Mailman 3 November 2008 - Twisted

[Twisted-Python] ssh and python shell with twisted
by Turi Nov. 13, 2008

Nov. 13, 2008

Let me preface by saying, I am new to python and of course Twisted. I am trying to play with the examples already available http://www.devshed.com/c/a/Python/SSH-with-Twisted/. I believe that is the example from Oreilly book on Twisted. I looked at the custom ssh server script and then the providing python shell over ssh script http://www.devshed.com/c/a/Python/SSH-with-Twisted/3/. What I am curious about is how to combine these two? So I want to be able to set up the custom ssh server, which … [View More]

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[Twisted-Python] Event notification and general RPC in Twisted...
by Blair Bethwaite Nov. 12, 2008

Nov. 12, 2008

Hi all, I'm thinking about using Twisted to rewrite some communications in a Grid computing application. E.g.: [JobServer]1 ---------- *[Proxy]1 ----------- *[Agents] Agents get jobs, report status, results, etc through Proxy to JobServer. Agents are often distributed across a private network that has no external interface, hence the proxy, which is run on a machine between the private network and internet. Also, the proxy may do some caching/queuing of particular messages - especially where … [View More]

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[Twisted-Python] client send twice but server reads once
by Aydın ŞEN Nov. 12, 2008

Nov. 12, 2008

Hi, In my code i'm sending sequential data from client like; self.transport.write('aydin') self.transport.write('adige') but server reads data like *'aydinadige' *How can i solve this, actually it is not clear how does dataReceived work for me best regards..

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[Twisted-Python] checking connection
by Benny Nov. 12, 2008

Nov. 12, 2008

Hi, I have been trying to find out how to keep checking the connection once the connection is made. Says I have successfully connected to the server, and i want to maintain and check that connection. How can i do that?

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[Twisted-Python] Import TypeError
by James Joplin Nov. 9, 2008

Nov. 9, 2008

I've been doing some embedded python work and everything has been working like a charm thusfar! Twisted has saved us tons of work, hats off to the development team. I have been having issues with shutting down twisted completely (I think). Even upon executing Py_Finalize or Py_EndInterpreter as necessary upon re-entering our browser plugin we hit an exception during twisted import. Here is my traceback : Traceback (most recent call last): File "<string>", line 1, in <module> … [View More]

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[Twisted-Python] Running a client within a thread... do I need to rewrite?
by Andrew McClain Nov. 9, 2008

Nov. 9, 2008

I have an existing twisted client connecting to a jabber server in order to send notifications for our web app. I'd like to fold in a STOMP message client into the my existing code, so I can do something like this: web app --> STOMP queue --> STOMP client --> jabber client --> jabber server Problem is, the STOMP client library I'm using creates a socket, spawns a thread, and listens, calling a callback method when it gets information. In order to integrate this with my twisted … [View More]

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[Twisted-Python] Weekly Bug Summary
by exarkun＠twistedmatrix.com Nov. 9, 2008

Nov. 9, 2008

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[Twisted-Python] freeing the reactor to do other jobs
by Jeff Dyke Nov. 7, 2008

Nov. 7, 2008

I'm using the XMLRPC server in twisted and a few methods call other, sometimes long running, functions/methods. I'm trying to get my brain around how to free the reactor to respond to other requests while this is happening. A scenario. A call is made to the server, which selects say 10K rows from a db and needs to check each row against a table and if they do not exist, insert them. """ Oversimplified version of the process """ def getData(self,user_id): rows = self.getUserData(user_id) … [View More]

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[Twisted-Python] making twisted provide good feedback (was Re: Having reactor run at the main thread...)
by glyph＠divmod.com Nov. 7, 2008

Nov. 7, 2008

(Moving this off the twisted-web list because it is of more general interest and contains nothing web-specific.) On 09:48 am, jml(a)mumak.net wrote: >On the other hand, there's a related invalid argument that gets used a >lot by library and framework authors: "if we provide X, people might >misuse it, so we should not provide X". This argument is also bogus >(that way lies Java). Provide safe, well-documented alternatives for >the abusers and let those who want to shoot … [View More]themselves in the foot do >so: sometimes they might actually know better than you. I find it peculiar that you think this is Java's disease. My perspective is that Java is unpleasant because it is remarkably tedious, redundant, and inconsistent, not because it lacks functionality. If anything, it's a mess of functionality, and there are too many ways to do the same thing. If you want to shoot yourself in the foot (or face, as the case may be) there's always the com.sun hierarchy, which despite being full of warnings signs and sparsely documented, is all public (at the language level) and accessible from Java programs which wish to go that way. In that sense it's relatively hacker friendly. For more fun with foot- shooting there's also AccessibleObject, which lets you call private methods and access private fields. I think the whole issue here is very complex, and so I'd like to repeat and perhaps more clearly explain my own views. I work at the bleeding edge of lots of software and am frequently frustrated when the authors of libraries that I use don't bother with "edge" cases that are necessary to the applications that I write. Twisted should provide excellent support for valid use-cases, no matter how obscure. On the other hand, it's equally frustrating to use a library where the incredibly obscure "you probably don't need this" and the 99%-of-the- time positive-path APIs are listed, without any particular ordering, in one giant flat list. It's particularly frustrating to google for "How do I (X)" and get a solution which uses an apparently reasonable API to do (X), only to discover months after using it that it's actually unsupported and you're not supposed to touch it and now your program is going to break horribly with the next minor version of the library. This isn't just a problem with documentation, because in reality nobody reads documentation. If you're writing a program, you're going to read _just_ enough of the API doc and do just enough groveling around with dir() and pydoc to get yourself to the point where something works. When it works, you will probably consider that sufficient proof that you used the APIs correctly, unless you had to type something that _looked_ particularly gross in the course of doing it, or you got a bunch of warnings out of your program when you ran it. This is the whole point of DeprecationWarning: somehow, your library code itself has to communicate with the the developer who is invoking it and tell them useful things about their use or misuse. I feel like Twisted has more of the latter problem than the former. There are a lot of methods which aren't really private (addReader/removeReader) that don't differentiate themselves as more or less private or refer you to the more portable and general APIs that you probably want (pauseProducing/resumeProducing). However, (modulo global reactors, of course) Twisted does support a lot of edge cases very nicely. Speaking from personal experience, there are a lot of people who show up in #twisted looking at <http://twistedmatrix.com/documents/8.1.0/api/twisted.internet._sslverify.ht…> when they should be looking at <http://twistedmatrix.com/documents/8.1.0/api/twisted.internet.ssl.html>, or <http://twistedmatrix.com/documents/8.1.0/api/twisted.internet.iocpreactor.t…> when they should be looking at <http://twistedmatrix.com/documents/8.1.0/api/twisted.internet.interfaces.IR…>. In the long term, we need to write both better documentation and more code that gets these people back onto the right track. I know I've used a few libraries which provided exactly this kind of feedback and it was very satisfying and educational. It's really an art, one that's difficult to master, and I don't know that I really know the right way to do it in the general case. The danger that comes along with doing it wrong is very nicely explained here: http://blogs.msdn.com/oldnewthing/archive/2008/10/06/8969399.aspx - if you make an API which doesn't work except for the "special" cases, then everyone just starts using the "special" version. [View Less]

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[Twisted-Python] Silencing PotentialZombieWarning
by Reza Lotun Nov. 6, 2008

Nov. 6, 2008

Hi All, I'm working on a multi-platform (win32 and os x) wx + Twisted app, where I've found the best solution is to run both in a separate thread - the main thread is wx, and the other is Twisted. It basically works like a charm (though I'd be interested in hearing about other approaches. I've also played with wxreactor way back, but didn't find it as stable). Because I spawn a few processes (using spawnProcess), and must run my reactor with installSignalHandlers=0, I get … [View More]

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