Mailman 3 May 2008 - Twisted

[Twisted-Python] Twisted Python 0.7.0 Prerelease Testing
by Glyph Lefkowitz Aug. 5, 2021

Aug. 5, 2021

hi there, folks: I'd really like to release 0.7.0 but I would like it to be at least a little bit tested before I do so. Could those of you with CVS trees check everything out and see if it performs as advertised? Deeper bugs than that will have to wait for the next release, but I'd at least like to know if it works for someone other than me. Thanks. ______ __ __ _____ _ _ | ____ | \_/ |_____] |_____| |… [View More]

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[Twisted-Python] regarding xml elements
by Raj kumar Oct. 2, 2013

Oct. 2, 2013

Hi, I have an xml file in my application, I have created an element using Example goes like this......... document.createElement("abc") and i appeneded it by using append() method. But how i can reflect this change to my xml file? and one more thing is i want to create element with some other parameters.... like............. <abc m=" " n=" "> </abc> and i have m and n values as strings with me. can anybody help me to create this element and write it to the existing xml … [View More]

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[Twisted-Python] Get IP of connecting client in XMLRPC server
by Remy C. Cool April 28, 2013

April 28, 2013

Hello, On 18 May 2004, the following message was posted to this mailinglist: Jp Calderone exarkun at divmod.com wrote: >Daniel Newton wrote: > > I have a simple XML-PRC server similar to the example below: > > from twisted.web import xmlrpc, server > > class Example(xmlrpc.XMLRPC): > """An example object to be published.""" > > def xmlrpc_add(self, a, b): > """Return sum of arguments.""" > return a + b def … [View More]

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[Twisted-Python] SQLAlchemy and Twisted
by alex clemesha Feb. 13, 2009

Feb. 13, 2009

Hi, I didn't want to hijack the 'Twisted Presentation Materials..' thread, so I started this one ... First off, in the other thread, Glenn, you mentioned Storm. I have heard of Storm, but never got any deeper that noticing that it is still a work in progress (maybe things have settled down ?) If anyone has anything to say on how it might be a good choice with Twisted, please feel free to enlighten us! But, I hoping to solve some immediate problems with Twisted and SQLAlchemy, so ... >… [View More]

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[Twisted-Python] suggestions for naming to help us preserve a Twisted trademark
by glyph＠divmod.com June 10, 2008

June 10, 2008

Hello, Twisted community: I'd really like "twisted" (and our various "dot product" subprojects) to be a trademark that the software freedom conservancy can protect and defend. For similar reasons, I'd like to have an unambiguous naming convention for projects which are *part* of Twisted versus those which are built on it or are compatible with it. There are a few projects out there that just call themselves "py- whatever" but use Twisted (for some reason, none come to mind at the … [View More]moment); that's fine, of course. The jabber transports which use Twisted are pyMSNt, pyICQt; I'm not sure if the "t" stands for "transport" or "twisted" :). There are also a few projects out there called "Twisted Whatever" which aren't part of Twisted; I can only hope that more projects will want to advertise their association with Twisted in this way. I'd like to suggest, however, that new projects use the word "Twisty" in this context rather than the hopefully trademarked "Twisted". i.e. if you are making an implementation of the protocol Bloobloo and want to give it a name associated with Twisted, please describe it as "Twisty Bloobloo: an implementation of bloobloo for Twisted", and name your packages similarly (twistybloobloo.stuff). Sun has a great webpage about how to use their trademarks in this capacity: http://www.sun.com/policies/trademarks/. I'm aware of 3 projects which are currently called "Twisted X" but are not actually a part of Twisted. The first is Twisted Goodies, which was named with our explicit permission. I appreciate that Ed asked first, and so he is welcome to continue using that name. (I'd still prefer that it be changed to "Twisty Goodies" just to help establish the convention and reduce potential user confusion, but realistically there has not been any actual user confusion about that package, and packages with our explicit permission I don't believe weaken our copyright claim.) Two other things that I'm aware of using names like this, however, do not have our permission, and if those authors are listening here (or if someone who knows the authors here could get in touch with them) I'd really like their names to be changed: Twisted SNMP and Twisted Storage. Most of all though I hope that all 1000-odd subscribers to this list have their own soon-to-be-released project which can make use of this new convention ;). Also, if a graphic designer out there could help with a modified version of the logo that could be used in the way that the Debian "open use" images, that would be helpful: http://www.debian.org/logos/#open-use [View Less]

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[Twisted-Python] DeferredList + LoopingCall
by J Davis June 5, 2008

June 5, 2008

Hello, I want to group several calls to a function() that returns a deferred into a DeferredList so that I can add callbacks that will fire once each call to function() has returned. Furthermore, I want to arrange it so that this process repeats every X seconds. The problem I'm having is understanding how I can combine the concept of a DeferredList with task.LoopingCall in this scenario. Or is that even the right approach to take? Thanks, -Jake

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[Twisted-Python] exceptions.SystemError: unknown opcode
by Miguel Filho June 2, 2008

June 2, 2008

Hello list, I have a twisted application in production for some time now, running under Fedora Core 6, Python 2.4.4 and twisted 2.4. I know, a little outdated. The process was running fine for some weeks without any problems, although I got this exception in my logs and I really have no idea what it means. The process did not die and is still running ok. 2008/05/13 16:03 BRT [-] Traceback (most recent call last): File "/usr/lib/python2.4/site-packages/twisted/application/app.py", … [View More]

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[Twisted-Python] Creating a protocol-agnostic chatbot with Twisted words
by Jo Vermeulen June 2, 2008

June 2, 2008

Hello, I am trying to create a chat bot that can work over both the XMPP and the MSN protocol using Twisted words. I have a couple of questions as a Twisted newbie :-) Is there any documentation on how to create a protocol-agnostic chatbot with Twisted words? Or are there applications using Twisted words that offer multiple front-ends? I have a XMPP version working, but had some problems finding my way around a few features. I don't know how to get a list of contacts, or initiatiate a group … [View More]

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[Twisted-Python] Re: suggestions for naming to help us preserve a Twisted Trademark
by Andrew Francis May 30, 2008

May 30, 2008

Hi: >When choosing which prefix to use, I would suggest against being too >concerned with which obscure software project already uses it. >ToscaWidgets is still in alpha according to their webpage, which >hasn't been updated in ages. I don't mean to deride another project, >but considering the high rate of failure of most OSS projects, unless >it has a community inertia as large as or larger than Twisted's, I say >every project for itself. I would be tempted to use … [View More]

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[Twisted-Python] unsubscribe
by Oscar Paytuvi May 30, 2008

May 30, 2008

On Fri, May 30, 2008 at 11:50 AM, <twisted-python-request(a)twistedmatrix.com> wrote: > 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 … [View More]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: suggestions for naming to help us preserve a Twisted > trademark (Jonathan Lange) > 2. How-to raise errors with sshclient conch example in Twisted > book (asset) > 3. Re: suggestions for naming to help us preserve a Twisted > trademark (glyph(a)divmod.com) > 4. Re: suggestions for naming to help us preserve a Twisted > trademark (Drew Smathers) > 5. Re: suggestions for naming to help us preserve a Twisted > trademark (Gabriel Rossetti) > 6. Re: suggestions for naming to help us preserve a Twisted > trademark (Chris Miles) > 7. Re: suggestions for naming to help us preserve a Twisted > trademark (Simon Pickles) > 8. Re: How-to raise errors with sshclient conch example in > Twisted book (Kuba Konczyk) > 9. Re: suggestions for naming to help us preserve a Twisted > trademark (Michael) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 30 May 2008 13:09:20 +1000 > From: "Jonathan Lange" <jml(a)mumak.net> > Subject: Re: [Twisted-Python] suggestions for naming to help us > preserve a Twisted trademark > To: "Twisted general discussion" <twisted-python(a)twistedmatrix.com> > Message-ID: > <d06a5cd30805292009l663319b8rb531c28641ba0216(a)mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1 > > On Fri, May 30, 2008 at 12:16 PM, Tim Stebbing <tjstebbing(a)gmail.com> > wrote: > >> More seriously, Emacs, Apache, Linux, Python, Debian and Ubuntu are > >> all trademarked. The Emacs trademark is held by the FSF, bastions of > >> ideological purity. So far, I've encountered only one person who finds > >> this suspicious. Hi Tim :) > >> > > > > 'other people do this thing so we should also do this thing' is not a > > great argument. I'm not against the idea, I just have some questions > > we're yet to have answered. > > > > That's not what I said. > > You said "trademarks make people suspicious". I provided > counter-examples, demonstrating that your statement is not true in the > general case. > > jml > > > > ------------------------------ > > Message: 2 > Date: Thu, 29 May 2008 20:40:32 -0700 > From: "asset" <asset(a)impactdamage.com> > Subject: [Twisted-Python] How-to raise errors with sshclient conch > example in Twisted book > To: <twisted-python(a)twistedmatrix.com> > Message-ID: > <2af3b464859b46a28b1fddbd6d5153a7(a)maila5.webcontrolcenter.com> > Content-Type: text/plain; charset="iso-8859-1" > > > 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 > con= > nection 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 > a= > round it. > > I imagine this is trivial and Im totally missing it. > > Any help would be greatly appreciated. > > Thx, > > TKiel > [View Less]

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[Twisted-Python] How-to raise errors with sshclient conch example in Twisted book
by asset May 30, 2008

May 30, 2008

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 … [View More]

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Re: [Twisted-Python] suggestions for naming to help us preserve a Twisted trademark
by Terry Jones May 30, 2008

May 30, 2008

>>>>> "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" May 29, 2008

May 29, 2008

> 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" May 29, 2008

May 29, 2008

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,… [View More]

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[Twisted-Python] interaction problems with wxreactor and conch under linux
by Mark Dillavou May 28, 2008

May 28, 2008

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 … [View More]

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[Twisted-Python] help with twisted webserver and rpy script
by Jody Gugelhupf May 28, 2008

May 28, 2008

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/… [View More]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/ [View Less]

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[Twisted-Python] Twistd and Duplicate Logs
by Andrew Francis May 28, 2008

May 28, 2008

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 … [View More]

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[Twisted-Python] xmlstream problem
by Gabriel Rossetti May 27, 2008

May 27, 2008

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>.… [View More]

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[Twisted-Python] Weekly Bug Summary
by exarkun＠twistedmatrix.com May 25, 2008

May 25, 2008

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[Twisted-Python] Implementing STARTTLS in a protocol
by Kevin Horn May 25, 2008

May 25, 2008

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 … [View More]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() [View Less]

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[Twisted-Python] the sequence of executing defers' callbacks
by Xian Chen May 23, 2008

May 23, 2008

Hi All, This is a fundamental question about Twisted. In the normal case, all the callbacks belonging to one defer object will be triggered following the chain sequence. ( Let's assume no errback will be fired.) such as callback1--->callbac2--->callbackN. However, if I want to trigger callback1 when MSG1 is ready, callback2 when MSG2 is ready, and so on, how can I do that? Of course, the MSGs are coming at random sequence. Thanks in advance, Xian Chen

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Re: [Twisted-Python] the sequence of executing defers' callbacks
by Terry Jones May 23, 2008

May 23, 2008

>>>>> "Xian" == Xian Chen <hoganxian(a)gmail.com> writes: Xian> However, if I want to trigger callback1 when MSG1 is ready, callback2 Xian> when MSG2 is ready, and so on, how can I do that? Xian> Of course, the MSGs are coming at random sequence. Hi Xian Do you have multiple functions that are returning these MSGx results? If so, it sounds like you might be looking for DeferredList. See the docs at http://twistedmatrix.com/projects/core/documentation/howto/defer.html Terry

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[Twisted-Python] Foolscap-0.2.7 released, Foolscap vs. debian openssl bug
by Brian Warner May 22, 2008

May 22, 2008

I released Foolscap-0.2.7 the other week, just a few days after the release of 0.2.6 . This fixes a brown-paper-bag bug in 0.2.6 that prevented the 'flogtool' utility from running at all. Tarballs can be obtained from foolscap.lothar.com and from PyPI. All releases are signed by my GPG public key: 0x1514A7BD. http://pypi.python.org/packages/source/f/foolscap/foolscap-0.2.7.tar.gz#md5… http://pypi.python.org/packages/source/f/foolscap/foolscap-0.2.7.zip#md5=95… For documentation, bugs, … [View More]and patches, please visit http://foolscap.lothar.com/trac . == Debian OpenSSL Bugs and Foolscap == As you've probably heard[1], last week the debian project published a security advisory that described how the openssl package has been using a 18-ish-bit random number generator for the last two years. As a result, keys and certificates generated by the affected versions (or used for DSA signatures by affected versions) should be considered compromised and immediately replaced. This affects the last 3 or 4 Ubuntu releases too (Dapper was correct, Edgy was broken). All affected releases now have fixed versions available for download, and obviously everyone using an affected release needs to upgrade immediately. [1]: http://lists.debian.org/debian-security-announce/2008/msg00152.html Since the bug affected key generation, keys which were created by the broken versions will remain broken even after openssl itself is upgraded. The Debian and Ubuntu projects have released tools to detect weak ssh keys that were generated by these versions and disable them. Other projects (including Foolscap) use generated keys for various purposes, so the effects of this bug will linger even after openssl has been fixed. How does this affect Foolscap? The short answer: Weak keys generated by the broken versions of openssl will enable a man-in-the-middle attack, which (if successful) would reveal the private swissnums that protect access to Referenceables. Foolscap users who have created Tubs while they had the broken versions installed should stop using the associated FURLs and generate new certificates/FURLs. The longer answer: There are three things in Foolscap that use random numbers: 1: TubIDs [COMPROMISED]. These are a hash of the public key that corresponds to a Tub's private key, and are included in FURLs (as the base32 part immediately following the pb:// prefix). This provides protection against a man-in-the-middle attack: when connecting to a FURL, the certificate of the remote end is compared against the TubID in the FURL, and the connection is dropped with extreme prejudice if they do not match. This validation is performed before any secrets are passed over the wire. 2: SwissNums [SAFE]. These are a randomly-generated name for a reference, created when tub.registerReference(obj) is called without a name= argument, and when a Referenceable is sent over the wire without being explicitly registered. They appear at the right-hand end of the FURL, after the last slash. Most Referenceables are given these unguessable names, because that limits access to parties that have been explicitly granted access. (when registerReference() is called with a guessable name, anyone who can guess that name will get reference to the given object). The capability-based security of foolscap Referenceables depends upon these swissnums remaining secret. 3: SSL transport sessions [VULNERABLE]. Foolscap runs over SSL, which uses random numbers to generate the Diffie-Hellman key agreement parameters. An eavesdropper who can guess one of these parameters will be able to determine the session key, and can decrypt the remainder of the conversation. TubIDs are derived from an SSL certificate that OpenSSL generates on demand, and if the broken version of OpenSSL was used for this purpose, than that certificate will be guessable. (at some point it would be great to write a tool that would generate the 128000-ish TubIDs that can be generated by the broken SSL, to create a blacklist like the ones created by debian/ubuntu for ssh keys). So if you've generated a TubID with the broken version of openssl, it is pretty easy to guess the corresponding private key. This allows an attacker to mount an undetectable man-in-the-middle attack: if they can convince you to make your TCP connection to their server instead of the right one, then they can impersonate the real server, and they'll get to see the unencrypted conversation (revealing the private swissnums). Swissnums are generated by calling os.urandom(), which was not affected by the openssl bug. As long as one of the other problems (man-in-the-middle attack) doesn't reveal your swissnums to an attacker, access to Referenceables will remain limited to the parties to whom you've explicitly granted it (by telling them the swissnum, in a FURL). Foolscap uses SSL for its encrypted transport, and SSL frequently uses Diffie-Hellman key negotiation to establish a session key. This key negotiation process depends upon random numbers, generated by the same buggy RNG that is used to create keys. So if one of the two ends of an encrypted session was using the buggy version of openssl, then an attacker may be able to guess the session key, and thus decrypt the conversation. (note, I'm not a cryptographer, and I'm not as confident about this attack as I am about the others). So like the MitM attack, it seems likely that swissnums used by sessions established during the buggy openssl era may be compromised: an eavesdropper who recorded that encrypted conversation may be able to decrypt it after the fact. Of course, the whole idea of capabilities is to implement the Principle Of Least Authority: each FURL gives access to a specific Referenceable that will only do some specific limited task. If an MitM/eavesdropper manages to guess your supposedly-unguessable swissnums, they'll still only be able to do whatever the Referenceable will let them do. So to summarize: if you've been using the buggy openssl libraries, here's what you need to do: 1: upgrade openssl 2: throw out your old FURLs (tell everyone that you've given them to to stop using them): this protects clients from the MitM attack. 3: throw out your old Tub certificates: the certFile= argument to Tub() provides a persistent location for this.. just delete that file. This prevents clients from ever successfully using the old FURLs to connect to your server. 4: restart the Tub, allowing it to create a new certificate 5: regenerate and distribute new FURLs You can also just upgrade openssl (and keep using your old certs and FURLs) if you're willing to remain vulnerable to man-in-the-middle attacks or eavesdroppers who have recorded your earlier conversations. cheers, -Brian [View Less]

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[Twisted-Python] Re: Twisted-Python Digest, Vol 50, Issue 26
by ixafei May 22, 2008

May 22, 2008

hi

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[Twisted-Python] Memory size of Deferreds
by Martin Geisler May 21, 2008

May 21, 2008

Hello, I am working on a project called VIFF (http://viff.dk/) which does secure multiparty computations. Twisted, and in particular the Deferred class, has been a great tool for this! Each variable in a computation is stored as a Deferred, and the computation builds an expression tree based on these Deferreds, which is then evaluated as the Deferreds call their callbacks. What worries me is the size of a single Deferred. One user wanted to do computations on very large lists of Deferreds … [View More]

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