Mailman 3 May 2007 - Twisted-web

Test
by Philippe Lafoucrière 06 Aug '21

06 Aug '21

Hi all just a test

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Problem with web2 HTTP server + authentication
by Mircea Amarascu 01 Jun '07

01 Jun '07

Hello, I'm using a web2 server with Basic authentication provided by twisted.web2.auth.basic There are cases when PUT requests with attachments from a client time out, as following: 1. When the client issues the first PUT request, without an Authentication header, the server responds with a 401 Unauthorized before receiving all the attachment (I see this in a TCP trace made with ngrep). I want to ask if this is the right behavior, I saw that Apache waits for the entire attachment before replying with 401. 2. The client I used sends the next PUT request right after the attachment, without an \r\n separator, e.g. ...<closing-xml-tag>PUT /resource HTTP/1.1 Host: ... Is this normal ? Sometimes, when the attachment is bigger, some 10KB, the second PUT sent by the client (with the Authentication header present), is not entirely received by the server, which times out as it waits for the entire attachment, with size = ContentLength. I've printed the data received on the TCP socket, in the doRead() method of twisted.internet.tcp.Connection, and I think sometimes in the processing the HTTPChannel or HTTPFactory stops reading the data, it close the connection for reading, or something like that. Did anyone got a similar behavior? Thank you.

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Trouble chaining Javascript module calls in Athena (example code attached).
by kgi 31 May '07

31 May '07

Hi all. I'm doing a lot of Athena stuff at the moment. Calls from client->server and server-> client (which is virtually 100% of the calls) are working wonderfully. However, I'm having difficulty getting one Javascript module to call directly onto another Javascript module (that is, client->client) in a way that I would expect, and I think it's something in the package/module system Athena uses that I haven't yet grokked. I've attached a minimal test case. Since it actually has a directory structure, I've tar-gzipped it; sorry for the additional inconvenience. Directions are in the README file. The only requirement is that you modify PYTHONPATH before twistd-ing the tac file (actually, it's a .py file, but it should be a .tac file). Briefly, the problem is this: I've got two Javascript modules associated with LiveElements; in the example these are XCall.A and XCall.B. XCall.A knows about XCall.B through an import "statement"; that is, it has a line: // import XCall.B It tries to call a method on XCall.B (XCall.B.chain()), but it can't see this method and throws an exception (which is caught by Nevow). Examining the Javascript objects through Firebug shows that XCall.B doesn't have any of the methods passed to its methods() method in the object top-level namespace; instead, these are all available in the "prototype" attribute. In other words, I can call XCall.B.prototype.chain(), but not XCall.B.chain(). Now, I know that the "prototype" attribute is the kooky way that Javascript implements some of its OO-ness, but all the Nevow code seems not to do it this way: it just imports and uses directly: // import Foo.Bar Foo.Bar.doStuff() so I'm confused as to why I can't do the same thing myself. I'm running Python 2.5, Twisted 2.5.0, and have the same problem on both Nevow 0.9.18 and on trunk head. Can anyone spot what I'm doing wrong? Thanks, Ricky

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nevow "context removal"
by aleuser＠inwind.it 30 May '07

30 May '07

Hi, I read the follwing http://divmod.org/trac/wiki/DivmodNevow/ContextRemoval but I cant find "page.Page" >>> from nevow.page import Page Traceback (most recent call last): File "<stdin>", line 1, in ? ImportError: cannot import name Page Where can I find it? Thanks Alessandro ------------------------------------------------------ Leggi GRATIS le tue mail con il telefonino i-mode di Wind http://i-mode.wind.it/

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XML-RPC and Authentication
by Andrey 27 May '07

27 May '07

In the xmlrpc auth with auth.wrapper example below, how to pass the avatar information to the EXAMPLE(XML_RPC) class? e.g. ============================= xmlrpc_welcome(){ return "Welcome "+username } ============================= Cheers Andrey from zope.interface import Interface, implements from twisted.cred import portal from twisted.cred import checkers from twisted.web2 import channel from twisted.web2 import http from twisted.web2 import responsecode from twisted.web2 import server from twisted.web2 import xmlrpc from twisted.web2.auth import digest from twisted.web2.auth import basic from twisted.web2.auth import wrapper from twisted.application import service, strports class IHTTPUser(Interface): pass class HTTPUser(object): implements(IHTTPUser) class HTTPAuthRealm(object): implements(portal.IRealm) def requestAvatar(self, avatarId, mind, *interfaces): if IHTTPUser in interfaces: return IHTTPUser, HTTPUser() raise NotImplementedError("Only IHTTPUser interface is supported") class Example(xmlrpc.XMLRPC): """An example object to be published.""" addSlash = True def xmlrpc_echo(self, request, x): """Return all passed args.""" return x def xmlrpc_add(self, request, a, b): """Return sum of arguments.""" return a + b portal = portal.Portal(HTTPAuthRealm()) checker = checkers.InMemoryUsernamePasswordDatabaseDontUse(guest='guest123') portal.registerChecker(checker) rsrc = Example() credFactories = (basic.BasicCredentialFactory('My Realm'), digest.DigestCredentialFactory('md5', 'My Realm')) ifaces = (IHTTPUser,) root = wrapper.HTTPAuthResource(rsrc, credFactories, portal, ifaces) site = server.Site(root) application = service.Application("XML-RPC Auth Demo") s = strports.service('tcp:8080', channel.HTTPFactory(site)) s.setServiceParent(application)

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Re: [Twisted-web] Different behavior of twistd with and without -n
by Terry Jones 26 May '07

26 May '07

>>>>> "Seb" == S�bastien LELONG <sebastien.lelong(a)dexia-securities.fr> writes: Seb> FWIW, I have an application running CherryPy over Twisted, using Seb> PyLucene. Since PyLucene isn't thread-safe, every thread must Seb> subclass PyLucene.PythonThread, so the underlying "java runtime Seb> garbage collector is aware about the python thread upon their Seb> creation" Seb> (http://lists.osafoundation.org/pipermail/pylucene-dev/2004-June/000037.html). Seb> Without this, the apps simply crashes (segfault, see also Seb> http://chandlerproject.org/PyLucene/ThreadingInPyLucene). Maybe Seb> there's something about that while twistd is daemonizing the process ? Hi S�bastien. I read those pages at some point, but seeing as my code doesn't use threads I never paid that much attention. My app runs through the code where it crashes multiple times before things die, so I'm not suffering from the kind of segfaulting you saw. From what I can tell, something is deliberately calling abort(3) when it detects a problem. It doesn't look like a signal is received or a system call is failing. Thanks a lot for the suggestion. I hope I'm understanding you right - that it's not an issue for me as I'm not using threads directly (but is Twisted? I'm not sure). Terry

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atomic log write
by Manlio Perillo 25 May '07

25 May '07

Hi. Since I want to write to the same log file from multiple Twisted processes, I need to know if the log write is atomic. Reading the twisted log source, I can see that the log entry is written using only one write, so the question is if this operation if always atomic, even for large buffers. Thanks Manlio Perillo

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Different behavior of twistd with and without -n
by Terry Jones 25 May '07

25 May '07

I'm not sure if this belongs in Twisted Python or Twisted Web. I have a twisted.web2 server that, among other things, makes calls to PyLucene. Without going into detail, I'd like to ask a general question to see if there's a high-level explanation for what I'm seeing. When I run twistd without -n, I can take actions in the web UI that fairly reliably cause a call into PyLucene that stops the twistd server. I don't know what's going on, but the server definitely dies (it no longer appears in ps, and you can't telnet to its port). There's nothing in the log file, no core file (I have ulimit -c unlimited), nothing. This is on Mac OS X 10.4.9, PyLucene 2.1.0-2, Python 2.5, Twisted trunk revision 20059. When I stick in debug prints to stderr, I can see that (usually) a call to PyLucene.IndexWriter.optimize and (sometimes) a call to PyLucene.IndexReader.open never returns. The weird thing is that when I run twistd -n using the same .tac file, I can't make the thing fall over. I can click away to my heart's content in the application UI, and it all just works. I also tried running twistd under pydb and the thing wouldn't crash. While I realize there's probably something up with PyLucene, I'm wondering if anyone can suggest why running with twistd -n is preventing the crashing. What else does -n do, other than (presumably) forking and running the server in the child? Regards, Terry

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Re: [Twisted-web] Different behavior of twistd with and without -n
by Terry Jones 25 May '07

25 May '07

Hi Glyph | The fork does some other things though, and it's hard to say which one is | affecting the execution of your program, especially since PyLucene is doing | a bunch of things at the machine-code level which are highly surprising to | Python programmers. I'm too old to be highly surprised any more, and I'm barely a Python programmer... :-) | Have you tried running 'strace' on this process yet? No, I hadn't, thanks. Running ktrace sheds a little light on things. The final output before it writes the core file is: 7826 Python CALL write(0x2,0xbfff971f,0x18) 7826 Python GIO fd 2 wrote 24 bytes "thread_get_state failed " 7826 Python RET write 24/0x18 7826 Python CALL sigprocmask(0x3,0xbfff9b08,0) 7826 Python RET sigprocmask 0 7826 Python CALL kill(0x1e92,0x6) 7826 Python RET kill 0 7826 Python PSIG SIGABRT SIG_DFL 7826 Python NAMI "/cores/core.7826" Nothing fails before that. The "thread_get_state failed\n" message does not appear in the twisted server log. The kill is an abort to this process (0x1e92 = 7826). So something (but not a system call) has gone wrong and the code has called abort. That at least explains why the server abruptly dies. Running gdb python /cores/core.7826 and using where/bt provides no useful info: (gdb) where #0 0x00000000 in _mh_dylib_header () >From the kdump output, the process is clearly in the middle of doing PyLucene things (there are a bunch of access calls to files that are in my PyLucene index directories). Grepping for 'thread_get_state failed' in Python, Twisted, and PyLucene gets me just one hit: $ grep -i 'thread_get_state failed' /usr/local/lib/* Binary file /usr/local/lib/libgcj.6.dylib matches Which is a GCJ library file distributed with the Mac OS X binary version of PyLucene. Google thread_get_state failed gives some leads. I'll go bug the PyLucene folks now... :-) Thanks again for the trace suggestion. Terry

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Re: [Twisted-web] Different behavior of twistd with and without -n
by Terry Jones 25 May '07

25 May '07

>>>>> "JP" == Jean-Paul Calderone <exarkun(a)divmod.com> writes: JP> A completely wild guess is that forking is confusing PyLucene in a JP> fatal way. Are you importing PyLucene in the .tac file itself? If so, JP> it may help to avoid doing this, so that no code from PyLucene even JP> gets a chance to run until after the process has already daemonized. Hi JP. Thanks for the suggestion. Yes, the PyLucene import does happen as a result of an import in the .tac file. I just made some changes to delay the import until PyLucene is actually needed. That didn't work, and nor did further hiding the import by using __import__. Is it right that all the -n switch to twistd does is prevent the fork? Terry

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