Laurence Rowe wrote:
Martin Aspeli wrote:
Martijn Faassen wrote:
Martin Aspeli wrote:
Brian Sutherland wrote:
For some reason this raises a warning bell in my head. I keep on
thinking: this is zope, the session is a classic case for a utility, we
should be getting it in views by an interface.
FWIW, I had the same though.
I think there's a trade-off here: we can use patterns that SQLAlchemy
and Pylons and others use directly (use a "global" that isn't
actually global) or we can use patterns that are ubiquitous in Zope
(look up utilities by interface).
To my mind, the latter is better because it makes us internally
consistent, and because it promotes one of the formalisms that IMHO
makes Zope 3 easier to work with.
The former integrates smoothly with SQLAlchemy.
Sure, that's why I said "trade-off". :)
This is a good point. But is it "the same" or "almost the same"? If it's
the latter, the explicitly different is better than faux identity.
It also is closer to the SQLAlchemy documentation.
It's also quite likely that someone writing a larger application that
does use the interface lookup pattern will get bored and write
Mmmm, I'm not so sure, but maybe.
The Zope component architecture is not about seeing explicit calls
into it everywhere. That's not the point of it. The point of it is
about making applications more flexible by allowing people to plug in
components. My approach allows you to do that.
Sure, but I also think that the CA has given us a few very basic, very
flexible idioms (adapters, utilities, subscribers) that permeate any and
all zope 3 applications. Internal consistency is a very good thing in a
A not-quite-global Session variable is another pattern to achieve what
we do elsewhere with global unnamed utilities when we use them as
effective singletons. Having two patterns to do the same thing is not good.
Put the question another way - a new user may ask, "why don't I have a
global thing with a capital first letter like Session to look up other
Anyway, the balance can come out somewhere else. People are free to
write their own integration approaches, it's just that mine is
actually about trying to make exactly this pattern work in the first
place. Then when I succeed people want it changed. :) Anyway, no
surprise: I knew that some want other patterns, and I'll be curious to
see the other approaches as well.
I'm not saying it's wrong, and I do think "natural" SQLAlchemy is a
strong selling point, since I'd wager there are more SQLAlchemy users
than Zope 3 users out there. I just think we need to be careful about
what patterns we promote and how it fits with the rest of our "story".
I don't think scoped sessions really map well to a utility:
session = getUtility(ISession)()
is just too ugly. Better to stick with Session() or ISession(context)
Why can't it just be
Note that I'm only playing devil's advocate here; I don't feel very
strongly about this.
Author of `Professional Plone Development`, a book for developers who
want to work with Plone. See http://martinaspeli.net/plone-book
Zope-Dev maillist - Zope-Dev@zope.org
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