Mailman 3 February 2005 - Twisted

[Twisted-Python] Use of twisted as web app core
by Ben.Young＠risk.sungard.com 11 Feb '05

11 Feb '05

Hi there, I am trying to evaluate the possible use of twisted as the event framework around which my web app will hang. I would like my app to be run under mod_fastcgi as I like the process control this brings as well as the automatic load balancing across processes. I would also like to use the spread communication toolkit (not twisted spread) to act as a control console to be able to send messages such as "flush cache" to all active processes, even if they are on multiple machines. This asynchronous requirement seems ideal for twisted as both of these mechanisms use sockets or file descriptors for communication. The questions I have are: fastcgi communicates by using the stdio stream as a socket. Is there a way in twisted of treating a fd number as is it were a socket? Has anyone written a fastcgi protocol object? I have looked at the fcgi.py (http://alldunn.com/python/fcgi.py) project and it seems like the project should be relatively easy to port. Has anyone used spread with twisted? I think you can use select to see if there is a message waiting, but then you have to use the spread api to actually access the message. Is twisted the way to go or should I use the simpler code of asyncore (although I have heard bad things about that) Cheers, Ben

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[Twisted-Python] best way to turn on SO_KEEPALIVE option on all sockets
by Alec Matusis 11 Feb '05

11 Feb '05

Hello, I was wondering what is the best way to turn on KEEPALIVE option on all sockets opened by my twisted server. I have inserted s.setsockopt(socket.SOL_SOCKET,socket.SO_KEEPALIVE,1) line into twisted/internet/base.py class BasePort(abstract.FileDescriptor): """Basic implementation of a ListeningPort.""" addressFamily = None socketType = None def createInternetSocket(self): s = socket.socket(self.addressFamily, self.socketType) s.setblocking(0) ++ s.setsockopt(socket.SOL_SOCKET,socket.SO_KEEPALIVE,1) but I am wondering if there is a better way of doing this, without actually modyfying twsited code... Thanks Alec Matusis.

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[Twisted-Python] Re: [Twisted-commits] r12963 - Add .todo unit tests for static.File range support.
by Itamar Shtull-Trauring 11 Feb '05

11 Feb '05

On Thu, 2005-02-10 at 15:20 -0700, Tommi Virtanen wrote: > Added: > trunk/twisted/web/test/test_static.py > Log: > Add .todo unit tests for static.File range support. Might be better to add this sort of stuff to web2, since that's where the active development is happening (especially since that probably has rewritten range header support).

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[Twisted-Python] Suggestion for Deferred docs
by snacktime 10 Feb '05

10 Feb '05

I know this would have helped me, maybe it would others. In the documentation on Deferred's in the howto section, the examples that show a blocking operation and then a non blocking operation do not show what happened to the blocking code, it just conveniently disappears. For someone new to async programming it might help to give an example that shows the blocking code being called via deferToThread. In other words show how you would handle blocking code. It doesn't matter if there are 10 ways of doing it, just one example I think would go a long ways to illustrating the complete idea. I know when I was reading about Deferreds for the first time, I was sitting there thinking 'Ok, I know the example doesn't block now because they just conveniently yanked out the blocking code!!, but what DID they do with it?' Chris

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[Twisted-Python] async code structure question
by snacktime 10 Feb '05

10 Feb '05

Since I'm new to having to structure everything for async programming, I thought I would see if my idea on how to restructure my code makes sense. Say I have a class with several functions that are called in order. Each function relies on the results of the previous function in order to proceed. To write this asynchronously, do I chain them together so that each function is called as a deferred, with the callback pointing to the next function and so forth down the list? Chris

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[Twisted-Python] Twisted builds for Python 2.4?
by Maciej Szumocki 10 Feb '05

10 Feb '05

At the http://twistedmatrix.com/products/download i see Windows installers for 2.2 and 2.3. What about Python 2.4? Maciej Szumocki

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[Twisted-Python] wxPython
by Neal Nelson 10 Feb '05

10 Feb '05

I can't seem to get wxPython to work with Twisted 1.3. I started developing a system some time ago but I've only just got back to it and the user interface no longer works, which is a bit of a problem. Should wx work or is this broken in Twisted?

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[Twisted-Python] twisted-web alive?
by snacktime 09 Feb '05

09 Feb '05

It could just be gmail, but given that I've sent two messages to twisted-web and neither showed up in my mailbox (and no replies either) I'm wondering if something is wrong with the twisted-web list? The messages do show up when I browse the archives. Chris

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[Twisted-Python] twisted.enterprise.adbapi appropriate?
by snacktime 09 Feb '05

09 Feb '05

Say I have a client/server application where the sequence basically goes like this: 1. client connects 2. server queries database 3. server uses results of query to do blocking operation (http POST to another server) 4. server inserts some data into database (1-3 inserts) 5. server sends reply to client Right now 2-4 is all in a single method that I just call with deferToThread, and the callback takes care of 5. I'm trying to understand what advantages I would get from doing this: - convert 2 and 4 to use twisted.enterprise.adbapi. - change 3 to use twisted.web.client. - then restructure the code a bit so I'm not calling 2-4 in a single method via deferToThread (since nothing would be blocking at this point). If twisted.enterprise.adbapi is going to open a new thread anyways, what advantages would there be to restructuring my code as outlined above? The only thing I can think of is that I would get connection pooling and not have to open/close a new connection on each request (which is definitely a plus). Am I on track here or am I missing something? Chris

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[Twisted-Python] Registration is accepted
by Stephen 09 Feb '05

09 Feb '05

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