Mailman 3 May 2008 - Twisted

[Twisted-Python] How-to raise errors with sshclient conch example in Twisted book
by asset 30 May '08

30 May '08

Ref: http://www.devshed.com/c/a/Python/SSH-with-Twisted/4/ Im new to Twisted and am trying to learn as quickly as I can. I apologize if this question is a waste of anybody's time. When working the with sshclient.py example (from the Twisted book, and the link above) I find the reactor hangs and does not raise an exception on connection failures or failed authentication. Ive been trying to work out how to catch these situations and shut down the reactor; or cleanup for another attempt, yet I cant seem to wrap my head around it. I imagine this is trivial and Im totally missing it. Any help would be greatly appreciated. Thx, TKiel

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Re: [Twisted-Python] suggestions for naming to help us preserve a Twisted trademark
by Terry Jones 29 May '08

29 May '08

>>>>> "Tim" == Tim Stebbing <tjstebbing(a)gmail.com> writes: Tim> If someone was to fork twisted, or implement it in a new language, I Tim> don't see how you could stop them referring to it as 'Twisted Blah', Tim> what else are they going to call it? Twisted Sister (http://en.wikipedia.org/wiki/Twisted_Sister) Terry

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Re: [Twisted-Python] chainDeferred does not pass result
by "Lutz Pälike" 29 May '08

29 May '08

> It's not a bug, it's how chainDeferred is meant to work. > -- Christopher Armstrong Can you explain why ? Wouldn't it be more useful to allow pulling intermediate results into side branches leaving the main call chain unaffected ? What makes this a wanted behaviour ? Thanks, Lutz -- Psssst! Schon vom neuen GMX MultiMessenger gehört? Der kann`s mit allen: http://www.gmx.net/de/go/multimessenger

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[Twisted-Python] chainDeferred does not pass result
by "Lutz Pälike" 29 May '08

29 May '08

I was trying to chain two Deferreds together but there is a problem with chainDeferred(). If i add Deferred object b in the middle of the call chain of object a, the result is correctly passed on to the branched call chain of b but the call chain of a is broken because b.callback() does not return a result. Am i missing something or is this a bug ? The example below illustrates the problem. If you uncomment the line deferred_a.chainDeferred(deferred_b) you should see result: None Cheers, Lutz #---------------- from twisted.internet import defer, reactor def square(res): return res*res def on_result(res): print "result: ", res return res def on_error(err): print err return err deferred_a = defer.Deferred() deferred_b = defer.Deferred() deferred_a.addCallback(square) # deferred_a.chainDeferred(deferred_b) deferred_a.addCallbacks(on_result, on_error) reactor.callLater(0.0, deferred_a.callback, 3) reactor.callLater(1.0, reactor.stop) reactor.run() #---------------- -- Super-Aktion nur in der GMX Spieleflat: 10 Tage für 1 Euro. Über 180 Spiele downloaden: http://flat.games.gmx.de

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[Twisted-Python] interaction problems with wxreactor and conch under linux
by Mark Dillavou 28 May '08

28 May '08

I have a large program that is built using wxpython and twisted in which the client sends commands through ssh (using conch) to the server. Under linux I have found some very strange results. If the user is not doing anything (i.e. not moving the mouse or doing anything to cause the window to redraw), then conch seems to stop processing and hang the whole twisted loop. As soon as the user moves the mouse, clicks a button, or does something to cause the window to refresh, then conch immediately starts processing again and the twisted loop begins calling callbacks again. I can't seem to reproduce this under windows or osx, and it doesn't seem to always happen under linux with wxgtk2. I have written a dumb little test program (attached), that hopefully shows this behavior. After connecting to a remote machine, through the gui you can specify a command, hit run command and the stdout will be displayed. The console prints out the time from two timers. One is setup using a reactor.callLater and another is setup using a wx.Timer. If a command that takes a while is run (cat a large file) and you don't move the mouse or do anything to cause the window to refresh, then you will see that the callLater callback stops being called (although the wx.Timer callback continues to be called). As soon as you move the mouse, the callLater callback begins firing again, and you'll eventually see the output of your command. This is really frustrating since we are using conch to send large commands or to download/upload large files, and it is common for the user to want to minimize the program and let it run in the background, but with this bug, twisted stops responding and the file stops sending until the user does something to cause the window to redraw. I'm not that familiar with conch, so maybe i'm doing something completely wrong in my connection code. Any critique on it would be nice. Thank you in advance, /Mark

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[Twisted-Python] help with twisted webserver and rpy script
by Jody Gugelhupf 28 May '08

28 May '08

hi there ppl :) i have a question, twisted is very new to me, i'm using the twisted webserver to control my tvcard, i wrote several scripts and got it all working, i also use a rpy script to switch stations from the website, only that it seems that i need to create for each station a rpy script, i'd rather have all stations in once rpy file and do it that way, i got it working in php, but is it possible to write php in rpy? here is an example of one of my rpy scripts to switch stations: #!/usr/bin/python import sys import os from www.web_types import HTMLResource, FreevoResource class TestResource(FreevoResource): def _render(self, request): fv = HTMLResource() fv.printHeader(_('LiveTV'), 'styles/main.css',selected=_('Test')) form = request.args command = "v4lctl setstation MTV" os.system(command) fv.res += "<html><script language=\"JavaScript\"> close();</script></html>" return String( fv.res ) resource = TestResource() the java stuff is so that when i click on the MTV.rpy link it closes the new window after the execution of the command, the main site where the MTV.rpy is displayed looks like this: #!/usr/bin/python import sys import os from www.web_types import HTMLResource, FreevoResource class TestResource(FreevoResource): def _render(self, request): fv = HTMLResource() fv.printHeader(_('LiveTV'), 'styles/main.css',selected=_('Test')) form = request.args fv.res += "<html>To start the stream server click <a href=\"http://10.0.0.1:8085/startstream.rpy\" target=\"_blank\">here.</a> To start the camera stream server click <a href=\"http://10.0.0.1:8085/startstreamcam.rpy\" target=\"_blank\">here.</a> To stop the stream-server click<a href=\"http://195.169.205.24:8085/stopstream.rpy\">here.</a> To switch to the channel you can simply click on the channel you want to watch. A new window will pop up and close itself automatically, then the channel should be changed.</html>" fv.res += "<html><br><a href=\"MTV.rpy\" target=\"_blank\"> MTV </a> <a href=\"TMF.rpy\" target=\"_blank\"> TMF </a> <a href=\"national.rpy\" target=\"_blank\"> National Geographic </a> <a href=\"discovery.rpy\" target=\"_blank\"> Discovery Channel </a> <a href=\"CNN.rpy\" target=\"_blank\"> CNN </a> <a href=\"BBC1.rpy\" target=\"_blank\"> BBC1 </a> <a href=\"BBC2.rpy\" target=\"_blank\"> BBC2 </a> <a href=\"net5.rpy\" target=\"_blank\"> Net5 </a> <a href=\"sbs6.rpy\" target=\"_blank\"> sbs6 </a> <a href=\"veronica.rpy\" target=\"_blank\"> Veronica </a> <a href=\"talpa.rpy\" target=\"_blank\"> talpa </a> <a href=\"rtl4.rpy\" target=\"_blank\"> rtl4 </a> <a href=\"rtl5.rpy\" target=\"_blank\"> rtl5 </a> <a href=\"rtl7.rpy\" target=\"_blank\"> rtl7 </a> <a href=\"een.rpy\" target=\"_blank\"> een </a> <a href=\"euronews.rpy\" target=\"_blank\"> Euronews </a> <a href=\"ard.rpy\" target=\"_blank\"> ARD </a> <a href=\"zdf.rpy\" target=\"_blank\"> ZDF </a> <a href=\"wdr.rpy\" target=\"_blank\"> WDR </a> <a href=\"gelderland.rpy\" target=\"_blank\"> TV Gelderland </a> <a href=\"ned1.rpy\" target=\"_blank\"> Nederland 1 </a> <a href=\"ned2.rpy\" target=\"_blank\"> Nederland 2 </a> <a href=\"ned3.rpy\" target=\"_blank\"> Nederland 3 </a> <a href=\"ketnet.rpy\" target=\"_blank\"> Ketnet/Canvas </a> <a href=\"lokal.rpy\" target=\"_blank\"> Lokaal Plus </a> <a href=\"upcinfo.rpy\" target=\"_blank\"> UpcInfo </a> <a href=\"trtint.rpy\" target=\"_blank\"> TRTint </a> <a href=\"rai1.rpy\" target=\"_blank\"> Rai Uno </a> <a href=\"eurosport.rpy\" target=\"_blank\"> Eurosport </a> <a href=\"nick.rpy\" target=\"_blank\"> Nick/Comedy Central </a> <a href=\"tellsell.rpy\" target=\"_blank\"> TellSell </a> <a href=\"tv5.rpy\" target=\"_blank\"> TV5 </a> <a href=\"cam.rpy\" target=\"_blank\"> cam </a></br></html>" fv.res += "<center><OBJECT ID=\"MediaPlayer\" WIDTH=320 HEIGHT=300 CLASSID=\"CLSID:22D6F312-B0F6-11D0-94AB-0080C74C7E95\" STANDBY=\"Loading Windows Media Player components...\" TYPE=\"application/x-oleobject\" /><param name=\"autoStart\" value=\"true\" /><PARAM NAME=\"error\" VALUE=\"item\" /><PARAM NAME=\"stretchToFit\" VALUE=\"false\" /><PARAM NAME=\"ShowStatusBar\" VALUE=\"true\" /><PARAM NAME=\"FileName\" VALUE=\"mms://10.0.0.1:8083\" /> <EMBED TYPE=\"application/x-mplayer2\" SRC=\"mms://10.0.0.1:8083\"NAME=\"MediaPlayer\" WIDTH=320 HEIGHT=300 ShowStatusBar=\"1\" /></EMBED></OBJECT></center>" return String( fv.res ) resource = TestResource() as you can see and as i said i need to create for each station a rpy file, can i not somehow put it all in one or make php work in rpy? thx for any input :) jody :D __________________________________________________________________ Looking for the perfect gift? Give the gift of Flickr! http://www.flickr.com/gift/

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[Twisted-Python] Twistd and Duplicate Logs
by Andrew Francis 28 May '08

28 May '08

Hi Folks: I use a twistd server under Windows XP and Ubuntu. I am using Twisted 8.0. I am using log rotation. I essential copy the log example in Abe Fettig's book. On a sidenote, I read that logs changed under Twisted 8.1? Should I move to that? Under Windows XP, the programme runs as expected, it generates logs xxx.log, xxx.log.1, xxx.log.2 Under Ubuntu, it generates two sets of logs xxx.log, xxx.log.1 and twistd.log, twisted.log.1 I am not sure why. What am I missing? Any advice would be appreciated. here is a sample of what I do: class TheLog(log.FileLogObserver): def emit(self, logEntryDict): #if not logEntryDict.get('isError'): return log.FileLogObserver.emit(self, logEntryDict) class TheLogService(service.Service): def __init__(self, logName, logDir): self.logName = logName self.logDir = logDir self.maxLogSize = MAX_LOG_FILE_SIZE self.theLog = TheLogBuilder() def getLogger(self): return self.theLog def startService(self): # logfile is a file-like object that supports rotation self.logFile = logfile.LogFile( self.logName, self.logDir, rotateLength=self.maxLogSize) self.logFile.rotate() # force rotation each time restarted self.theLog = TheLog(self.logFile) self.theLog.start() def stopService(self): self.theLog.stop() self.logFile.close() del(self.logFile) Cheers, Andrew

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[Twisted-Python] xmlstream problem
by Gabriel Rossetti 27 May '08

27 May '08

Hello, I am using xmlstream.XmlStream to process...XML streams :-) I'm having a bit of a problem, I have a client and a server, both protocols inherit from xmlstream.XmlStream. When the client sends 4 messages, one after another, I get a parse error. I debugged my program, and the buffer the expat parser is given contains in effect, 4 messages consecutively like so : str: <message>...</message><message>...</message><message>...</message><message>...</message> (I replaced the child elements with "..." for your reading enjoyment) and I get this Exception when debugging (otherwise it stays hidden) : ExpatError: junk after document element: line 1, column 196 now column 196 is the end of the 1st msg's root element, I think it doesn't like the next message being right after the first. I did override xmlstream.XmlStream.onDocumentEnd() because I didn't want it to close the connection in between messages, but in my method I told it to initialize the stream using : self._initializeStream() I did this since I noticed that closing the connection forces a new parser to be created when the previous statement is called. The reason I don't want the connection to be closed is that I'd like a persistent connection to be held. Does anyone know how to either have the messages given to the parser as separate messages so that it doesn't freak out? Thank you, Gabriel

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[Twisted-Python] Weekly Bug Summary
by exarkun＠twistedmatrix.com 24 May '08

24 May '08

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[Twisted-Python] Implementing STARTTLS in a protocol
by Kevin Horn 24 May '08

24 May '08

Howdy list, I'm trying to implement a protocol using Twisted which has a "STARTTLS" command to switch the protocol from plain TCP to TCP over TLS. I've mostly been going by the way that the imap4.py module seems to do it, but I can't seem to get a handshake to complete. I found this page ( http://wiki.vislab.usyd.edu.au/moin.cgi/SSLCertNotes ) which was helpful, but I don't want to force client cert authentication. In order to separate this problem from other issues, I've adapted the echo protocol code from above the above page to try and get a simple test case (my code below) I am recieving the following output and traceback when running the client code ( on both Windows and Linux ): using TLSv1: >tls_echoclient.py Sending: Hello, world! receive: ERROR: Must authenticate Sending: STARTTLS receive: READY Sending: Continuing connection lost (protocol) connection lost: [('SSL routines', 'SSL3_READ_BYTES', 'sslv3 alert handshake failure'), ('SSL routines', 'SSL3_READ_BYTES', 'ssl handshake failure')] Traceback (most recent call last): File "C:\Documents and Settings\kevinh\Desktop\mine_id\sandbox\funsize\sslecho\tls_echoclient.py", line 58, in <module> reactor.run() File "C:\Python25\lib\site-packages\twisted\internet\posixbase.py", line 223, in run self.mainLoop() File "C:\Python25\lib\site-packages\twisted\internet\posixbase.py", line 234, in mainLoop self.doIteration(t) File "C:\Python25\lib\site-packages\twisted\internet\selectreactor.py", line 140, in doSelect _logrun(selectable, _drdw, selectable, method, dict) --- <exception caught here> --- File "C:\Python25\lib\site-packages\twisted\python\log.py", line 51, in callWithLogger return callWithContext({"system": lp}, func, *args, **kw) << SNIP >> File "C:\Python25\lib\site-packages\twisted\internet\base.py", line 490, in stop "Can't stop reactor that isn't running.") twisted.internet.error.ReactorNotRunning: Can't stop reactor that isn't running. What am I doing wrong? Is there a SSL config option I'm setting incorrectly? Do I need to use a different SSL Context? Am I totally off base? Thanks, Kevin Horn ========= tls_echoserver.py # adapted from: http://wiki.vislab.usyd.edu.au/moin.cgi/SSLCertNotes import sys from OpenSSL import SSL from twisted.python import log from twisted.internet import ssl, reactor from twisted.protocols.basic import LineReceiver from twisted.internet.protocol import Factory private_key_file = "privkey_dsa.pem" cert_file_name = "cacert.pem" sslmethod = ssl.SSL.TLSv1_METHOD #~ sslmethod = ssl.SSL.SSLv23_METHOD class Echo(LineReceiver): donetls = 0 def sendLine(self, line): print "Sending:",line LineReceiver.sendLine(self,line) def lineReceived(self, line): print "Got:",line if self.donetls: print "Sending OK" self.transport.write("OK") elif line == "STARTTLS": self.sendLine("READY") #~ self.tlsCtx = CtxFactory() self.tlsCtx = ssl.DefaultOpenSSLContextFactory(private_key_file, cert_file_name, sslmethod) self.transport.startTLS(self.tlsCtx) self.donetls = 1 else: self.sendLine("ERROR: Must authenticate") factory = Factory() factory.protocol = Echo reactor.listenTCP(8000, factory) reactor.run() ========= tls_echoclient.py # adapted from: http://wiki.vislab.usyd.edu.au/moin.cgi/SSLCertNotes from OpenSSL import SSL import sys from twisted.internet.protocol import ClientFactory from twisted.protocols.basic import LineReceiver from twisted.internet import ssl, reactor class EchoClient(LineReceiver): end="Bye-bye!" def connectionMade(self): self.sendLine("Hello, world!") # Signals error def connectionLost(self, reason): print 'connection lost (protocol)' reactor.stop() def sendLine(self, line): print "Sending:",line LineReceiver.sendLine(self,line) def lineReceived(self, line): print "receive:", line if line == "ERROR: Must authenticate": self.sendLine("STARTTLS") elif line == "READY": #~ self.ctx = CxtFactory() self.ctx = ssl.ClientContextFactory() self.ctx.method = ssl.SSL.TLSv1_METHOD #~ self.ctx.method = ssl.SSL.SSLv23_METHOD self.transport.startTLS(self.ctx) self.sendLine("Continuing"); else: self.sendLine("wibble") class EchoClientFactory(ClientFactory): protocol = EchoClient def clientConnectionFailed(self, connector, reason): print 'connection failed:', reason.getErrorMessage() reactor.stop() def clientConnectionLost(self, connector, reason): print 'connection lost:', reason.getErrorMessage() reactor.stop() factory = EchoClientFactory() reactor.connectTCP('localhost', 8000, factory) reactor.run()

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