Mailman 3 March 2009 - Twisted

[Twisted-Python] Re:how to pass on the connection failed or connection lost error
by khawar hasham March 6, 2009

March 6, 2009

Hi, I tried to use this suggestion but I could not make it work. here is the test I am using in my application class def callSend(self, msg): plugin.send(msg) Now in plugin class def send(self, msg): print 'before call' threads.blockingCallFromThread(reactor, remotesend, msg) print 'after call' def handleError(self, error): error.… [View More]raiseException() def remotesend(self, msg): deferred = defer.Deferred() reactor.connectTCP('localhost',9999,myfactory) deffered.addErrback(self.handleError) return deffered now myfactory class .. clientConnectionFailed def clientConnectionFailed(self, connector, reason): reason.raiseException() now the problem is, code has become synchronous as code is waiting after threads.blockingCallFromThread, how to fire the defer returned from 'remotesend'. Do i need to fire it or twisted will take care of it. I think I can't refer this deferred object since it is being passed to threads.blockingCallFromThread function on which I have no control. any suggestions --- On Wed, 3/4/09, twisted-python-request(a)twistedmatrix.com <twisted-python-request(a)twistedmatrix.com> wrote: From: twisted-python-request(a)twistedmatrix.com <twisted-python-request(a)twistedmatrix.com> Subject: Twisted-Python Digest, Vol 60, Issue 6 To: twisted-python(a)twistedmatrix.com Date: Wednesday, March 4, 2009, 11:00 AM Send Twisted-Python mailing list submissions to twisted-python(a)twistedmatrix.com To subscribe or unsubscribe via the World Wide Web, visit http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python or, via email, send a message with subject or body 'help' to twisted-python-request(a)twistedmatrix.com You can reach the person managing the list at twisted-python-owner(a)twistedmatrix.com When replying, please edit your Subject line so it is more specific than "Re: Contents of Twisted-Python digest..." Today's Topics: 1. Re: how to pass on the connection failed or connection lost error (Jean-Paul Calderone) ---------------------------------------------------------------------- Message: 1 Date: Wed, 4 Mar 2009 09:59:42 -0500 From: Jean-Paul Calderone <exarkun(a)divmod.com> Subject: Re: [Twisted-Python] how to pass on the connection failed or connection lost error To: twisted-python(a)twistedmatrix.com Message-ID: <20090304145942.12853.42253504.divmod.quotient.17917(a)henry.divmod.com> Content-Type: text/plain; format=flowed On Wed, 4 Mar 2009 06:39:59 -0800 (PST), khawar hasham <hasham_james_007(a)yahoo.com> wrote: >Hi > >let me first explain the application that I am developing. I have an application that will use the twisted part as a plugin. this twisted part will act as server and as client both. >my application call the plugin method to send data to server module using connectTCP. now the problem is I can not pass on the connection failed exception to my calling application. Since you're running the reactor in one thread and the rest of your application in another thread, your question is basically one of message passing. You've already found reactor.callFromThread which is good; I think you just want the slightly more featureful version, available in twisted.internet.threads, blockingCallFromThread. This is implemented in terms of callFromThread, but additionally allows the caller to get the result of the function being called - including waiting on a Deferred if the function being called returns one. If you switch to this, then you only need to make Plugin.clientsend return a Deferred which eventually fires with a result or a Failure. Jean-Paul ------------------------------ _______________________________________________ Twisted-Python mailing list Twisted-Python(a)twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python End of Twisted-Python Digest, Vol 60, Issue 6 ********************************************* [View Less]

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[Twisted-Python] A few comments on deferreds
by Terry Jones March 6, 2009

March 6, 2009

Here are a few comments on deferreds. I'll keep this short. These sort of posts don't seem to generate much/any discussion (e.g., http://bit.ly/YkSD which I thought was cool). I'm not sure why - I find deferreds infinitely interesting, and don't understand why other people don't seem to share the passion :-) 1. If you have a deferred d1, and you call d1.chainDeferred(d2) I think it makes sense for there to be a flag inside the deferred class that warns you if you later call d1.… [View More]

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[Twisted-Python] Interview question on deferreds
by Terry Jones March 6, 2009

March 6, 2009

I'm going to post a few short comments on deferreds. As a fun standalone warm-up exercise, here's an interview-style question for people who claim to understand Twisted's deferreds. What will the following code print, and why? from twisted.internet import defer def e_ok(x): print 'extra is ok:', x return x def e_nok(f): # Propagate the failure (by returning it). print 'extra failed' return f def raiser(_): raise Exception('… [View More]

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[Twisted-Python] Twisted Sprint at PyCon
by glyph＠divmod.com March 5, 2009

March 5, 2009

There will be an extended Twisted sprint at PyCon this year. I hope that everyone on this list who is attending will be present :). Technically I'm the sprint leader, but I would very much appreciate help from anyone else who is in an organizing mood. Please sign up on the PyCon wiki here: http://us.pycon.org/2009/sprints/projects/twisted/

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[Twisted-Python] Twisted developers: please donate your time!
by Itamar Shtull-Trauring March 5, 2009

March 5, 2009

As part of the TSF's fundraising efforts, we are trying to get upfront donations of time you will spend developing Twisted. It will then get matched by a donor, if we are successful in getting this grant. So if you're planning on working on Twisted anyway this year, your work will count twice as much! So, if you're interested, please reply, saying something like "I will spend two weeks working on Gopher support over the next year." -Itamar

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Re: [Twisted-Python] Twisted developers: please donate your time!
by Florent Aide March 4, 2009

March 4, 2009

On Wed, Mar 4, 2009 at 11:20 PM, Florent Aide <florent.aide(a)gmail.com> wrote: > Itamar Shtull-Trauring a écrit : > > So, if you're interested, please reply, saying something like "I will > spend two weeks working on Gopher support over the next year." > > > Hi all, > > I have worked in the last days on a demo application using twisted and > evolved from the simple pop3 + smtp exemple found in the Twisted book to add > a web interface (minimalistic … [View More]

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[Twisted-Python] Re: Twisted developers: please donate your time!
by Andrew Francis March 4, 2009

March 4, 2009

Hi Itamar and Colleages: >As part of the TSF's fundraising efforts, we are trying to get upfront >donations of time you will spend developing Twisted. It will then get >matched by a donor, if we are successful in getting this grant. So if >you're planning on working on Twisted anyway this year, your work will >count twice as much! I would happy to donate some time to developing Twisted. However since the only Twisted code I have really looked at is the reactor, I am not sure … [View More]

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[Twisted-Python] how to pass on the connection failed or connection lost error
by khawar hasham March 4, 2009

March 4, 2009

Hi let me first explain the application that I am developing. I have an application that will use the twisted part as a plugin. this twisted part will act as server and as client both. my application call the plugin method to send data to server module using connectTCP. now the problem is I can not pass on the connection failed exception to my calling application. To explain it further, here is the dummy code class MyReactor(threading.Thread): … [View More]def __init__(self): threading.Thread.__init__(self) def run(self): reactor.run(installSignalHandlers=0) class MyFactory(ClientFactory): def __init__(self): self.msg = None def setMsg(self, msg): self.msg = msg def connectionFailed(self, connector, reason): #here i need to send the exception back to the user class Plugin: def __init__(self): self.running = False def send(self, msg): reactor.callFromThread(self.clientsend, msg) def clientsend(self, msg): myfactory = MyFactory() myfactory.setMsg(msg) reactor.connectTCP ('localhost',9999) if( not self.running): mr = MyReactor() mr.start() self.running = True def startServer(self): reactor.listenTCP(9999,ServerFactory()) if( not self.running): mr = MyReactor() mr.start() self.running = True class PluginTest: def __init__(self): self.plugin = Plugin() def start(self): self.plugin.startServer() def send(self,msg): try: self.plugin.send(msg) except: #I want to print send error here # error could be connection fail ptest = PluginTest() #I m not starting the server so that I could get the connectionfail error ptest.send('hi') Can you suggest me any work around to get the exception in the PluginUser.send method [View Less]

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[Twisted-Python] too many file descriptors in select
by John Aherne March 3, 2009

March 3, 2009

I have started to get this message coming up on a fairly regular basis now. I have an application that is very simple and has run by and large without problem for about 7 months. But over the pas 4 - 6 weeks has started to produce this error 'too many file descriptors in select'. The application basically falls over at this point, since it can't service any more requests. I am running on Windows XP sp2, python 2.4.4, twisted 2.5. The application consists of about 150+ vehicles sending back … [View More]

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[Twisted-Python] util.quote deprecated
by Pet March 3, 2009

March 3, 2009

Hi, what is a proper way to escape user input in database query strings? I've used quote from twisted.enterprise.util, but it is deprecated now. Is there any other module for this purpose? Thanks, Pet

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[Twisted-Python] Bug in twisted.names.client
by Nicolas Toper March 2, 2009

March 2, 2009

Hi, It seems the resolv file in twisted.names.client#maybeParseConfig is never closed. This creates a exceptions.IOError: [Errno 24] Too many open files: '/etc/resolv.conf (FYI I am resolving a domain very often in my script). Am I correct? Would you like me to submit a patch to correct this? Best, Nicolas http://www.m--x--m.net

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[Twisted-Python] Weekly Bug Summary
by exarkun＠twistedmatrix.com March 1, 2009

March 1, 2009

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[Twisted-Python] Why do I get an AlreadyCalledError?
by Conrad Winchester March 1, 2009

March 1, 2009

Hi all, I am writing a restful twisted (8.1.0) server and am trying to return useful error statuses from requests. The problem is that even following the documentation extremely carefully I am getting an AlreadyCalled Error every time I generate a failure. Here is my main class (leaving out code that I feel is not relevant to the question: from xml.dom import minidom from twisted.web import server, resource from FWGException import FWGException class DeferredPostHandler(resource.… [View More]Resource,minidom.Document): NOT_IMPLEMENTED = 501 BAD_REQUEST = 400 def writeError(self, failure, request, *args, **kw): failure.trap(FWGException) request.setResponseCode(self.errorCode) request.write("Error handling request: %s" % failure.getErrorMessage()) request.finish() def writeResult(self, result, request, *args, **kw): self.writexml(request) request.finish() def render_GET(self, request): self.process=self.db.runInteraction(self.processForm,request) self.process.addCallbacks(self.writeResult, self.writeError, [request], {}, [request], {}) return server.NOT_DONE_YET I have a handler that extends this from DeferredPostHandler import DeferredPostHandler from twisted.web import http from twisted.python.failure import Failure from FWGException import FWGException class CollectionAdminHandler(DeferredPostHandler): def __init__(self, task, db, config): DeferredPostHandler.__init__(self,db) self.config = config self.task = task self.errorCode = http.OK def processForm(self, cursor, request): if self.task == 'add': self.addCollection(cursor, request) elif self.task == 'delete': self.deleteCollection(cursor, request) else: self.errorCode = DeferredPostHandler.NOT_IMPLEMENTED fail = Failure(FWGException("Unsupported Task")) self.process.errback(fail) def addCollection(self, cursor, request): fail = None if self.isValidAddRequest(request): pass else: self.errorCode = DeferredPostHandler.BAD_REQUEST fail = Failure(FWGException("Missing Parameter")) if fail: self.process.errback(fail); def deleteCollection(self, cursor, request): print 'Delete Collection' def isValidAddRequest(self, request): return 'title' in request.args and 'category' in request.args and 'date' in request.args Unfortunately whenever I call self.process.errback(fail) I get the following stack trace in my log Traceback (most recent call last): File "startserver.py", line 23, in <module> reactor.run() File "/Library/Python/2.5/site-packages/Twisted-8.1.0-py2.5- macosx-10.5-i386.egg/twisted/internet/base.py", line 1048, in run self.mainLoop() File "/Library/Python/2.5/site-packages/Twisted-8.1.0-py2.5- macosx-10.5-i386.egg/twisted/internet/base.py", line 1057, in mainLoop self.runUntilCurrent() --- <exception caught here> --- File "/Library/Python/2.5/site-packages/Twisted-8.1.0-py2.5- macosx-10.5-i386.egg/twisted/internet/base.py", line 677, in runUntilCurrent f(*a, **kw) File "/Library/Python/2.5/site-packages/Twisted-8.1.0-py2.5- macosx-10.5-i386.egg/twisted/internet/defer.py", line 243, in callback self._startRunCallbacks(result) File "/Library/Python/2.5/site-packages/Twisted-8.1.0-py2.5- macosx-10.5-i386.egg/twisted/internet/defer.py", line 298, in _startRunCallbacks raise AlreadyCalledError twisted.internet.defer.AlreadyCalledError: I can not understand why this is happening :-( Can anybody help? BTW I am using POST instead of PUT because my client can't do PUT Conrad Winchester [View Less]

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