Mailman 3 June 2003 - Twisted

RE: [Twisted-Python] (Summary) The problem with Twisted...
by POYEN OP Olivier (DCL) June 5, 2003

June 5, 2003

> On the other hand, I think more and better docs for > developers (i.e. the > APIs and "HOWTO"s, which are misnamed I think) is definitely > worthwhile. > The more developers we can attract, the better tested our designs and > implementation will be, and the better quality our project > will become. At > the moment, the docs are still somewhat of a barrier to new > developers, but > thankfully not the insurmountable hurdle they used to be :) > If I may, … [View More]I'd like to add a little something on Docs, from my little newbie point of few: I've read cl.py a lot, and you can sometimes find people complaining about Twisted Docs. And the usual response, which does not lack of common sense, is to *not* try to grasp all at the same time, but just go at a specific point, looking for *just* what you want. That's why there are lots of how to. But, you know, I'm just the average geek guy, and thus, went to twisted-matrix website, and download and print the whole How-To pdf, with it's 250 pages. And, like, I assume, every-one, I try read it first page-> last page. Confusing. Yes because there are lots of stuff to get your mind around, but also because you don't want to do that: at many point, you find introdocution stuff in the middle of an how to you would have needed before. Let me give an example: One of the first thing I read was the "visions" paragraph which quote something like that "in many place in others how-to, you'll find what is twisted; but here let's not speak about that, but let show what It should be". No, on the first page , I want to know what it is ! Then, followed an overview of many components. Great, but I did'nt get yet the whole picture of it (what is it ? What is twisted ?) . Because I need this big picture before I can put each component in its own box. Then I've have a quite excellent overview of twisted enterprise. Reallly good, but I still didn't get the whole picture, and I've many details about lot's of other stuff. Even at the beginning of the paragraph, it's written something like 'in order to understand this overview, you should already know how to build a server, what is a reactor....'. It perhaps not quotes exactly that, but you get the point: I read from page one, and you want me to know stuff I did'nt even read yet ! Other example: latter, you have two of the most important how-to: 'make a server'& 'make a client'. These one, on the contrary, start very gently. And in the overview, I learn almost what I wanted, to get the "big picture" of twisted: an asynchroneous loop, and after that , no blocking calls, only callback. (maybe I'm wrong). Why did I not get those lines in the beginning. It really helps me understanding the big picture of twisted. Those commentaries are not agressif, because the docs are just "how to", not a book or a turorial. And those how-to are quite well made. So, all my point is that the documentation is not so bad, because you did put all the necessary stuff. My point is that you need a book, with almost the same content, but a different organization of the data. You need a normal book, cecause people like to have a single entrance point they can read through, linearly. And I think you should enforce the "try to get the whole thing, the big picture of twisted and then go to a specific point" mantra. BTW, I'll be happy to help, and since I'm still a newbie, and since I still did not get twisted , that may be helpful ! HTH OPQ ----------------------------------------------------------------- Ce message est confidentiel ; son contenu ne represente en aucun cas un engagement de la part de Dexia Credit Local ou de Dexia CLF Banque. Toute publication, utilisation ou diffusion, meme partielle, doit etre autorisee prealablement par l'emetteur. Si vous n'etes pas destinataire de ce message, merci d'en avertir immediatement l'expediteur. This message is confidential ; its contents do not constitute a commitment by Dexia Credit Local or Dexia CLF Banque. Any unauthorised disclosure, use or dissemination, either whole or partial, is prohibited. If you are not the intended recipient of the message, please notify the sender immediately. ----------------------------------------------------------------- Consultez notre site internet www.dexia-clf.fr La cle d'une gestion optimisee du secteur public local ----------------------------------------------------------------- [View Less]

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[Twisted-Python] twisted newbie question about UDP
by Jaroslav Jakl June 5, 2003

June 5, 2003

Hello all, I have the following problem with UDP communication in twisted: I tried an example from howto doc. chapter 4.4.2 and it produce EWOULDBLOCK error after first received packet. Question is how to handle EWOULDBLOCK exception, because it isn't handled EWOULDBLOCK in udp.port.doRead(). The second question is how to set REUSEADDR on UDP socket in twisted. I need it because we have several processes communicating on the same UDP port (not all writen in python). Thanks in advance, Jaroslav Jakl

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[Twisted-Python] win32 status -- pretty good!
by Itamar Shtull-Trauring June 5, 2003

June 5, 2003

Discounting tests that are unix only and shouldn't be run on win32 (I will fix this too), there are only about 3 failures that look like real bugs when using default reactor. This is quite good. Looks like we're actually in good shape on Windows. And hopefully soon all tests will pass. Of course, then there's the win32event reactor to deal with. -- Itamar Shtull-Trauring http://itamarst.org/ http://www.zoteca.com -- Python & Twisted consulting

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RE: [Twisted-Python] ReverseProxy performance??
by Lance Kurisaki June 4, 2003

June 4, 2003

Since no one else has responded, I'll give it a shot... >Does anyone have figures about the performance of ReverseProxy? I have not done (or seen) any performance evaluation of the ReverseProxy. >How many connections can it handle simultaneously. Unknown. >Does it support SSL? >Can it terminate an SSL-tunnel and forward the request unencrypted? Yes, that's how I'm using it. I want an SSL reverse proxy in front of a Zope server and don't want something as heavy as Apache or Squid. … [View More]

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[Twisted-Python] ReverseProxy does not forward GET URL parameters
by Lance Kurisaki June 4, 2003

June 4, 2003

The ReverseProxy does not forward GET parameters in a URL. For example, if the client GETs "/script?arg1=a&arg2=b", the destination server sees only "GET /script". The following patch fixes that. Lance Index: twisted/web/proxy.py =================================================================== RCS file: /cvs/Twisted/twisted/web/proxy.py,v retrieving revision 1.14 diff -u -r1.14 proxy.py --- twisted/web/proxy.py 3 Jun 2003 04:45:35 -0000 1.14 +++ twisted/web/proxy.py … [View More]

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[Twisted-Python] Excel, Twisted, and wxPython
by Andrew Dalke June 4, 2003

June 4, 2003

Hi, I'm working on an add-in for Excel, under MS Windows. This takes information from the current selection and uses XML-RPC to call a remote server. The call may take a while, so I want to have a "Cancel" button. I decided to use wxPython for the GUI, with a modal dialog. Basically, a wxGauge (for the progress bar) and a "Cancel" button. The RPC call itself may take several minutes, so I need to use either threads or Twisted, and obviously I decided on the latter. (This is an … [View More]

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[Twisted-Python] Twisted.IM : Simple IRC-bot?? ICQ-support?
by Thomas Weholt ( PRIVAT ) June 3, 2003

June 3, 2003

Q1 : I need to get started using Twisted building a simple IRC-bot. It should listen to everything being said on a given channel ( or channels ) and perform certain tasks when trigger-words are found, printing the result in the channel it was called from. Does anybody have any code I can look at. Tried the code in the test-folder in the source-distr, but that didn't make much sense to me, so I was hoping somebody had a piece of code more in the line of what I described above. Q2: What about … [View More]

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[Twisted-Python] ReverseProxy does not log requests
by Lance Kurisaki June 3, 2003

June 3, 2003

The ReverseProxy does not log its requests. The following patch adds request logging and silences the "Starting factory..." and "Stopping factory..." log messages. I'm not sure if the "proper" place to do the logging is in the render() method of ReverseProxyResource, but it seems to work... :-) Lance Index: twisted/web/proxy.py =================================================================== RCS file: /cvs/Twisted/twisted/web/proxy.py,v retrieving revision 1.13 diff -c -r1.13 proxy.… [View More]

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RE: [Twisted-Python] ReverseProxy doesn't send X-Forwarded-For header
by Lance Kurisaki June 3, 2003

June 3, 2003

I understand your reasons and agree. My only reservation is that if someone wants to send the header, it's not immediately obvious (wasn't to me, anyway) what the proper line of code is and where it should go. It took me a while to figure it out. Perhaps if we make it dependent on an instance attribute, such as "sendXForwardedFor", which is by default set to 0? I have no problem if you decide to leave it out entirely, though... Lance -----Original Message----- From: Moshe Zadka [mailto:… [View More]

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[Twisted-Python] xmlrpc doesn't catch XML parsing exceptions
by Andrew Dalke June 3, 2003

June 3, 2003

I used the Twisted code to connect to a URI which wasn't providing XML-RPC services but is providing HTML. The XML-RPC code tried to parse the HTML response, and failed. It reported the failure correctly, but also spewed a traceback to stdout. Here's what stdout looks like Traceback (most recent call last): File "E:\Python22\Lib\site-packages\twisted\internet\default.py", line 473, in doSelect _logrun(selectable, _drdw, selectable, method, dict) File "E:\Python22\Lib\site-… [View More]packages\twisted\python\log.py", line 64, in callWi thLogger callWithContext({"system": lp}, func, *args, **kw) File "E:\Python22\Lib\site-packages\twisted\python\log.py", line 51, in callWi thContext return context.call({ILogContext: newCtx}, func, *args, **kw) File "E:\Python22\Lib\site-packages\twisted\python\context.py", line 32, in ca llWithContext return func(*args,**kw) --- <exception caught here> --- File "E:\Python22\Lib\site-packages\twisted\internet\default.py", line 482, in _doReadOrWrite why = getattr(selectable, method)() File "E:\Python22\Lib\site-packages\twisted\internet\tcp.py", line 219, in doR ead return self.protocol.dataReceived(data) File "E:\Python22\Lib\site-packages\twisted\protocols\basic.py", line 179, in dataReceived return self.rawDataReceived(data) File "E:\Python22\Lib\site-packages\twisted\protocols\http.py", line 341, in r awDataReceived self.handleResponseEnd() File "E:\Python22\Lib\site-packages\twisted\protocols\http.py", line 323, in h andleResponseEnd self.handleResponse(b) File "E:\Python22\Lib\site-packages\twisted\web\xmlrpc.py", line 174, in handl eResponse self.factory.parseResponse(contents) File "E:\Python22\Lib\site-packages\twisted\web\xmlrpc.py", line 199, in parse Response response = xmlrpclib.loads(contents) File "E:\Python22\lib\xmlrpclib.py", line 804, in loads p.feed(data) File "E:\Python22\lib\xmlrpclib.py", line 390, in feed self._parser.Parse(data, 0) xml.parsers.expat.ExpatError: mismatched tag: line 10, column The reason is twisted.web.xmlrpc, which has def parseResponse(self, contents): if not self.deferred: return try: response = xmlrpclib.loads(contents) except xmlrpclib.Fault, error: self.deferred.errback(error) self.deferred = None else: self.deferred.callback(response[0][0]) self.deferred = None There's nothing which handles an XML parsing error. I don't know who to blame here. I would like a except "XML parsing error", error: here as well, but there's no way to spell that. The xmlrpclib code chooses the fastest parser available, and the different parsers could throw different exceptions. Eg, the Expat parser throws an ExpatError, which is derived directly from Exception, and shares no other base class with The best I can think of now is to catch anything which isn't a "normal" Python exception, that is except (StandardError, SystemExit, StopIteration): raise except (xmlrpclib.Fault, Exception), error: self.deferred.errback(error) (could also use a bare except, but I think that's overkill for this case.) Even that's not perfect. xmllib.Error is derived from RuntimeError(!). OTOH, that module is deprecated .... Oh! Since Fault is derived from exception, could just catch Exception instead of the 2-ple I have there. Let me point out that Twisted did a good job of catching the error at a higher level and correctly sending it to my handler, so even if this had occurred in production code the app would have kept working as expected. This is good. Andrew dalke(a)dalkescientific.com [View Less]

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