Request's storage #242
Description
Thinking on adding sessions to aiohttp.web I'we found that may be implemented as separate project.
API would be like:
from aiohttp_session import get_session
def handler(request):
session = get_session(request)
session['key'] = value
The session object may be implemented as Pyramid does (I just guess to borrow the code from aiorest: https://github.com/aio-libs/aiorest/blob/master/aiorest/session/base.py#L9).
Session loading and storing may be implemented by session middleware.
But I need the way to get session object from web-handler.
The most native way is storing session object in request by middleware on loading.
Those I guess to add request.storage property which is a regular python dict. Middleware may store the session in the dict under, say, 'aiohttp_session' key -- and user may return it back by get_session() call.
The same technique may be used, say, for saving database transaction for committing uncommitted transactions on web-handler finishing (and rolling back on exception from web-handler).
Another options is to save session as request._session (we use it for now but I don't like changing request's namespace, it should be considered as constant object).
The third option is to use global dict with Request objects as keys, but I hate singletons.
The fourth is to add Request.set_property() as Pyramid does but I personally don't like the idea of mutating the list of request public properties on request's execution. That may make a mess easy.
Resume: I propose to add per request dict storage (as well as we already have per application one) and allow to third-party libraries to make accessors to that storage if needed.