def test_changes():
a = {'a': 12, 'b': '34'}
b = {'a': 1, 'b': '34'}
changes = get_changes(a, b)
assert changes == {'a': 1}
with pytest.raises(KeyError):
get_changes(a, {})
def _get_changes(self, persistable):
changes = {}
existing = None
registry = self.type_registry
if isinstance(persistable, PersistableType):
if issubclass(persistable, Relationship):
# not stored in the db; must be static
return None, {}
query = """
MATCH
{}
OPTIONAL MATCH
(attr)-[:DECLAREDON*0..]->(cls)
RETURN
cls, collect(attr.name)
""".format(get_match_clause(persistable, 'cls', registry))
# don't use self.query since we don't want to convert the py2neo
# node into an object
rows = self._execute(query)
cls_node, attrs = next(rows, (None, None))
if cls_node is None:
# have not found the cls
return None, {}
existing_cls_attrs = cls_node._properties
# Make sure we get a clean view of current data.
registry.refresh_type(persistable)
new_cls_attrs = registry.object_to_dict(persistable)
# If any existing keys in "new" are missing in "old", add `None`s.
# Unlike instance attributes, we just need to remove the properties
# from the node, which we can achieve by setting the values to None
for key in set(existing_cls_attrs) - set(new_cls_attrs):
new_cls_attrs[key] = None
changes = get_changes(old=existing_cls_attrs, new=new_cls_attrs)
attrs = set(attrs)
modified_attrs = {}
descr = registry.get_descriptor(persistable)
for name, attr in descr.declared_attributes.items():
if name not in attrs:
modified_attrs[name] = attr
del_attrs = set(attrs)
for name in Descriptor(persistable).attributes.keys():
del_attrs.discard(name)
for name in del_attrs:
modified_attrs[name] = None
if modified_attrs:
changes['attributes'] = modified_attrs
# we want to return the existing class
type_id = get_type_id(persistable)
existing = registry.get_descriptor_by_id(type_id).cls
else:
try:
query = 'MATCH {} RETURN obj'.format(
get_match_clause(persistable, 'obj', registry)
)
except NoUniqueAttributeError:
existing = None
else:
existing = self.query_single(query)
if existing is not None:
existing_props = registry.object_to_dict(existing)
props = registry.object_to_dict(persistable)
if existing_props == props:
return existing, {}
changes = get_changes(old=existing_props, new=props)
return existing, changes
def _get_changes(self, persistable):
changes = {}
existing = None
obj_type = type(persistable)
registry = self.type_registry
if isinstance(persistable, PersistableType):
# this is a class, we need to get it and it's attrs
idx_name = get_index_name(PersistableType)
self._conn.get_or_create_index(neo4j.Node, idx_name)
type_id = get_type_id(persistable)
query_args = {
'type_id': type_id
}
query = join_lines(
'START cls=node:%s(id={type_id})' % idx_name,
'MATCH attr -[:DECLAREDON*0..]-> cls',
'RETURN cls, collect(attr.name?)'
)
# don't use self.query since we don't want to convert the py2neo
# node into an object
rows = self._execute(query, **query_args)
cls_node, attrs = next(rows, (None, None))
if cls_node is None:
# have not found the cls
return None, {}
existing_cls_attrs = cls_node.get_properties()
new_cls_attrs = registry.object_to_dict(persistable)
# If any existing keys in "new" are missing in "old", add `None`s.
# Unlike instance attributes, we just need to remove the properties
# from the node, which we can achieve by setting the values to None
for key in set(existing_cls_attrs) - set(new_cls_attrs):
new_cls_attrs[key] = None
changes = get_changes(old=existing_cls_attrs, new=new_cls_attrs)
attrs = set(attrs)
modified_attrs = {}
descr = registry.get_descriptor(persistable)
for name, attr in descr.declared_attributes.items():
if name not in attrs:
modified_attrs[name] = attr
del_attrs = set(attrs)
for name in Descriptor(persistable).attributes.keys():
del_attrs.discard(name)
for name in del_attrs:
modified_attrs[name] = None
if modified_attrs:
changes['attributes'] = modified_attrs
# we want to return the existing class
existing = registry.get_descriptor_by_id(type_id).cls
else:
existing = self.get(obj_type, **get_attr_filter(persistable,
registry))
if existing is not None:
existing_props = registry.object_to_dict(existing)
props = registry.object_to_dict(persistable)
if isinstance(persistable, Relationship):
# if the relationship has endoints, also consider
# whether those have changed
for rel_attr in ['start', 'end']:
new = getattr(persistable, rel_attr, None)
if new is None:
continue
ex_rel_attr = getattr(existing, rel_attr)
ex_rel_identifier = get_attr_filter(ex_rel_attr,
registry)
if new != ex_rel_identifier:
props[rel_attr] = new
if existing_props == props:
return existing, {}
changes = get_changes(old=existing_props, new=props)
return existing, changes