Merge pull request #50 from maximkulkin/openstruct-default-object-con…

…structor

OpenStruct default object constructor

lollipop/compat.py

@@ -22,5 +22,10 @@
 
 if PY26:
     from .ordereddict import OrderedDict
+    from UserDict import DictMixin
 else:
     from collections import OrderedDict
+    try:
+        from collections import MutableMapping as DictMixin
+    except ImportError:
+        from collections.abc import MutableMapping as DictMixin

lollipop/types.py

@@ -1,6 +1,7 @@
 from lollipop.errors import ValidationError, ValidationErrorBuilder, \
     ErrorMessagesMixin, merge_errors
-from lollipop.utils import is_list, is_dict, make_context_aware, constant, identity
+from lollipop.utils import is_list, is_dict, make_context_aware, \
+    constant, identity, OpenStruct
 from lollipop.compat import string_types, int_types, iteritems, OrderedDict
 import datetime
 
@@ -1186,8 +1187,10 @@ def load(self, data, *args, **kwargs):
         errors_builder.raise_errors()
 
         result = super(Object, self).load(result, *args, **kwargs)
-        if self.constructor:
-            result = self.constructor(**result)
+
+        result = self.constructor(**result) \
+            if self.constructor else OpenStruct(result)
+
         return result
 
     def load_into(self, obj, data, inplace=True, *args, **kwargs):

lollipop/utils.py

@@ -1,5 +1,6 @@
 import inspect
 import re
+from lollipop.compat import DictMixin, iterkeys
 
 
 def identity(value):
@@ -66,3 +67,61 @@ def to_snake_case(s):
 def to_camel_case(s):
     """Converts snake-case identifiers to camel-case."""
     return re.sub('_([a-z])', lambda m: m.group(1).upper(), s)
+
+
+class OpenStruct(DictMixin):
+    """A dictionary that also allows accessing values through object attributes."""
+    def __init__(self, data=None):
+        self.__dict__.update({'_data': data or {}})
+
+    def __getitem__(self, key):
+        return self._data[key]
+
+    def __setitem__(self, key, value):
+        self._data[key] = value
+
+    def __delitem__(self, key):
+        del self._data[key]
+
+    def __iter__(self):
+        for key in self._data:
+            yield key
+
+    def __len__(self):
+        return len(self._data)
+
+    def __contains__(self, key):
+        return key in self._data
+
+    def keys(self):
+        return self._data.keys()
+
+    def iterkeys(self):
+        for k in iterkeys(self._data):
+            yield k
+
+    def iteritems(self):
+        for k, v in self._data.iteritems():
+            yield k, v
+
+    def __hasattr__(self, name):
+        return name in self._data
+
+    def __getattr__(self, name):
+        if name not in self._data:
+            raise AttributeError(name)
+        return self._data[name]
+
+    def __setattr__(self, name, value):
+        self._data[name] = value
+
+    def __delattr__(self, name):
+        if name not in self._data:
+            raise AttributeError(name)
+        del self._data[name]
+
+    def __repr__(self):
+        return '<%s %s>' % (
+            self.__class__.__name__,
+            ' '.join('%s=%s' % (k, repr(v)) for k, v in self._data.iteritems()),
+        )

tests/test_types.py

@@ -1526,6 +1526,13 @@ def test_loading_passes_context_to_inner_type_load(self):
         assert foo_type.load_context == context
         assert bar_type.load_context == context
 
+    def test_constructing_objects_with_default_constructor_on_load(self):
+        result = Object({'foo': String(), 'bar': Integer()})\
+            .load({'foo': 'hello', 'bar': 123})
+
+        assert result.foo == 'hello'
+        assert result.bar == 123
+
     def test_constructing_custom_objects_on_load(self):
         MyData = namedtuple('MyData', ['foo', 'bar'])
         assert Object({'foo': String(), 'bar': Integer()}, constructor=MyData)\

tests/test_utils.py

@@ -1,5 +1,7 @@
+from lollipop.compat import iterkeys, itervalues, iteritems
 from lollipop.utils import call_with_context, to_camel_case, to_snake_case, \
-    constant, identity
+    constant, identity, OpenStruct
+import pytest
 
 
 class ObjMethodDummy:
@@ -115,3 +117,171 @@ def test_constant_returns_function_that_takes_any_arguments_and_always_returns_g
         assert f(456) == 123
         assert f(1, 3, 5) == 123
         assert f(1, foo='bar') == 123
+
+
+class TestOpenStruct:
+    def test_getting_values(self):
+        o = OpenStruct({'foo': 'hello', 'bar': 123})
+        assert o['foo'] == 'hello'
+        assert o['bar'] == 123
+
+    def test_getting_nonexisting_values_raises_KeyError(self):
+        o = OpenStruct({'foo': 'hello', 'bar': 123})
+
+        with pytest.raises(KeyError):
+            x = o['baz']
+
+    def test_setting_values(self):
+        o = OpenStruct({'foo': 'hello'})
+        o['foo'] = 'goodbye'
+        o['bar'] = 111
+
+        assert o['foo'] == 'goodbye'
+        assert o['bar'] == 111
+
+    def test_contains(self):
+        o = OpenStruct({'foo': 'hello'})
+
+        assert 'foo' in o
+        assert 'bar' not in o
+
+        o['bar'] = 123
+
+        assert 'foo' in o
+        assert 'bar' in o
+
+    def test_deleting_values(self):
+        o = OpenStruct({'foo': 'hello'})
+
+        del o['foo']
+        assert 'foo' not in o
+
+        o['bar'] = 123
+        del o['bar']
+        assert 'bar' not in o
+
+    def test_deleting_nonexisting_values_raises_KeyError(self):
+        o = OpenStruct({'foo': 'hello'})
+
+        with pytest.raises(KeyError):
+            del o['bar']
+
+    def test_keys(self):
+        assert sorted(OpenStruct().keys()) == []
+
+        o = OpenStruct({'foo': 1, 'bar': 2})
+        assert sorted(o.keys()) == sorted(['foo', 'bar'])
+
+        o['baz'] = 2
+        assert sorted(o.keys()) == sorted(['foo', 'bar', 'baz'])
+
+    def test_values(self):
+        assert sorted(OpenStruct().values()) == []
+
+        o = OpenStruct({'foo': 123})
+        assert sorted(o.values()) == sorted([123])
+
+        o['bar'] = 456
+        assert sorted(o.values()) == sorted([123, 456])
+
+    def test_items(self):
+        assert sorted(OpenStruct().items()) == []
+
+        o = OpenStruct({'foo': 'hello'})
+        assert sorted(o.items()) == sorted([('foo', 'hello')])
+
+        o['bar'] = 123
+        assert sorted(o.items()) == sorted([('foo', 'hello'), ('bar', 123)])
+
+    def test_iterkeys(self):
+        assert sorted(iterkeys(OpenStruct())) == []
+
+        o = OpenStruct({'foo': 123})
+        assert sorted(iterkeys(o)) == sorted(o.keys())
+
+        o['bar'] = 456
+        assert sorted(iterkeys(o)) == sorted(o.keys())
+
+    def test_itervalues(self):
+        assert sorted(itervalues(OpenStruct())) == []
+
+        o = OpenStruct({'foo': 'hello'})
+        assert sorted(itervalues(o)) == sorted(o.values())
+
+        o['bar'] = 'howdy'
+        assert sorted(itervalues(o)) == sorted(o.values())
+
+    def test_iteritems(self):
+        assert sorted(iteritems(OpenStruct())) == []
+
+        o = OpenStruct({'foo': 'hello'})
+        assert sorted(iteritems(o)) == sorted(o.items())
+
+        o['bar'] = 123
+        assert sorted(iteritems(o)) == sorted(o.items())
+
+    def test_length(self):
+        assert len(OpenStruct()) == 0
+
+        o = OpenStruct({'foo': 'hello'})
+        assert len(o) == 1
+
+        o['bar'] = 123
+        assert len(o) == 2
+
+    def test_iter(self):
+        assert [x for x in OpenStruct()] == []
+
+        o = OpenStruct({'foo': 'hello'})
+        assert sorted([x for x in o]) == sorted(o.keys())
+
+        o['bar'] = 123
+        assert sorted([x for x in o]) == sorted(o.keys())
+
+    def test_hasattr(self):
+        o = OpenStruct({'foo': 'hello'})
+        o['bar'] = 123
+
+        assert hasattr(o, 'foo')
+        assert hasattr(o, 'bar')
+        assert not hasattr(o, 'baz')
+
+    def test_getattr(self):
+        o = OpenStruct({'foo': 'hello'})
+        o['bar'] = 123
+
+        assert o.foo == 'hello'
+        assert o.bar == 123
+
+    def test_getattr_on_nonexisting_key_raises_AttributeError(self):
+        o = OpenStruct({'foo': 'hello'})
+
+        with pytest.raises(AttributeError):
+            x = o.baz
+
+    def test_setattr(self):
+        o = OpenStruct({'foo': 'hello'})
+
+        o.foo = 'goodbye'
+        o.bar = 123
+
+        assert o.foo == 'goodbye'
+        assert o.bar == 123
+        assert o['foo'] == o.foo
+        assert o['bar'] == o.bar
+
+    def test_delattr(self):
+        o = OpenStruct({'foo': 'hello'})
+        o['bar'] = 123
+
+        del o.foo
+        assert not hasattr(o, 'foo')
+
+        del o.bar
+        assert not hasattr(o, 'bar')
+
+    def test_delattr_on_nonexisting_key_raises_AttributeError(self):
+        o = OpenStruct()
+
+        with pytest.raises(AttributeError):
+            del o.foo