Mailman 3 August 2007 - Twisted-web

Test
by Philippe Lafoucrière Aug. 5, 2021

Aug. 5, 2021

Hi all just a test

3 2

Deferred inside XMLRPC method
by Daniel de la Cuesta Aug. 30, 2007

Aug. 30, 2007

2 1

Nevow application as a plugin
by tarjei Aug. 23, 2007

Aug. 23, 2007

Hi, as part of making my application ready for prime time, I'm looking for solutions / suggestions to a few problems. My goal is to be able to launch the application using twistd <appname> --some-param and not have to know the path to the app.tap file and be able to mix normal twistd commandline options and extra application specific options. Does anyone have an example of a Nevow application running as a plugin? [1] Is the document referenced above using the new plugin system or the old one? (twisted.plugins vs twisted.python.plugin) I have found some nuts and bolts, but I am not too sure on how they fit together. As I've understood it, if I got a package myapp that contains the modules for the application, then there should be a file inside this directory called plugins.tml that defines the twisted plugin. This file contains a method: register('myapp', 'myapp.tap', description='My webapp', type='tap', tapname='myapp') then I can run "twisted myapp" to run this class. I would expect there to be an extra interface to do the actual creation of services. As I've understood it, that is the role of the function makeService(config) function that should be placed in myapp/tap.py. Is this correct or very wrong? What is the correct way to do this? What is missing? I tried to find the interface for the register function, but I didn't find it. Please give me some pointers or an example of how to do this. As you can see, I think I understand 20% of plugins - but am missing the other 80. I've tried subclassing the Options class to be able to add my own configuration options. When I do this and try to start the application using twistd -oy app.tap, it bombs out because the normal twistd commandline options are not included. What am I doing wrong? class VdOptions(usage.Options): optParameters = [ ['config', 'c', '/etc/app.ini'], ] cli = VdOptions() try: cli.parseOptions() # When given no argument, parses sys.argv[1:] except usage.UsageError, errortext: print '%s: %s' % (sys.argv[0], errortext) print '%s: Try --help for usage details.' % (sys.argv[0]) sys.exit(1) Links: 1.http://twistedmatrix.com/projects/core/documentation/howto/tutorial/confi… Thanks a lot for any input on this. Kind regards, Tarjei

2 1

RH init.d
by tarjei Aug. 23, 2007

Aug. 23, 2007

Does anyone have a sample init.d file for Redhat for running a twisted application from standard python? I.e. a wrapper around twisted -oy app.tac ? Regards, Tarjei

1 0

Nevow, IRequest and REST
by Vincent Bernat Aug. 21, 2007

Aug. 21, 2007

Hi ! In REST world, to overcome limitations of some navigators or limitations of XHTML, there is a method called "overloaded" POST. When you want to use PUT or DELETE method but you cannot, you use POST and you add "_method" to POST arguments whose value is either "PUT" or "DELETE". I have inherited from rend.Page and used some code like this to implement this idea: request = inevow.IRequest(ctx) if request.method == "POST" and request.args.get("_method") in ["PUT", "DELETE"]): request.method = request.args.get("_method") del request.args["_method"] However, I now would like to use the same snippet in rend.Fragment. I could subclass rend.Fragment but maybe there is a better way to centralize all those modifications in one place. Could I redefine IRequest adapter (where is it?) to achieve this? And how to explain to the registry that my adapter must be used in place of the original adapter? In a similar manner, I would like to modify stan such that T.form(method="PUT") to be turned into T.form(method="POST")[T.input(type="hidden", name="_method", value="PUT")]. Is it some easy way to do this ? Thanks !

1 0

rest webservice and big data.
by Sébastien HEITZMANN Aug. 20, 2007

Aug. 20, 2007

Hi I'm new to twisted programming and I'm wonder how to do the following thing. I would like to save in a file the content of a PUT method. But i need this in a stream mode ( the data may be handred of MB ) Here is a part of my code. class DataResource(resource.Resource): def __init__(self, dbConnection): resource.Resource.__init__(self) def render_PUT(self, request): request.content.seek(0) file('data.dat','wb').write(request.content.read()) request.write('OK') request.finish() Thats inspired by an exemple of the oreilly book. Is there a way to get a coolback juste after the header was sended and to handle the reading of the remaining data myself ? I use only web, not the new web2 api. Thanks in advance for any help or link. Sebastien.

4 5

Passing events to (Athena) event handlers.
by kgi Aug. 6, 2007

Aug. 6, 2007

Hi all. In the thread entitled "How to insert an Athena event handler using Stan?" in October and November 2006, Jean-Paul Calderone said: """ The issue with the handler you showed me is most likely that the handler thinks its first argument is an event, but it is actually a node. There is no way to access the event object right now, but I have been considering just passing it as the next argument. """ and: """ [Though] this may shortly change to function doFoo(self, node, event) (which is completely backwards compatible, of course, due to the magic of javascript sucking so much). """ I've just hit this particular issue. Up until now all my events have been heavily node-based (e.g. tabbing out of a field, submitting a form, etc), where you can generally get away with just having access to the node the even happened on. However, not having access to the event itself renders handlers for events like 'onkeyup' almost useless, unless you register them with the top-level document (like the Nevow.Athena._checkEscape() works), and as far as I can tell it makes implementing certain things like drag and drop much more difficult. Is there a branch with experimental support for this? If not, I've been digging around in where I think the relevant code is, namely: Nevow/nevow/athena.py line 1062: _handlerFormat = "return Nevow.Athena.Widget.handleEvent(this, %(event)s, %(handler)s);" and: Nevow/nevow/js/Divmod/Runtime/__init__.js line 963: The Javascript looks like: Nevow.Athena.Widget.handleEvent = function handleEvent(node, eventName, handlerName) { var widget = Nevow.Athena.Widget.get(node); var method = widget[handlerName]; var result = false; if (method === undefined) { Divmod.msg("Undefined event handler: " + handlerName); } else { result = Nevow.Athena.Widget.dispatchEvent( widget, eventName, handlerName, function() { return method.call(widget, node); }); } return result; }; It looks like: 1. Adding an event argument to the handler format in the Python (I don't think that _rewriteEventHandlerToAttribute() needs modification); 2. Adding the corresponding 'event' argument to handleEvent() in the JS; 3. Adding IE hacks (using window.event instead of event, etc) to the start of handleEvent(); 4. Adding the event to the list of arguments of method.call() within the anonymous function passed as the fourth argument to dispatchEvent() would achieve this, and as JP pointed out, this should be backwards compatible, as no extant JS handler functions should be declaring additional arguments. Note that within dispatchEvent() itself the callable is invoked as callable.call(widget), but it looks like the 'widget' argument is ignored entirely by the anonymous function, which contains its own method call with its own "closure-y" arguments. Because of this I reckon dispatchEvent() needs no modification whatsoever. Would a patch posted as a trac ticket be acceptable? I searched trac for 'event' and couldn't find anything resembling this. What would the unit test requirements be for a change like this be? Thanks, Ricky

2 2

athena and widget.nodeById
by Phil Mayers Aug. 3, 2007

Aug. 3, 2007

I've got this: class logwatch(athena.LiveFragment): jsClass = u"app.logwatch" docFactory = loaders.stan( T.div(render=T.directive('liveFragment'))[ T.div(id='content'), ]) def msg(self, m): return self.callRemote('msg', m) ...and in app.js app.logwatch = Nevow.Athena.Widget.subclass('app.logwatch'); app.logwatch.methods( function msg(self, m) { // MochiKit is included... appendChildNodes( self.nodeById('content'), P(null, m) ); }) This fails for some reason - I think because the HTML the page generates looks like this: <div id="athena:1" xmlns:athena="http://divmod.org/ns/athena/0.7" athena:class="app.logwatch"> logs <div id="athenaid:1-athenaid:1-content"/> </div> ...node the athena node id prefixs the child IDs twice? Also, the exception this code generates under Firefox (2.0.0.4) also breaks the javascript-python exception bridge code: File "/usr/lib64/python2.5/site-packages/twisted/internet/defer.py", line 107, in maybeDeferred result = f(*args, **kw) File "/usr/lib/python2.5/site-packages/nevow/athena.py", line 434, in renderHTTP response = self.messageDeliverer.basketCaseReceived(ctx, messageData) File "/usr/lib/python2.5/site-packages/nevow/athena.py", line 638, in basketCaseReceived self.livePage.liveTransportMessageReceived(ctx, msg) File "/usr/lib/python2.5/site-packages/nevow/athena.py", line 886, in liveTransportMessageReceived method(ctx, *args) File "/usr/lib/python2.5/site-packages/nevow/athena.py", line 929, in action_respond callDeferred.errback(getJSFailure(result, self.jsModules.mapping)) File "/usr/lib/python2.5/site-packages/nevow/athena.py", line 403, in getJSFailure text = '%s: %s' % (exc[u'name'], exc[u'message']) exceptions.KeyError: u'name' Ideas?

1 1

Adding Athena JS handlers in render methods?
by kgi Aug. 1, 2007

Aug. 1, 2007

Hi all. I hit something earlier today that has me stumped. It might be a case of programming blindness, but on the other hand I might just be trying to do something that isn't supported. Up until now, I've been adding Athena event handlers directly in the docFactory's stan. However, I needed to add something with an Athena event handler that needs data from an asynchronous external source, so I added data and render methods. These normally Just Work, in the case of "vanilla" XHTML, but the Athena handlers don't seem to be processed by _rewriteEventHandlerToAttribute(). In other words, instead of a proper event handler being inserted into the XHTML, like so: <a href="#" onclick="return Nevow.Athena.Widget.handleEvent(this, "onclick", "onclick");">Click Me 0</a> a tag like this appears: <a href="#"><athena:handler handler="onclick" event="onclick"></athena:handler>Click Me 1</a> Here's some sample code to illustrate this. It's not a complete example in that there's no JS code to be invoked when you click on the first link, but it's runnable enough that you can load the page and view the page source. The first link, "Click Me 0", has correct event handlers inserted. The second and third links ("Click Me 1" and "Click Me 2") both have incorrect event handlers inserted. One of them simply returns a piece of stan, the other also makes a supposedly asynchronous call. Am I trying to do something unsupported, or is this a bug? Thanks, Ricky == from twisted.internet import defer from nevow import athena from nevow import loaders from nevow import flat from nevow import tags as T from nevow.page import renderer _js = athena.handler ( event = 'onclick', handler = 'onclick' ) class MyElement ( athena.LiveElement ): docFactory = loaders.stan ( T.div ( render = T.directive ( 'liveElement' ) ) [ T.a ( href = '#' ) [ _js, "Click Me 0" ], T.br, T.div ( render = T.directive ( 'someStan1' ) ), T.br, T.div ( render = T.directive ( 'someStan2' ) ), ] ) def someStan1 ( self, context, name ): return T.a ( href = '#' ) [ _js, "Click Me 1" ] renderer ( someStan1 ) def someStan2 ( self, context, name ): def _cb ( r ): return T.a ( href = '#' ) [ _js, r ] d = self._getData() d.addCallback ( _cb ) return d renderer ( someStan2 ) def _getData ( self ): return defer.succeed ( "Click Me 2") class MyPage ( athena.LivePage ): docFactory = loaders.stan ( T.html [ T.head ( render = T.directive ( "liveglue" ) ), T.body [ T.div ( render = T.directive ( "myelement" ) ) ], ] ) def render_myelement ( self, request, tag ): e = MyElement() e.setFragmentParent ( self ) return e ###################################################################### from twisted.application import service, internet from nevow import appserver port = 7060 application = service.Application ( "example" ) res = MyPage() site = appserver.NevowSite ( res ) webService = internet.TCPServer ( port, site ) webService.setServiceParent ( application )

3 4

Twisted and RESTful app
by Vincent Bernat Aug. 1, 2007

Aug. 1, 2007

Hi ! I would like to add a RESTful interface to an existing Twisted application. To allow a human to interact easily with the application, I want to output bare minimal XHTML (1990 HTML without any presentation, just some class to allow to easily parse the result). I have looked at twisted.web framework. One good point is that there are different methods for each action (GET, HEAD, POST, PUT, DELETE). However, there is nothing to generate XHTML easily. I have looked at Nevow which contains two interesting ways to generate XHTML code (Stan and templates). But the only method to render is renderHTTP. I suppose that the HTTP action is somewhere in the context, but I did not find where yet. I could mix twisted.web with Stan or with Nevow templates. I could also just use twisted.web and use ElementTree to generate simple XHTML page. But do some of you have some suggestions about implementing a RESTful service using Twisted ? Thanks !

2 1