Mailman 3 July 2012 - Twisted

[Twisted-Python] ANN: pythonpackages.com beta
by Alex Clark July 31, 2012

July 31, 2012

Hi Twisted folks, I am reaching out to various Python-related programming communities in order to offer new help packaging your software. If you have ever struggled with packaging and releasing Python software (e.g. to PyPI), please check out this service: - http://pythonpackages.com The basic idea is to automate packaging by checking out code, testing, and uploading (e.g. to PyPI) all through the web, as explained in this introduction: - http://docs.pythonpackages.com/en/latest/introduction.html Also, I will be available to answer your Python packaging questions most days/nights in #pythonpackages on irc.freenode.net. Hope to meet/talk with all of you soon. Alex -- Alex Clark · http://pythonpackages.com/ONE_CLICK

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[Twisted-Python] FW: Large (GB) File Upload
by Bob Novas July 31, 2012

July 31, 2012

Hi - I'd like some guidance, please, on writing a TCPServer that can efficiently receive and process (to a database) large files received from a browser client form (multipart/form-data). I'd like to be able to process the command and headers without waiting for allContentReceived, if possible. In other words, I'd like to actually handle the incoming stream rather than buffer it to a file or a string and then handle the Request when all content is received. Note that the server is used only by a local browser by a single user. It is not used by a large user populace. Is this possible? Are there any examples? Any guidance would be appreciated. This was the best I could find - http://twistedmatrix.com/pipermail/twisted-python/2007-July/015738.html, but it's pretty dated. Thanks, Bob

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[Twisted-Python] Weekly Bug Summary
by exarkun＠twistedmatrix.com July 29, 2012

July 29, 2012

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[Twisted-Python] Deferreds and progress
by Tobias Oberstein July 27, 2012

July 27, 2012

With Twisted, a Deferred can have it's callback only triggered once. With Deferreds in popular JavaScript libraries (when.js, jQuery Deferred, upcoming JS PromiseA proposal), there is a "progress()" callback for receiving results incrementally (or merely reporting on progress until the final result arrives). Progress can be triggered more than once. Is there anything comparable in Twisted? Cheers, Tobias

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[Twisted-Python] Password hash for Perspective Brokers
by Louis July 26, 2012

July 26, 2012

Hello I have a problem with checkers in Twisted, which could be solved by adding a new feature. I think I can write the necessary code, but before doing so, I would like to hear you about it. # The problem If I am right, the only way passwords can be hashed when using authentication with perspective brokers is using MD5 [1]. However, there are two flaws with it. * First, MD5 is no longer considered sure. It may be possible, from the hashed password, to find the original one. * Second, in the current implementation of Twisted, no salt is used to hash the password. A salt is considered good practise : it is harder to find the password from the hashed form, and two identical passwords have different hashed form, which prevent someone looking at the hashed passwords to see if two users have the same password. # A solution I tried to implement the solution proposed in [1], and I think I can manage to do it. However, this seems to be a not-so-smart hack, which is not guaranteed to work in future releases of Twisted. That is why I am proposing a patch. The patch would introduce some arguments to class PBServerFactory [2] to use (or not) a salt, and a different hash function. I am not settled down yet about the new signature of this class, but what is sure is that the default must be the actual behaviour, not to break programs already using Twisted. Then, I hesitate between * two arguments (salt, hash) : salt is a boolean, telling whether to use a salt or not ; hash is the function used to hash the password; * one argument, with possible values being "legacy", "crypt" or "glib2", where: ** "legacy": current behaviour : hashed passwords are md5 hashed passwords without salt; ** "crypt" : crypt [3] behaviour (I would like it to be compatible with [4]): hashed passwords are strings where the first two characters are the salt, and the following ones are the hashed password (using this salt); ** "glib2" : glib2 [5] behaviour: hashed password is of the form $ID$SALT$HASH, where ID identifies the encryption method, SALT being the salt, and HASH being the password, hashed using given encryption method and salt. # My implementation I have not implemented it yet, but I you think my idea is good, I offer to write it. I think I have understood well enough the relevant pieces of code to do so. Of course, I would also write the corresponding tests. Some ideas or comments ? Cheers, Louis [1] http://markmail.org/message/wlzmeesplsriym2a [2] http://twistedmatrix.com/documents/current/api/twisted.spread.pb.PBServerFa… [3] http://man7.org/linux/man-pages/man3/crypt.3.html [4] http://www.giuseppetanzilli.it/mod_auth_pgsql2/#encrypted [5] http://www.gnu.org/software/libc/manual/html_node/crypt.html#crypt

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[Twisted-Python] stopping a twistd daemon: SIGTERM or SIGKILL
by Tom Sheffler July 25, 2012

July 25, 2012

Hi Twisted Folks, We use monit to start and stop our twistd daemons. I have set up monit to restart some of the daemons when they grow too large. I use the following command: /bin/bash -c 'kill -s SIGTERM `cat /var/run/sensrtunw/sensrtunw.pid`' Occasionally, this is unsuccessful in killing the twistd process, and I need to use a SIGKILL manually as a last resort. Any ideas why? I believe the SIGTERM method will do a clean shutdown, calling the appropriate stopService methods. This would be the preferred method. The only thing that comes to mind is that the process does have a very few threads ... I believe these are the database connections. Could there be a race condition that prevents twistd from stopping? Shall I simply use SIGKILL in all cases? Suggestions or comments appreciated. -Tom

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[Twisted-Python] SMTP authentication
by Sarah Addis July 24, 2012

July 24, 2012

I am currently trying to use a SMTP server to send emails. However I keep getting the same python authentication error outlined below. The SMTP server requires authentication and can advertise CRAM-MD5 as an accepted authentication method but fails when the client tries to use it. No other methods are tried after the failure, Python's smtplib just raises an Exception. I have attached the traceback below 2012-07-19 15:21:45+0100 [ESMTPSender,client] Unhandled error in Deferred: 2012-07-19 15:21:45+0100 [ESMTPSender,client] Unhandled Error Traceback (most recent call last): * ****Failure: twisted.mail.smtp.AUTHDeclinedError: 535 5.7.0 authentication failed*** <<< 250 HELP >>> STARTTLS <<< 220 2.0.0 Ready to start TLS >>> EHLO localhost.localdomain <<< 250-server.company.co.uk Hello [111.111.11.111], pleased to meet you <<< 250-ENHANCEDSTATUSCODES <<< 250-PIPELINING <<< 250-8BITMIME <<< 250-SIZE 20480000 <<< 250-DSN <<< 250-ETRN * **<<< 250-AUTH DIGEST-MD5 CRAM-**MD5 LOGIN PLAIN* <<< 250-DELIVERBY <<< 250 HELP * **>>> AUTH CRAM-**MD5* <<< 144 $DMwMTEEMDA2OC41MzA1DDVAaGQkcmlh&i5sYXRlbnMuY28udWs+ >>> bGJ1aWxk3XIgYWRhZTUzNmY0OWU1YzU0NmY1MjM0OGIwNGE3^zhjYTg= <<< 535 5.7.0 authentication failed 2012-07-19 15:21:45+0100 [-] SVNPoller: polling 2012-07-19 15:21:45+0100 [ESMTPSender,client] Stopping factory <twisted.mail.smtp.ESMTPSenderFactory instance at 0x5385908> I have googled this problem extensively, the most useful website being https://code.djangoproject.com/ticket/9488 but I am unsure how to implement this solution within the twisted files. I would appreciate any guidance on how to proceed with fixing this problem and which files I should be looking at changing!

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[Twisted-Python] Ping on Ticket
by Dan Milstein July 23, 2012

July 23, 2012

Just wanted to make sure I followed the proper steps. Two weeks ago, I submitted a patch to an existing bug in twisted.mail.imap4, along with new tests + a description of what I did: http://twistedmatrix.com/trac/ticket/4080 Is there anything else I should be doing, at this point? Thanks, -Dan

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[Twisted-Python] Autobahn 0.5.5 released
by Tobias Oberstein July 23, 2012

July 23, 2012

Hello, AutobahnPython 0.5.5 has been released adding new WebSocket and WAMP features. 1) WebSocket/WAMP servers now not only can run standalone, but also take part as a Twisted Web Resource in a Site. This allows to run multiple Web services on one port under differents paths: i.e. mix plain File serving, with WebSocket and WAMP - this was a requested feature. Also, notably, all of RFC6455, Hybi-10+ and Hixie-76 protocol versions are supported. The latter still being needed for Safari (desktop/mobile) i.e. Here is an example: https://github.com/tavendo/AutobahnPython/tree/master/examples/websocket/ec… 2) For WAMP, you now can register custom RPC handlers. Please see the docs for details. 3) WAMP-CRA, the challange-response authentication now fully workes Deferred based, which streamlines ist use. 4) The optional status page a WebSocket server can render (for clients accessing it not via WebSocket, but accidently via HTTP) can now be provided a redirect target, so that automatic redirect to another page happens, after a timeout. == Project Homepage: http://autobahn.ws/ Package: http://pypi.python.org/pypi/autobahn WAMP Protocol: http://wamp.ws/ Cheers, Tobias

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[Twisted-Python] deferred graph?
by Dan Stromberg July 22, 2012

July 22, 2012

Hi. I'm a Twisted neophyte, but I've been using Python a long time. My question: Is there a way of producing a deferred graph in a Python program at a given point in time? Perhaps something based on graphviz and objgraph.py? We're able to detect when we're having the problem, we just don't (yet) know its cause. Background: I'm looking at some code with a bit over 200 addCallback/addErrback/addCallbacks in it. It's got a problem where sometimes the deferreds seem to just stop executing. I see in the doc it says that this can happen if you've neglected to add an errback to the end of one or more of your deferred chains. One of the people who's been here longer than me, indicated that he's gone through the code looking for such issues, and didn't find any. This suggests to me that either there's some other cause, or that it really is a deferred without a final errback, but it's hidden in a dark corner of the code somewhere. Thanks!

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