Last active
August 29, 2015 14:25
-
-
Save inizovtsev/3fb58a2fd611b7de9b72 to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
test = dict( | |
len=1, | |
objects=[ | |
dict(foo='bar'), | |
dict(bar='baz'), | |
], | |
sub_object=dict(foo='bar') | |
) | |
COLLECTION_PROXY_METHODS = ('__getitem__', '__setitem__', '__len__', '__repr__') | |
LIST_PROXY_METHODS = COLLECTION_PROXY_METHODS + ('append',) | |
DICT_PROXY_METHODS = COLLECTION_PROXY_METHODS + () | |
def assertion(condition, message): | |
if not condition: | |
raise AssertionError(message) | |
def proxy(name): | |
def wrapper(self, *args, **kwargs): | |
return getattr(self._obj, name)(*args, **kwargs) | |
return wrapper | |
def create_collections_wrapper(assertion_f=None, list_index_suffix='_', dict_keys_suffix='_'): | |
if assertion_f is None: | |
assertion_f = assertion | |
def get_data_from_dict(self, name): | |
alt_name = name | |
obj = self._obj | |
if name.startswith(dict_keys_suffix): | |
alt_name = name[len(dict_keys_suffix):] | |
assertion_f(name in obj or alt_name in obj, "key '{}' not found".format(name)) | |
return obj.get(alt_name, obj.get(name)) | |
def get_data_from_list(self, name): | |
obj = self._obj | |
assertion_f( | |
name.startswith(list_index_suffix), | |
"list index should start with '{}'".format(list_index_suffix) | |
) | |
index = name[len(list_index_suffix):] | |
assertion_f( | |
index.isdigit(), | |
"list index should be digit, not {}".format(index) | |
) | |
index = int(index) | |
assertion_f( | |
index < len(obj), | |
"index {} is out of range ({})".format(index, len(obj)) | |
) | |
return obj[index] | |
class BaseCollectionWrapper(object): | |
def __init__(self, obj): | |
self._obj = obj | |
def __getattr__(self, name): | |
return wrap(self._get_data(name)) | |
DictWrapper = type('DictWrapper', (BaseCollectionWrapper,), dict( | |
_get_data=get_data_from_dict, | |
**{method: proxy(method) for method in DICT_PROXY_METHODS} | |
)) | |
ListWrapper = type('ListWrapper', (BaseCollectionWrapper,), dict( | |
_get_data=get_data_from_list, | |
**{method: proxy(method) for method in LIST_PROXY_METHODS} | |
)) | |
def wrap(obj): | |
if isinstance(obj, dict): | |
return DictWrapper(obj) | |
elif isinstance(obj, list): | |
return ListWrapper(obj) | |
else: | |
return obj | |
return wrap | |
w = create_collections_wrapper()(test) | |
print w._objects._1.bar |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment