Fix serialization in filesystem backend with binary content that is also valid UTF-8

2 files changed, 25 insertions, 16 deletions

diff --git a/requests_cache/serializers/pipeline.py b/requests_cache/serializers/pipeline.py
index 3bbfbda..2a22761 100644
--- a/requests_cache/serializers/pipeline.py
+++ b/requests_cache/serializers/pipeline.py
@@ -3,7 +3,7 @@
    :classes-only:
    :nosignatures:
 """
-from typing import Any, Callable, List, Union
+from typing import Any, Callable, Sequence, Union
 
 from ..models import CachedResponse
 
@@ -29,22 +29,26 @@ class Stage:
 
 
 class SerializerPipeline:
-    """A sequence of steps used to serialize and deserialize response objects.
-    This can be initialized with :py:class:`Stage` objects, or any objects with ``dumps()`` and
-    ``loads()`` methods
+    """A pipeline of stages chained together to serialize and deserialize response objects.
+
+    Args:
+        stages: A sequence of :py:class:`Stage` objects, or any objects with ``dumps()`` and
+            ``loads()`` methods
+        is_binary: Indicates whether the serialized content is binary
     """
 
-    def __init__(self, stages: List):
-        self.steps = stages
-        self.dump_steps = [step.dumps for step in stages]
-        self.load_steps = [step.loads for step in reversed(stages)]
+    def __init__(self, stages: Sequence, is_binary: bool = False):
+        self.is_binary = is_binary
+        self.stages = stages
+        self.dump_stages = [stage.dumps for stage in stages]
+        self.load_stages = [stage.loads for stage in reversed(stages)]
 
     def dumps(self, value) -> Union[str, bytes]:
-        for step in self.dump_steps:
+        for step in self.dump_stages:
             value = step(value)
         return value
 
     def loads(self, value) -> CachedResponse:
-        for step in self.load_steps:
+        for step in self.load_stages:
             value = step(value)
         return value
diff --git a/requests_cache/serializers/preconf.py b/requests_cache/serializers/preconf.py
index 6cf83bc..35453b5 100644
--- a/requests_cache/serializers/preconf.py
+++ b/requests_cache/serializers/preconf.py
@@ -34,7 +34,9 @@ orjson_preconf_stage = CattrStage(orjson.make_converter)  #: Pre-serialization s
 yaml_preconf_stage = CattrStage(pyyaml.make_converter)  #: Pre-serialization steps for YAML
 toml_preconf_stage = CattrStage(tomlkit.make_converter)  #: Pre-serialization steps for TOML
 ujson_preconf_stage = CattrStage(ujson.make_converter)  #: Pre-serialization steps for ultrajson
-pickle_serializer = SerializerPipeline([base_stage, pickle])  #: Complete pickle serializer
+pickle_serializer = SerializerPipeline(
+    [base_stage, pickle], is_binary=True
+)  #: Complete pickle serializer
 utf8_encoder = Stage(dumps=str.encode, loads=lambda x: x.decode())  #: Encode to bytes
 
 
@@ -55,7 +57,9 @@ try:
         """Create a serializer that uses ``pickle`` + ``itsdangerous`` to add a signature to
         responses on write, and validate that signature with a secret key on read.
         """
-        return SerializerPipeline([base_stage, pickle, signer_stage(secret_key, salt)])
+        return SerializerPipeline(
+            [base_stage, pickle, signer_stage(secret_key, salt)], is_binary=True
+        )
 
 except ImportError as e:
     signer_stage = get_placeholder_class(e)
@@ -70,8 +74,8 @@ try:
         import bson
 
     bson_serializer = SerializerPipeline(
-        [bson_preconf_stage, bson]
-    )  #: Complete BSON serializer; using pymongo's ``bson.json_util`` if installed, otherwise standalone ``bson`` codec
+        [bson_preconf_stage, bson], is_binary=False
+    )  #: Complete BSON serializer; uses pymongo's ``bson.json_util`` if installed, otherwise standalone ``bson`` codec
 except ImportError as e:
     bson_serializer = get_placeholder_class(e)
 
@@ -88,7 +92,7 @@ except ImportError:
 
 _json_stage = Stage(dumps=partial(json.dumps, indent=2), loads=json.loads)
 json_serializer = SerializerPipeline(
-    [_json_preconf_stage, _json_stage]
+    [_json_preconf_stage, _json_stage], is_binary=False
 )  #: Complete JSON serializer; uses ultrajson if available
 
 
@@ -100,7 +104,8 @@ try:
         [
             yaml_preconf_stage,
             Stage(yaml, loads='safe_load', dumps='safe_dump'),
-        ]
+        ],
+        is_binary=False,
     )  #: Complete YAML serializer
 except ImportError as e:
     yaml_serializer = get_placeholder_class(e)