-    def decode(cls, value: str) -> Any:
-        return pickle.loads(codecs.decode(value.encode(), "base64"))  # nosec:B403,B301
+    def decode(cls, value: bytes) -> Any:
+        return pickle.loads(value)  # nosec:B403,B301
 
     @classmethod
-    def decode_as_type(cls, value: str, *, type_: Any) -> Any:
+    def decode_as_type(cls, value: bytes, *, type_: Optional[_T]) -> Any:
         # Pickle already produces the correct type on decoding, no point
         # in paying an extra performance penalty for pydantic to discover
         # the same.

tests/test_codecs.py

@@ -36,7 +36,7 @@ class PDItem(BaseModel):
 )
 def test_pickle_coder(value: Any) -> None:
     encoded_value = PickleCoder.encode(value)
-    assert isinstance(encoded_value, str)
+    assert isinstance(encoded_value, bytes)
     decoded_value = PickleCoder.decode(encoded_value)
     assert decoded_value == value
 
@@ -55,12 +55,12 @@ def test_pickle_coder(value: Any) -> None:
 )
 def test_json_coder(value: Any, return_type) -> None:
     encoded_value = JsonCoder.encode(value)
-    assert isinstance(encoded_value, str)
+    assert isinstance(encoded_value, bytes)
     decoded_value = JsonCoder.decode_as_type(encoded_value, type_=return_type)
     assert decoded_value == value
 
 
 def test_json_coder_validation_error() -> None:
-    invalid = '{"name": "incomplete"}'
+    invalid = b'{"name": "incomplete"}'
     with pytest.raises(ValidationError):
         JsonCoder.decode_as_type(invalid, type_=PDItem)