Mailman 3 July 2009 - Twisted

[Twisted-Python] getPage using ssl proxy
by Konrads Smelkovs Aug. 1, 2009

Aug. 1, 2009

Hello, I am writing some scraper scripts and need to pass them through an intercepting proxy. getPage does not support a proxy argument and this code I found on internet won't work with SSL proxy (stalls indefinitely): def getPage(url, contextFactory=None, *args, **kwargs): scheme, host, port, path = _parse(url) factory = HTTPClientFactory(url, *args, **kwargs) if 0: # use a proxy host, port = 'localhost', 8080 factory.path = url if scheme == 'https': … [View More]

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[Twisted-Python] twisted.positioning: status report and request for comments/feedback
by Laurens Van Houtven July 31, 2009

July 31, 2009

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi! Most of you might remember that I was working on a twisted generic positioning (GPS and things like it) framework, and here's a preliminary status report. First of all, we've moved from twisted.protocols.positioning to twisted.positioning. Yay! Seriously though: work is mostly coming along nicely, and a serious patch for separate review is probably only a few days' work away. For those interested, the ticket is here: http://twistedmatrix.com/… [View More]trac/ticket/3926 And you can check out work in progress from launchpad: https://code.launchpad.net/~lvh/twisted/positioning As you might remember, we (thanks to the adhoc code reviews from glyph, tazle, dash andexarkun) decided on an implementation slightly different from the original one, using: - an NMEAReceiver class, which *only* does the receiving bit and is perfectly stateless: this does things like unpacking the sentence and checking the checksum - an IPositioningReceiver (now renamed IPositioningProvider, but I'm not sure that's the right name yet) interface that has a bunch of *sane* callbacks -- ones you actually want instead of ones that are directly a consequence of NMEA being a steaming pile of dung - an NMEAAdapter that would adapt the receiver and keep as much state as necessary internally to produce the meaningful callbacks as defined in the interface I'm having a bit of trouble implementing this this way, and I'd love to hear your comments or suggestions on the topic. Here's the code right now: http://bit.ly/1azA5q The interface lives in this file: http://bit.ly/3wWL2c I originally thought that the NMEAAdapter (which adapts an NMEAReceiver to the IPositioningReceiver interface) was really an adapter in the twisted.python.components sense of the word, so that you could do something like PositioningReceiver(NMEAReceiver()) and you'd get and NMEAAdapter object, as described in the Twisted components howto. The problem is attaching the method stubs in NMEAReceiver (nmea_GPGGA, nmea_GPRMC, nmea_GPGSV) to the methods in the NMEAAdapter that actually interpret these sentences. Ordinarily, you'd subclass that class to override those stubs. How do you feel this should be done while keeping the adapter? Should we keep the adapter at all? Of course, I could do ugly things in the adapters' __init__ like: def __init__(self, receiver): receiver.nmea_GPGGA = self.nmea_GPGGA receiver.nmea_GPRMC = self.nmea_GPRMC receiver.nmea_GPGSV = self.nmea_GPGSV But that looks like a really bad idea: it's like I'm subverting inheritance. Instead, I'm currently doing this by subclassing the receiver (thanks to exarkun for this suggestion): class NMEAAdapter(NMEAReceiver): This fixes the method stubs being correctly assigned (I suppose the correct term would be overriding, through plain old inheritance). The problem is that neither the interface nor components/adapters are involved in any way, so I feel like I'm missing something important. Thanks for reading Laurens -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) Comment: Use GnuPG with Firefox : http://getfiregpg.org (Version: 0.7.7) iEYEARECAAYFAkpwyB4ACgkQT5v5zGkvKT5zPwCbB9IXwaUhP4mr33961ifG7Q92 exMAoLMh5pMXgBT0Q6kvkppCQCWJ26eZ =9Rfs -----END PGP SIGNATURE----- [View Less]

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Re: [Twisted-Python] Deferred documentation rewrite
by Terry Jones July 31, 2009

July 31, 2009

>>>>> "Michael" == Michael Hudson <micahel(a)gmail.com> writes: Michael> The accompanying paper is here: http://mumak.net/stuff/twisted-intro.html I agree, that's a really nicely done document. It would be good to extend it, moving into a description and explanation of deferreds. Terry

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[Twisted-Python] Missing Interface?
by Kevin Horn July 31, 2009

July 31, 2009

the following classes: twisted.cred.credentials.CramMD5Credentials twisted.mail.imap4.PLAINCredentials twisted.mail.imap4.LOGINCredentials all seem to implement the same interface, yet there is no Interface defined for these objects. "But Kevin", you might be thinking, "They all implement twisted.cred.credentials.IUsernameHashedPassword or t.c.c.IUsernamePassword". That's true, but they all have additional methods which make them useful for handling SASL authentication in various protocols. … [View More]

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Re: [Twisted-Python] Deferred documentation rewrite
by Terry Jones July 30, 2009

July 30, 2009

> Right. Everything you could do synchronously, you can do asynchronously > (and a bit more too). It just /looks/ really weird. At some point I realized that it helps to realize that code that looks synchronous really isn't at all. Probably all the programming that almost all of us will ever do is not synchronous. You type x = y + 3 and you get into the habit of thinking that x just got assigned the value of y + 3. But there's a whole set of levels of operations, all invisible to … [View More]you, that are frantically rearranging atoms behind the scenes to pull off this tiny miracle. Instead of trying to wrap your head around the so-called "weird" asynchronous operation of Twisted, it's easier to let fall the comforting illusion that you're in the synchronous world to begin with - whatever that's supposed to mean (it's more like a fairy tale IMO). You're not. It's more accurate to think that that line of code arranges for x to *eventually* hold the value of y + 3. Then it's a small step to thinking that x = y + 3 z = f(x) is just another slightly bigger part of the same illusion. Those lines of code aren't executed one after another at all. You're just brought up with the fairy tale that they are - or at least you study computer science and spend so much time with high-level languages that you start to take it for granted that they are done one after the other. But the second line is *eventually* executed after the first, assuming nothing went wrong (e.g., y could be None). At that point - everything is asynchronous - you have the right mindset to think perfectly clearly about Twisted code. And there's no jump to make at all. The only things you have to get your head around are 1) the fact that Twisted code doesn't give you the comforting linear illusion of so-called synchronous code as you type it in your editor (inlineCallbacks helps a lot with improving that), and 2) that Twisted's deferreds are the way of maintaining the flow of results (both correct and incorrect) through time as your program executes. I.e., you've lost the step-at-a-time line-by-line results computed on line N are available on line N+1 flow of code you can so easily read in your editor, and in exchange you have deferreds. I could go on, obviously :-) But I just wanted to point out that the shift from thinking "synchronously" to "asynchronously" is much easier to make if you realize the former is a convenient illusion and in fact you've always been doing things asynchronously. Terry [View Less]

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[Twisted-Python] Possible Twisted sprint
by Jonathan Lange July 30, 2009

July 30, 2009

Hello all, I've recently returned from EuroPython where I got a chance to work with Thomas Hervé on Twisted. In the giddy rush of success I thought, "Wouldn't it be great if we could get a whole week to do this?". I propose that: - we arrange a week long sprint in Boston this year. - we ask the PSF & the TSF to assist with travel expenses for some of the more distant community members - the Boston folk arrange a venue - individuals figure out how to get the time to attend. - we … [View More]

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[Twisted-Python] PLAINAuthenticator in twisted.mail.imap4
by Kevin Horn July 29, 2009

July 29, 2009

I was digging through the Twisted IMAP code tonight and I noticed something puzzling... PLAINAuthenticator.challengeResponse() uses the following statement to send auth credentials to the server return '%s\0%s\0' % (self.user, secret) which would give auth credentials of the form: authid<NUL>password<NUL> (where <NUL> is the NUL character) However, both RFC2595 and RFC4616 (both define the PLAIN SASL mechanism), say that credentials should be … [View More]

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[Twisted-Python] PPA repo
by Esteve Fernandez July 28, 2009

July 28, 2009

Hi all, could any of the admins of the twisted-dev Launchpad team create a PPA? I'd do it myself, but I don't have permission (AFAIK, only admins do). We're currently providing packages for Ubuntu Hardy from Fluidinfo's PPA (see ticket #3102 - http://twistedmatrix.com/trac/ticket/3102), but I think it's more appropriate to host them at Twisted's. Another reason for that is that we've been building some custom packages for Twisted at Fluidinfo, which contain backported stuff from trunk and I'd … [View More]

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[Twisted-Python] License for code in twisted's sandbox?
by Vishal Shetye July 28, 2009

July 28, 2009

Hi, I had posted a query about laxdb on this list http://twistedmatrix.com/pipermail/twisted-python/2009-July/020030.html laxdb code is in sandbox and is not released with twisted. The file itself does not have any license. Can it be used assuming the same license as that of twisted. -- vishal

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Re: [Twisted-Python] Simple Epoll Reactor question
by Andrew Francis July 28, 2009

July 28, 2009

Hi Glyph: Can do. Tell me how to submit a document patch. Cheers, Andrew Message: 3 Date: Sun, 19 Jul 2009 12:59:22 -0400 From: Glyph Lefkowitz <glyph(a)twistedmatrix.com> Subject: Re: [Twisted-Python] Simple Epoll Reactor question To: Twisted general discussion <twisted-python(a)twistedmatrix.com> Message-ID: <d9047f780907190959k60c53022qb4d348ac886e2d80(a)mail.gmail.com> Content-Type: text/plain; charset=UTF-8 On Sun, Jul 19, 2009 at 12:08 PM, Andrew Francis<… [View More]

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