Mailman 3 March 2004 - Twisted

[Twisted-Python] Deterministic TimerService
by Norm Petterson 04 Mar '04

04 Mar '04

Hi, Thanks for such a useful framework. While working on an industrial data logger using Twisted, I found that application.internet.TimerService calls my own callLater callable function before reissuing the next callLater. Consequently, instead of a time period c, the callable function runs every c+x, where x is the duration of my own function, and thus appears to slip over time. Based on my past experiences with DEC RSX "mark time" and VMS "set timer" in similar situations, I recommend changing: def setupCall(): self.callable(*self.args, **self.kwargs) self._call = reactor.callLater(self.step, setupCall) to def setupCall(): self._call = reactor.callLater(self.step, setupCall) self.callable(*self.args, **self.kwargs) Reissuing the timer request first appears to work more as I'd expect, particularly as I am using timestamp information for each scan to compute an appropriate bsddb record number in a persistent circular buffer. Any other opinions? Regards, Norm Petterson

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[Twisted-Python] Running twisted tap file as NT service.
by Max Thiercy 04 Mar '04

04 Mar '04

I'm trying to implement a small dedicated service on both Windows and Unix. So, I'm interesting in the capability of converting a twisted .tap file to an NT/2K/XP service. I read some useful mails from Cory Dodt (end of january 2004) but these mails mention a tool named 'tap2ntsvc' that I can't find anywhere. Could you tell me where I can find this tool ? Thanks in advance. Max THIERCY.

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[Twisted-Python] deferDirWalk code snipped
by Michal Pasternak 04 Mar '04

04 Mar '04

Hi, attached is a simple defer analogue to os.path.walk. It can be paused, it can be restarted. I've wrote this code making some simple gtk backup application. Perhaps this could be placed in examples somewhere (or even included in the library). If someone would like to comment on my code, feel free to do it, I always like constructive criticism ;) Keep hacking, -- Michal Pasternak :: http://pasternak.w.lub.pl :: http://winsrc.sf.net "There's so much comedy on television. Does that cause comedy in the streets?" -- Dick Cavett

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[Twisted-Python] Re: [Stackless] Stackless and Twisted
by Christopher Armstrong 03 Mar '04

03 Mar '04

Ok, here's a completely rewritten stackless support module for Twisted. I used to have one that did all kinds of stupid unnecessary stuff with the reactor and junk, but it's gone now. For you CVS Twisted users, this is in sandbox/radix/threadless.py. It offers two functions: blockOn and deferredTasklet. deferredTasklet is a function decorator that you should use on your stacklessy code that you want to integrate with Twisted. blockOn is a function that you should pass a Deferred to wait for it to fire. Use it in your stacklessy-code. There's a TEST function (that's automatically run when you execute the module) that shows this off with some somewhat helpful comments. There are also prints sprinkled throughout the code to show you what's going on. -- Twisted | Christopher Armstrong: International Man of Twistery Radix | Release Manager, Twisted Project ---------+ http://radix.twistedmatrix.com/

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Re: [Twisted-Python] [Request] IMAP Server Sample code
by exarkun＠divmod.com 03 Mar '04

03 Mar '04

On Tue, 02 Mar 2004 11:49:29 +0000, David Burton <david(a)zeos.org> wrote: >Hi guys, I'm new to the list, but I've had a look through the site and > the mailing list archives, looking for some sample code which would help > me in setting up the basics of an IMAP server - specifically to get mail > from a POP account (which is easy enough), store it in a database > (again, easy enough), and set up the interface to the database messages > (and possible other non-email goodies) using IMAP (currently not a clue). > I've tried looking through the API and the source code, but I don't know > what I should be returning from the likes of authenticateLogin to > confirm (or refect logins), and what to return via listCapabilities (I'm > currently . Any lists of which methods should generally work without > overriding, which ones should be overridden, what needs to be returned, > etc gratefully received. twisted.protocols.imap4.IMAP4Server is written so that, in most cases, it need not be subclassed. The preferred way to implement a server is to implement the interfaces IMAP4Server depends on. The two required interfaces are IAccount and IMailbox, both of which are defined in twisted.protocols.imap4. There are several other optional interfaces as well. Ideally, accounts and mailboxes are hooked up to an IMAP4Server protocol instance via twisted.cred. Here is a brief example: from twisted.cred import portal from twisted.protocols import imap4 class Account: __implements__ = (imap4.IAccount,) # Actually implement the interface here def logout(): # Cleanup logic goes here class Realm: __implements__ = (portal.IRealm,) def requestAvatar(self, avatarID, mind, *interfaces): if imap4.IAccount not in interfaces: raise NotImplementedError return imap4.IAccount, Account(avatarID), logout p = portal.Portal(Realm()) # Contrive to have your ServerFactory's buildProtocol # set the "portal" attribute of the IMAP4Server instance # it creates to the `p' defined above. For more information, refer to the cred and component howtos available on the Twisted website. Jp

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[Twisted-Python] resource.render_METHOD
by Richard.Townsend＠edl.uk.eds.com 03 Mar '04

03 Mar '04

> Hmm. I suppose render() could grope through methods on self to find all > 'render_FOO' methods when an exception occurs.. OTOH, we could just get > rid of the allowed methods reporting. What's the use? Perhaps the Resource.render() method could check for self.allowedMethods instead of server.UnsupportedMethod.allowedMethods, then I could set it as a class attribute in each derived class?

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[Twisted-Python] resource.render_METHOD
by Richard.Townsend＠edl.uk.eds.com 02 Mar '04

02 Mar '04

I have a server application that creates a number of web resources (derived from resource.Resource). Some of the resources only handle GET requests, while others only handle POSTs. Currently the resources only override the render() method. I want to change them to override render_GET() or render_POST() as appropriate. I notice that if a resource receives a request it doesn't handle, then an UnsupportedMethod exception is raised. This returns HTML to the client containing a message that uses UnsupportedMethod.allowedMethods. This defaults to an empty tuple. Because my resources support different request methods, I have to set allowedMethods in each resource's render() method e.g. def render(self, request): server.UnsupportedMethod.allowedMethods = ('POST',) resource.Resource.render(self, request) So I still need to override the render() method. Is there a neater way to do this? I'm using Twisted 1.2.0 regards Richard Townsend

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[Twisted-Python] [Request] IMAP Server Sample code
by David Burton 02 Mar '04

02 Mar '04

Hi guys, I'm new to the list, but I've had a look through the site and the mailing list archives, looking for some sample code which would help me in setting up the basics of an IMAP server - specifically to get mail from a POP account (which is easy enough), store it in a database (again, easy enough), and set up the interface to the database messages (and possible other non-email goodies) using IMAP (currently not a clue). I've tried looking through the API and the source code, but I don't know what I should be returning from the likes of authenticateLogin to confirm (or refect logins), and what to return via listCapabilities (I'm currently . Any lists of which methods should generally work without overriding, which ones should be overridden, what needs to be returned, etc gratefully received. I'm quite happy to play around a bit, so long as there's a little hint as to what kind of stuff should be returned - I'm really needing to get listing of capabilities and authentication figured out first of all, so if anyone can help... (As an aside, the reason for the project is that my general impressions are that XMail is one of the few free POP3 mail servers on Windows, and very capable, but missing IMAP - I'm trying to create an extension to do this.) Thanks in advance, David Burton

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[Twisted-Python] Using Twisted together with Windows Namespace Extensions
by Thorsten Henninger 02 Mar '04

02 Mar '04

Hi everybody, I try to implement an ActiveX component for a Windows Namespace Extension, such that the data of my server, a twisted perspective broker, can be accessed and browsed via the Windows explorer. The challenge on writing something like this is, that once Windows asks my ActiveX component to open a folder, a file or any other object, Windows expects an immediate answer. But asking by twisted server just returns a deferred. To emulate those synchronous calls, I could use the "deferredResult" methods from twisted.trials. But that way, I would not be able to handle parallel requests, e.g. from two or more explorers or other applications. Does anybody know, how to emulate a synchronous call in twisted? Am I right, that using the deferredResult method causes problems with parallel requests? I guess, the solution may be similar to the render method return server.NOT_DONE_YET solution used in web.resource and twisted.web.server. thanks for any help on this, Thorsten -- brainbot technologies AG boppstrasse . 64 . 55118 mainz . germany fon +49 6131 211639-1 . fax +49 6131 211639-2 http://brainbot.com/ mailto:henni@brainbot.com

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[Twisted-Python] Running a reactor in IPython
by Thorsten Henninger 02 Mar '04

02 Mar '04

Hi all, At my company, we heavily use IPython for debugging and testing. The following code shows, how to run a reactor together with IPython: from twisted.internet import reactor from twisted.python import threadable threadable.init(1) import threading class MyThread(threading.Thread): def run(self): print "starting reactor.." reactor.run(installSignalHandlers=False) if __name__=="__main__": m=MyThread() m.start() from IPython.Shell import IPythonShellEmbed ipshell = IPythonShellEmbed() ipshell() # this call anywhere in your program will start IPython have fun, Thorsten -- brainbot technologies AG boppstrasse . 64 . 55118 mainz . germany fon +49 6131 211639-1 . fax +49 6131 211639-2 http://brainbot.com/ mailto:henni@brainbot.com

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