Mailman 3 January 2011 - Twisted

[Twisted-Python] Twisted and ICP protocol
by Roberto Franchesco 11 Jan '11

11 Jan '11

Hello All, I have been trying to get a squid proxy to "talk" to a twisted proxy and I came across an old email from this list where someone mentioned that they had implemented a basic ICP protocol in twisted. Does anyone still have that implementation? Or any good pointers on setting me off in the right direction as to how to do this? -Rob

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[Twisted-Python] Twisted and PEP 3148 support
by Alex Grönholm 11 Jan '11

11 Jan '11

There has been some discussion over email between myself and several Twisted developers regarding the possibility of adding support for PEP 3148 futures and executors to Twisted. I'm starting this thread to move the conversation to this mailing list to gain a broader audience. For those who do not know what PEP 3148 is about, suffice to say that it's an API for deferred execution of code. The reference implementation can be found in the Python 3.2 standard library under the package name concurrent.futures. A backport that works on Python 2.5, 2.6, 2.7 and 3.1 has been made available by Brian Quinlan and myself and is available for download at the Python Package Index. A brief summary of the email conversations: * The purpose of integrating PEP 3148 support is the intended shift towards a common API for creating asynchronous applications * Deferreds and Futures are alike in purpose but very different under the hood * Support for the Futures API cannot be integrated directly to Deferreds because of the "result" attribute which is a method in Future but a value in Deferred * Some people suggested wrapping Futures in Deferreds, though I have yet to hear a rationale for this * PEP 3148 executor support could be directly integrated to Twisted's thread pools (and by extension, reactors) as there are no naming conflicts that I'm aware of The main focus of the discussion is to figure out how to best integrate support for this new API to Twisted. If possible, existing protocols should remain compatible through the use of adapters or some other mechanism. If not, a way to port them over with a minimal amount of work would be the next target.

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[Twisted-Python] Want something fixed?
by exarkun＠twistedmatrix.com 10 Jan '11

10 Jan '11

Hi all, I'd like someone to do a review on #4395 - a ticket about some conch key exchange bugs. The branch isn't very large, a little under 500 lines of diff (with nearly a hundred of those deletions). In exchange for a thorough review (and perhaps a re-review if issues are found which need to be fixed), I'd be happy to spend as much as a full day working on some other issue of the reviewer's choice. Thanks, Jean-Paul

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[Twisted-Python] Twisted Names - strange RuntimeError
by Angelo Dell'Aera 09 Jan '11

09 Jan '11

Hi, while developing a code based on Twisted Names I'm finding myself catching RuntimeErrors like the one reported below. 2011-01-09 10:32:13+0100 [twisted.names.dns.DNSDatagramProtocol (UDP)] Unhandled Error Traceback (most recent call last): File "/usr/lib64/python2.6/site-packages/twisted/python/log.py", line 84, in callWithLogger return callWithContext({"system": lp}, func, *args, **kw) File "/usr/lib64/python2.6/site-packages/twisted/python/log.py", line 69, in callWithContext return context.call({ILogContext: newCtx}, func, *args,**kw) File "/usr/lib64/python2.6/site-packages/twisted/python/context.py", line 59, in callWithContext return self.currentContext().callWithContext(ctx, func, *args, **kw) File "/usr/lib64/python2.6/site-packages/twisted/python/context.py", line 37, in callWithContext return func(*args,**kw) --- <exception caught here> --- File "/usr/lib64/python2.6/site-packages/twisted/internet/epollreactor.py", line 220, in _doReadOrWrite why = selectable.doWrite() File "/usr/lib64/python2.6/site-packages/twisted/internet/base.py", line 1083, in doWrite raise RuntimeError, "doWrite called on a %s" % reflect.qual(self.__class__) exceptions.RuntimeError: doWrite called on a twisted.internet.udp.Port The code which produces this error is really complex and is part of an intelligence data gathering framework I'm developing for the Honeynet Project (for those interested in details please take a look at my technical blog http://buffer.antifork.org/blog/category/tip/ ). I realized that . the RuntimeError is raised really rarely (I see one of such errors every 2-3 days and during this time frame millions of DNS requests and replies are handled) . using different Twisted versions doesn't make the problem disappear (the attached traceback refers to version 10.2.0) . selecting a different reactor doesn't make the problem disappear Unfortunately I have not a test code for reproducing the issue and sincerely speaking I really don't know how to write it because this condition is so rarely met that I'm not able to understand what leads to it. I could be wrong but taking a look at twisted.internet.udp.Port I see it defines a write method so I really do not understand the reason why the BasePort doWrite method raises such error. Thanks for your attention and cheers, -- Angelo Dell'Aera 'buffer' Antifork Research, Inc. http://buffer.antifork.org Metro Olografix

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[Twisted-Python] Amazon AWS, Google app engine and Twisted
by Pandelis Theodosiou 09 Jan '11

09 Jan '11

This may be a dumb question but I'll make it anyway: Is it possible to use Amazon AWS or Google app engine as a hosting envirorment for a Twisted application? Pandelis <http://int.ask.com/web?siteid=10000861&webqsrc=999&l=dis&q=ask%20>

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[Twisted-Python] Weekly Bug Summary
by exarkun＠twistedmatrix.com 09 Jan '11

09 Jan '11

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[Twisted-Python] multicast
by Pandelis Theodosiou 05 Jan '11

05 Jan '11

I'm trying to make a Multicast client. I've tried the simple script found in: http://twistedmatrix.com/documents/10.1.0/core/howto/udp.html#auto3 While it shows no errors, it doesn't receive any data. How can I check what the problem is? It runs on a Debian 64-bit machine where I've installed Python2.6 and Twisted 10.0.2.0 Could it be some firewall setting? Is it possible I've somehow screwed with the installation procedure? Pandelis from twisted.internet.protocol import DatagramProtocol from twisted.internet import reactor from twisted.application.internet import MulticastServer class MulticastClientUDP(DatagramProtocol): def datagramReceived(self, datagram, address): print "Received:" + repr(datagram) # Send multicast on 224.0.0.1:8005, on our dynamically allocated port reactor.listenUDP(0, MulticastClientUDP()).write('UniqueID', ('233.75.215.44', 60044)) reactor.run() <http://int.ask.com/web?siteid=10000861&webqsrc=999&l=dis&q=233.75.215.44>

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[Twisted-Python] job server project
by Umut Aydin 04 Jan '11

04 Jan '11

Hello everybody I just completed an article about writing a job server with Twisted Framework. It's also based on my job server project called Jobbar. http://umut.mobi/blog/2010/12/31/jobbar-distributed-job-server/ I'm still working on it. Happy new year. - Umut

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[Twisted-Python] Weekly Bug Summary
by exarkun＠twistedmatrix.com 02 Jan '11

02 Jan '11

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[Twisted-Python] twcgi duplicate Content-Type
by Laurens Van Houtven 01 Jan '11

01 Jan '11

Hi! I'm using twcgi to serve a Fossil repository through CGI (it's that or xinetd). For some reason, Chrome wasn't rendering the CSS. Looking at the HTTP response headers for the GET request for the CSS file, I saw this: HTTP/1.1 200 OK Date: Sat, 01 Jan 2011 00:14:58 GMT Content-Length: 13484 Expires: Sat, 8 Jan 2011 00:14:58 GMT Content-Type: text/html Content-Type: text/css; charset=utf-8 Server: TwistedWeb/10.2.0 I'm pretty sure duplicate Content-Type headers aren't supposed to happen. After some digging, I'm convinced the Server, Date and the first Content-Type are the default values set in t.w.server [1]. Meanwhile, twcgi [2] users self.request.responseHeaders.addRawHeader, so the default header is never overwritten. I'm pretty sure that's not supposed to happen, but I'm not sure what the correct way to fix this is. Options: 1) Should a list of things that need setRawHeader be introduced? 2) Should setRawHeader be the default, and instead have a list of things that need addRawHeader? 3) Should that twcgi code use request.setHeader instead, like the t.w.server code? I have a feeling it's the last option. but like I said, I'm not sure. [1] http://twistedmatrix.com/trac/browser/tags/releases/twisted-10.2.0/twisted/… [2] http://twistedmatrix.com/trac/browser/tags/releases/twisted-10.2.0/twisted/… cheers and happy new year, lvh

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