Wrap backend-specific exceptions in SerializationError/DeserializationError

Author: agronholm

docs/api.rst

@@ -15,6 +15,12 @@ Serializer API
 .. autoclass:: CustomizableSerializer
 .. autoclass:: CustomTypeCodec
 
+Exceptions
+----------
+
+.. autoexception:: SerializationError
+.. autoexception:: DeserializationError
+
 Marshalling callbacks
 ---------------------
 

docs/versionhistory.rst

@@ -7,6 +7,9 @@ This library adheres to `Semantic Versioning 2.0 <https://semver.org/>`_.
 
 - Dropped support for Python 3.7 and 3.8
 - **BACKWARD INCOMPATIBLE** Bumped minimum Asphalt version to 5.0
+- **BACKWARD INCOMPATIBLE** The ``Serializer.serialize()`` and
+  ``Serializer.deserialize()`` methods now raise ``SerializationError`` and
+  ``DeserializationError`` regardless of back-end when something goes wrong
 
 **6.0.0** (2022-06-04)
 

src/asphalt/serialization/__init__.py

@@ -1,16 +1,16 @@
-from typing import Any
-
 from ._api import CustomizableSerializer as CustomizableSerializer
 from ._api import CustomTypeCodec as CustomTypeCodec
 from ._api import Serializer as Serializer
 from ._component import SerializationComponent as SerializationComponent
+from ._exceptions import DeserializationError as DeserializationError
+from ._exceptions import SerializationError as SerializationError
 from ._marshalling import default_marshaller as default_marshaller
 from ._marshalling import default_unmarshaller as default_unmarshaller
 from ._object_codec import DefaultCustomTypeCodec as DefaultCustomTypeCodec
 
 # Re-export imports, so they look like they live directly in this package
-key: str
-value: Any
-for key, value in list(locals().items()):
-    if getattr(value, "__module__", "").startswith(f"{__name__}."):
-        value.__module__ = __name__
+for __value in list(locals().values()):
+    if getattr(__value, "__module__", "").startswith(f"{__name__}."):
+        __value.__module__ = __name__
+
+del __value

src/asphalt/serialization/_api.py

@@ -38,15 +38,23 @@ class Serializer(metaclass=ABCMeta):
     serialization support for custom types.
     """
 
-    __slots__ = ()
+    __slots__ = ("__weakref__",)
 
     @abstractmethod
     def serialize(self, obj: Any) -> bytes:
-        """Serialize a Python object into bytes."""
+        """
+        Serialize a Python object into bytes.
+
+        :raises SerializationError: if serialization fails
+        """
 
     @abstractmethod
     def deserialize(self, payload: bytes) -> Any:
-        """Deserialize bytes into a Python object."""
+        """
+        Deserialize bytes into a Python object.
+
+        :raises DesrializationError: if deserialization fails
+        """
 
     @property
     @abstractmethod

src/asphalt/serialization/_exceptions.py

@@ -0,0 +1,6 @@
+class SerializationError(Exception):
+    """Raised when serialization fails."""
+
+
+class DeserializationError(Exception):
+    """Raised when deserialization fails."""

src/asphalt/serialization/serializers/cbor.py

@@ -5,6 +5,7 @@
 import cbor2
 from asphalt.core import qualified_name, resolve_reference
 
+from .. import DeserializationError, SerializationError
 from .._api import CustomizableSerializer
 from .._object_codec import DefaultCustomTypeCodec
 
@@ -129,10 +130,16 @@ def __init__(
         self.decoder_options: dict[str, Any] = decoder_options or {}
 
     def serialize(self, obj: Any) -> bytes:
-        return cbor2.dumps(obj, **self.encoder_options)
+        try:
+            return cbor2.dumps(obj, **self.encoder_options)
+        except cbor2.CBOREncodeError as exc:
+            raise SerializationError(str(exc)) from exc
 
     def deserialize(self, payload: bytes) -> Any:
-        return cbor2.loads(payload, **self.decoder_options)
+        try:
+            return cbor2.loads(payload, **self.decoder_options)
+        except cbor2.CBORDecodeError as exc:
+            raise DeserializationError(str(exc)) from exc
 
     @property
     def mimetype(self) -> str:

src/asphalt/serialization/serializers/json.py

@@ -6,6 +6,7 @@
 
 from asphalt.core import resolve_reference
 
+from .. import DeserializationError, SerializationError
 from .._api import CustomizableSerializer
 from .._object_codec import DefaultCustomTypeCodec
 
@@ -81,11 +82,17 @@ def __init__(
         self._decoder = JSONDecoder(**self.decoder_options)
 
     def serialize(self, obj: Any) -> bytes:
-        return self._encoder.encode(obj).encode(self.encoding)
+        try:
+            return self._encoder.encode(obj).encode(self.encoding)
+        except Exception as exc:
+            raise SerializationError(str(exc)) from exc
 
     def deserialize(self, payload: bytes) -> Any:
-        text_payload = payload.decode(self.encoding)
-        return self._decoder.decode(text_payload)
+        try:
+            text_payload = payload.decode(self.encoding)
+            return self._decoder.decode(text_payload)
+        except Exception as exc:
+            raise DeserializationError(str(exc)) from exc
 
     @property
     def mimetype(self) -> str:

src/asphalt/serialization/serializers/msgpack.py

@@ -5,6 +5,7 @@
 from asphalt.core import resolve_reference
 from msgpack import ExtType, packb, unpackb
 
+from .. import DeserializationError, SerializationError
 from .._api import CustomizableSerializer
 from .._object_codec import DefaultCustomTypeCodec
 
@@ -103,10 +104,16 @@ def __init__(
         self.unpacker_options.setdefault("raw", False)
 
     def serialize(self, obj: Any) -> bytes:
-        return packb(obj, **self.packer_options)  # type: ignore[no-any-return]
+        try:
+            return packb(obj, **self.packer_options)  # type: ignore[no-any-return]
+        except Exception as exc:
+            raise SerializationError(str(exc)) from exc
 
     def deserialize(self, payload: bytes) -> Any:
-        return unpackb(payload, **self.unpacker_options)
+        try:
+            return unpackb(payload, **self.unpacker_options)
+        except Exception as exc:
+            raise DeserializationError(str(exc)) from exc
 
     @property
     def mimetype(self) -> str:

src/asphalt/serialization/serializers/pickle.py

@@ -4,6 +4,7 @@
 from typing import Any
 
 from .._api import Serializer
+from .._exceptions import DeserializationError, SerializationError
 
 
 class PickleSerializer(Serializer):
@@ -26,10 +27,16 @@ def __init__(self, protocol: int = pickle.HIGHEST_PROTOCOL):
         self.protocol: int = protocol
 
     def serialize(self, obj: Any) -> bytes:
-        return pickle.dumps(obj, protocol=self.protocol)
+        try:
+            return pickle.dumps(obj, protocol=self.protocol)
+        except Exception as exc:
+            raise SerializationError(str(exc)) from exc
 
     def deserialize(self, payload: bytes) -> Any:
-        return pickle.loads(payload)
+        try:
+            return pickle.loads(payload)
+        except Exception as exc:
+            raise DeserializationError(str(exc)) from exc
 
     @property
     def mimetype(self) -> str:

src/asphalt/serialization/serializers/yaml.py

@@ -5,6 +5,7 @@
 
 from ruamel.yaml import YAML
 
+from .. import DeserializationError, SerializationError
 from .._api import Serializer
 
 
@@ -35,12 +36,18 @@ def __init__(self, safe: bool = True):
         self._yaml = YAML(typ="safe" if safe else "unsafe")
 
     def serialize(self, obj: Any) -> bytes:
-        buffer = StringIO()
-        self._yaml.dump(obj, buffer)
-        return buffer.getvalue().encode("utf-8")
+        try:
+            buffer = StringIO()
+            self._yaml.dump(obj, buffer)
+            return buffer.getvalue().encode("utf-8")
+        except Exception as exc:
+            raise SerializationError(str(exc)) from exc
 
     def deserialize(self, payload: bytes) -> Any:
-        return self._yaml.load(payload)
+        try:
+            return self._yaml.load(payload)
+        except Exception as exc:
+            raise DeserializationError(str(exc)) from exc
 
     @property
     def mimetype(self) -> str:

tests/test_serializers.py

@@ -2,8 +2,10 @@
 
 import re
 import sys
+from binascii import unhexlify
 from datetime import datetime, timezone
 from functools import partial
+from socket import socket
 from types import SimpleNamespace
 from typing import Any, cast
 
@@ -12,7 +14,11 @@
 from cbor2 import CBORTag
 from msgpack import ExtType
 
-from asphalt.serialization import CustomizableSerializer
+from asphalt.serialization import (
+    CustomizableSerializer,
+    DeserializationError,
+    SerializationError,
+)
 from asphalt.serialization.serializers.cbor import CBORSerializer, CBORTypeCodec
 from asphalt.serialization.serializers.json import JSONSerializer
 from asphalt.serialization.serializers.msgpack import (
@@ -115,6 +121,16 @@ def test_basic_types_roundtrip(serializer: CustomizableSerializer, input: Any) -
     assert deserialized == input
 
 
+def test_serialization_error(serializer: CustomizableSerializer) -> None:
+    with pytest.raises(SerializationError), socket() as sock:
+        serializer.serialize(sock)
+
+
+def test_deserialization_error(serializer: CustomizableSerializer) -> None:
+    with pytest.raises(DeserializationError):
+        serializer.deserialize(unhexlify("c11b9b9b9b0000000000"))
+
+
 @pytest.mark.parametrize("serializer_type", ["cbor", "pickle", "yaml"])
 def test_circular_reference(serializer: CustomizableSerializer) -> None:
     a: dict[str, Any] = {"foo": 1}