Mailman 3 March 2005 - Twisted

[Twisted-Python] streaming producer
by Andrea Arcangeli March 9, 2005

March 9, 2005

Could somebody explain the semantics of the streaming parameter to registerProducer? I believe I have to set it to 1. I need to stop data coming from a process protocol, and to do so I need to register a producer somehow. I need to stop the process protocol when the TCP transport buffer (or the sendstring buffer or both? I'm using int32protocol) grows too much (let's say 10mbytes, I like to allow huge buffering, but at the same time I can't avoid the producer or people could trigger oom … [View More]

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RE: [Twisted-Python] TCP Packet Size Considerations: Extra Info
by Grant McDonald March 9, 2005

March 9, 2005

Now i do feel stupid! The documentation doesn't mention anything about sending multiple packets..... how can i tell if a packet is part of a multiple packet set? After looking at the output more carefully i realised that it was sending a packet the size of 8760 and 8077 which together total 16837. Where is the information to say it is a split transmission? -----Original Message----- From: twisted-python-bounces(a)twistedmatrix.com [mailto:twisted-python-bounces@twistedmatrix.com]On Behalf Of … [View More]

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[Twisted-Python] TCP Packet Size Considerations: Extra Info
by Grant McDonald March 9, 2005

March 9, 2005

After adding some code to report the transmission size i can confirm that 16837 bytes are sent and 8077 bytes are received via the previous code. Regards, Grant

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RE: [Twisted-Python] TCP Packet Size Considerations
by Grant McDonald March 9, 2005

March 9, 2005

JP wrote: > There are no such known limits. I might even go as far to say that there > are no such limits, if I were feeling daring. :) Do you have a short > program which demonstrates this behavior that you can share? > Perhaps after looking at that someone can suggest the cause of the disconnects. After looking into it some more myself i realised an uncaught exception was dropping the connection but the after cutting my test code back to minimal functionality the … [View More]inconsistency with received data was still there. The last 4KB of the data was received and the first 14KB discarded somewhere! I have created a minimal example from my initial test code. Start the simpleserver with twistd.py -y simpleserver.py and just run the simpleclient.py the builder.dat file is just a nonsense file that is about 18KB in size. Testing on my machine produced a received.dat file which was 4KB in size. I am currently using Python 2.3.3 and Twisted 1.3.0. The code is as follows (and is also attached for convenient running): ### ------------ simpleclient.py --------------------------------- from twisted.internet.protocol import Protocol import twisted.internet.error from simpleprotos import SimpleClientFactory factory = SimpleClientFactory() # open a large nonsense file to send (18KB) f = file('builder.dat') data = f.read() print len(data) f.close() from twisted.internet import reactor reactor.connectTCP('127.0.0.1', 10000, factory) reactor.callLater(1.0, factory.sendMessage, data) reactor.run() ### ------------- end --------------------------------------------- ### ------------ simpleserver.py ---------------------------------- from twisted.application import internet # services that run TCP/SSL/etc. from twisted.application import service from simpleprotos import ServerDataConnection, SimpleFactory def makeService(): factory = SimpleFactory() # here we create a ConnectionManager return internet.TCPServer(10000, factory) application = service.Application("Connection Manager") sc = service.IServiceCollection(application) sc.addService(makeService()) ### ------------- end --------------------------------------------- ### ------------ simpleprotos.py ---------------------------------- from twisted.internet.protocol import ClientFactory, Factory, Protocol class SimpleClientFactory(ClientFactory): def buildProtocol(self, addr): self.p = ClientDataConnection() self.p.factory = self return self.p def sendMessage(self, data): if hasattr(self, 'p'): self.p.sendData(data) class SimpleFactory(Factory): def buildProtocol(self, addr): self.p = ServerDataConnection() self.p.factory = self return self.p class ServerDataConnection(Protocol): def closeConnection(self): self.transport.loseConnection() def dataReceived(self, data): f = file('received.dat', 'w') f.write(data) f.close() class ClientDataConnection(Protocol): def closeConnection(self): self.transport.loseConnection() def sendData(self, data): self.transport.write(data) ### ------------- end --------------------------------------------- Regards, Grant McDonald [View Less]

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[Twisted-Python] TCP Packet Size Considerations
by Grant McDonald March 8, 2005

March 8, 2005

Hi All, I am translating a twisted UDP implementation to a TCP implementation and i have come across some unexpected errors related to the amount of data written to a TCP transport. When a large amount of data is written to a TCP connection (approx. 9KB) the connection is dropped and transmission is unsuccessful. Between about 4KB-9KB (approx.) the connection is not dropped but the transmission is incomplete as the unpickling raises a ValueError (insecure pickle string). Under 4KB transmission … [View More]

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[Twisted-Python] Re: [Twisted-commits] r13090 - Use ThreadedResolver instead of BlockingResolver by default - the thread import issue is moot, PyOpenSSL imports thread unconditionally.
by Itamar Shtull-Trauring March 8, 2005

March 8, 2005

On Mon, 2005-03-07 at 22:31 -0700, Jp Calderone wrote: > Use ThreadedResolver instead of BlockingResolver by default - the thread import issue is moot, PyOpenSSL imports thread unconditionally. Not true. Some BSDs don't do threading in Python, and we need to support them. Remember, the pyOpenSSL support is optional. The fact pyOpenSSL does the import unconditionally is a bug.

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[Twisted-Python] Twisted Allen-Bradley PLC Protocol
by Paul Campbell March 8, 2005

March 8, 2005

I've successfully gotten twisted to talk to Allen Bradley PLC 5's using Ron Gage's "ABEL" library as a template. Needless to say, the twisted way is cleaner and easier to maintain (in my opinion at least). However, there's a slight twist to the code and I'm trying to think if there's a better way, and the protocol is similar to so many other things (SSL comes to mind). To communicate with AB PLC's, first you initiate a TCP/IP connection. This is text book twisted. Second, you initiate … [View More]

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[Twisted-Python] wxreactor and dialog on win xp problem
by Michele Petrazzo March 8, 2005

March 8, 2005

I have a problem with wxreactor on win xp. I insert a ShowModal() of a TextEntryDialog after an event of a button in a frame. The ShowModal function of the dialog, don't return me the control after the dialog has close, but only when the global application has closed. I try this with a bit of print. Show the example for tests. On my linux-box, with the same wxpython and twisted version, all work well. python 2.3.4 wx 2.5.3.1 twisted 1.3.0 Thanks, Michele

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[Twisted-Python] Help With Twisted as a Client (newbie warning)
by Steve Milner March 8, 2005

March 8, 2005

I'm trying to get a better handle on how to write a client using twisted that would react to a GUI. What I am wanting to do is to somehow be able to work with xmlclient (which is based in sux.XMLParser) so I can write to the transport. Here is the connection code: <snip> # Overrides the protocol.XlientFactory with a bit of reconnect code and sets # the protocol to xmlclient factory = CUClientFactory() factory.clients = [] sslFactory = ClientContextFactory() application = service.… [View More]

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RE: [Twisted-Python] watch a directory (Win32)
by Henning.Ramm＠mediapro-gmbh.de March 8, 2005

March 8, 2005

>... and call it with reactor.callLater(0,someFunctionThatCallsWaiting) >regularily Oh, sure, thanks. I just didn't understand how stupid and non-magic these Win32 functions are. Best regards, Henning Hraban Ramm Südkurier Medienhaus / MediaPro Support/Admin/Development Dept.

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