Ensure serializers are instances (#379)

Author: argaen

.codecov.yml

@@ -4,8 +4,8 @@ codecov:
 
 coverage:
   status:
-    patch: yes
-    changes: yes
+    patch: no
+    changes: no
 
 comment:
   layout: "reach, diff, flags, files, footer"

Makefile

@@ -5,29 +5,29 @@ lint:
 	flake8
 
 install-dev:
-	pipenv install '-e .' --dev
+	pipenv install --dev
 
 pylint:
 	pylint --disable=C0111 aiocache
 
 unit:
-	coverage run -m pytest tests/ut
+	pipenv run coverage run -m pytest tests/ut
 	@if [ $(cov-report) = true ]; then\
     coverage combine;\
     coverage report;\
 	fi
 
 acceptance:
-	pytest -sv tests/acceptance
+	pipenv run pytest -sv tests/acceptance
 
 doc:
 	make -C docs/ html
 
 functional:
-	bash examples/run_all.sh
+	pipenv run bash examples/run_all.sh
 
 performance:
-	pytest -sv tests/performance
+	pipenv run pytest -sv tests/performance
 
 test: lint unit acceptance functional
 

Pipfile.lock

@@ -130,7 +130,7 @@ class MemcachedCache(MemcachedBackend, BaseCache):
 
     Config options are:
 
-    :param serializer: obj derived from :class:`aiocache.serializers.StringSerializer`.
+    :param serializer: obj derived from :class:`aiocache.serializers.BaseSerializer`.
     :param plugins: list of :class:`aiocache.plugins.BasePlugin` derived classes.
     :param namespace: string to use as default prefix for the key used in all operations of
         the backend. Default is None

aiocache/backends/memcached.py

@@ -112,7 +112,7 @@ class SimpleMemoryCache(SimpleMemoryBackend, BaseCache):
 
     Config options are:
 
-    :param serializer: obj derived from :class:`aiocache.serializers.StringSerializer`.
+    :param serializer: obj derived from :class:`aiocache.serializers.BaseSerializer`.
     :param plugins: list of :class:`aiocache.plugins.BasePlugin` derived classes.
     :param namespace: string to use as default prefix for the key used in all operations of
         the backend. Default is None.

aiocache/backends/memory.py

@@ -221,7 +221,7 @@ class RedisCache(RedisBackend, BaseCache):
 
     Config options are:
 
-    :param serializer: obj derived from :class:`aiocache.serializers.StringSerializer`.
+    :param serializer: obj derived from :class:`aiocache.serializers.BaseSerializer`.
     :param plugins: list of :class:`aiocache.plugins.BasePlugin` derived classes.
     :param namespace: string to use as default prefix for the key used in all operations of
         the backend. Default is None.

aiocache/backends/redis.py

@@ -85,7 +85,7 @@ class BaseCache:
     Base class that agregates the common logic for the different caches that may exist. Cache
     related available options are:
 
-    :param serializer: obj derived from :class:`aiocache.serializers.StringSerializer`. Default is
+    :param serializer: obj derived from :class:`aiocache.serializers.BaseSerializer`. Default is
         :class:`aiocache.serializers.StringSerializer`.
     :param plugins: list of :class:`aiocache.plugins.BasePlugin` derived classes. Default is empty
         list.

aiocache/base.py

@@ -11,7 +11,25 @@
     import json
 
 
-class NullSerializer:
+_NOT_SET = object()
+
+
+class BaseSerializer:
+
+    DEFAULT_ENCODING = 'utf-8'
+
+    def __init__(self, *args, encoding=_NOT_SET, **kwargs):
+        self.encoding = self.DEFAULT_ENCODING if encoding is _NOT_SET else encoding
+        super().__init__(*args, **kwargs)
+
+    def dumps(self, value):
+        raise NotImplementedError('dumps method must be implemented')
+
+    def loads(self, value):
+        raise NotImplementedError('loads method must be implemented')
+
+
+class NullSerializer(BaseSerializer):
     """
     This serializer does nothing. Its only recommended to be used by
     :class:`aiocache.SimpleMemoryCache` because for other backends it will
@@ -26,24 +44,20 @@ class NullSerializer:
         my_list.append(2)
         await cache.get("key")  # Will return [1, 2]
     """
-    encoding = 'utf-8'
-
-    @classmethod
-    def dumps(cls, value):
+    def dumps(self, value):
         """
         Returns the same value
         """
         return value
 
-    @classmethod
-    def loads(cls, value):
+    def loads(self, value):
         """
         Returns the same value
         """
         return value
 
 
-class StringSerializer:
+class StringSerializer(BaseSerializer):
     """
     Converts all input values to str. All return values are also str. Be
     careful because this means that if you store an ``int(1)``, you will get
@@ -54,13 +68,7 @@ class StringSerializer:
     If you want to keep python types, use ``PickleSerializer``. ``JsonSerializer``
     may also be useful to keep type of symple python types.
     """
-    encoding = 'utf-8'
-
-    def __init__(self, *args, **kwargs):
-        super().__init__(*args, **kwargs)
-
-    @classmethod
-    def dumps(cls, value):
+    def dumps(self, value):
         """
         Serialize the received value casting it to str.
 
@@ -69,22 +77,20 @@ def dumps(cls, value):
         """
         return str(value)
 
-    @classmethod
-    def loads(cls, value):
+    def loads(self, value):
         """
         Returns value back without transformations
         """
         return value
 
 
-class PickleSerializer(StringSerializer):
+class PickleSerializer(BaseSerializer):
     """
     Transform data to bytes using pickle.dumps and pickle.loads to retrieve it back.
     """
-    encoding = None
+    DEFAULT_ENCODING = None
 
-    @classmethod
-    def dumps(cls, value):
+    def dumps(self, value):
         """
         Serialize the received value using ``pickle.dumps``.
 
@@ -93,8 +99,7 @@ def dumps(cls, value):
         """
         return pickle.dumps(value)
 
-    @classmethod
-    def loads(cls, value):
+    def loads(self, value):
         """
         Deserialize value using ``pickle.loads``.
 
@@ -106,7 +111,7 @@ def loads(cls, value):
         return pickle.loads(value)
 
 
-class JsonSerializer(StringSerializer):
+class JsonSerializer(BaseSerializer):
     """
     Transform data to json string with json.dumps and json.loads to retrieve it back. Check
     https://docs.python.org/3/library/json.html#py-to-json-table for how types are converted.
@@ -116,9 +121,7 @@ class JsonSerializer(StringSerializer):
         - ujson dumps supports bytes while json doesn't
         - ujson and json outputs may differ sometimes
     """
-
-    @classmethod
-    def dumps(cls, value):
+    def dumps(self, value):
         """
         Serialize the received value using ``json.dumps``.
 
@@ -127,8 +130,7 @@ def dumps(cls, value):
         """
         return json.dumps(value)
 
-    @classmethod
-    def loads(cls, value):
+    def loads(self, value):
         """
         Deserialize value using ``json.loads``.
 
@@ -140,14 +142,21 @@ def loads(cls, value):
         return json.loads(value)
 
 
-class MsgPackSerializer(StringSerializer):
+class MsgPackSerializer(BaseSerializer):
     """
     Transform data to bytes using msgpack.dumps and msgpack.loads to retrieve it back. You need
     to have ``msgpack`` installed in order to be able to use this serializer.
+
+    :param encoding: str. Can be used to change encoding param for ``msg.loads`` method.
+        Default is utf-8.
+    :param use_list: bool. Can be used to change use_list param for ``msgpack.loads`` method.
+        Default is True.
     """
+    def __init__(self, *args, use_list=True, **kwargs):
+        self.use_list = use_list
+        super().__init__(*args, **kwargs)
 
-    @classmethod
-    def dumps(cls, value):
+    def dumps(self, value):
         """
         Serialize the received value using ``msgpack.dumps``.
 
@@ -156,8 +165,7 @@ def dumps(cls, value):
         """
         return msgpack.dumps(value)
 
-    @classmethod
-    def loads(cls, value):
+    def loads(self, value):
         """
         Deserialize value using ``msgpack.loads``.
 
@@ -166,4 +174,4 @@ def loads(cls, value):
         """
         if value is None:
             return None
-        return msgpack.loads(value, encoding=cls.encoding)
+        return msgpack.loads(value, encoding=self.encoding, use_list=self.use_list)

aiocache/serializers.py

@@ -5,7 +5,7 @@
 from marshmallow import fields, Schema, post_load
 
 from aiocache import SimpleMemoryCache
-from aiocache.serializers import StringSerializer
+from aiocache.serializers import BaseSerializer
 
 
 class RandomModel:
@@ -21,12 +21,16 @@ def __eq__(self, obj):
         return self.__dict__ == obj.__dict__
 
 
-class MarshmallowSerializer(Schema, StringSerializer):
+class MarshmallowSerializer(Schema, BaseSerializer):
     int_type = fields.Integer()
     str_type = fields.String()
     dict_type = fields.Dict()
     list_type = fields.List(fields.Integer())
 
+    # marshmallow Schema class doesn't play nicely with multiple inheritance and won't call
+    # BaseSerializer.__init__
+    encoding = 'utf-8'
+
     def dumps(self, *args, **kwargs):
         # dumps returns (data, errors), we just want to save data
         return super().dumps(*args, **kwargs).data

examples/marshmallow_serializer_class.py

@@ -2,15 +2,15 @@
 import zlib
 
 from aiocache import RedisCache
-from aiocache.serializers import StringSerializer
+from aiocache.serializers import BaseSerializer
 
 
-class CompressionSerializer(StringSerializer):
+class CompressionSerializer(BaseSerializer):
 
     # This is needed because zlib works with bytes.
     # this way the underlying backend knows how to
     # store/retrieve values
-    encoding = None
+    DEFAULT_ENCODING = None
 
     def dumps(self, value):
         print("I've received:\n{}".format(value))

examples/serializer_class.py

@@ -11,7 +11,8 @@
 
 from marshmallow import fields, Schema, post_load
 
-from aiocache.serializers import NullSerializer, StringSerializer, PickleSerializer, JsonSerializer
+from aiocache.serializers import (
+    BaseSerializer, NullSerializer, StringSerializer, PickleSerializer, JsonSerializer)
 
 
 class MyType:
@@ -24,8 +25,9 @@ def __eq__(self, obj):
         return self.__dict__ == obj.__dict__
 
 
-class MyTypeSchema(Schema, StringSerializer):
+class MyTypeSchema(Schema, BaseSerializer):
     r = fields.Integer()
+    encoding = 'utf-8'
 
     def dumps(self, *args, **kwargs):
         return super().dumps(*args, **kwargs).data
@@ -161,7 +163,7 @@ class TestAltSerializers:
 
     @pytest.mark.asyncio
     async def test_get_set_alt_serializer_functions(self, cache):
-        cache.serializer = StringSerializer
+        cache.serializer = StringSerializer()
         await cache.set(pytest.KEY, "value", dumps_fn=dumps)
         assert await cache.get(pytest.KEY) == "v4lu3"
         assert await cache.get(pytest.KEY, loads_fn=loads) == "value"

tests/acceptance/test_serializers.py

@@ -4,7 +4,7 @@
 from aiocache.base import BaseCache, API
 from aiocache import caches, RedisCache, MemcachedCache
 from aiocache.plugins import BasePlugin
-from aiocache.serializers import NullSerializer
+from aiocache.serializers import BaseSerializer
 
 
 def pytest_namespace():
@@ -56,7 +56,8 @@ def mock_cache(mocker):
     for cmd in API.CMDS:
         mocker.spy(cache, cmd.__name__)
     mocker.spy(cache, "close")
-    cache.serializer = asynctest.Mock(spec=NullSerializer)
+    cache.serializer = asynctest.Mock(spec=BaseSerializer)
+    cache.serializer.encoding = 'utf-8'
     cache.plugins = [asynctest.Mock(spec=BasePlugin)]
     return cache