On Wed, Jan 27, 2021, at 1:12 PM, 'Jonathan Vanasco' via sqlalchemy wrote: > I've been working with a handful of SQLAlchemy and Pyramid based projects > recently, and two situations have repeatedly come up: > > 1. Given a SQLAlchemy Object, access the SQLAlchemy Session > 2. Given a SQLAlchemy Object or Session, access the Pyramid Request object > > The general solutions I've used to handle this is: > > 1. An Object can use the runtime inspection API to grab it's active session: > > from sqlalchemy import inspect > > @property > def _active_session(self): > dbSession = inspect(self).session > return dbSession
There's a much older function sqlalchemy.orm.object_session() that also does this. I prefer giving people the inspect() interface because I'd rather expose the first class API and not confuse things. but object_session() isn't going away. > > 2. Attach the Pyramid request to the session_factory when a session is > created: > > def get_tm_session(request): > dbSession = session_factory() > zope.sqlalchemy.register(dbSession, transaction_manager=transaction_manager, > keep_session=True) > if request is not None: > def _cleanup(request): > dbSession.close() > request.add_finished_callback(_cleanup) > # cache our request onto the dbsession > dbSession.pyramid_request = request > return dbSession > > I've needed to implement these patterns in a lot of projects. This makes me > wonder if there is/could be a better way. That request would be better placed in session.info which is the official dictionary for third-party things to go. > > > 1. Would it be beneficial if ORM objects could surface the current Session, > if any, as a documented property ? I do this in my base classes, but with > the overhead of the inspect system, and I repeat this in every project. as a property? no, we can't do that. we try to add zero "names" to the class of any kind. there's "_sa_instance_state", "_sa_instrumentation_manager" and that's as far as we go; doing absolute zero to the namespace of the mapped class is a fundamental rule of the ORM. > > 2. Would it be better for the sessionmaker had any of ? > > a. An official namespace were developers could attach information. I'm > using `pyramid_request` because I doubt SQLAlchemy will every step on that - > but it would be nice if there were a dedicated attribute/object/namespace on > the Session session.info: https://docs.sqlalchemy.org/en/13/orm/session_api.html?highlight=session%20info#sqlalchemy.orm.session.Session.info > b. `sqlalchemy.orm.session.Session()` could accept a > dict/payload/object/whatever on init, which would be attached to a single > session in the aforementioned dedicated namespace. Session.info: :) https://docs.sqlalchemy.org/en/13/orm/session_api.html?highlight=session%20info#sqlalchemy.orm.session.Session.params.info > > The usage would be something like: > > sess = Session(customized={"request": request}) > > which might then me accessed as: > > sess.customized.request poof! it's done > > > > > > > -- > SQLAlchemy - > The Python SQL Toolkit and Object Relational Mapper > > http://www.sqlalchemy.org/ > > To post example code, please provide an MCVE: Minimal, Complete, and > Verifiable Example. See http://stackoverflow.com/help/mcve for a full > description. > --- > You received this message because you are subscribed to the Google Groups > "sqlalchemy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sqlalchemy+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sqlalchemy/b5031f10-c2c8-4065-b968-3a55f2bf6daen%40googlegroups.com > > <https://groups.google.com/d/msgid/sqlalchemy/b5031f10-c2c8-4065-b968-3a55f2bf6daen%40googlegroups.com?utm_medium=email&utm_source=footer>. -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/34cedbfb-ddc8-4c3d-a9b1-94e4e4a92b3a%40www.fastmail.com.
