[Twisted-Python] Re: Teach Me Twisted?
steve at holdenweb.com
Sat Jan 26 09:22:45 EST 2008
Jean-Paul Calderone wrote:
> On Fri, 25 Jan 2008 18:49:46 -0500, Steve Holden <steve at holdenweb.com>
>> Cary Hull wrote:
>>> Hey, I think some Twisted related sessions at PyCon would be great.
>>> Based on what's been discussed so far, I would like to humbly suggest
>>> the following (kind of breaking it down):
>>> 1) Simple line based chat server/client.
>>> 2) Same thing except using AMP.
>>> 3) twistd and plugins
>> These are things I would really like to get to, but I'm pretty sure
>> half an hour isn't going to cover it. Maybe we should be thinking BOF
>> instead, then we can take an evening over it under less stressful
>> conditions (and, who knows, even drink a beer or two in the process).
> Maybe I can get you to go a little bit further than that in restricting
> what you'd like to see covered.
Aah, sweet sanity! Sorry about the delay in my reply, I wanted to wait
until I could do this post justice (and it's not like PyCon is tomorrow).
> Off the top of my head, and only continuing until I get bored with making
> this point, here's what a "Twisted" session could cover:
> * event driven programming
Please. I've used event-driven scenarios in GUI frameworks, but I've
never seen anything (please note: this does *not* imply that nothing
exists) that makes clear the relationship between the Twisted reactor
and the code surrounding it.
> * Deferreds (making them; using them; debugging them; defgen;
These are in essence the fundamentals, no? A complete picture of the
lifetime of a failed and a successful deferred would, I feel, go a long
way towards filling in the picture. Plus how deferreds can interact with
> * core reactor APIs
This too should go into the "must know" category, right?
> * scheduling
If we could cover everything up to this point I'd be happy. Like you I
think it's important to limit the scope if we want to achieve something
worthwhile, and I can't spend *all* my PyCon time on Twisted. It will be
up to you guys to make it enjoyable enough to keep me there :-)
Hopefully with community guidance I can lay the foundations for a
mechanism (a pedagogy, if you will) that many people can use to flesh
the rest out.
> * implementing existing (TCP; UDP; IP) protocols
What, you mean they aren't all implemented yet? :-)
> * designing new (TCP; UDP; IP) protocols
Good. That Twisted can get access to the raw network layer is something
I wasn't aware of.
> * using existing protocols in twisted core
Probably more essential than protocol design and implementation, I'd
> * integrating a protocol implementation with cred
To make it an authenticated protocol? Haven't met cred yet.
> * process control/interaction
I suppose one of the issues with twisted, like other asynchronous
frameworks, is that you can screw things up really badly just by
thoughtlessly blocking somewhere inside a handler. So this is probably
> * implementing a realm
> * implementing credentials/checkers
> * writing services
> * writing plugins (twistd; lore; cred)
> * handy general-purpose python utilities
> * adding new kinds of event sources to the reactor
> * gui/pygame/etc integration
> * threading
> * using SQL databases
> * Perspective Broker
> * writing unit tests
> * using trial
> * extending trial
While the above remaining core issues are all valuable, I don't see us
getting to them at PyCon.
> Wandering outside of the core of Twisted:
> * serving web pages
> * running a chat server
> * extending the chat server
> * jabber (jabber; jabber; jabber; sasl; jabber)
I gather you think jabber is significant?
> * marking up documentation
The more widely this knowledge is disseminated, hopefully, the better
the documentation will be.
> * dns servers and clients
> * usenet servers and clients
> * ssh/sftp clients/servers
> * telnet clients/servers
> * asynchronous terminal interaction
> * terminal widget rendering
> * smtp client/server
> * imap4 client/server
> * pop3 client/server
> Are any of these the things you have in mind? Can I get you to pick
> a very small number of them (1 or 2 per hour at most, I suspect; some
> are smaller, others are quite large)? Or did you have something else
> in mind?
Your detailed knowledge of the structure of Twisted lays bare the huge
amount of work that *could* be done. However, there may be perfectly
adequate existing materials on some or all of these topics, and I am
happy to be pointed towards them.
Steve Holden +1 571 484 6266 +1 800 494 3119
Holden Web LLC http://www.holdenweb.com/
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