Improved 'from_env' decorator

classsettings/__init__.py

@@ -1,4 +1,4 @@
 from .settings import Settings, Config
 from .env import from_env, get_env_setting
 
-__version__ = '1.0.0'
+__version__ = '1.0.1'

classsettings/env.py

@@ -7,22 +7,26 @@
 
 
 @defaultargs
-def from_env(key=None):
+def from_env(key=None, through=None):
     """
     Gets environment variable by given key.
-    If key is not given, uses decorated function's name.
     If key is not present within environ, calls given function and raises
     :class:`ImproperlyConfigured` if it returns `None`.
+
+    :param key: env. variable name, defaults to function's name
+    :param through: callable should be applied to result
     """
     def decorator(func):
         @functools.wraps(func)
         def decorated(*args, **kwargs):
             try:
-                return get_env_setting(key or func.__name__)
+                value = get_env_setting(key or func.__name__)
             except ImproperlyConfigured as e:
-                default = func(*args, **kwargs)
-                if default is not None: return default
-                raise e
+                value = func(*args, **kwargs)
+                if value is None:
+                    raise e
+
+            return through(value) if through else value
 
         return decorated
     return decorator

tests.py

@@ -118,6 +118,7 @@ def tearDown(self):
 
     def test_has_default(self):
         self.assertEqual(os.environ.get('CLASSSETTINGS_ENV'), None)
+
         @from_env(key='CLASSSETTINGS_ENV')
         def getter(): return 'default'
 
@@ -127,13 +128,35 @@ def getter(): return 'default'
 
     def test_no_default(self):
         self.assertEqual(os.environ.get('CLASSSETTINGS_ENV'), None)
+
         @from_env(key='CLASSSETTINGS_ENV')
         def getter(): pass
 
         self.assertRaises(ImproperlyConfigured, getter)
         os.environ['CLASSSETTINGS_ENV'] = 'value'
         self.assertEqual(getter(), 'value')
 
+    def test_through_with_env(self):
+        self.assertEqual(os.environ.get('CLASSSETTINGS_ENV'), None)
+
+        filter_func = lambda val: val.upper()
+
+        @from_env(key='CLASSSETTINGS_ENV', through=filter_func)
+        def getter(): pass
+
+        os.environ['CLASSSETTINGS_ENV'] = 'value'
+        self.assertEqual(getter(), 'VALUE')
+
+    def test_through_with_default(self):
+        self.assertEqual(os.environ.get('CLASSSETTINGS_ENV'), None)
+
+        filter_func = lambda val: val.upper()
+
+        @from_env(key='CLASSSETTINGS_ENV', through=filter_func)
+        def getter(): return 'default'
+
+        self.assertEqual(getter(), 'DEFAULT')
+
 
 class UtilsTestCase(unittest.TestCase):