Sqlalchemy And Falcon - Session Initialization

I'm wondering where the best place would be to create a scoped session for use in falcon. From reading the flask-sqlalchemy code, it, in a round about way, does something like this

Solution 1:

You can use middleware

Example.

1. Create engine, session_factory and scoped_session object.

   from sqlalchemy import create_engine
   from sqlalchemy.orm import scoped_session
   from sqlalchemy.orm import sessionmaker
   
   import settings
   
   
   engine = create_engine(
       '{engine}://{username}:{password}@{host}:{port}/{db_name}'.format(
       **settings.POSTGRESQL
       )
   )
   
   session_factory = sessionmaker(bind=engine)
   Session = scoped_session(session_factory)
   

2. Create middleware.

   classSQLAlchemySessionManager:
       """
       Create a scoped session for every request and close it when the request
       ends.
       """def__init__(self, Session):
           self.Session = Session
   
       defprocess_resource(self, req, resp, resource, params):
           resource.session = self.Session()
   
       defprocess_response(self, req, resp, resource, req_succeeded):
           ifhasattr(resource, 'session'):
               Session.remove()
   

3. Register middleware.

   importfalconapp= falcon.API(middleware=[
       SQLAlchemySessionManager(Session),
   ])
   

4. Session is accessible in every request.

   import falcon
   
   
   classMyAPI:
   
       defon_get(self, req, resp):
           # You can access self.session here# self.session.add(foo)# self.session.commit()

Solution 2:

There is a package on pypi, falcon-sqla, that provides a middleware to manage SQLAlchemy sessions with Falcon.

It uses the request context object to add a different session to each http request, avoiding the need to use a scoped session.