"""
Common structures
"""
import collections
[docs]class BaseIterable(object):
"""
A collections container that provides a pre-filled container. This container
type is used when an element retrieval returns all of an elements data in a
single query and will contain multiple values for the same serialized type.
Elements can be retrieved from the container through iteration,
slicing, or by using `get` and providing either the index or an
attribute / value pair.
If subclassing, it may be useful to override `get` to provide a restricted
interface to common attributes to fetch.
Examples::
>>> for status in engine.nodes[0].interface_status:
... status
...
InterfaceStatus(aggregate_is_active=False, ....
By index::
>>> engine.nodes[0].interface_status[1]
Slicing::
>>> engine.nodes[0].interface_status[1:5:2]
>>> engine.nodes[0].interface_status[::-1]
Using get by index or attribute::
>>> engine.nodes[0].interface_status.get(1)
>>> engine.nodes[0].interface_status.get(interface_id=2)
:param iterable item: items for which to perform iteration. Can be
another class with an __iter__ method also to chain iterators.
"""
def __init__(self, items):
self.items = items
def __getitem__(self, index):
if not isinstance(index, (int, slice)):
raise TypeError('Invalid index specified. Must be int or slice.')
if isinstance(index, slice):
return self.items[index.start:index.stop:index.step]
else:
return self.items[index]
[docs] def get(self, *args, **kwargs):
"""
Get an element from the iterable by an arg or kwarg.
Args can be a single positional argument that is an index
value to retrieve. If the specified index is out of range,
None is returned. Otherwise use kwargs to provide a key/value.
The key is expected to be a valid attribute of the iterated class.
For example, to get an element that has a attribute name of 'foo',
pass name='foo'.
:raises ValueError: An argument was missing
:return: the specified item, type is based on what is
returned by this iterable, may be None
"""
if self:
if args:
index = args[0]
if index <= len(self) -1:
return self[args[0]]
return None
elif kwargs:
key, value = kwargs.popitem()
for item in self.items:
if getattr(item, key, None) == value:
return item
else:
raise ValueError('Missing argument. You must provide an '
'arg or kwarg to fetch an element from the collection.')
def __iter__(self):
return iter(self.items)
def __bool__(self):
return bool(self.items)
__nonzero__ = __bool__
def __len__(self):
return len(self.items)
def __repr__(self):
return "%s(items: %s)" % (self.__class__.__name__, len(self))
[docs] def count(self):
"""
Return the number of entries
:rtype: int
"""
return len(self)
[docs] def all(self):
"""
Return the iterable as a list
"""
return list(self)
[docs]class SerializedIterable(BaseIterable):
"""
A pre-serialized list of elements. This is used when it's easier to
provide a pre-serialized class as long as all elements are of the
same type.
:param iterable item: items for which to perform iteration. Can be
another class with an __iter__ method also to chain iterators.
:param model: optional class to serialize each iteration.
"""
def __init__(self, items, model):
items = [model(**r) for r in items]
super(SerializedIterable, self).__init__(items)
class NestedDict(collections.MutableMapping):
"""
Generic dict structure that can be used to objectify
complex json. This dict allows attribute access for data
stored in the data dict by overridding getattr.
"""
def __init__(self, data=None, **kwargs):
self.data = data if data else {}
self.update(self.data, **kwargs)
def __setitem__(self, key, value):
self.data[key] = value
def __getitem__(self, key):
return self.data[key]
def __delitem__(self, key):
del self.data[key]
def __iter__(self):
return iter(self.data)
def __len__(self):
return len(self.data)
def __getattr__(self, key):
if key in self:
return self[key]
raise AttributeError("%r object has no attribute %r"
% (self.__class__, key))