Mailman 3 November 2003 - Twisted

[Twisted-Python] Python a post-Object Oriented Language?
by John Benson 20 Nov '03

20 Nov '03

Hi, I saw the above characterization in one of the itamarst.org twisted presentation slides. Although I'm just a journeyman programmer and somewhat unaccustomed to the rarefied atmosphere of many twisted Python discussions, I'm curious to hear why Python would be "post-OOP". If I recall correctly, my little O'Reilly C++ book said that OOP meant you had 4 things (abstraction, encapsulation, hierarchy and something else that escapes me at the moment, maybe "coolness"). I also recall that compiled C++ had a hard time doing the neat tricks that an interpreted language can do and was necessarily limited by its origin as a preprocessor step in front of a classic C compiler. There were some minor differences like automatic constructor chaining in C++, as opposed to manual __init__ chaining in Python. There were some major differences like being able to dynamically set attributes on an object, and the replacement of data hiding by convention in Python. Given that background, I'm just curious to hear the grounds on which Python can be classified as post-OOP. Any comments?

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[Twisted-Python] Forum vs. mailing list
by Hegedus, Matthew S 19 Nov '03

19 Nov '03

Philippe Lafoucrière mentions his favoring of a forum over a mailing list. A forum sounds much better to me. Topics can be nicely separated, past knowledge can be easily searched, and email inboxes can be freed from much clutter (or at least make room for spam). Is it not too late to implement a forum? Matthew Hegedus -----Original Message----- From: Philippe Lafoucrière [mailto:lafou@wanadoo.fr] Sent: Thursday, November 13, 2003 3:14 PM To: Twisted Subject: Re: [Twisted-Python] Deferred model > I'm sure this has been answered a million times before, but here > goes... I'm sure too. But I proposed a long time ago (and several times) to use a forum instead of a mailing list... > Deferreds do not magically turn blocking code into non-blocking code. > If you place blocking code in a wmfactory_ method, it will still > interfere with the event loop. > > If you have blocking code, you can either rewrite it in a non-blocking > manner, or you can use a separate thread to run it. > <http://twistedmatrix.com/documents/howto/threading> > > If you give more detail about what you're trying to do, I'm sure one > of the Twisted gurus can explain what the best approach(es) might be. I thought of using the setUp method of page. I can start the calculation when the page loads, but I don't know what to call (in the callback) when it's done (a wmfactory_xxx ?). I'll check the threading part you gave me. Thank you ! -- Philippe _______________________________________________ Twisted-Python mailing list Twisted-Python(a)twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python

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[Twisted-Python] Retrieving Woven html element IDs
by Justin Johnson 19 Nov '03

19 Nov '03

In woven, html elements are automatically given an id (eg. <div id="woven_id_18612312">... where the number is id(self) for the view). I have a div tag I'm trying to using to dump error logs into on the fly with LivePage and display them to the user. It seems that I cannot reference a tag by name with javascript, so I need access to the auto-generated id. If I had the id I could do something similar to the example below. Does anyone know if it's possible to lookup this id in woven? Thanks. -Justin <html> <head> <title>test</title> <script type="text/javascript"> function displayErrors() { id = 'errors' document.getElementById(id).innerHTML += '<span>some error</span><br/>' } </script> </head> <body> <a href="#" onclick="displayErrors()">add to errors</a> <div id="errors"> </div> </body> </html>

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[Twisted-Python] win32eventreactor bug?
by Justin Johnson 19 Nov '03

19 Nov '03

I was running twistd on windows, serving out a custom tap which is just a web app and a pb service. As it was doing it's thing, suddenly a ton of output started dumping on the log. Did I find a bug in the win32 event reactor, or am I hitting some sort of limit? I can send some code along if necessary, but nothing in the log looks specific to my code. Thanks. -Justin 2003/11/18 09:07 Central Standard Time [-] Unexpected error in main loop. 2003/11/18 09:07 Central Standard Time [-] Traceback (most recent call last): File "C:\Python23\Lib\site-packages\twisted\application\app.py", line 165, in run runApp(config) File "C:\Python23\Lib\site-packages\twisted\scripts\twistw.py", line 5 4, in runApp app.runReactorWithLogging(config, oldstdout, oldstderr) File "C:\Python23\Lib\site-packages\twisted\application\app.py", line 61, in runReactorWithLogging reactor.run() File "C:\Python23\Lib\site-packages\twisted\internet\default.py", line 122, in run self.mainLoop() --- <exception caught here> --- File "C:\Python23\Lib\site-packages\twisted\internet\default.py", line 133, in mainLoop self.doIteration(t) File "C:\Python23\Lib\site-packages\twisted\internet\win32eventreactor .py", line 171, in doWaitForMultipleEvents val = MsgWaitForMultipleObjects(handles, 0, timeout, QS_ALLINPUT | Q S_ALLEVENTS) pywintypes.error: (87, 'MsgWaitForMultipleObjects', 'The parameter is in correct.') 2003/11/18 09:07 Central Standard Time [-] Unexpected error in main loop. 2003/11/18 09:07 Central Standard Time [-] Traceback (most recent call last): File "C:\Python23\Lib\site-packages\twisted\application\app.py", line 165, in run runApp(config) File "C:\Python23\Lib\site-packages\twisted\scripts\twistw.py", line 5 4, in runApp app.runReactorWithLogging(config, oldstdout, oldstderr) File "C:\Python23\Lib\site-packages\twisted\application\app.py", line 61, in runReactorWithLogging reactor.run() File "C:\Python23\Lib\site-packages\twisted\internet\default.py", line 122, in run self.mainLoop() --- <exception caught here> --- File "C:\Python23\Lib\site-packages\twisted\internet\default.py", line 133, in mainLoop self.doIteration(t) File "C:\Python23\Lib\site-packages\twisted\internet\win32eventreactor .py", line 171, in doWaitForMultipleEvents val = MsgWaitForMultipleObjects(handles, 0, timeout, QS_ALLINPUT | Q S_ALLEVENTS) pywintypes.error: (87, 'MsgWaitForMultipleObjects', 'The parameter is in correct.') 2003/11/18 09:07 Central Standard Time [-] Unexpected error in main loop.

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[Twisted-Python] SOAP client for Twisted
by Dave Kuhlman 19 Nov '03

19 Nov '03

I've added minimal SOAP client support to Twisted. I did it by copying a bit of code from twisted/web/xmlrpc.py and by using some of the functionality from SOAPpy and adding it to twisted/web/soap.py. I've tested it lightly and it seems to work. Is this of interest to the Twisted project? If so, let me know and I'll send it along. Someone who knows Twisted better than I will have to look at the code to make sure that, given the way I implemented it, it does not block. Dave -- Dave Kuhlman dkuhlman(a)rexx.com http://www.rexx.com/~dkuhlman

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[Twisted-Python] new ftp implementation
by Jonathan Simms 18 Nov '03

18 Nov '03

Hello all, Just wanted to announce there is a new version of the ftp server/protocol. the new protocol: - Supports cred, so you can control/abstract the filesystem - includes an anonymous-only avatar/realm - supports pipelining of commands - intentionally does not support globbing (to help prevent security holes) - connection limiting (ex. max 100 users) - individual timeouts for protocol interpreter idle time and dtp connection times todos: - the permissions-checking needs improvement. I intend to set up an option on the FTPFactory that will let you set the uid of the anonymous user, but that's coming in the next week. - path purification code needs improvement (to prevent intentionally stupid paths like "\\//*/*/../../*/.." from borking the server) - a couple of other minor odds-and-ends there's an example tac file in sandbox/slyphon/ftp_refactor/ftpsrv.tac comments, suggestions, etc. welcomed -Jonathan Simms slyphon(a)twistedmatrix.com

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[Twisted-Python] UNIXServer and its socket
by Matteo Giacomazzi 18 Nov '03

18 Nov '03

In my application I have a server that listens on a UNIX socket. When I kill the application, the socket file remains in the filesystem so when I restart it I always achieve an "Address already in use" error. Should I delete it manually any time I stop the application or is there a more elegant way to solve this problem? The application is a plugin for twistd. Thank you in advance. Matteo

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[Twisted-Python] Browser oddities and Woven...
by Stuart Hungerford 18 Nov '03

18 Nov '03

Hi all, I probably shouldn't be too surprised, but I'm experiencing some odd behaviour with IE 6.0 .vs. Mozilla 1.5, both on Windows XP. I've developed a Woven application that generates three HTML pages, let's call them A, B, and C. A's render() method does a redirect to B. B's view methods generate an XHTML meta tag with the content attribute set to a refresh and new URL for C: <meta content="10;http://example.org/C" http-equiv="refresh" /> With Mozilla as the client everything thing goes as I expected with pages progressing from A to B to C. With IE as the client it goes from A to B, then loops continually on B, i.e A, B, B, B, ... without ever reaching C. I suspect there's some request header I need to set or set differently? Can anyone offer me advice on this strange situation? Cheers, Stu -- :: Stuart Hungerford (stuart.hungerford(a)anu.edu.au) :: ANU Internet Futures Group

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[Twisted-Python] another probably very simple question
by Phil Christensen 18 Nov '03

18 Nov '03

this is actually the first time i've ever written a PB client in python. since my java client was calling the remote methods out of the awt/swing event thread, i never had to deal with this particular issue. while i'm waiting for the update to the java pb packages (*cough*itamar*cough* ;-) ), i figured it would be worthwhile to do up a text-based client in python. i know this relates to my poor understanding of deferreds, but i just can't figure out exactly how to go about doing what i want to do. i want to be able to continually prompt the user for a string that gets sent to a "parse" method on the remote object. i'm not exactly sure the right way to do this. do I just add a callback to the deferred returned by def main(): config = Options() if(config['login'] == None): config['login'] = getpass.getuser() passwd = getpass.getpass("%s@%s's password: " % (config['login'], config['host'])) client = TextClient() factory = pb.PBClientFactory() reactor.connectTCP(config['host'], int(config['port']), factory) defer = factory.login(credentials.UsernamePassword(config['login'], passwd), client) defer.addCallback(connected) reactor.run() def connected(perspective): command = raw_input("> "); defer = perspective.callRemote("parse", command)

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[Twisted-Python] model question
by vicky lupien 18 Nov '03

18 Nov '03

I have a web based application. I want to create a model from a sql query that will be accessible from the web page. I want to be able to create my model in the setUp fonction. I also want to access my model from the web page like this: model="plan_id" (where plan_id is a column from my sql query) I don't know if someone understand what I want. Here's a part of my class: class SummaryDB: """PublisherDB Class""" def __init__(self, dbpool): self.dbpool = dbpool def getSummary(self, plan_id): sql = "select * from plan where plan_id = '%s'" %plan_id return self.dbpool.runQueryDict(sql) class SummaryPage(pages.BasePage): templateFile = "summary.html" def initialize(self, dbpool): self.dbpool = dbpool self.db = SummaryDB(self.dbpool) def setUp(self, request, *args): # I want to do somethings like : # self.model = ({'details' : self.db.getSummary(plan_id)} # and then, access to details by my web page self.contextMenu = menus.build_search_menu() And here's my template: <html> <head> <title> Title </title> </head> <body> <br /> <table border="0" width="100%" cellspacing="1" cellpadding="2"> <tr> <th class="header" colspan="2"> Sommaire </th> </tr> <tr> <td class="label" width="25%"> Number </td> <td class="area" width="75%" model="details/plan_id"> 2165</td> #plan_id is a column from the sql query </tr> </table> </body> </html>

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