sqlalchemy.ext.asyncio.scoping.async_scoped_session

Return the current :class:`.AsyncSession`, creating it using the :attr:`.scoped_session.session_factory` if not present. :param \**kw: Keyword arguments will be passed to the :attr:`.scoped_session.session_factory` callable, if an existing :class:`.AsyncSession` is not present. If the :class:`.AsyncSession` is present and keyword arguments have been passed, :exc:`~sqlalchemy.exc.InvalidRequestError` is raised.

Return True if the instance is associated with this session. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. .. container:: class_bases Proxied for the :class:`_orm.Session` class on behalf of the :class:`_asyncio.AsyncSession` class. The instance may be pending or persistent within the Session for a result of True.

Construct a new :class:`_asyncio.async_scoped_session`. :param session_factory: a factory to create new :class:`_asyncio.AsyncSession` instances. This is usually, but not necessarily, an instance of :class:`_asyncio.async_sessionmaker`. :param scopefunc: function which defines the current scope. A function such as ``asyncio.current_task`` may be useful here.

Iterate over all pending or persistent instances within this Session. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. .. container:: class_bases Proxied for the :class:`_orm.Session` class on behalf of the :class:`_asyncio.AsyncSession` class.

Place an object into this :class:`_orm.Session`. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. .. container:: class_bases Proxied for the :class:`_orm.Session` class on behalf of the :class:`_asyncio.AsyncSession` class. Objects that are in the :term:`transient` state when passed to the :meth:`_orm.Session.add` method will move to the :term:`pending` state, until the next flush, at which point they will move to the :term:`persistent` state. Objects that are in the :term:`detached` state when passed to the :meth:`_orm.Session.add` method will move to the :term:`persistent` state directly. If the transaction used by the :class:`_orm.Session` is rolled back, objects which were transient when they were passed to :meth:`_orm.Session.add` will be moved back to the :term:`transient` state, and will no longer be present within this :class:`_orm.Session`. .. seealso:: :meth:`_orm.Session.add_all` :ref:`session_adding` - at :ref:`session_basics`

Add the given collection of instances to this :class:`_orm.Session`. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. .. container:: class_bases Proxied for the :class:`_orm.Session` class on behalf of the :class:`_asyncio.AsyncSession` class. See the documentation for :meth:`_orm.Session.add` for a general behavioral description. .. seealso:: :meth:`_orm.Session.add` :ref:`session_adding` - at :ref:`session_basics`

Undocumented

Return an :class:`_asyncio.AsyncSessionTransaction` object. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. The underlying :class:`_orm.Session` will perform the "begin" action when the :class:`_asyncio.AsyncSessionTransaction` object is entered:: async with async_session.begin(): # .. ORM transaction is begun Note that database IO will not normally occur when the session-level transaction is begun, as database transactions begin on an on-demand basis. However, the begin block is async to accommodate for a :meth:`_orm.SessionEvents.after_transaction_create` event hook that may perform IO. For a general description of ORM begin, see :meth:`_orm.Session.begin`.

Return an :class:`_asyncio.AsyncSessionTransaction` object which will begin a "nested" transaction, e.g. SAVEPOINT. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. Behavior is the same as that of :meth:`_asyncio.AsyncSession.begin`. For a general description of ORM begin nested, see :meth:`_orm.Session.begin_nested`.

Undocumented

Close out the transactional resources and ORM objects used by this :class:`_asyncio.AsyncSession`. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. This expunges all ORM objects associated with this :class:`_asyncio.AsyncSession`, ends any transaction in progress and :term:`releases` any :class:`_asyncio.AsyncConnection` objects which this :class:`_asyncio.AsyncSession` itself has checked out from associated :class:`_asyncio.AsyncEngine` objects. The operation then leaves the :class:`_asyncio.AsyncSession` in a state which it may be used again. .. tip:: The :meth:`_asyncio.AsyncSession.close` method **does not prevent the Session from being used again**. The :class:`_asyncio.AsyncSession` itself does not actually have a distinct "closed" state; it merely means the :class:`_asyncio.AsyncSession` will release all database connections and ORM objects. .. seealso:: :ref:`session_closing` - detail on the semantics of :meth:`_asyncio.AsyncSession.close`

Commit the current transaction in progress. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class.

reconfigure the :class:`.sessionmaker` used by this :class:`.scoped_session`. See :meth:`.sessionmaker.configure`.

Return a :class:`_asyncio.AsyncConnection` object corresponding to this :class:`.Session` object's transactional state. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. This method may also be used to establish execution options for the database connection used by the current transaction. .. versionadded:: 1.4.24 Added \**kw arguments which are passed through to the underlying :meth:`_orm.Session.connection` method. .. seealso:: :meth:`_orm.Session.connection` - main documentation for "connection"

Mark an instance as deleted. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. The database delete operation occurs upon ``flush()``. As this operation may need to cascade along unloaded relationships, it is awaitable to allow for those queries to take place. .. seealso:: :meth:`_orm.Session.delete` - main documentation for delete

Execute a statement and return a buffered :class:`_engine.Result` object. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. .. seealso:: :meth:`_orm.Session.execute` - main documentation for execute

Expire the attributes on an instance. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. .. container:: class_bases Proxied for the :class:`_orm.Session` class on behalf of the :class:`_asyncio.AsyncSession` class. Marks the attributes of an instance as out of date. When an expired attribute is next accessed, a query will be issued to the :class:`.Session` object's current transactional context in order to load all expired attributes for the given instance. Note that a highly isolated transaction will return the same values as were previously read in that same transaction, regardless of changes in database state outside of that transaction. To expire all objects in the :class:`.Session` simultaneously, use :meth:`Session.expire_all`. The :class:`.Session` object's default behavior is to expire all state whenever the :meth:`Session.rollback` or :meth:`Session.commit` methods are called, so that new state can be loaded for the new transaction. For this reason, calling :meth:`Session.expire` only makes sense for the specific case that a non-ORM SQL statement was emitted in the current transaction. :param instance: The instance to be refreshed. :param attribute_names: optional list of string attribute names indicating a subset of attributes to be expired. .. seealso:: :ref:`session_expire` - introductory material :meth:`.Session.expire` :meth:`.Session.refresh` :meth:`_orm.Query.populate_existing`

Expires all persistent instances within this Session. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. .. container:: class_bases Proxied for the :class:`_orm.Session` class on behalf of the :class:`_asyncio.AsyncSession` class. When any attributes on a persistent instance is next accessed, a query will be issued using the :class:`.Session` object's current transactional context in order to load all expired attributes for the given instance. Note that a highly isolated transaction will return the same values as were previously read in that same transaction, regardless of changes in database state outside of that transaction. To expire individual objects and individual attributes on those objects, use :meth:`Session.expire`. The :class:`.Session` object's default behavior is to expire all state whenever the :meth:`Session.rollback` or :meth:`Session.commit` methods are called, so that new state can be loaded for the new transaction. For this reason, calling :meth:`Session.expire_all` is not usually needed, assuming the transaction is isolated. .. seealso:: :ref:`session_expire` - introductory material :meth:`.Session.expire` :meth:`.Session.refresh` :meth:`_orm.Query.populate_existing`

Remove the `instance` from this ``Session``. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. .. container:: class_bases Proxied for the :class:`_orm.Session` class on behalf of the :class:`_asyncio.AsyncSession` class. This will free all internal references to the instance. Cascading will be applied according to the *expunge* cascade rule.

Remove all object instances from this ``Session``. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. .. container:: class_bases Proxied for the :class:`_orm.Session` class on behalf of the :class:`_asyncio.AsyncSession` class. This is equivalent to calling ``expunge(obj)`` on all objects in this ``Session``.

Flush all the object changes to the database. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. .. seealso:: :meth:`_orm.Session.flush` - main documentation for flush

Return an instance based on the given primary key identifier, or ``None`` if not found. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. .. seealso:: :meth:`_orm.Session.get` - main documentation for get

Return a "bind" to which the synchronous proxied :class:`_orm.Session` is bound. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. Unlike the :meth:`_orm.Session.get_bind` method, this method is currently **not** used by this :class:`.AsyncSession` in any way in order to resolve engines for requests. .. note:: This method proxies directly to the :meth:`_orm.Session.get_bind` method, however is currently **not** useful as an override target, in contrast to that of the :meth:`_orm.Session.get_bind` method. The example below illustrates how to implement custom :meth:`_orm.Session.get_bind` schemes that work with :class:`.AsyncSession` and :class:`.AsyncEngine`. The pattern introduced at :ref:`session_custom_partitioning` illustrates how to apply a custom bind-lookup scheme to a :class:`_orm.Session` given a set of :class:`_engine.Engine` objects. To apply a corresponding :meth:`_orm.Session.get_bind` implementation for use with a :class:`.AsyncSession` and :class:`.AsyncEngine` objects, continue to subclass :class:`_orm.Session` and apply it to :class:`.AsyncSession` using :paramref:`.AsyncSession.sync_session_class`. The inner method must continue to return :class:`_engine.Engine` instances, which can be acquired from a :class:`_asyncio.AsyncEngine` using the :attr:`_asyncio.AsyncEngine.sync_engine` attribute:: # using example from "Custom Vertical Partitioning" import random from sqlalchemy.ext.asyncio import AsyncSession from sqlalchemy.ext.asyncio import create_async_engine from sqlalchemy.ext.asyncio import async_sessionmaker from sqlalchemy.orm import Session # construct async engines w/ async drivers engines = { 'leader':create_async_engine("sqlite+aiosqlite:///leader.db"), 'other':create_async_engine("sqlite+aiosqlite:///other.db"), 'follower1':create_async_engine("sqlite+aiosqlite:///follower1.db"), 'follower2':create_async_engine("sqlite+aiosqlite:///follower2.db"), } class RoutingSession(Session): def get_bind(self, mapper=None, clause=None, **kw): # within get_bind(), return sync engines if mapper and issubclass(mapper.class_, MyOtherClass): return engines['other'].sync_engine elif self._flushing or isinstance(clause, (Update, Delete)): return engines['leader'].sync_engine else: return engines[ random.choice(['follower1','follower2']) ].sync_engine # apply to AsyncSession using sync_session_class AsyncSessionMaker = async_sessionmaker( sync_session_class=RoutingSession ) The :meth:`_orm.Session.get_bind` method is called in a non-asyncio, implicitly non-blocking context in the same manner as ORM event hooks and functions that are invoked via :meth:`.AsyncSession.run_sync`, so routines that wish to run SQL commands inside of :meth:`_orm.Session.get_bind` can continue to do so using blocking-style code, which will be translated to implicitly async calls at the point of invoking IO on the database drivers.

Undocumented

Close this Session, using connection invalidation. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. For a complete description, see :meth:`_orm.Session.invalidate`.

Return ``True`` if the given instance has locally modified attributes. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. .. container:: class_bases Proxied for the :class:`_orm.Session` class on behalf of the :class:`_asyncio.AsyncSession` class. This method retrieves the history for each instrumented attribute on the instance and performs a comparison of the current value to its previously committed value, if any. It is in effect a more expensive and accurate version of checking for the given instance in the :attr:`.Session.dirty` collection; a full test for each attribute's net "dirty" status is performed. E.g.:: return session.is_modified(someobject) A few caveats to this method apply: * Instances present in the :attr:`.Session.dirty` collection may report ``False`` when tested with this method. This is because the object may have received change events via attribute mutation, thus placing it in :attr:`.Session.dirty`, but ultimately the state is the same as that loaded from the database, resulting in no net change here. * Scalar attributes may not have recorded the previously set value when a new value was applied, if the attribute was not loaded, or was expired, at the time the new value was received - in these cases, the attribute is assumed to have a change, even if there is ultimately no net change against its database value. SQLAlchemy in most cases does not need the "old" value when a set event occurs, so it skips the expense of a SQL call if the old value isn't present, based on the assumption that an UPDATE of the scalar value is usually needed, and in those few cases where it isn't, is less expensive on average than issuing a defensive SELECT. The "old" value is fetched unconditionally upon set only if the attribute container has the ``active_history`` flag set to ``True``. This flag is set typically for primary key attributes and scalar object references that are not a simple many-to-one. To set this flag for any arbitrary mapped column, use the ``active_history`` argument with :func:`.column_property`. :param instance: mapped instance to be tested for pending changes. :param include_collections: Indicates if multivalued collections should be included in the operation. Setting this to ``False`` is a way to detect only local-column based properties (i.e. scalar columns or many-to-one foreign keys) that would result in an UPDATE for this instance upon flush.

Copy the state of a given instance into a corresponding instance within this :class:`_asyncio.AsyncSession`. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. .. seealso:: :meth:`_orm.Session.merge` - main documentation for merge

Expire and refresh the attributes on the given instance. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. A query will be issued to the database and all attributes will be refreshed with their current database value. This is the async version of the :meth:`_orm.Session.refresh` method. See that method for a complete description of all options. .. seealso:: :meth:`_orm.Session.refresh` - main documentation for refresh

Dispose of the current :class:`.AsyncSession`, if present. Different from scoped_session's remove method, this method would use await to wait for the close method of AsyncSession.

Rollback the current transaction in progress. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class.

Execute a statement and return a scalar result. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. .. seealso:: :meth:`_orm.Session.scalar` - main documentation for scalar

Execute a statement and return scalar results. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. :return: a :class:`_result.ScalarResult` object .. versionadded:: 1.4.24 Added :meth:`_asyncio.AsyncSession.scalars` .. versionadded:: 1.4.26 Added :meth:`_asyncio.async_scoped_session.scalars` .. seealso:: :meth:`_orm.Session.scalars` - main documentation for scalars :meth:`_asyncio.AsyncSession.stream_scalars` - streaming version

Execute a statement and return a streaming :class:`_asyncio.AsyncResult` object. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class.

Execute a statement and return a stream of scalar results. .. container:: class_bases Proxied for the :class:`_asyncio.AsyncSession` class on behalf of the :class:`_asyncio.scoping.async_scoped_session` class. :return: an :class:`_asyncio.AsyncScalarResult` object .. versionadded:: 1.4.24 .. seealso:: :meth:`_orm.Session.scalars` - main documentation for scalars :meth:`_asyncio.AsyncSession.scalars` - non streaming version