Mailman 3 November 2005 - Twisted-web

why doesn't work nevow.example.callremote with IE (InternetExplorer)?
by Peter Arwanitis 09 Nov '05

09 Nov '05

Hi there, callremote example demonstrates the notifyOnDisconnect() feature for athena-livepages (using twisted2.0.1 / nevow0.6.0 / python2.3.5 on winXP). Firefox triggers with a reload of the page or a change to another page the callbacks added to notifyOnDisconnect _immediately_ --> perfect! 'A client lives!' 'A client dies!' twisted.internet.error.ConnectionDone: Connection was closed cleanly. 'A client lives!' 'A client dies!' twisted.internet.error.ConnectionDone: Connection was closed cleanly. ... Why doesn't this work with IE, too??? The connections dies in a delayed timeout... but not immediately. The problem is, that meanwhile open connections from IE to webserver was established, and they are limited to TWO!!! And the whole things hangs, waiting for timeouts to free the connections.So this will be a serious bottleneck! (at least for my design :-/) 'A client lives!' 'A client lives!' ... ... later: 'A client dies!' twisted.internet.error.TimeoutError: User timeout transports created by client. thanks to exarkun on irc and his hint to http://www.winguides.com/registry/display.php/536, you can play with number of needed connections, but leaving / refreshing a livepage The mechanism is based on twisted.web.server.Request.notifyFinish() and hopes that this one is throwing a "twisted.internet.error.ConnectionDone: Connection was closed cleanly." if the connection got lost. But this error to trigger the req.notifyFinish().addErrback(...) does not come with IE leaving or reloading a page. Is this specific for me, or can somebody else reproduce this "feature". Does someone have deeper knowledge about the live-connection hold with IE from athena? And how notifyOnDisconnect() could work with IE, too??? thanks a lot greetings from germany, munich Peter (=PA=)

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Instance of child element class never goes away?
by Jay 09 Nov '05

09 Nov '05

Hi, all. This is my first swing at using twisted...and I'm not much of a python jockey either. I'm using twisted.web2, python 2.4.2 on FreeBSD. I've got a simple (two page) application right now -- most of it is shamelessly cribbed from the example provided in the documentation. There's the TopLevel which has one child page -- child_antitrypsin. child_antitrypsin is an instance of a Query class that returns a plain old HTML string via http.Response. Now, to get that string, the Query class has to send a request to another server, get and parse an XML document and construct the string. All well and good. The problem I'm having is that the first child_antitrypsin that gets instantiated seems to be the only one that ever gets created. Refreshing the page -- or clicking on the link -- gives me the string twice...or three times or however many. So, if the first result was "APPLE", the second time, I'd get "APPLEAPPLE" and so on. lynx -dump -head shows that the Last-Modified time is always the same (ie, the creation time). The behavior I expected was for the link to get clicked, the child to get instantiated, do its work, return a result and go away. Do I need to explicitly kill the child object? Thanks! -- Jay.

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Problems with web2.test.test_static.TestFileSaver
by Wilfredo Sánchez Vega 07 Nov '05

07 Nov '05

web2.test.test_static.TestFileSaver has been failing on my DAV branch. dreid and I were looking into it at SHDH and were generally baffled by the breakage. I remain baffled, but have managed to figure out that the test isn't breaking due to the addition of code, but by the simple existence of the test modules in my code. I can reproduce the problem in trunk by doing the following: cd twisted/web2 mkdir dav touch dav/__init__.py mkdir test touch dav/test/__init__.py echo "import twisted.web2.static" > dav/test/test_OPTIONS.py And then run "trial twisted.web2" and watch it blow up in TestFileSaver. In twisted.web2.test.test_static.TestFileSaver.testCompareFileContents (), when the callback gotFname() gets called, if the dav test is not present, then fname is being set to this string: fname = "y>\ntwisted.web2.test.test_static/TestFileSaver/ testCompareFileContents/2336.1/4eb6d0fcd8319ae61aa0639f3c4c1128: File type not allowed MimeType('text', 'plain', {})" ... which is apparently including some previous error condition which is being passed along in a strange sort of way. -wsv

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HTTP client TODOs
by Jan Alonzo 07 Nov '05

07 Nov '05

Hi, Good day everyone! I have a project that I want to port to Twisted. It's an HTTP client (feed aggregator) and one of the reasons why I want to port it is so that I can take advantage of what twisted has to offer and focus on other more important features (and having test apps is, I guess, also good for the project right? :) I am new to twisted and one of my priority right now is to help out with the HTTP client code in the web2 module. Is there a TODO specific to the client library somewhere that I can look at? Cheers, -- Jan Alonzo <jmalonzo(a)unpluggable.com>

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Re: Memory leak with twisted web server on QNX
by Nagy Zsombor 07 Nov '05

07 Nov '05

Hello everyone! [this is my first post] I had a serious memory leak with twisted 2.0.1 and twisted web 0.5, when I created a web server with TLS, and every client connection increased the memory usage. I played with it a lot, and found out, if I comment out line of code in twisted.internet.posixbase, the leak is gone... This one: 322 def _startTLS(self): 323 self.TLS = 1 324 klass = self.__class__ 325 class TLSConnection(_TLSMixin, klass): 326 implements(interfaces.ISSLTransport) !! 327 #components.backwardsCompatImplements(TLSConnection) 328 self.__class__ = TLSConnection So if I uncomment this 'backwardCompatImplements' there is a serious memory leak, if I comment it out, there is no leak. I can show you the test programs if you want me to. Bye, Zsombor

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problems with select boxes.
by Alberto Trujillo 07 Nov '05

07 Nov '05

Hi everybody: My question is the next one. I have implement a form in stan with two select box. The first one is full of datas (select1), and the second one is empty(select2). Also I have two buttons, one to transfer datas from select1 to select2 (button1) and the other to do the opposite. Until now I only can get the value of the item which is selected, but I don't know how to get the text. This is what I'm doing. /T.input(name="button1", value="+", type="button", onclick=livepage.server.handle("addItem", / /livepage.get("select1").value, livepage.get("select1").text)/ /..../ /def handle_addItem(self,ctx, value, text):/ / print "value: %s text: %s" % (value, text)/ / yield livepage.set("select2", value, text)/ I only can see the value with the print function, because text is undefined. How can I get the text, and how can add this values after in the select2? I'm running Nevow 0.5. Thanks in advance.

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Re: Memory leak with twisted web server on QNX
by Nagy Zsombor 05 Nov '05

05 Nov '05

> This should be fixed in r15022. Could you give it a try and let me know? If it fixes it, we should be able to get this into the next point release. Yes, it fixes it, there is no leak now! :) Thanks! Zsombor Nagy (in my previous mail, i wrote it wrong. it was in twisted.internet.tcp, not in posixbase, of course)

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Memory leak with twisted web server on QNX
by denis.leborgne＠rieter.com 04 Nov '05

04 Nov '05

Hi, I use twisted as a very simple web server to serve python scripts. I now have a problem of memory leak on the server. I use Python 2.2.1 on QNX 6.3, Twisted version is 1.3.0. I made the following test scripts : Web server from twisted.web import server, resource,static,script from twisted.internet import reactor root = static.File("site") root.processors = {'.py': script.PythonScript, '.rpy': script.ResourceScript} site = server.Site(root) reactor.listenTCP(8500, site) reactor.run() Test script (.rpy file) from twisted.web import resource class Test(resource.Resource): isLeaf = True def render_GET(self, request): return """<html> <head> <meta http-equiv="refresh" content="5"> </head> Hello, world!</html>""" resource = Test() About every 4 "refresh", the memory used by my server increases by 96k, with nor release of memory. I checked the object number by watching len(gc.get_objects()), but it is stable. Any idea to help me to solve this problem, my server is expected to run continuously. Thanks. Denis

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transferring datas between select box.
by Alberto Trujillo 03 Nov '05

03 Nov '05

Hi everybody: My question is the next one. I have a form with two select box. The first one is full of datas (select1), and the second one is empty(select2). Also I have two buttons, one to transfer datas from select1 to select2 (button1) and the other to do the opposite. I have done this before with javascript, but now I need to do it in Nevow 0.5 and with livepage. Could anybody help me? Thanks in advance.

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livepage connection "timing out"/dying randomly
by Robby Dermody 02 Nov '05

02 Nov '05

Hey guys, I seem to have a problem with client browsers to my guarded livepage application loosing their livepage connections. It seems that the guard session doesn’t expire, but the livepage system on the server side seems like it will loose track of the client’s nevow handle. This is under the Nevow 0.5.0 release, and it happens under both IE 6.0.x and Firefox 1.0.x. Basically, my server app makes livepage calls to the client browser js via clientHandle.call() to reflect dynamically updated data as it happens… (maybe one call every 4 seconds). At this point I found this problem (that at some point these updates in the client would stop, while the server was still making the livepage call() invocations like everything was fine and dandy). The problem was that things just seemed to die, and I could find no error output showing why. Well, in my search for a fix/error output, I added a js function on the client that calls server.handle('refreshSession()') every 120 seconds via the use of repeated setTimeout() calls. The corresponding handle_refreshSession() function on the server gets that client's session object and touch()es it. This will start out working fine for usually a few hours (the session timeout is 1200 seconds currently), and the client will stay logged in. Then after some seemingly arbitrary amount of time, I will start getting the following errors, one set for each refreshSession() call: From the client side (firefox java console): Error: syntax error Source File: http://216.148.216.20:8800/mon/nevow_glue.js Line: 155 Source Code: <html><head><title>Exception</title></head><body><style type="text/css"> From a glance at nevow_glue.js, it looks like the server returned an exception page to the client and nevow_clientToServerEvent() in nevow_glue.js didn’t like that when it tried to evaluate it as javascript code, or some kind of javascript result. On the server side I get the following python exception: ---**** EXCEPTION START ****--- Traceback (most recent call last): File "/usr/lib/python2.4/site-packages/twisted/internet/defer.py", line 216, in addCallback callbackKeywords=kw) File "/usr/lib/python2.4/site-packages/twisted/internet/defer.py", line 207, in addCallbacks self._runCallbacks() File "/usr/lib/python2.4/site-packages/twisted/internet/defer.py", line 328, in _runCallbacks self.result = callback(self.result, *args, **kw) File "/usr/lib/python2.4/site-packages/nevow/appserver.py", line 308, in handleSegment return defer.maybeDeferred( --- <exception caught here> --- File "/usr/lib/python2.4/site-packages/twisted/internet/defer.py", line 117, in maybeDeferred result = f(*args, **kw) File "/usr/lib/python2.4/site-packages/nevow/livepage.py", line 596, in locateChild client = self.clientFactory.clientHandles[handleId] exceptions.KeyError: '2' ---**** EXCEPTION END ****--- In this case, the key ‘2’ was the setting of the client’s “nevow_clientHandleID” variable. This will happen every time the client tries to make the call (e.g. every 120 seconds). I think these two types of updates I’m doing (one where the server tries to call a js method on the client when its data is updated, and one where the client periodically “pings” the server) are both exposing the same error. The only difference is that the one where the client pings the server with the server.handle() call exposes some error messages of what may be going wrong. Might I be forgetting to do something, or using livepage improperly? My goal is to make it so that, as long as a client’s browser is logged in and at my page, they will keep getting livepage events indefinitely. Might the newest version from the repository fix this? Thanks for any help, Robby

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