[Twisted-Python] Re: Teach Me Twisted?
steve at holdenweb.com
Wed Jan 23 22:47:26 EST 2008
alex clemesha wrote:
> On Jan 23, 2008 4:36 PM, <glyph at divmod.com <mailto:glyph at divmod.com>> wrote:
> On 12:10 am, clemesha at gmail.com <mailto:clemesha at gmail.com> wrote:
> >Thanks Steve Holden for organizing this, it's a great idea.
> >Some nice topics might include:
> Thanks for the suggestions. Do you have any others? :-)
> For my usage of twisted, these are important to me and I am
> the most familiar with them. (See below)
> I hate to
> rain on your parade here, but I think maybe my explanation of why I
> don't like these suggestions will spark discussion of more different
> >a) Start off simple with a " twisted.web2" example (everyone "gets"
> I think that this is actually something we should avoid in a tutorial.
> The web situation in Twisted is complicated
> ( http://twistedmatrix.com/trac/wiki/WebDevelopmentWithTwisted).
> web2 in
> particular is suffering from an extreme lack of maintenance and still
> has never "officially" been released; work is just starting to get
> underway to unify t.web2 and nevow into t.web and reduce the confusion,
> but this is all still in progress and who knows when, how, or even if it
> will be completed.
> Oh yes, I know, I know. While learning twisted I read *most* (that's
> alot ;)
> of posts to the twisted-web mailing list. So I am very familiar with
> the state.
Interesting. I am also subscribed to the twisted.web newsgroup, and I
have been surprised about how quiet it's been. I imagine that if
twisted.web2 would be very good for things like high-volume web services
work. It has relatively few advantages in the heavily-competitive
templating world, and I have to say that my early experience with Nevow,
while it caused me to admire the system, wasn't entirely trouble-free. I
think that may be partly because it wasn't being used in a Twisted
environment (I'm thinking of the python.org reorganization that was put
in effect after PyCon 2006).
> That said, oh how I wish you guys could make twisted.web2 the one and
> It would be good for beginners and others alike.
> Note however: I can only barely imagine how hard that might be,
> so I am *definitely not* complaining ... Twisted is excellent, thanks
> very much for it.
Hear, hear. And the world needs to know, hence my enthusiasm for "Teach
> If you get a group of experienced Twisted folks
> together to talk about writing web applications, you're more likely to
> spark a debate than an educational session.
Twisted's not alone there, of course.
> Even if all these problems were fixed, and there were a really good,
> well-supported, universally understood web server for Twisted, the
> benefits of Twisted's programming model are not immediately obvious to
> the bread and butter of the web programming world. Learning how to use
> some combination of Twisted tools to generate a web page will always be
> at least a little bit harder than writing the sort of glorified CGI
> script that most web frameworks require these days - unless you're
> something like Athena, which might be too much complexity to address in
> a single tutorial session. (And while Athena is more polished and "one
> right way" than the lower-level HTTP stuff, there is still a painful
> dearth of documentation, not to mention the fact that you need to write
Right. I think a Django replacement might be a bit ambitious for an open
space session or two ...
Maybe once I get into Twisted I'll be able to lend a hand with t.w2
development (or maybe not).
> "Comet" (aka what Athena does) is one of my main uses of twisted, see
> is some code that I use.
> That and other ajax-y stuff. Not much templating html, etc.
That's neat, but definitely a few too many layers for a starter project.
> Twisted really shines best when you're writing a client as well as a
> server. Chat is the quintessential application where Twisted makes the
> most sense - and the lack of a well-documented chat server is much less
> of a problem than the lack of a well-documented web server, since you
> can easily define a wire protocol and wacky semantics for your purpose-
> built tutorial chat application.
I'd suggest possibly a client/server game , but I am under the
impression that's already taken care of.
> >b) then plug that into a simple sqlite database using
> >" twisted.enterprise"
> twisted.enterprise is similarly a scary and inconsistent area, and
> requires understanding the interaction of the DB thread and the reactor
> thread. (And at least part of this section would have to be dedicated
> to "and never, ever touch anything in this package aside from adbapi".)
We'll definitely stay away from that, then.
> I only ever use 'adbapi'. The reason I say this is database functionality
> is pretty darn important for all non-trivial programs, so programmers
> to know about this functionality, wouldn't you agree?
Important but not fundamental, I'd say.
> >d) Show how using "twistd" is really convient
> >(i.e. "twistd -ny server.tac" and "twistd -y server.tac", with some
> >capability, etc)
Yes, yes, yes! If I could come away with a clear understanding of how a
.tac file encapsulated one or more Twisted network services I'd be happy.
> This, however, is a great suggestion. Twisted plugins should be
> part of
> this discussion.
> Thanks again for Twisted!
This is great. Keep it coming! Still looking for reading suggestions ...
Steve Holden +1 571 484 6266 +1 800 494 3119
Holden Web LLC http://www.holdenweb.com/
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