Mailman 3 November 2006 - Twisted

[Twisted-Python] Using Conch as a ssh server on MS Windows
by Rasjid Wilcox Nov. 26, 2006

Nov. 26, 2006

I would like to have occasional remote admininitrative command line access to a number of MS Windows machines that I help maintain. There are over 200 machines, but usage would be very limited and sparodic, so the commerical solutions are too expensive for the benefit gaiined. Windows XPs built in telnet server is free, but insecure. And if possible, I would like to avoid the Cygwin route, particulary on machines that I don't have physical access to. So has anyone used the ssh server in … [View More]

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[Twisted-Python] Weekly Bug Summary
by exarkun＠twistedmatrix.com Nov. 26, 2006

Nov. 26, 2006

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Re: [Twisted-Python] Keeping a list of connected PB clients
by Phil Christensen Nov. 26, 2006

Nov. 26, 2006

On Nov 24, 2006, at 5:16 PM, Yi Qiang wrote: > On 11/19/06, Phil Christensen <phil(a)bubblehouse.org> wrote: > On Nov 19, 2006, at 7:00 PM, Yi Qiang wrote: > > There does not seem to be a corresponding clientConnectionLost > > method for the Factory class. Any suggestions would be appreciated. > > My approach to this was to put any post-connection cleanup in the > Avatar's "logout" method. > > Hi Phil, > Do you happen to be able to share the code you'… [View More]ve written to > accomplish just this? Where do you store your list of connected > clients? I'm CC'ing the list for posterity, but this is actually pretty straightforward. I'm guessing the issue is that you're over-thinking this. First of all, here's some code from your original post: On Nov 19, 2006, at 7:00 PM, Yi Qiang wrote: > from twisted.spread import pb > > class DSagePBServerFactory(pb.PBServerFactory): [snip snip snip] > def clientConnectionMade(self, broker): > self.clients.append((broker.transport, > broker.transport.getPeer().host, > broker.transport.getPeer().port)) > print self.clients First thing, there's not necessarily any need to subclass the PBServerFactory if this is all you're doing. In the interest of forward-compatibility (always a good idea with Twisted ;-), I try to avoid making subclasses of essential framework classes unless I have a very good reason (or a very bad one ;-). The place where you want to do all this is really in your Realm instance. I think it's possible to create a PB server that doesn't require login, but I've never had any need for it, so you're kind of on your own there. > class MyRealm: > """ > Holds a reference to the main service object. > """ > __implements__ = portal.IRealm > > def __init__(self, service): > """ > Create a realm with the given service. > """ > self.service = service > > def requestAvatar(self, avatarId, mind, *interfaces): > """ > This function is called after the user has verified their > identity. It returns an object that represents the user > in the system, i.e., an avatar. > """ > if pb.IPerspective in interfaces: > avatar = self._getPBAvatar(avatarId, mind) > ####################### <-- RIGHT HERE > return pb.IPerspective, avatar, avatar.logout > else: > raise NotImplementedError("no interface") This is where you want to maintain your client list. The hardest part is deciding on a place to put it that will be accessible from all your code; I usually use a singleton pattern of some kind, where I can import a module that holds onto client references and provides functions to manipulate/retrieve that list. So, that point where I put all those hashes is a pretty good place to add clients your client queue. The 'mind' argument is usually a reference to the client on the other end, assuming your client passes it properly. My client does this: > # self.client is a Referenceable on the client side. > defer = self.factory.login(credentials.UsernamePassword > (username, password), self.client) > defer.addCallback(connected_callback, self) This way, you can find all the necessary info you might need to identify the user on the other end in the properties of this object. You'll also see that right after the hashes, I return a three-tuplet that has avatar.logout as its third item. This is a method defined on my avatar object, but any callable object can be returned here, and that callable, of course, can remove clients from your list. So one approach to keeping track of client connections would be: > class MyRealm(pb.Avatar): > # ... snip > # ... snip > def requestAvatar(self, avatarId, mind, *interfaces): > """ > This function is called after the user has verified their > identity. It returns an object that represents the user > in the system, i.e., an avatar. > """ > if pb.IPerspective in interfaces: > avatar = MyAvatar() > > import clienttracker > clienttracker.append(avatar) > > return pb.IPerspective, avatar, avatar.logout > else: > raise NotImplementedError("no interface") > > class MyAvatar(pb.Avatar): > # ... snip > # ... snip > def logout(self): > import clienttracker > clienttracker.remove(self) There's a lot of flexibility there. You could move the clienttracker.append call right inside your Avatar constructor -- the only reason I didn't is because my server supports a number of protocols besides PB, and I wanted to deal with them universally. One thing this approach doesn't do is keep track of clients that connect, but fail authentication. To do that, you'd need to subclass Broker, but that's a tough one. I looked into this once before, and it certainly appears doable -- in the end, a Broker is still a Protocol, which means it has a transport property you can get client addresses out of. Of course, if a user fails authentication, they are immediately disconnected, so this would only be a problem if you are concerned about malevolent users. It would be possible to write a client that connects but never authenticates; enough of those could cause some discomfort on the server side, but if that happens, you likely have more problems than keeping track of a client list. Hope this helps... -phil [View Less]

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Re: [Twisted-Python] Anyone added NAPTR support to Twisted Names ?
by glyph＠divmod.com Nov. 25, 2006

Nov. 25, 2006

On 07:06 pm, roland.hedberg(a)adm.umu.se wrote: >If anyone wants the fix I can send you a diff. Please open a ticket in the Twisted tracker for further discussion, and attach your patch there - hopefully with tests :).

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[Twisted-Python] Anyone added NAPTR support to Twisted Names ?
by Roland Hedberg Nov. 25, 2006

Nov. 25, 2006

Hi! There is no support what I can see in the present distribution, but someone might have needed it and done a local patch. I've made a not so well thought out attempt to add it myself, but I my client (dig) responds with "Warning: Message parser reports malformed message packet." So, I'm obviously made some error. Anyone that can lend me a hand ? -- Roland

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[Twisted-Python] twisted SNMP problem
by Dennis Jacobfeuerborn Nov. 25, 2006

Nov. 25, 2006

Hi, I'm trying to write a small program that gets some SNMP values from a host using the twistedsnmp module. I modified one of the example programs for that purpose but I'm not sure if I'm approaching this the right way. Basically if I run the attached script things work out fine but as soon as I comment in the line starting with "l2 = ..." and try to run the script again it will freeze and I'm forced to do a "kill -9" to get rid of it. My guess is that I'm running into trouble with the … [View More]

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Re: [Twisted-Python] Need Exception that will stop ther reactor within twistd
by glyph＠divmod.com Nov. 25, 2006

Nov. 25, 2006

On 05:14 pm, ncesar(a)lunix.com.ar wrote: >I have the following code, >I want my GoodByeException to exit the reactor loop (basacally do a >reactor.stop()) and then twistd exit the reactor's main loop. I'm programming >a bigger application and sudentlly some exceptions are really Fatal, but the >applications keeps on running (sometimes with no services attending). So make GoodByeException.__init__ call reactor.stop() instead of setting the useless 'args' attribute. This is bad … [View More]

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[Twisted-Python] Need Exception that will stop ther reactor within twistd
by Nicolas D. Cesar Nov. 24, 2006

Nov. 24, 2006

I have the following code, ------------------miniserver.tac------------------------- from twisted.application.internet import TCPServer from twisted.application import service from twisted.internet import protocol from twisted.python.failure import DefaultException class GoodByeException(DefaultException): def __init__(self, *args, **kwargs): DefaultException.__init__(self, *args, **kwargs) self.args = "I wanna quit....\n but I'm stuck inside a twisted application" … [View More]class FortyTwoProtocol(protocol.Protocol): def connectionMade(self): raise GoodByeException() return class FortyTwoFactory(protocol.ServerFactory): protocol = FortyTwoProtocol def __init__(self): pass application = service.Application("Total Perspective Vortex") theService = service.MultiService() fact42 = FortyTwoFactory() server42 = TCPServer(4242, fact42) theService.addService(server42) theService.setServiceParent(application) ------------------------------------------------------------------ I want my GoodByeException to exit the reactor loop (basacally do a reactor.stop()) and then twistd exit the reactor's main loop. I'm programming a bigger application and sudentlly some exceptions are really Fatal, but the applications keeps on running (sometimes with no services attending). Any sugestions will be appreciated . Greetings, PS: this is the log ------------------------------------------------------------------- $ twistd -noy miniserver.tac 2006/11/24 14:05 ART [-] Log opened. 2006/11/24 14:05 ART [-] twistd 2.4.0 (/usr/bin/python 2.4.4) starting up 2006/11/24 14:05 ART [-] reactor class: <class 'twisted.internet.selectreactor.SelectReactor'> 2006/11/24 14:05 ART [-] Loading miniserver.tac... 2006/11/24 14:05 ART [-] Loaded. 2006/11/24 14:05 ART [-] __builtin__.FortyTwoFactory starting on 4242 2006/11/24 14:05 ART [-] Starting factory <__builtin__.FortyTwoFactory instance at 0xa7850a2c> 2006/11/24 14:05 ART [__builtin__.FortyTwoFactory] Traceback (most recent call last): File "/usr/lib/python2.4/site-packages/twisted/python/log.py", line 38, in callWithContext return context.call({ILogContext: newCtx}, func, *args, **kw) File "/usr/lib/python2.4/site-packages/twisted/python/context.py", line 59, in callWithContext return self.currentContext().callWithContext(ctx, func, *args, **kw) File "/usr/lib/python2.4/site-packages/twisted/python/context.py", line 37, in callWithContext return func(*args,**kw) File "/usr/lib/python2.4/site-packages/twisted/internet/selectreactor.py", line 139, in _doReadOrWrite why = getattr(selectable, method)() --- <exception caught here> --- File "/usr/lib/python2.4/site-packages/twisted/internet/tcp.py", line 769, in doRead protocol.makeConnection(transport) File "/usr/lib/python2.4/site-packages/twisted/internet/protocol.py", line 333, in makeConnection self.connectionMade() File "miniserver.tac", line 14, in connectionMade raise GoodByeException() __builtin__.GoodByeException: I wanna quit.... but I'm stuck inside a twisted application 2006/11/24 14:05 ART [-] Received SIGINT, shutting down. 2006/11/24 14:05 ART [-] (Port 4242 Closed) 2006/11/24 14:05 ART [-] Stopping factory <__builtin__.FortyTwoFactory instance at 0xa7850a2c> 2006/11/24 14:05 ART [-] Main loop terminated. 2006/11/24 14:05 ART [-] Server Shut Down. ----------------------------------------------------------------------- -- Nicolás D. César <ncesar(a)lunix.com.ar> Lunix S.R.L. -[ http://www.lunix.com.ar ]- GnuPG Public Key: gpg --keyserver wwwkeys.pgp.net --recv-key 0x3606F3E6 [View Less]

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[Twisted-Python] Need Exception that will stop ther reactor within twistd
by Nicolas D. Cesar Nov. 24, 2006

Nov. 24, 2006

I have the following code, ------------------miniserver.tac------------------------- from twisted.application.internet import TCPServer from twisted.application import service from twisted.internet import protocol from twisted.python.failure import DefaultException class GoodByeException(DefaultException): def __init__(self, *args, **kwargs): DefaultException.__init__(self, *args, **kwargs) self.args = "I wanna quit....\n but I'm stuck inside a twisted application" … [View More]class FortyTwoProtocol(protocol.Protocol): def connectionMade(self): raise GoodByeException() return class FortyTwoFactory(protocol.ServerFactory): protocol = FortyTwoProtocol def __init__(self): pass application = service.Application("Total Perspective Vortex") theService = service.MultiService() fact42 = FortyTwoFactory() server42 = TCPServer(4242, fact42) theService.addService(server42) theService.setServiceParent(application) ------------------------------------------------------------------ I want my GoodByeException to exit the reactor loop (basacally do a reactor.stop()) and then twistd exit the reactor's main loop. I'm programming a bigger application and sudentlly some exceptions are really Fatal, but the applications keeps on running (sometimes with no services attending). Any sugestions will be appreciated . Greetings, PS: this is the log ------------------------------------------------------------------- $ twistd -noy miniserver.tac 2006/11/24 14:05 ART [-] Log opened. 2006/11/24 14:05 ART [-] twistd 2.4.0 (/usr/bin/python 2.4.4) starting up 2006/11/24 14:05 ART [-] reactor class: <class 'twisted.internet.selectreactor.SelectReactor'> 2006/11/24 14:05 ART [-] Loading miniserver.tac... 2006/11/24 14:05 ART [-] Loaded. 2006/11/24 14:05 ART [-] __builtin__.FortyTwoFactory starting on 4242 2006/11/24 14:05 ART [-] Starting factory <__builtin__.FortyTwoFactory instance at 0xa7850a2c> 2006/11/24 14:05 ART [__builtin__.FortyTwoFactory] Traceback (most recent call last): File "/usr/lib/python2.4/site-packages/twisted/python/log.py", line 38, in callWithContext return context.call({ILogContext: newCtx}, func, *args, **kw) File "/usr/lib/python2.4/site-packages/twisted/python/context.py", line 59, in callWithContext return self.currentContext().callWithContext(ctx, func, *args, **kw) File "/usr/lib/python2.4/site-packages/twisted/python/context.py", line 37, in callWithContext return func(*args,**kw) File "/usr/lib/python2.4/site-packages/twisted/internet/selectreactor.py", line 139, in _doReadOrWrite why = getattr(selectable, method)() --- <exception caught here> --- File "/usr/lib/python2.4/site-packages/twisted/internet/tcp.py", line 769, in doRead protocol.makeConnection(transport) File "/usr/lib/python2.4/site-packages/twisted/internet/protocol.py", line 333, in makeConnection self.connectionMade() File "miniserver.tac", line 14, in connectionMade raise GoodByeException() __builtin__.GoodByeException: I wanna quit.... but I'm stuck inside a twisted application 2006/11/24 14:05 ART [-] Received SIGINT, shutting down. 2006/11/24 14:05 ART [-] (Port 4242 Closed) 2006/11/24 14:05 ART [-] Stopping factory <__builtin__.FortyTwoFactory instance at 0xa7850a2c> 2006/11/24 14:05 ART [-] Main loop terminated. 2006/11/24 14:05 ART [-] Server Shut Down. ----------------------------------------------------------------------- -- Nicolás D. César <ncesar(a)lunix.com.ar> Lunix S.R.L. -[ http://www.lunix.com.ar ]- GnuPG Public Key: gpg --keyserver wwwkeys.pgp.net --recv-key 0x3606F3E6 [View Less]

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[Twisted-Python] cred question
by Michele Petrazzo Nov. 23, 2006

Nov. 23, 2006

Hi, I'm trying to use the various checkers.* that implement the ICredentialsChecker, for authenticate a spread.pb client, but I have a lot of problem with all the checkers except the InMemoryUsernamePasswordDatabaseDontUse (and FilePasswordDB without hash function) that work. The output message are: """Failure: twisted.cred.error.UnhandledCredentials: No checker for twisted.cred.credentials.IUsernameHashedPassword, twisted.spread.pb.IUsernameMD5Password, twisted.spread.interfaces.IJellyable """ … [View More]

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