Merge pull request #44 from alexei/bugfix-properly_handle_empty_or_otherwise_missing_values

Properly handle empty or otherwise missing values

Author: alexei

adapters/adapters.py

@@ -36,9 +36,9 @@ def adapt(self, data=None):
         instance = self.get_instance()
         for field_name, field in self.fields.items():
             value = field.get_attribute(data or self.data)
-            if value is undefined:
-                continue
             adapted_value = field.adapt(value)
+            if adapted_value is undefined:
+                continue
             if isinstance(instance, collections.Mapping):
                 instance[field_name] = adapted_value
             else:

adapters/base.py

@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 
 from .helpers import get_attribute
-from .utils import undefined
+from .utils import EMPTY_VALUES, undefined
 
 
 class BaseField(object):
@@ -32,23 +32,34 @@ def bind(self, field_name, adapter):
         else:
             self.lookup_attrs = self.source.split('.')
 
+    @property
+    def is_bound(self):
+        return hasattr(self, 'field_name') and hasattr(self, 'adapter')
+
     def get_attribute(self, obj):
-        value = get_attribute(obj, self.lookup_attrs)
-        if value is undefined:
+        return get_attribute(obj, self.lookup_attrs)
+
+    def adapt(self, data):
+        if data in EMPTY_VALUES or data is undefined:
             if self.default is not undefined:
                 return self.default
             elif self.required:
-                raise ValueError((
-                    "Required value not found for field "
-                    "`{adapter_name}.{field_name}`. Provide a default value."
-                ).format(
-                    adapter_name=self.adapter.__class__.__name__,
-                    field_name=self.field_name,
-                ))
+                if self.is_bound:
+                    error = (
+                        "Required value not found for field "
+                        "`{adapter_name}.{field_name}`. "
+                        "Provide a default value."
+                    ).format(
+                        adapter_name=self.adapter.__class__.__name__,
+                        field_name=self.field_name,
+                    )
+                else:
+                    error = "Required value not found. Provide a default value."
+                raise ValueError(error)
             else:
                 return undefined
         else:
-            return value
+            return self.prepare(data)
 
-    def adapt(self, data):
+    def prepare(self, data):
         return data

adapters/fields.py

@@ -5,6 +5,7 @@
 from decimal import Decimal
 
 from .base import BaseField
+from .utils import EMPTY_VALUES, undefined
 
 
 __all__ = [
@@ -36,16 +37,21 @@ def get_attribute(self, obj):
 
 class BooleanField(BaseField):
     def adapt(self, data):
+        if data in EMPTY_VALUES or data is undefined:
+            data = False
+        return super(BooleanField, self).adapt(data)
+
+    def prepare(self, data):
         return bool(data)
 
 
 class CharField(BaseField):
-    def adapt(self, data):
+    def prepare(self, data):
         return str(data)
 
 
 class DateField(BaseField):
-    def adapt(self, data):
+    def prepare(self, data):
         if isinstance(data, datetime.date):
             return data
         elif isinstance(data, str):
@@ -55,7 +61,7 @@ def adapt(self, data):
 
 
 class DateTimeField(BaseField):
-    def adapt(self, data):
+    def prepare(self, data):
         if isinstance(data, datetime.datetime):
             return data
         elif isinstance(data, str):
@@ -65,7 +71,7 @@ def adapt(self, data):
 
 
 class DecimalField(BaseField):
-    def adapt(self, data):
+    def prepare(self, data):
         return Decimal(data)
 
 
@@ -74,17 +80,17 @@ class VerbatimField(BaseField):
 
 
 class FloatField(BaseField):
-    def adapt(self, data):
+    def prepare(self, data):
         return float(data)
 
 
 class IntField(BaseField):
-    def adapt(self, data):
+    def prepare(self, data):
         return int(data)
 
 
 class TimeField(BaseField):
-    def adapt(self, data):
+    def prepare(self, data):
         if isinstance(data, datetime.time):
             return data
         elif isinstance(data, str):

adapters/utils.py

@@ -3,7 +3,14 @@
 import collections
 
 
-__all__ = ['BindingDict', 'undefined']
+__all__ = ['BindingDict', 'EMPTY_VALUES', 'undefined']
+
+
+EMPTY_VALUES = [None, '', [], (), {}]
+
+
+class undefined:
+    pass
 
 
 class BindingDict(collections.MutableMapping):
@@ -29,7 +36,3 @@ def __len__(self):
 
     def __repr__(self):
         return dict.__repr__(self.fields)
-
-
-class undefined:
-    pass

build.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+python setup.py bdist_wheel

publish.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+twine upload dist/* -r pypi

setup.py

@@ -9,11 +9,12 @@
 setup(
     name='python-adapters',
     packages=['adapters'],
-    version='1.0.1',
+    version='2.0.0',
     description='Python adapters',
     author='Alexei',
     author_email='hello@alexei.ro',
     url='https://github.com/alexei/python-adapters',
-    download_url='https://github.com/alexei/python-adapters/archive/1.0.1.tar.gz',  # noqa
-    keywords=['adapter pattern']
+    download_url='https://github.com/alexei/python-adapters/archive/2.0.0.tar.gz',  # noqa
+    keywords=['adapter pattern'],
+    install_requires=['python-dateutil>=2.6.0'],
 )

test test.shtest renamed to test.sh

@@ -29,7 +29,6 @@ def test_object_to_object(self):
                 'country': 'US',
             })
         })
-
         self.assertEqual(actual.first_name, expected.first_name)
         self.assertEqual(actual.last_name, expected.last_name)
         self.assertEqual(actual.address.line1, expected.address.line1)

tests/test_adapter.py

@@ -139,3 +139,19 @@ def test_adapter_method_field(self):
             'avg': 3,
         }
         self.assertDictEqual(actual, expected)
+
+    def test_optional_field(self):
+        data = [None, '', [], (), {}]
+        expected = adapters.utils.undefined
+        field = adapters.IntField(required=False)
+        for entry in data:
+            actual = field.adapt(entry)
+            self.assertEqual(actual, expected)
+
+    def test_optional_field_with_default(self):
+        data = [None, '', [], (), {}]
+        expected = 42
+        field = adapters.IntField(required=False, default=expected)
+        for entry in data:
+            actual = field.adapt(entry)
+            self.assertEqual(actual, expected)