Ok. I'll generate a docs PR for sqlalchemy and pyramid. this comes up so much.
On Wednesday, January 27, 2021 at 2:25:29 PM UTC-5 Mike Bayer wrote: > > > 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+...@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/a36086e9-499f-43af-969f-4f5cf3c0ff96n%40googlegroups.com.
