Mailman 3 June 2003 - Twisted

[Twisted-Python] Bad inconsistency with buildProtocol
by Pavel Pergamenshchik 20 Jun '03

20 Jun '03

It looks like buildProtocol gets passed inconsistent values for addr. In a program that connects to itself: pahan@dunce:~/Twisted$ python echo.py EchoServerFactory from ('127.0.0.1', 43044) EchoClientFactory to ('INET', 'localhost', 8000) For incoming connections, addr gets passed straight from <socketobj>.accept, which is not in the proper format.

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[Twisted-Python] passing exceptions to an xmlrpc client
by Justin Johnson 19 Jun '03

19 Jun '03

When doing something like: proxy.callRemote('add', 1, 2).addCallbacks(printValue, printError) ...my understanding is that the callback function (printValue) will get called unless an exception is raised by 'add', or 'add' returns a twisted.python.failure.Failure. However, if I am calling a remote method on a twisted xmlrpc service, raised exceptions and returned Failure's can't really be returned to the client side. So really my errback would only get called if there were some other problem with the service, like loss of network connection or something like that, right? If I use the perspective broker will I be able to raise exceptions or return failures in my remote methods and have them get passed back to the client appropriately? I'm trying to make sure I can handle all errors in my errbacks, and not have to do some special processing of errors specific to my method in the callbacks. Thanks. -Justin

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[Twisted-Python] xmlrpc ExpatError
by Justin Johnson 19 Jun '03

19 Jun '03

Hello, I have an xmlrpc server using twisted.web.xmlrpc.XMLRPC. I have been able to contect to it fine using just python's xmlrpclib on the client, and am now switching over to use twisted on the client as well. I'm getting a wierd error though that I'm not sure how to track down. Below is are snippets of my client code, server code, and the error I'm getting. Any help you can provide is appreciated. -Justin [client] def connectToServer(server): s = Proxy('http://%s:%s' % (server, config.portNumber)) return s def printValue(output): print "success" #print "success: %s" % output reactor.stop() def printError(output): print "error" #print "error: %s" % output reactor.stop() # Subcommand: mkvob def doMkvob(options): vobs = options["vobs"].split(",") original_site = options["original"] group = options["group"] s = connectToServer(config.siteToServer[original_site]) print "Successfully connected to %s (%s)." % (original_site, config.siteToServer[original_site]) print "Calling remote mkvob ..." d = s.callRemote('mkvob', vobs, group).addCallbacks(printValue, printError) reactor.run() [/client] [server] class CCService(xmlrpc.XMLRPC): """Service for handling remote VOB creation, removal, and general ClearCase maintenance. """ def xmlrpc_mkvob(self, vobs, group): """Create VOBs and apply standard triggers. """ log("we're in") output = "" rtn = SUCCESS for tag in vobs: log("Start mkvob for VOB '%s'" % tag) vob = VOB(tag, group) try: output += vob.make() output += vob.applyTriggers() except errors.CmdError, e: rtn = FAILURE output = e.stdout + e.stderr log("Error raised: cmd=%s, status=%s, stdout=%s, stderr=%s" % (e.cmd, e.status, e.stdout, e.stderr)) log("End mkvob for VOB '%s'" % tag) return (rtn, output) [/server] Traceback (most recent call last): File "E:\Python22\Lib\site-packages\twisted\protocols\basic.py", line 173, in dataReceived self.lineReceived(line) File "E:\Python22\Lib\site-packages\twisted\protocols\http.py", line 893, in l ineReceived self.allContentReceived() File "E:\Python22\Lib\site-packages\twisted\protocols\http.py", line 932, in a llContentReceived req.requestReceived(command, path, version) File "E:\Python22\Lib\site-packages\twisted\protocols\http.py", line 504, in r equestReceived self.process() --- <exception caught here> --- File "E:\Python22\Lib\site-packages\twisted\web\server.py", line 156, in proce ss self.render(resrc) File "E:\Python22\Lib\site-packages\twisted\web\server.py", line 162, in rende r body = resrc.render(self) File "E:\Python22\Lib\site-packages\twisted\web\xmlrpc.py", line 103, in rende r args, functionPath = xmlrpclib.loads(request.content.read()) File "E:\Python22\lib\xmlrpclib.py", line 805, in loads p.close() File "E:\Python22\lib\xmlrpclib.py", line 393, in close self._parser.Parse("", 1) # end of data xml.parsers.expat.ExpatError: no element found: line 1, column 0

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[Twisted-Python] Howto use the Gnutella-protocol
by Thomas Weholt ( PRIVAT ) 18 Jun '03

18 Jun '03

Is the gnutella-protocol in Twisted so complete I can use it to query a gnutella-network and download files? If so, does anybody have any example code? Any hints, clues etc. on this matter would be highly appreciated. Best regards, Thomas

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[Twisted-Python] distrib.UserDirectory improvements
by Paul Boehm 18 Jun '03

18 Jun '03

hi, moshez suggested me to extend distrib.UserDirectory for my needs. attached is what i am using right now. i hope to integrate this into distrib.py for cvs, later. please give me feedback! paul

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[Twisted-Python] socket communications in flash
by e okyere 17 Jun '03

17 Jun '03

Hello: I am looking at doing low-level sock comms with flash mx and hopefully c++ and upon hitting this thread: http://twistedmatrix.com/pipermail/twisted-python/2002-May/001121.html thought I should contact you to see if you have any experience in that line. If so, I'd appreciate any resources you can share or point to. Thanks a lot. _______ | \___/ o(. .)o --ooO--(_)--Ooo-- e okyere , clifton, va

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[Twisted-Python] Installing Twisted on Win32
by Jonathan Ard 17 Jun '03

17 Jun '03

Stupid question: Is there any way to install Twisted on Windows XP without Administrator Privileges? I tried using the binary installer from the Web Site, but it keeps telling me that I don't have the rights to install it. Thanks, Jonathan --

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[Twisted-Python] Problem combining pb and spawnProcess[3]
by Stefan Fleiter 17 Jun '03

17 Jun '03

Hi, I need this for a project, so this is quite urgent. I got no answer to this until now, so I try again. Maybe somebody could tell me where to ask, if nobody knows a solution, tkanks. ------ I have two seperate processes communicating by Perspective Broker. One, the server, shall start an external program and send the output to the client. See code below. I get the following traceback (part of it): --------------------------------------------- File "/export/home/s/stfl/Twisted/twisted/spread/pb.py", line 472, in expressionReceived raise ProtocolError("Non-list expression received.") twisted.spread.pb.ProtocolError: Non-list expression received. Failure: twisted.spread.pb.PBConnectionLost: I've simplified the code to the following: server (listener.py): ----------------------- #!/usr/bin/env python from twisted.spread import pb from twisted.internet import reactor, app, protocol from twisted.cred import authorizer import os class ABPP(protocol.ProcessProtocol): def __init__(self, receiver): self.receiver = receiver def connectionMade(self): print "connection to client-prg made!" # XXX Here the error is triggered mydef = self.receiver.callRemote("receiveMessage", "connection made!") mydef.addCallback(self.t) def t(self, x): print 't:', x class ABListener(pb.Root): def __init__(self): self.receiver = None def remote_takeMessageReceiver(self, receiver): print 'self.receiver = receiver', receiver self.receiver = receiver def remote_dir(self): pp = ABPP(self.receiver) command = ['/bin/ls'] reactor.spawnProcess(pp, command[0], command, env=os.environ) reactor.run() if __name__ == '__main__': import listener ab_app = app.Application("ABListener") ab_app.listenTCP(8848, pb.BrokerFactory(ABListener())) ab_app.run(save=0) client (client.py) ----------------------- #!/usr/bin/env python from twisted.spread import pb from twisted.internet import reactor class MessageReceiver(pb.Referenceable): def remote_receiveMessage(self, message): print 'server echoed:', message, '<br>' class CComHandler: def __init__(self, mr): self.mr = mr self.remRef = None def gotObject(self, object): self.remRef = object mydef = self.remRef.callRemote("takeMessageReceiver", self.mr) mydef.addCallbacks(self.gaveMr, self.gotErr) def gaveMr(self, reason): print 'gave MessageReceiver' mydef = self.remRef.callRemote("dir") mydef.addCallbacks(self.calledDir, self.gotErr) def calledDir(self, reason): print 'called dir remotely<br>' def gotErr(self, reason): print 'Error: %s<br>' % reason reactor.stop() def doDir(): mr = MessageReceiver() c = CComHandler(mr) pb.getObjectAt("localhost", 8848, 30).addCallback(c.gotObject) reactor.run() if __name__ == "__main__": machine = 'mymachine' packages = [('myPackage', 'myVersion')] doDir()

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[Twisted-Python] Twisted cred perspective unicode support
by rdrb＠123.cl 17 Jun '03

17 Jun '03

I got problems using Twisted cred with Python2.2.0. My perspectives names are based on a url encoding. I have found that there is a problem when PerspectiveName is unicode. I also discovered that the error message is not explicative. The CVS does not have a solution for this problems. Both diminute problem are solved in the next patch. Twisted is a great tool. Thanks you for Twisted. RodrigoB. - Post patch for twisted.cred.perspective (Type -> Types, report error type): the cause: ---------- import types isinstance(u"/test1", types.StringType) =>0 The patch: ---------- class Perspective: """I am an Identity's view onto a service. I am the interface through which most 'external' code should interact with a service; I represent the actions a user may perform upon a service, and the state associated with that user for that service. """ _service_cached = 0 # Has my service cached me from a loaded store, or do I live in memory usually? def __init__(self, perspectiveName, identityName="Nobody"): """Create me. I require a name for myself and a reference to the service I participate in. (My identity name will be 'Nobody' by default, which will normally not resolve.) """ if not isinstance(perspectiveName, types.StringTypes): raise TypeError("Expected string, got '%s' (%s)."% (perspectiveName, type(perspectiveName))) if not isinstance(identityName, types.StringTypes): raise TypeError("Expected string, got '%s' (%s)."% (identityName, type(identityName))) self.perspectiveName = perspectiveName self.identityName = identityName The diff --------- $ diff perspective.py /usr/local/lib/python2.2/site-packages/twisted/cred/perspective.py 49,52c49,52 < if not isinstance(perspectiveName, types.StringType): < raise TypeError("Expected string, got %s."% perspectiveName) < if not isinstance(identityName, types.StringType): < raise TypeError("Expected string, got %s."% identityName) --- > if not isinstance(perspectiveName, types.StringTypes): > raise TypeError("Expected string, got '%s' (%s)."% (perspectiveName, type(perspectiveName))) > if not isinstance(identityName, types.StringTypes): > raise TypeError("Expected string, got '%s' (%s)."% (identityName, type(identityName)))

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[Twisted-Python] Getting Rid of Application in a Compatible Way
by Moshe Zadka 16 Jun '03

16 Jun '03

I suggest to write ApplicationService classes which look like: class TCPListener(ApplicationService): def __init__(self, port, factory, backlog=5, interface='', *args, **kwargs): self.port = port self.factory = factory self.backlog = backlog self.interface = interface ApplicationService.__init__(self, *args, **kwargs) def __getstate__(self): d = self.__dict__.copy() d['_port'] = None return d def startService(self): ApplicationService.startService(self) self._port = reactor.listenTCP(self.port, self.factory, self.backlog, self.interface) def stopService(Self): ApplicationService.stopService(self) self._port.stopListening() self._port = None Now, instead of application.listenTCP we can use TCPListener(8080, server.Site(resource), "foo").setServiceParent(application) The only problem is needing to choose unique names. I suggest ApplicationService will lose the unPythonic if not isinstance(serviceName, types.StringType): raise TypeError("%s is not a string." % serviceName) And add to app.py class Unique: pass This means that "unnamed" services are now possible: TCPListener(8080, server.Site(resource), Unique()).setServiceParent(application) You can still access a service by its "serviceName", but you have to get the name from the service. This means stuff like cred will still work. Of course, similar Services can be written for UNIXListener, SSLListener, etc. -- Moshe Zadka -- http://moshez.org/ Buffy: I don't like you hanging out with someone that... short. Riley: Yeah, a lot of young people nowadays are experimenting with shortness. Agile Programming Language -- http://www.python.org/

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