Mailman 3 December 2002 - Twisted

[Twisted-Python] PcapIO
by Neil Blakey-Milner 21 Dec '02

21 Dec '02

Hi again, I'm currently using this PcapIO class in a traffic analyser, and thought people might find it useful, possibly for inclusion in twisted. It relies on pylibpcap (http://pylibpcap.sourceforge.net/). If interested, it's easy enough to use the example code in the pylibpcap distribution in your protocol's dataReceived. Neil -- Neil Blakey-Milner nbm(a)mithrandr.moria.org

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[Twisted-Python] SCGIChannel: SCGI protocol support
by Neil Blakey-Milner 20 Dec '02

20 Dec '02

Hi all, SCGI (http://www.mems-exchange.org/software/scgi/) is a replacement for the CGI protocol, in a similar manner to FCGI. Through mod_scgi on apache, you can delegate sections of a web site served by apache to be handled via SCGI: <Location "/jobsearch"> SCGIServer 127.0.0.1 4000 SCGIHandler On </Location> SCGIChannel serves as a replacement to HTTPChannel, performing the request with the information given over SCGI, and returning the reply. A couple of changes are necessary to make use of inheritance of HTTPChannel and server.Site to work as expected with its protocol. These are in scgi-changes.patch. I work around the lack of these changes in the scgichannel.py attached. Use the above apache directives and this file to see what it does. Opinions requested. Neil -- Neil Blakey-Milner nbm(a)mithrandr.moria.org

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[Twisted-Python] New SerialPort transport and associated goodies
by Bob Ippolito 20 Dec '02

20 Dec '02

For those of you that haven't noticed, I've added a SerialPort transport with some help from Itamar. It's dependent on pyserial (http://pyserial.sf.net/), and currently supports posix and Jython. It'll eventually support win32. I've done two GPS protocols, NMEA 0183 (almost all receivers support this) and Rockwell Zodiac (for the DeLorme Earthmate, which doesn't). There's other protocols for Trimble and Garmin receivers, but they support NMEA. There is a new gpsfix example in doc/examples, and I've refactored the MouseMan example to use the new SerialPort transport.. however, I don't own any serial mice, so someone else is going to have to test it. -bob

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[Twisted-Python] New SerialPort transport and associated goodies
by Bob Ippolito 20 Dec '02

20 Dec '02

For those of you that haven't noticed, I've added a SerialPort transport with some help from Itamar. It's dependent on pyserial (http://pyserial.sf.net/), and currently supports posix and Jython. It'll eventually support win32. I've done two GPS protocols, NMEA 0183 (almost all receivers support this) and Rockwell Zodiac (for the DeLorme Earthmate, which doesn't). There's other protocols for Trimble and Garmin receivers, but they support NMEA. There is a new gpsfix example in doc/examples, and I've refactored the MouseMan example to use the new SerialPort transport.. however, I don't own any serial mice, so someone else is going to have to test it. -bob

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[Twisted-Python] woven nested lists
by Glyph Lefkowitz 18 Dec '02

18 Dec '02

This is on its way to becoming a FAQ, so when LordVan asked how to do list nesting in woven on the IRC channel, I figured I should post something here rather than just answer the question there. http://www.twistedmatrix.com/users/glyph/py/src/nestedlist.py As it happens, I discovered a woven bug in the process :-). The code here has 2 embedded templates ('template' and 'brokenTemplate'), one of which works with CVS as of a few days ago and one of which works with CVS as of a few minutes ago. You can see my commit message about that if you're interested in the details: http://www.twistedmatrix.com/pipermail/twisted-commits/2002-December/005021… -- | <`'> | Glyph Lefkowitz: Traveling Sorcerer | | < _/ > | Lead Developer, the Twisted project | | < ___/ > | http://www.twistedmatrix.com |

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[Twisted-Python] Creating a new selectable (for Pg async interface)
by Gerhard Häring 18 Dec '02

18 Dec '02

Hello, I'd like to learn asynchronuous programming with Twisted, because I think this will make me a better programmer, no matter if I'll use this paradigma in the end or not. So I thought about wrapping PostgreSQL's asynchronous interface to be usable from a Twisted app. I did once chat a little with Itamar about this on #twisted, and now I finally got around starting this. I don't really know much about twisted, so please correct me if this is wrong: A reactor is the Twisted main loop, which selects on selectables, and invokes doRead() on them when data is available. Itamar told me I'd need to implement twisted.internet.abstract.FileDescriptor, so this is what I did (very incomplete code): #v+ from twisted.internet import abstract from pyPgSQL import libpq class PgAsyncConn(abstract.FileDescriptor): def __init__(self): abstract.FileDescriptor.__init__(self) # PostgreSQL stuff self.conn = libpq.PQconnectdb("host=gargamel dbname=gerhard") self.fileno = self.conn.socket.fileno self.startReading() def write(self, data): print "writing" def query(self, callback, errback, *args, **kwargs): print "sending query ..." self.conn.sendQuery(*args) self.callback, self.errback = callback, errback print "query sent." def operation(self, callback, errback, *args, **kwargs): print "operation" def doRead(self): self.conn.consumeInput() if not self.conn.isBusy: print "data available" res = self.conn.getResult() print "got result." bla = self.conn.getResult() assert bla is None print "query sucessfully processed." # call callback here self.callback(res) def connectionLost(self, reason): """The connection was lost. """ self.conn.finish() #v- Now I'm at the point where I'd like to try this code out. *But* obviously something is still missing. I believe my PgAsyncConn would need to be registered with the reactor?! Is this true and if yes, how do I do it? Btw. I'll try to keep my new baby interface-compatible with twisted.enterprise.adbapi as much as possible. Next question: I'd like to try my code out. Is there a good way to test this under Twisted, apart from writing a little server like the Echo example of the docs, and trying to call PgAsyncConn from it? TIA, Gerhard -- Favourite database: http://www.postgresql.org/ Favourite programming language: http://www.python.org/ Combine the two: http://pypgsql.sf.net/

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[Twisted-Python] test_nmea failing
by Jp Calderone 18 Dec '02

18 Dec '02

exarkun:~/projects/python/Twisted$ python2.1 admin/runtests -v -t --file twisted/test/test_nmea.py reactor class: twisted.internet.default.SelectReactor testGPSMessages (twisted.test.test_nmea.NMEAReceiverTestCase) ... FAIL ====================================================================== FAIL: testGPSMessages (twisted.test.test_nmea.NMEAReceiverTestCase) ---------------------------------------------------------------------- Traceback (most recent call last): File "./twisted/test/test_nmea.py", line 114, in testGPSMessages self.failUnlessEqual(expectedResult, actualResult, "\nInput:\n%s\nExpected: %r\nResults: %r\n" % (message, expectedResult, actualResult)) File "./pyunit/unittest.py", line 279, in failUnlessEqual raise self.failureException, (msg or '%s != %s' % (repr(first), repr(second))) AssertionError: Input: $GPGLL,4250.5589,S,14718.5084,E,092204.999,A*2D Expected: (-42.842648333299998, 147.30847333299999, 33724.999000000003, 1) Results: (-42.842648333333337, 147.30847333333332, 33724.999000000003, 1) ---------------------------------------------------------------------- It does occassionally pass with 2.1, and it seems to always pass with 2.2. Jp -- Examinations are formidable even to the best prepared, for even the greatest fool may ask more than the wisest man can answer. -- C.C. Colton -- 12:00am up 1 day, 9:44, 2 users, load average: 0.00, 0.00, 0.00

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[Twisted-Python] Event-driven version of gzip module?
by l.m.orchard 17 Dec '02

17 Dec '02

Still getting my head around Twisted, so hopefully I make sense in asking this: Does there happen to be an event-driven version of the gzip module for Twisted? That is, instead of expecting a file object to actively read and seek at will, it accepts chunks of data from a stream and hits a callback with decompressed chunks as they're available. (Would this involve a deferred?) I was trying to do something with just zlib, but I forgot that that doesn't do anything to handle the header of a gzip stream like the gzip module itself does. Trying to handle on-the-fly HTTP decompression - at present things work fine if I slurp the whole response body down into a file object and let gzip have at it, but I'd rather stream things through a pipeline a chunk at a time than buffer it all up first. Dropped into #twisted on freenode, but didn't get much response, so I figured I'd post here too. -- l.m.orchard <deus_x(a)pobox.com> http://www.decafbad.com ...see you space cowboy

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Re: [Twisted-Python] woven headache
by Donovan Preston 16 Dec '02

16 Dec '02

A List of Links into HTML The easiest way to do this is to use the List and Anchor widgets to handle the list and a string, respectively. If you had an RPY that looked like this (the main model is a list of strings): LinkList.rpy ---- from twisted.web.woven import page resource = page.Page(['http://www.google.com', 'http://www.foo.com'], templateFile="LinkList.html") ---- Your template file would look like this: LinkList.html ---- <html> <ul view="List" model=".">  <li pattern="listItem">  <a view="Anchor" model="." />  </li> </ul> </html> ---- There you go. Unfortunately the base Anchor widget is pretty dumb. It just takes a string model, and sets the node href= to the string, and adds a text node to the <a> node. Next installment: writing a custom widget that does fancier stuff. Donovan

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[Twisted-Python] woven headache
by Jaakko Niemi 15 Dec '02

15 Dec '02

Hello, So, I tried to do a list of links from a list. Is the right way to do this to point href in self.attributes into a list? If it cannot handle a list, then I don't see how this could be done. --j

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