Mailman 3 July 2004 - Twisted

Re: [Twisted-Python] reactor.stop stops entire twistd
by Sergio Trejo July 29, 2004

July 29, 2004

I'm curious what would happen if two separate reactor callLater() methods were executed on two separate functions (we'll call them a() and b()) ... such that a() and b() would be scheduled to run at the same exact moment. How would Twisted handled such a situation? Is there such a thing as callLater() "collision" even if the probability of such collission is quite low? Cheers, Serg >From: Matt Goodall <matt(a)pollenation.net> >Reply-To: Twisted general discussion <twisted-python(a)twistedmatrix.com> >To: Twisted discussion stuff <twisted-python(a)twistedmatrix.com> >Subject: Re: [Twisted-Python] reactor.stop stops entire twistd >Date: Wed, 28 Jul 2004 10:15:50 +0100 > >On Wed, 2004-07-28 at 09:41, Tsai Li Ming wrote: > > Hi, > > > > I have the following codes: > > > > > > site = server.Site(Core()) > > application = service.Application('server') > > sc = service.IServiceCollection(application) > > q = internet.TCPServer(8081, site) > > q.setServiceParent(sc) > > > > # twistd -y server.tac > > > > The core class uses methods that uses getProcessOutput, reactor.run aad > > reactor.stop. However, the whole application gets shutdown because of > > the reactor.stop. > > > > How do I avoid having my entire application getting stopped? > >Calling reactor.stop() is supposed to shutdown the application (see >below) so please could you explain what you actually wanted to stop by >calling reactor.stop(). > >In the meantime, here's a couple of points to consider ... > >1. The reactor is the event loop for the process and, once running, >*everything* happens because of an event. If you stop the reactor then >you are explicitly telling the reactor to stop processing events and end >the application. > >2. twistd manages the creation and activation of the reactor for you (as >well as other useful stuff such as logging). You should not call >reactor.run() in your application. > >Cheers, Matt > >-- > __ > / \__ Matt Goodall, Pollenation Internet Ltd > \__/ \ w: http://www.pollenation.net > __/ \__/ e: matt(a)pollenation.net > / \__/ \ t: +44 (0)113 2252500 > \__/ \__/ > / \ Any views expressed are my own and do not necessarily > \__/ reflect the views of my employer. > > >_______________________________________________ >Twisted-Python mailing list >Twisted-Python(a)twistedmatrix.com >http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python _________________________________________________________________ Tired of spam? Get advanced junk mail protection with MSN 8. http://join.msn.com/?page=features/junkmail

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[Twisted-Python] Wiring a new reactor/Client into Twisted
by Eugene Coetzee July 28, 2004

July 28, 2004

Hi, I'm using Twisted in an industrial application to replace a multi-threaded C++ driver which I developed some time ago to drive an array of serial ports (COM port expander) simultaneously. This is quite a typical application found in industrial control, building security/access control systems, etc. where an extended multi-drop serial protocol like RS485/422 is used together with a standard message format such as Modbus to do remote data aquisition and control of embedded devices. These kind of systems make use of what is refered to as a master/slave serial driver i.e. there is only one master (typically a PC) and a slave device may only respond to polls from the master. My aim is to create a new Twisted package - say twisted.industrial - which I hope contribute to the Twisted platform. I want to achieve this by extending Twisted without modifying any Twisted sources, reusing as much as possible of existing Twisted code and * doing things very much the "Twisted way" * :) The main problem is that most of Twisted's base classes seems to have TCP/UDP network connectivity in mind. I have managed to subclass SelectReactor in order to create SerialSelectReactor, base.BaseConnector to create SerialConnector, SerialPort to create ExtendedSerialPort and I have the following piece of code working. *********************************************************** if __name__=='__main__': from serialreactor import serialreactor factory = ModbusFactory() factory.protocol=Modbus() serialreactor.connectSerial('/dev/ttyS0',9600,factory) print "start reactor" serialreactor.run() print "exit reactor" *********************************************************** This is good but I want to run more than one serialport (or serial protocol) simultaneously - i.e I need to drive up to 64 serial ports at the same time. I believe I need to do something like: ************************************************************ if __name__=='__main__': from serialapplication import SerialClient,service application=service.Application('Serial',uid=1,gid=1) factory = ModbusFactory() factory.protocol=Modbus() print "start client" internet.SerialClient(79,factory).setServiceParent(service.IServiceCollection(app lication)) print "exit client" ************************************************************** But I'm finding difficulty in grasping the code in application.internet (do not understand why it was done like that) since I want to subclass _AbstractClient which is seems to be the product of some clever text manipulation and dynamic "class creation". Any comments, suggestions, recommendations and am I one the right track? regards, Eugene

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[Twisted-Python] authentication problem
by Frédéric Gobry July 28, 2004

July 28, 2004

Hi, I'm setting up a service with both a web and a perspective broken interface. I'd like to share the credential mechanism between the two. Enclosed are code excerpts from the server and the test client. On the server I get the following error when the client tries to connect: 2004/07/27 23:00 CEST [Broker,0,127.0.0.1] Failure: twisted.cred.error.UnhandledCredentials: No checker for twisted.spread.interfaces.IJellyable, twisted.cred.credentials.IUsernameHashedPassword, twisted.cred.credentials.ICredentials, twisted.spread.pb.IUsernameMD5Password Any idea what's wrong? Thanks! Frédéric

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[Twisted-Python] reactor.stop stops entire twistd
by Tsai Li Ming July 28, 2004

July 28, 2004

Hi, I have the following codes: site = server.Site(Core()) application = service.Application('server') sc = service.IServiceCollection(application) q = internet.TCPServer(8081, site) q.setServiceParent(sc) # twistd -y server.tac The core class uses methods that uses getProcessOutput, reactor.run aad reactor.stop. However, the whole application gets shutdown because of the reactor.stop. How do I avoid having my entire application getting stopped? Thanks, Liming

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[Twisted-Python] important
by washort＠twistedmatrix.com July 28, 2004

July 28, 2004

;-)

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Re: [Twisted-Python] "local" semantics soughtin twisted.protocols.smtp.sendmail
by Sergio Trejo July 28, 2004

July 28, 2004

JP, Glad that I was able to help out. Any guess as to what the original author meant by "local"? By using \n to delimit new lines, isn't that essentially saying the same thing as the oringal author? Perhaps of interest, the way I arrived at this nuance in the documentation is that a project I'm working on requires a node running an SMTP server to receive mail and then parse the contents of each mail message I'm sending with my Twisted application. Each line in the body of a mail message I'm sending contains API key, value pairs that are parsed by software on the node. I originally used the built-in Python smtplib.server.sendmail() method, and in order for it to work with the parsing software on the remote node, I had to end each line with a carriage return and a line feed as in: key=value\r\n key2=value2\r\n However, what I found different is that the node's parsing software didn't like it when I'd send mail as in the above example (with carriage return and line feed) via the Twisted SMTP module equivalent. To remedy this, I just had to remove the carriage returns, so its no big deal. But I am still curious as to why Python's sendmail eats the /r/n and why not with the Twisted equivalent. Perhaps just a silly nit pick but perhaps there is a deeper logical reasoning to this (I.e., could Twisted be making an improvement on the Python smtplib)? Thanks for any further insight. -Serg >From: Jp Calderone <exarkun(a)divmod.com> >Reply-To: Twisted discussion stuff <twisted-python(a)twistedmatrix.com> >To: Twisted discussion stuff <twisted-python(a)twistedmatrix.com> >Subject: Re: [Twisted-Python] "local" semantics >soughtin twisted.protocols.smtp.sendmail >Date: Tue, 27 Jul 2004 15:15:31 -0400 > >Sergio Trejo wrote: >>The API documentation for twisted.protocols.smtp.sendmail method states >>that the incoming msg parameter ((a string or a file object) must contain >>contain lines >>that end with a line feed character because, verbatim: "Line endings must >>be >>local (I.e., '\n')" ... the URL that I'm quoting from is >>http://www.twistedmatrix.com/documents/current/api/ >>twisted.protocols.smtp.html#sendmail >> >>I am curious what is meant by the word "local" to describe the use of line >>endings in the API documentation. Does local mean something specific to an >>operating system of which the Python interpreter is compiled for and runs >>on top of (and if so, doesn't that break the philosophy of Python which is >>mostly OS agnostic)? >> > > The documentation is wrong. Use \n to delimit newlines. I'll go fix >the docs in SVN. Thanks for pointing this out. > > Jp > >>Sergio >> _________________________________________________________________ Add photos to your e-mail with MSN 8. Get 2 months FREE*. http://join.msn.com/?page=features/featuredemail

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[Twisted-Python] "local" semantics sought in twisted.protocols.smtp.sendmail
by Sergio Trejo July 27, 2004

July 27, 2004

The API documentation for twisted.protocols.smtp.sendmail method states that the incoming msg parameter ((a string or a file object) must contain contain lines that end with a line feed character because, verbatim: "Line endings must be local (I.e., '\n')" ... the URL that I'm quoting from is http://www.twistedmatrix.com/documents/current/api/ twisted.protocols.smtp.html#sendmail I am curious what is meant by the word "local" to describe the use of line endings in the API documentation. Does local mean something specific to an operating system of which the Python interpreter is compiled for and runs on top of (and if so, doesn't that break the philosophy of Python which is mostly OS agnostic)? Sergio _________________________________________________________________ MSN 8 with e-mail virus protection service: 2 months FREE* http://join.msn.com/?page=features/virus

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[Twisted-Python] Re: hello
by warner＠lothar.com July 27, 2004

July 27, 2004

that is interesting...

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[Twisted-Python] ANN: Hep 0.5, Yarn 0.1
by Abe Fettig July 27, 2004

July 27, 2004

I've got a new release of Hep available at http://www.fettig.net/projects/hep/. For those unfamiliar with it, Hep is a mutliprotocol message server. It provides a proxy/translation layer between email and the web, so you can read RSS feeds and write weblog posts from the comfort of your favorite mail client (using either POP3 or IMAP). I'm also releasing a new library called Yarn (http://www.fettig.net/projects/yarn/), a seperate package containing all the messaging-system-abstraction bits that used to be in Hep. Yarn lets you work with RSS and Atom feeds, weblogs, Maildir directories, etc., using a common Folder/Message API. It supports authentication, sharing connections between users, and tracking metadata between sessions. It's fully unicode-aware. It uses plugins to make it easy to add support for new protocols and file formats. Yarn is a little short on docs at the moment, but if you're feeling curious there's some code in the examples/ directory that will get you started. I'll have some tutorials up on my website soon, though. Both Hep and Yarn make heavy use of Twisted (even mktap/twistd). Many thanks to the Twisted team, especially exarkun for his work on IMAP - I'm so glad I didn't have to write that code myself! Abe

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[Twisted-Python] reconnecting from the client
by Bosnjak Zoran ITWEP July 27, 2004

July 27, 2004

Hello, in my simple client I need a mechanism for reconnecting to the server: 1. If the server is not responding at the momment, the client should keep trying to connect 2. If the connection once become active and the server is restarted, the client should reconnect 3. If the connection is active and no data can be transmited / received for X seconds (link down, router down), the client should try to reconnect as in the case (1.) (as if the client has never been connected) It should react in less then 10 seconds. Unfortunately I can not detect the situation (3.). If I unplug the ethernet while connected, none of my methods is called (ever). I couldn't find anything like this in the documentation or in the examples. Here is my testfile: -------------- from twisted.internet.protocol import Protocol, ReconnectingClientFactory from twisted.internet import reactor class Echo(Protocol): def dataReceived(self, data): print data def connectionLost(self, reason): print 'connection lost', reason def connectionMade(self): reactor.callLater(1.0, self.ping) print 'connection made' def ping(self, *args): self.transport.write('test') reactor.callLater(1.0, self.ping) class EchoClientFactory(ReconnectingClientFactory): maxDelay = 3 def startedConnecting(self, connector): print 'started to connect' def buildProtocol(self, addr): print 'connected' self.resetDelay() return Echo() def clientConnectionLost(self, connector, reason): print 'lost connection', reason ReconnectingClientFactory.clientConnectionLost(self, connector, reason) def clientConnectionFailed(self, connector, reason): print 'connection failed', reason ReconnectingClientFactory.clientConnectionFailed(self, connector, reason) reactor.connectTCP('10.10.2.77', 23, EchoClientFactory()) reactor.run() -------------- regards, Zoran Bosnjak

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