def _set_relationship_load_option(
query: Query,
relationship: RelationshipProperty,
load_option: RelationshipLoadOption,
) -> Query:
"""
Sets a model's relationship loading technique for a select query. Eager loading
will perform the necessary join at the time the select query is executed. Lazy
loading will issue a distinct select statement for the relationship at the time
when the property is first accessed.
Arguments:
query {Query} -- Base select query
relationship {RelationshipProperty} -- Model's relationship property
load_option {RelationshipLoadOption} -- Relationship loading technique
Returns:
Query -- Select query with relationship loading options
"""
if load_option == RelationshipLoadOption.LAZY:
query = query.options(lazyload(relationship))
elif load_option == RelationshipLoadOption.EAGER:
query = query.options(joinedload(relationship))
return query
def _eagerload_includes(cls,
query: Query,
qs: QueryStringManager,
permission_user: PermissionUser = None,
self_json_api: SqlalchemyDataLayer = None):
"""
Processes "include" param from querystring and applies permissions for included models.
Use eagerload feature of sqlalchemy to optimize data retrieval for include querystring parameter
:param Query query: sqlalchemy queryset
:param QueryStringManager qs: a querystring manager to retrieve information from url
:param PermissionUser permission_user: пермишены для пользователя
:param self_json_api:
:return Query: the query with includes eagerloaded
"""
current_schema = self_json_api.resource.schema
model = self_json_api.model
for include in qs.include:
if SPLIT_REL in include:
joinedload_object = cls._get_joinedload_object_for_splitted_include(
include, qs, permission_user, current_schema, model)
else:
# Возможно пользовать неимеет доступа, к данному внешнему ключу
if cls._is_access_foreign_key(include, model,
permission_user) is False:
continue
joinedload_object = cls._get_joinedload_object_for_include(
include, qs, permission_user, current_schema, model)
query = query.options(joinedload_object)
return query
def data_layer_get_object_update_query(self,
*args,
query: Query = None,
qs: QueryStringManager = None,
view_kwargs=None,
self_json_api=None,
**kwargs) -> Query:
"""
Во время создания запроса к БД на выгрузку объекта. Тут можно пропатчить запрос к БД.
Навешиваем ограничения на запрос, чтобы не тянулись поля из БД, которые данному
пользователю не доступны. Также навешиваем фильтры, чтобы пользователь не смог увидеть
записи, которые ему не доступны
:param args:
:param Query query: Сформированный запрос к БД
:param QueryStringManager qs: список параметров для запроса
:param view_kwargs: список фильтров для запроса
:param self_json_api:
:param kwargs:
:return: возвращает пропатченный запрос к бд
"""
permission: PermissionUser = self._get_permission_user(view_kwargs)
permission_for_get: PermissionForGet = permission.permission_for_get(
self_json_api.model)
# Навешиваем фильтры (например пользователь не должен видеть некоторые поля)
for i_join in permission_for_get.joins:
query = query.join(*i_join)
query = query.filter(*permission_for_get.filters)
# Навешиваем ограничения по атрибутам (которые доступны & которые запросил пользователь)
name_columns = permission_for_get.columns
if qs:
user_requested_columns = qs.fields.get(
self_json_api.resource.schema.Meta.type_)
if user_requested_columns:
name_columns = list(
set(name_columns) & set(user_requested_columns))
# Убираем relationship поля
name_columns = [
i_name for i_name in name_columns
if i_name in self_json_api.model.__table__.columns.keys()
]
required_columns_names = []
for i_name in name_columns:
required_columns_names.extend(
get_required_fields(i_name, self_json_api.model))
name_columns = list(set(name_columns) | set(required_columns_names))
query = query.options(load_only(*name_columns))
if qs:
query = self._eagerload_includes(query,
qs,
permission,
self_json_api=self_json_api)
# Запретим использовать стандартную функцию eagerload_includes для присоединения сторонних молелей
self_json_api.eagerload_includes = lambda x, y: x
return query
def data_layer_get_collection_update_query(self,
*args,
query: Query = None,
qs: QueryStringManager = None,
view_kwargs=None,
self_json_api=None,
**kwargs) -> Query:
"""
Во время создания запроса к БД на выгрузку объектов. Тут можно пропатчить запрос к БД
:param args:
:param Query query: Сформированный запрос к БД
:param QueryStringManager qs: список параметров для запроса
:param view_kwargs: список фильтров для запроса
:param self_json_api:
:param kwargs:
:return: возвращает пропатченный запрос к бд
"""
permission: PermissionUser = self._get_permission_user(view_kwargs)
permission_for_get: PermissionForGet = permission.permission_for_get(
self_json_api.model)
# Навешиваем фильтры (например пользователь не должен видеть некоторые поля)
for i_join in permission_for_get.joins:
query = query.join(*i_join)
query = query.filter(*permission_for_get.filters)
# Навешиваем ограничения по атрибутам (которые доступны & которые запросил пользователь)
name_columns = permission_for_get.columns
user_requested_columns = qs.fields.get(
self_json_api.resource.schema.Meta.type_)
if user_requested_columns:
name_columns = list(
set(name_columns) & set(user_requested_columns))
# required fields (from Meta.required_fields)
required_columns_names = []
for i_name in name_columns:
required_columns_names.extend(
get_required_fields(i_name, self_json_api.model))
# remove relationship fields
name_columns = list(
set(name_columns)
& set(get_columns_for_query(self_json_api.model)))
name_columns = list(set(name_columns) | set(required_columns_names))
query = query.options(load_only(*name_columns))
# Запретим использовать стандартную функцию eagerload_includes для присоединения сторонних молелей
setattr(self_json_api, "eagerload_includes", False)
query = self._eagerload_includes(query,
qs,
permission,
self_json_api=self_json_api)
return query
def get_collection_contents_qry(self, parent_id, limit=None, offset=None):
"""Find first level of collection contents by containing collection parent_id"""
DCE = model.DatasetCollectionElement
qry = Query(DCE).filter(DCE.dataset_collection_id == parent_id)
qry = qry.order_by(DCE.element_index)
qry = qry.options(joinedload('child_collection'), joinedload('hda'))
if limit is not None:
qry = qry.limit(int(limit))
if offset is not None:
qry = qry.offset(int(offset))
return qry
def _add_join(self, query: Query) -> Query:
for key in self._foreings:
planet_table = PLANET_TABLES[key]
resonance_attr = getattr(self.resonance_cls, "%s_id" % key)
query = query.outerjoin(planet_table, resonance_attr == planet_table.id)
if self._load_related:
options = contains_eager(getattr(self.resonance_cls, key), alias=planet_table)
query = query.options(options)
return query
def _add_join(self, query: Query) -> Query:
for key in self._foreings:
planet_table = PLANET_TABLES[key]
resonance_attr = getattr(self.resonance_cls, '%s_id' % key)
query = query.outerjoin(planet_table,
resonance_attr == planet_table.id)
if self._load_related:
options = contains_eager(getattr(self.resonance_cls, key),
alias=planet_table)
query = query.options(options)
return query
def _alter_query__add_nested_nplus1loader(self, query: Query,
mapper: Mapper, attr_name: str,
is_relationship: bool):
""" When loading a nested relationship, apply another nplus1loader to it """
# Only apply to relationships
if is_relationship:
Model = self.parent.class_
relationship = getattr(Model, attr_name)
related_Model = relationship.property.mapper.class_
return query.options(
defaultload(relationship).default_columns(
related_Model).nplus1loader('*'), )
# No special options for columns
else:
return query
def load(self, query_builder: Query, relations: List[str]) -> Query:
return query_builder.options(
[orm.joinedload_all(relation) for relation in relations]
)
