Mailman 3 May 2005 - Twisted-web

Grouping controls in formless layouts
by Phil Mayers 25 May '05

25 May '05

All, I have a table-based layout (yes I know) which uses the slots/patterns and an XML template to lay the form out: <form xmlns:n="http://nevow.com/ns/nevow/0.1" n:pattern="freeform-form">  <table> <n:invisible n:pattern="argument" n:render="remove"> <tr><td><n:slot-name="input"/></td></tr> </n> </table> </form> ...however I want to group some of the controls together in the table. The problem is that this: <form xmlns:n="http://nevow.com/ns/nevow/0.1" n:pattern="freeform-form">  <table> <n:invisible n:pattern="argument" n:render="remove"> <tr> <td><n:slot-name="description"/></td> <td><n:slot-name="input"/></td> </tr> </n> <tr> <td>Age</td> <n:invisible n:pattern="argument!!age" n:render="remove"> <td><n:slot-name="input"/></td> </n> <n:invisible n:pattern="argument!!ageunits" n:render="remove"> <td><n:slot-name="input"/></td> </n> </table> </form> ...generates this: <table> <tr> <td>field 1</td> <td><input type="text" name="field1"/></td> </tr> <td><input type="text" name="age"/></td> <td><select name="age"></select></td> <tr> <td>Age</td> </tr> </table> ...that is, the patterns are yanked out of their inner context (as you would expect I guess). The labours of why this needs to be table-based need not be raised here - suffice it to say I'm not the one making the decision. Having said that I can see the argument that making a proper resizing gridbag-style layout with CSS is basically impossible (and that infuriates me). I suspect I can subclass annotate.Typed or use the complexType stuff to somehow group a textbox and dropdown together into one logical bit of HTML that is rendered as a single "control". Does anyone have any examples of how I might do that or similar to aggregate various form control?

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LivePage erratic under IE 6.0
by Garth T Kidd 25 May '05

25 May '05

To see whether LivePage is the right foundation for a side-project, I've written a rudimentary ping program that updates the client DOM. Under FireFox, all works as expected. Under IE, it worked for text pings (handled entirely in ping()) but not for numeric pings (handled by the Blaster class). Then it stopped working at all. I'm most puzzled. Versions: nevow 0.4.1 twisted 2.0.0 python 2.3.5 IE 6.0.2800.1106.xpsp2.040919-1003CO Script: from nevow import loaders from nevow import tags from nevow import livepage from nevow import appserver from twisted.internet import reactor class Blaster: def __init__(self, client, tenths): self.client = client self.tenths = tenths self.now = 0.0 def __call__(self): self.client.set('head', str(self.now)) self.now = self.now + self.tenths/10.0 if self.now < 10: reactor.callLater(self.tenths/10.0, self) def ping(client, payload): try: Blaster(client, float(payload))() except ValueError: client.set('head', payload) reactor.callLater(1, client.set, 'head', "Do it again!") ping = livepage.handler(ping, livepage.document.getElementById('payload').value) class Twister(livepage.LivePage): addSlash = True docFactory = loaders.stan( tags.html[ tags.head[ tags.directive('liveid'), tags.directive('liveglue') ], tags.body[ tags.h1(id='head') ["Twist me, baby!"], tags.div(id='pingform') [ tags.form(name='ping', onsubmit=ping) [ tags.input(name='payload', id='payload'), tags.button['Ping!'] ] ] ] ] ) if __name__ == '__main__': reactor.listenTCP(7080, appserver.NevowSite(Twister())) reactor.run()

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Reactor in a multithreaded program
by Ellers 23 May '05

23 May '05

Hi all What is the right way to use a reactor in a multithreaded program? The program I'm writing is a command line program that needs to use the readline package. Readline blocks so I need to put the reactor (or the readline call) in a separate thread. I can start the reactor ok if I set installSignalHandlers=0. But calling reactor.stop() from the main thread doesn't seem to stop it. What is the best way? Thanks :) Ellers

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twisted+nevow in production environment
by Little 21 May '05

21 May '05

I'd like to read some tips/tricks/known issues/sucsessful stories/e.t.s about twisted and nevow in production environment (e.g. in Internet) Server configuration, start/stop, logging, monitoring, availability Some tips about programming style (for example, like in PHP - "never use global variable mapping, use $_POST[] $_GET[] instead") And so on. I'll done my project next month, and i must pulish it in internet. Is there any official web-resources of such thematic?

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twisted web / reactor.callInThread()
by Andreas De Stefani 21 May '05

21 May '05

hi all, I am using reactor.callInThread(methodname, args ...) to start a function in a new thread from a twisted web application. Today i got problems with my server, and when i looked at the currently running processes there where about 50 twisted processes running, some of them where days/weeks old. I increased the Threadpoolsize previously with the command reactor.suggestThreadPoolSize(50) to 50 in order to have more parallel executions... Could it be that some of the threads didnt get terminated and cleaned up correctly, or are the processes just visible because the threadPoolSize was set as high? ...I'm almost sure my function terminates correctly... any help or information about this behaviour would be appreciated thanks Andy

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broadcast events; sessions
by ellers＠ellerton.net 19 May '05

19 May '05

Hello all :) Can anyone help me with these questions? - I need to include in my server the ability to sent a broadcast of an event out to listeners. The listeners will be GUIs that are normally communicating with the server by calling XML-RPC. Naturally, when the server wants to broadcast an event back it will need some other mechanism. Is UDP what I should be looking for? Although my app is a system monitoring tool, I guess this in this respect the behaviour I want is similar a chat server, as in the demo chatserver.py? - The server will have a HTTP interface as well as XML-RPC (I know XML-RPC is HTTP but you know what I mean) and I need the flow to go like (a) user logs in with SSL (b) user redirected to non-SSL page (c) subsequent operations in web pages use session info like username (d) XML-RPC calls should also have same SSL/login sequence I figure this requires the use of cookies and sessions. Are there any tips or fully functional "rich" demos that cover this ground? (I'm thankful for the demos online and test progs ... but what I REALLY need is substantial docs and/or samples, fully functional extensive applications) Thanks for any tips - much appreciated :) Ellers

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nevow meets docutils
by Eric Faurot 19 May '05

19 May '05

Hi all, I've written a bit of code to: - make docutils somewhat useable for the programer, - use nevow for rendering document in a flexible way. It is maybe a bit hackish, but it suits my needs for now. People using docutils and/or nevow might be interrested. Feedback would be appreciated (is it utter crap?). Run nevowdemo.py to try out (produces nevowdemo.html from nevowdemo.txt). You'll need a recent docutils, nevow and zope.interface. Eric.

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Bootstrapping for Nevow
by Manuel Holtgrewe 17 May '05

17 May '05

Hi First of all, I'd like to introduce myself in three lines: I'm Manuel Holtgrewe, stuying computer sciences in Germany. One of my interested is web programming and "scripting" (or better dynamically typed) languages like Python and (sorry to mention it in one sentence with it:) PHP. I am - or better was - one of the developers of the Binarycloud project [1] that tried to bring structure into PHP web developing. I'm currently trying to replace Binarycloud with some Python based for my freelancing work and have reached at Nevow. == Okay, now to the real reason of this mail. I talked to some of the Nevow community (namely dialtone, mg and others) on IRC and they agreed that it might be a good idea to provide some small bootstrap utilities to get you started with a new Nevow page without having to copy anything manually from your old projects etc. This would also lead to "best practice" for a Nevow project and help to "standardize" things, i.e. allow to document it and to give people that are new to Nevow (like me) a way to see how Things Are Done With Nevow. Okay, the way I would imagine such a tool is shown in the thing I hacked up [2]. It basically only copies some files from a skelleton directory and sets you up with a minimal project workspace. A quick explanations of my thougths that went into the skelleton: . |-- ntools | |-- __init__.py | |-- project.py |-- scripts | |-- mkproject.py `-- skel |-- doc |-- project | |-- __init__.py | `-- site | |-- __init__.py | |-- html | | |-- index.html | `-- resources | `-- header-logo.png `-- server.tac - A doc directory is created in the project's directory to hold things like notes and diagrams. - There is a module package called site that holds the things that are specific to the current site and are not very likely to be reused in other applications. Those components should go into their own packages parallel to "site". - The project.site (__init__.py) module defines the "entry points" for the "site" component. Things are spread into other modules in the site package so you don't get a 1MB Python file. Maybe that's not good Python style, please correct me then. - The project.site package contains a resources and a html directory that contain the root template and global images, CSS files etc. that are not reused in other components. - Other components would have their own resources directory and the SiteRoot rend.Page subclass will provide URLs like the following so all resources are at one place: * /resources/site/someimage.png * /resources/forumcomponent/somecss.css This has the advantage that in the CSS you can have things like @url(../site/someimage.png). You could, of course, make the CSS be dynamically generated, but I like static things because they can be easier to maintain. Okay, so did I head into the completely wrong direction with my "best practice" proposals? If yes, please tell me what you use and I can learn from it and we could maybe make that tool useful. I also think we could add things like "package" generation for components parallel to site. Regards, Manuel Holtgrewe [1] http://www.binarycloud.com [2] http://www.ggnore.net/~mholtgrewe/misc/nevowtools.tar.gz

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SLUT, twisted based experimental graphix framework
by stephan) 17 May '05

17 May '05

I would like to thank everybody who helped me gain knowledge about twisted. Please feel free to check out my twisted-based thesis project: http://slut.sourceforge.net/index.html #stephan

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ldaptor , python-ldap , nevow
by jean-marc.pouchoulon＠ac-montpellier.fr 16 May '05

16 May '05

Bonjour, I try to run ldaptor examples with python2.4.1 , twisted 2.0, nevow 0.4.1, fedora core 3. .05_form gives me "Deferred instance has no attribute 'original'" and some warnings. (the previous examples ran correctly.) Does anyone has an updated code ? ( I used the latest code I've got from svn ) I search also python-ldap examples with twisted and nevow. Thanks.

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