Mailman 3 April 2003 - Twisted

[Twisted-Python] 1.0.4alpha2 fails accepttests for mail
by Kevin Turner April 10, 2003

April 10, 2003

Packages of 1.0.4alpha2 are on their way to distribution centers now. The reason it's marked "alpha" rather than "release candidate" is because accepttests.runMailTest fails. - Kevin, Acting Release Manager -- The moon is first quarter, 51.4% illuminated, 7.5 days old.

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[Twisted-Python] twistd causing AssertionError, exiting abruptly
by Alex Levy April 10, 2003

April 10, 2003

When I run 'twistd -nf web.tap', twistd spits out the following traceback and exits. I'm really not sure what this means; help? This is a fresh CVS copy. [-] Log opened. [-] twistd 1.0.4alpha1 (/usr/bin/python 2.2.1) starting up [-] license user: Nobody <> [-] organization: No Organization [-] reactor class: twisted.internet.default.SelectReactor [-] Loading web.tap... [-] Loaded. [*web*] twisted.web.server.Site starting on 8888 [*web*] Starting factory <twisted.web.server.Site … [View More]

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[Twisted-Python] Re: ApplicationService orderization
by Kevin Turner April 9, 2003

April 9, 2003

[Recap: Last night, Bob was complaining that the order that services were started and stopped was undefined, saying Bob> well if you have service A dependent on service B Bob> and you don't want service A to actually start service B Bob> like let's say you have a database service or something Bob> and you have another service that wants to persist stuff using the Bob> database service so he made the order in which services are started defined as the order in which they were … [View More]

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[Twisted-Python] incredibly minor "fix"
by Rich Cavanaugh April 9, 2003

April 9, 2003

I know, I couldn't have possibly found something smaller. The warning was annoying me. This is a patch to FormErrorModel to add the request argument to the wmfactory method. Also, I was the one in #twisted this weekend asking about woven.guard. I pretty much figured it out, it seems so easy now. I have some ideas for making it easy (subclassing PerspectiveWrapper) to use any resource to display the login prompt (not the auto-generated FormProcessor). Is this something I should submit, or … [View More]

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[Twisted-Python] Windows <strike>i hate it</strike> Process API
by Christopher Armstrong April 9, 2003

April 9, 2003

So, I've discovered[1] something new about Windows. Basically, there's no such thing as `argv' in win32-land, and each program has to parse its command-line manually (I had known that they had to do wild-card expansion manually, but not parse the entire damned string). This isn't so much the problem as there is no sane Win32 API for starting a process with a sequence of arguments. The reason this is a problem is that Twisted's Process API uses sequences of arguments. In light of this, I have a … [View More]

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[Twisted-Python] flow - a state-machine consumer
by Clark C. Evans April 9, 2003

April 9, 2003

After being convinced on IRC that my use cases arn't what Deferred is meant to solve, Donovan "wzZzy" and I put together a first pass at a more granular 'consumer'. I'm now using it to build some fairly complicated web pages from a database, and may find its way into Woven (although perhaps not in its current form). Anyway, the tool includes: 0. the Flow dispatcher, which is a reactor like mechanism driving events. 1. a mechanism to execute a function in a thread, where the … [View More]

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[Twisted-Python] Resource bug?
by Itamar Shtull-Trauring April 9, 2003

April 9, 2003

Any reason the following is not the way resources work by default? And would the change break backwards compatability? *** resource.py.~1.23.~ Mon Mar 10 12:10:16 2003 --- resource.py Tue Apr 8 11:18:50 2003 *************** *** 57,64 **** def listStaticEntities(self): return self.children.items() ! listNames = listStaticNames ! listEntities = listStaticEntities def listDynamicNames(self): return [] --- 57,67 ---- def listStaticEntities(self):… [View More]

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[Twisted-Python] Default reactor without signal handling
by Peter Hansen April 8, 2003

April 8, 2003

In twisted.internet.reactor, a call to twisted.internet.default.install() is made automatically. That call constructs a SelectReactor with signal handling enabled, without any option for avoiding this behaviour. What's the recommended approach for installing a reactor without the signal handling behaviour turned on? (For the curious, I'm trying to refactor an existing Zope-based application which has a "back end" server using a proprietary protocol on a non-standard socket. Currently we … [View More]

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[Twisted-Python] How do I upload files using FTPClient?
by Daniel Burr April 8, 2003

April 8, 2003

I am currently designing a code-deploying service, to be used in conjunction with a variety of source control tools. I'm looking to use Twisted in the implementation of the file-transfer mechanism, as Twisted's broad protocol support would make it easy for me to switch from say, FTP to HTTP, or to some custom protocol I roll myself. I've experimented with twisted.protocols.ftp.FTPClient, and the one thing I can't seem to grok is how to perform file uploads. I've read through the code, and it … [View More]

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[Twisted-Python] more thoughts on resumable async data flows
by Clark C. Evans April 8, 2003

April 8, 2003

Howdy. I've made quite a few changes to flow.py and it's quickly approaching maturity. To summarize, flow.py is a way to express sequential, streaming data flows that are interruptable as a collection of small, atomic operations. This is needed since sometimes an operation must block, flow.py takes care of resuming your flow at a later time. It's trivial, but here is an example... def printResult(data): print data def addOne(data): return data+1 def finished(): print "… [View More]finished" def dataSource(data): return [1, 1+data, 1+data*2] a = Flow() a.addBranch(dataSource, finished) a.addCallable(addOne) a.addCallable(printResult) a.execute(2) a.execute(8) The above code constructs a flow, starting with a 'branch' operation that generates a series of events, in this case, the lists [1,3,5] and then in a second execution, [1,9,17]. For each one of these events, a function addOne is called on them, and then the output of that function is directed to be printed. This mechanism works with generators... def simpleGenerator(data): for x in range(data): yield x b = Flow() b.addBranch(simpleGenerator) b.addCallable(printResult) b.execute(5) While this may not be all that useful, what Flow brings to the table is the ability to PauseFlow within a processing stage, for example class simpleIterator: def __init__(self, data): self.data = data def __iter__(self): return self def next(self): print "." if self.data < 0: raise StopIteration ret = self.data self.data -= 1 # # imagine a blocking operation here... sometime if ret % 2: raise PauseFlow # <= Goes to main event loop return ret c = Flow() c.addBranch(simpleIterator) c.addCallable(printResult) c.execute(5) The above code produces 4, 2, 0 ; while this may not be all that interesting, if there were N stages above this code, they would all be resumed properly. By tossing PauseFlow, the entire Flow event loop is stopped, and a reactor.callLater(0, loop-again) is called; giving other events in the queue to work. Thus, the flow construct provides a way to not only manage a bunch of useful code snippets into a process; but more importantly gives a way that the entire flow can be interruped and then resumed later when data arrives. Anyway, it's in the sandbox if anyone wants to play... Clark P.S. Unfortunately, it looks like PauseFlow doesn't work in the context of a generator... pity. Hopefully I'm doing something wrong. [View Less]

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