Re: [pylons-devel] correct way to close a sqlalchemy session?

[Jeff Dairiki]

On Wed, Apr 6, 2016 at 12:57 PM, Jonathan Vanasco <jonat...@findmeon.com>
wrote:

> I edited my original post before hitting submit, and managed to clear out
> the important stuff.  Ha.
>
> On Wednesday, April 6, 2016 at 2:42:38 PM UTC-4, Jeff Dairiki wrote:
>>
>> I use a reified request property to create the SqlAlchemy session.
>> The factory function adds an "add_finished_callback" to close the session.
>
>
> I do that in all my personal/work apps.
> Right now, I'm using the stock scaffold with global scoped session for a
> side project that I'm open sourcing.
>
>
I'm not very familiar with the stock scaffold.  I just went to look at it
and was initially confused, since the scaffold in the master branch
currently uses a reified request property to construct the SqlAlchemy
session (without a global scoped session).  (See models/__init__.py
<https://github.com/Pylons/pyramid/blob/master/pyramid/scaffolds/alchemy/%2Bpackage%2B/models/__init__.py_tmpl>.)
 Maybe that's enough motivation to go that way?


>
>>   (Why don't you have access to the request?)
>>
>
> I'm trying to keep things simple and do this in app/__init__.py.
>
> the `main` function only has a config object, the request doesn't exist
> yet.
>
> def main(global_config, **settings):
> config = Configurator(settings=settings)
> wsgi_app = config.make_wsgi_app()
> return wsgi_app
>
> so I need to somehow use a hook that has a request object.  two things
> that came to mind:  tweens and events.
>
>
> def db_cleanup__tween_factory(handler, registry):
> def db_cleanup__tween(request):
> try:
> response = handler(request)
> return response
> finally:
> DBSession.close()
> return db_cleanup__tween
>
> def db_cleanup__event(event):
> event.request.add_finished_callback(lambda request:
> DBSession.close())
>
> def main(global_config, **settings):
> ...
> config.add_tween('app.db_cleanup__tween_factory', over=EXCVIEW)
> config.add_subscriber("app.db_cleanup__event",
> "pyramid.events.NewRequest")
> ...
>
>
Of course, either will work.  FWIW, of the two, I'd vote for the tween —
the logic seems clearer to me, not that either is a brain-twister.

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Re: [pylons-devel] correct way to close a sqlalchemy session?

[Jeff Dairiki]

I use a reified request property to create the SqlAlchemy session.  The
factory function adds an "add_finished_callback" to close the session.
 (Why don't you have access to the request?)

On Wed, Apr 6, 2016 at 11:30 AM, Jonathan Vanasco 
wrote:

> A few routes I have need to explicitly commit the session, and require me
> to use "long lasting sessions" (
> https://pypi.python.org/pypi/zope.sqlalchemy#long-lasting-session-scopes)
>
> Since this disables transaction's call to "close" on commit, what is the
> best way to close the SqlAlchemy session?
>
> I ended up using a Tween, but my first thought was to use
> "add_finished_callback" (but there was only a config object, not a request
> object).
>
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Re: Setting cookies in Pyramid for @action()s or HTTPFound redirects?

[Jeff Dairiki]

On Thu, Mar 10, 2011 at 01:07:32PM -0800, Seth wrote:

 Are those of us not returning real Response objects stuck with building 
 our cookie strings manually, or am I missing something here?

I think you should be able to use a sacrificial WebOb Response object
to construct the cookies for you.

Here's an untested example of what I mean:

import webob   

res = webob.Response()
res.set_cookie(cookie_name, cookie_value,
   path='/', max_age=max_age, httponly=True)
request.response_headerlist =  [
('Set-Cookie', _)
for _ in res.headers.getall('Set-Cookie') ]

Jeff

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Re: Setting cookies in Pyramid for @action()s or HTTPFound redirects?

[Jeff Dairiki]

On Sat, Mar 12, 2011 at 01:55:21PM -0600, Michael Merickel wrote:
 Going through the trouble of creating a webob response is much more
 complicated than simply adding a response_callback.
 
 def _set_cookie(request, response):
 response.set_cookie()
 request.add_response_callback(_set_cookie)

That does look like generally a better solution than mine.  Thanks!

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