Mailman 3 March 2009 - Twisted

[Twisted-Python] Re: So how does everyone use an ORM in twisted?
by Maciej Szumocki March 18, 2009

March 18, 2009

> From: Ryan Lepidi <ryeguy1(a)gmail.com> > Subject: [Twisted-Python] So how does everyone use an ORM in twisted? > To: twisted-python(a)twistedmatrix.com > Message-ID: > <bb39cd350903170805p2fca87casbc3cd6c932bb9439(a)mail.gmail.com> > Content-Type: text/plain; charset="iso-8859-1" > > I have searched a bit, and it seems as though you can't use SQL Alchemy with > twisted due to SA being thread unsafe. The only solution I found was sAsync, > but this is old and unmaintained. What is everyone else doing for database > access for a multiuser server? Is everyone really using raw sql queries or > is there some easy solution that I'm missing? > > I'm not even stuck on SQL Alchemy; if there is some other ORM that works in > this case, I'd be willing to learn it. I'm using SQLAlchemy with Twisted in a large project without problems. Why would you think you cannot? You just need to run SA operations in non-reactor threads (i currently use my own threadpool and deferToThread but it's only slightly modified standard twisted one), and you need to make sure each connection/session is not used by more than thread at a time, that's all. Maciej Szumocki

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[Twisted-Python] Ticket 1009
by Andrew Francis March 17, 2009

March 17, 2009

Hi Colleagues: I guess I am making today "Look at Twisted Documentation Day." I am looking at ticket 1009. For inline generator examples, here is the example I use in "Adventures in Stackless Python Twisted Integration." In turn, this example comes from the discussions in I believe January 2008 with JP Calerone. I can modify the example (and perhaps add illustrations) to show situations where inline generators are handy. """ Example of using an inline generator to make a Twisted call from a protocol handler """ class MyRequestHandler(http.Request): @defer.inlineCallbacks def process(self): try: result = \ yield client.getPage("http://localhost") except Exception, err: log.err(err, "process getPagecall failed") else: self.setHeader('Content-Type', 'text/html') self.write(result) self.finish() Cheers, Andrew

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[Twisted-Python] Ticket 1138 Re: Twisted-Python Digest, Vol 60, Issue 12
by Andrew Francis March 17, 2009

March 17, 2009

Hello Colleagues: >For ticket 1138 (cool movie), when I access the URL: >http://twistedmatrix.com/projects/core/documentation/howto/tutorial/deferre… >I get, URL not found. Which deferred tutorial are you referring to? >"Deferreds are Beautiful (A Tutorial) at : >http://twistedmatrix.com/projects/core/documentation/howto/deferredindepth.…. >I see the reference to python.util there. Looking at Ticket 1138. Again, I believe the ticket should be referring to the deferredindepth.html document "Deferreds are Beautiful." To answer the question: no you do not need python.util. I also put a minor correction in deferred_ex.py to get rid of the syntax warning in line 57. Cheers, Andrew

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[Twisted-Python] Novice question on twisted framework
by Sury Soni March 17, 2009

March 17, 2009

Hi, I have an existing application, written using Ice Middleware (www.zeroc.com) This application is my source of infinite queue (server) Following is my application (processing client to my infinite queue server) idea to be implemented using Twisted Framework. I can loop through my infinite queue and receive email data (Using .next() kind of function) Using this email data object, I need to trigger event to send email using ESMTPSenderFactory and ESMTPSender. As, later I would be extending ESMTP* classes to do my little funky stuff. What is the best code design I can use to implement this stuff. Following is basic algorithm kind of code I am doing right now, but I feel I am missing something. #================ #Code Begins Here: .tac file #================ import StringIO from twisted.application import service from twisted.application import internet from twisted.internet import protocol, defer from twisted.mail import smtp, relaymanager from twisted.internet import reactor Def process_queue: While True: Try: Data = my_queue.next() getMailExchange('localhost).addCallback(cbMailExchange, data) Except: Break Reactor.stop() reactor.callLater(0, process_queue) application = service.Application("SMTP Client Tutorial") class SMTPTutorialClient(smtp.ESMTPClient): mailFrom = "test(a)test.com" mailTo = "receiver(a)test.com" mailData = '''\ Date: Fri, 6 Feb 2004 10:14:39 -0800 From: Test <test(a)test.com> To: Receiver <receiver(a)test.com> Subject: Test Mail! Hello, how are you, goodbye. ''' def __init__(self, secret="", identity="", data = ""): smtp.ESMTPClient.__init__(self, secret=secret, identity=identity) self.secret = secret self.identity = identity self.data = data def getMailFrom(self): result = self.mailFrom self.mailFrom = None return result def getMailTo(self): return [self.mailTo] def getMailData(self): return StringIO.StringIO(self.mailData+self.data) def sentMail(self, code, resp, numOk, addresses, log): print 'Sent', numOk, 'messages' #reactor.stop() def getMailExchange(host): def cbMX(mxRecord): return str(mxRecord.name) return relaymanager.MXCalculator().getMX(host).addCallback(cbMX) class SMTPClientFactory(protocol.ClientFactory): protocol = SMTPTutorialClient def __init__(self, data): self.data = data def buildProtocol(self, addr): return self.protocol(secret=None, identity='example.com', data=self.data) def cbMailExchange(exchange, data): smtpClientService = internet.TCPClient(exchange, 2500, SMTPClientFactory(data)) smtpClientService.setServiceParent(application) #reactor.run() reactor.run() #================ #Code Ends Here #================ I have couple of #reactor.run() commented code, I feel like lost between application and reactor based code. My understanding is that function process_queue drives the control flow of my application. Please correct me. What is happening is, when my loop is finished in function process_queue, then only actual events of SMTP factory and protocol objects are created. Therefore, I am not getting event driven code, which is the beauty of Twisted Framework. Please advice the best document to look and fix this code. Thanks. ____________________________________ Sury Prakash Soni Developer ____________________________________ Next Digital Level 8, 15 William St, Melbourne VIC 3000 Australia p +61 3 8612 6888 f +61 3 8612 6899 m 0433 661 327 ssoni(a)nextdigital.com <mailto:ssoni@nextdigital.com> www.nextdigital.com <http://www.nextdigital.com/> ____________________________________ This email and any attachments are intended only for the use of the recipient and may be confidential and/or legally privileged. Next Digital Group Pty Ltd ("Next Digital") disclaims liability for any errors, omissions, viruses, loss and/or damage arising from using, opening or transmitting this email. If you are not the intended recipient you must not use, interfere with, disclose, copy or retain this email and you should notify the sender immediately by return email or by contacting Next Digital by telephone on +61 3 8612 6888.

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[Twisted-Python] Noob Question
by Shelby Ramsey March 15, 2009

March 15, 2009

Hello: I've been playing with twisted (to take advantage of deferreds) and trying to accomplish this: -- log into a machine as a client -- send auth -- receive "events" from the machine The events have a Content-Length: \d+ as the protocol for determining the length of the message. What I'm struggling with is how to parse that and then receive just that length as an individual message ... Thanks for any help that can be provided. SDR

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[Twisted-Python] Twisted.mail SMTP server question
by Kalman KHIRALY March 15, 2009

March 15, 2009

Hi! I would like to use twisted mail for the following purpose: Redirect all incoming myname(a)mydomain.com mails to a specified gmail address: myname(a)mydomain.com -> myname.mydomain(a)gmail.com Is it possible to use Twisted.Mail for this? Any pointers would be highly appreciated. If not can somebody recommend me a nice python solution for this? Best regards, Khiraly ps: 4 year ago I did the above feature using postfix and mysql. It took me more the 2 months to correctly set up all this stuff (and having an administrator web page where I could change, add, remove the email address, and wrote into the mysql database) Unfortunetly, I do not have anymore my work, the server crashed, etc. And in my view, it was horribly overcomplicated. So Im looking a simple and elegant solution (so this rules out qmail and postfix). It is like setting up apache with ssl+virtualhost for a simple index.html file;)

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[Twisted-Python] Weekly Bug Summary
by exarkun＠twistedmatrix.com March 15, 2009

March 15, 2009

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[Twisted-Python] Using sqlalchemy in twisted.
by Peter Cai March 13, 2009

March 13, 2009

Hi, all I am using sqlalchemy in twisted in my project in the way below. Defer any database operation so the twisted's main thread won't be blocked. And I use scoped_session, so that sessions won't have to be created again and again. ====================================== class Database() def __init__(self, conn_str): self.conn_str = conn_str self.engine = create_engine(self.conn_str, echo=False) self.Session = scoped_session(sessionmaker(bind = self.engine, expire_on_commit=False)) def getObjectById(self, klass, id): return threads.deferToThread(self._getObjectById, klass, id) def _getObjectById(self, klass, id): sess = self.Session() return sess.query(klass).get(id) ====================================== The code doesn't work. When I limit the thread numbers to 1 reactor.suggestThreadPoolSize(1) Everything goes fine. Other wise the server would be blocked and must be killed by "kill 9 ...". The result conflicts with my understanding of sqlalchemy. Since I don't share any object between threads, there should be no problem! Ah.... It always have risk to use something you haven't tried before .... I think I have no choice but always set thread pool size to 1 ... -- look to the things around you,the immediate world around you, if you are alive,it will mean something to you ——Paul Strand

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[Twisted-Python] Gsoc 2009
by kartik rustagi March 11, 2009

March 11, 2009

Hello everyone, Is twisted applying as an organization in this year's Gsoc? I as a student will be interested in working for it. Regards Kartik Rustagi

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[Twisted-Python] getting sshsimpleserver.py to work within a wrapper
by jkv March 10, 2009

March 10, 2009

Hi, I just recently got aware of twisted and im currently playing around with it. Is there any way to make reactor.listen listen on stdio instead of a real network connection? In one of the examples (sshsimpleserver.py) reactor.listenTCP is used to listen on the network socket, as far as i can read from the twisted core documentation there are no builtin way to make reactor.listen* listen on stdin instead... Any hints? Regards, jkv

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