Merge pull request #3 from devinaconley/type_0.0.3

Support for nested field types

Author: devinaconley

objectfactory/__init__.py

@@ -6,4 +6,4 @@
 from .factory import Factory
 from .field import Nested, List
 
-__version__ = '0.0.2'
+__version__ = '0.0.3'

objectfactory/field.py

@@ -41,7 +41,20 @@ def deserialize_field( self, instance, value ):
         """
         if value is None:
             return
-        obj = Factory.create_object( value )
+
+        if '_type' in value:
+            obj = Factory.create_object( value )
+            if self._field_type and not isinstance( obj, self._field_type ):
+                raise ValueError(
+                    '{} is not an instance of type: {}'.format(
+                        type( obj ).__name__, self._field_type.__name__ )
+                )
+        elif self._field_type:
+            obj = self._field_type()
+            obj.deserialize( value )
+        else:
+            raise ValueError( 'Cannot infer type information' )
+
         setattr( instance, self._key, obj )
 
 
@@ -50,10 +63,10 @@ class List( Field ):
     field type for list of serializable objects
     """
 
-    def __init__( self, default=None ):
+    def __init__( self, default=None, name=None, field_type=None ):
         if default is None:
             default = []
-        super().__init__( default )
+        super().__init__( default=default, name=name, field_type=field_type )
 
     def serialize_field( self, instance, deserializable=True ):
         """
@@ -82,5 +95,17 @@ def deserialize_field( self, instance, value ):
         """
         lst = []
         for body in value:
-            lst.append( Factory.create_object( body ) )
+            if '_type' in body:
+                obj = Factory.create_object( body )
+                if self._field_type and not isinstance( obj, self._field_type ):
+                    raise ValueError(
+                        '{} is not an instance of type: {}'.format(
+                            type( obj ).__name__, self._field_type.__name__ )
+                    )
+            elif self._field_type:
+                obj = self._field_type()
+                obj.deserialize( body )
+            else:
+                raise ValueError( 'Cannot infer type information' )
+            lst.append( obj )
         setattr( instance, self._key, lst )

objectfactory/serializable.py

@@ -16,10 +16,11 @@ class Field( object ):
     serializable objects
     """
 
-    def __init__( self, default=None, name=None ):
+    def __init__( self, default=None, name=None, field_type=None ):
         self._name = name
         self._key = None  # note: this will be set from parent metaclass __new__
         self._default = default
+        self._field_type = field_type
 
     def __get__( self, instance, owner ):
         return getattr( instance, self._key, self._default )

setup.py

@@ -5,7 +5,7 @@
 
 setuptools.setup(
     name='objectfactory',
-    version='0.0.2',
+    version='0.0.3',
     author='Devin A. Conley',
     author_email='devinaconley@gmail.com',
     description='A python package for the serializable model / factory pattern',

test/test_fields.py

@@ -2,6 +2,9 @@
 module for testing functionality of serializable fields
 """
 
+# lib
+import pytest
+
 # src
 from objectfactory import Factory, Serializable, Field, Nested, List
 from .test_serializable import MyBasicClass
@@ -21,7 +24,16 @@ class MyComplexClass( Serializable ):
     """
     complex class to test hierarchical serialization
     """
-    nested = Nested( MyBasicClass )
+    nested = Nested()
+    prop = Field()
+
+
+@Factory.register_class
+class MyTypedComplexClass( Serializable ):
+    """
+    complex class to test hierarchical serialization
+    """
+    nested = Nested( field_type=MyBasicClass )
     prop = Field()
 
 
@@ -34,6 +46,15 @@ class MyOtherComplexClass( Serializable ):
     nested_list_prop = List()
 
 
+@Factory.register_class
+class MyOtherTypedComplexClass( Serializable ):
+    """
+    complex class to test list serialization
+    """
+    str_prop = Field()
+    nested_list_prop = List( field_type=MyBasicClass )
+
+
 @Factory.register_class
 class MyClassWithFieldOptionals( Serializable ):
     """
@@ -98,6 +119,56 @@ def test_deserialize( self ):
         assert obj.nested.str_prop == 'random string'
         assert obj.nested.int_prop == 4321
 
+    def test_deserialize_typed( self ):
+        """
+        test deserialization without _type field
+
+        expect nested json to be deserialized into a MyBasicClass object that is
+        a member of MyTypedComplexClass, even without nested _type field
+
+        :return:
+        """
+        body = {
+            '_type': 'MyComplexClass',
+            'prop': 'really cool property',
+            'nested': {
+                'str_prop': 'random string',
+                'int_prop': 4321
+            }
+        }
+
+        obj = MyTypedComplexClass()
+        obj.deserialize( body )
+
+        assert isinstance( obj, MyTypedComplexClass )
+        assert obj.prop == 'really cool property'
+        assert isinstance( obj.nested, MyBasicClass )
+        assert obj.nested.str_prop == 'random string'
+        assert obj.nested.int_prop == 4321
+
+    def test_deserialize_enforce( self ):
+        """
+        test deserialization enforcing field type
+
+        expect an error to be thrown on deserialization because the nested
+        field is of the incorrect type
+
+        :return:
+        """
+        body = {
+            '_type': 'MyComplexClass',
+            'prop': 'really cool property',
+            'nested': {
+                '_type': 'MyBasicClassWithLists',
+                'str_prop': 'random string',
+                'int_prop': 4321
+            }
+        }
+
+        obj = MyTypedComplexClass()
+        with pytest.raises( ValueError ):
+            obj.deserialize( body )
+
 
 class TestPrimitiveList( object ):
     """
@@ -267,6 +338,43 @@ def test_deserialize( self ):
             assert nested_obj.str_prop == nested_strings[i]
             assert nested_obj.int_prop == nested_ints[i]
 
+    def test_deserialize_typed( self ):
+        """
+        test deserialization without _type field
+
+        expect list of nested json objects to be deserialized into a list
+        of MyBasicClass objects that is a member of MyComplexClass, even without
+        _type field specified
+
+        :return:
+        """
+        body = {
+            '_type': 'MyOtherTypedComplexClass',
+            'str_prop': 'really great string property',
+            'nested_list_prop': []
+        }
+        nested_strings = ['some string', 'another string', 'one more string']
+        nested_ints = [101, 102, 103]
+
+        for s, n in zip( nested_strings, nested_ints ):
+            body['nested_list_prop'].append(
+                {
+                    'str_prop': s,
+                    'int_prop': n
+                }
+            )
+
+        obj = MyOtherTypedComplexClass()
+        obj.deserialize( body )
+
+        assert isinstance( obj, MyOtherTypedComplexClass )
+        assert obj.str_prop == 'really great string property'
+        assert len( obj.nested_list_prop ) == 3
+        for i, nested_obj in enumerate( obj.nested_list_prop ):
+            assert isinstance( nested_obj, MyBasicClass )
+            assert nested_obj.str_prop == nested_strings[i]
+            assert nested_obj.int_prop == nested_ints[i]
+
 
 class TestFieldOptionals( object ):
     """