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Watching TV with vlc on Linux via T-Home Entertain

admin — Sat, 20 Feb 2010 22:25:55 +0000

For quite a while we are receiving TV via Internet. The original reason is that I got at most 2 MBit/s via ADSL due to line noise, but VDSL supports 25 MBit/s on the same line. Of course, you couldn’t order the DSL line without also getting a phone flat rate and IPTV.

Most of the channels are encrypted and can only be received with the original “Media Receiver”, which is a proprietary (and Microsoft) solution. But at least, I can watch the public service broadcasts using these playlists for VLC or mplayer.

Extra commas are allowed in debian/control

admin — Thu, 12 Nov 2009 12:31:20 +0000

Today the question came up at work if it is allowed to have extra commas in debian/control dependency fields as in

Depends: ${misc:Depends}, ${shlib:Depends}

The substitution misc:Depends may well be empty. So is this allowed?

It actually is as Tollef Fog Heen quickly replied on IRC (thanks). It is also covered by a test case in the dpkg source tree, so it is unlikely to go away.

There seems to be no documentation about it though (neither policy nor manual pages cover this). Maybe I will send a patch.

Vodafone software for Linux!?

admin — Tue, 03 Nov 2009 21:42:35 +0000

While researching the UMTS stick to buy for our Acer Aspire One netbook, I stumbled across some postings about using the Vodafone UMTS stick with Linux (see here (german)).

That forum discussion contains a link to https://forge.betavine.net/projects/vodafonemobilec/ where you can find “Vodafone Mobile Connect Card driver for Linux is a GPRS/UMTS/HSDPA device manager written in Python, licensed under the GPL”. I am impressed and just ordered two of these sticks.

Emacs: Marking lines in source code

admin — Fri, 30 Oct 2009 14:08:53 +0000

Today I ported some code to a new API. What I really like about that API upgrade: They changed a structure of the interface to a completely new structure, which basically had the same contents with a few new fields. Of course, the order has changed as well and the field names were revised.

Comparing those structure definitions is really no joy, I wished I were able to mark what I dealt with in the header files. With Emacs, that was really a trivial task:

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(defun mark-overlay ()
"Marks the region using a special background color."
(interactive)
(let ((ovl (make-overlay (point) (mark))))
(overlay-put ovl 'face '(:background "light green"))))

(global-set-key [?\C-+] 'mark-overlay)

That was easy. Simple hitting ^+ with the region I dealt with now notes that by adding a green background.

Passing optparse results as keyword arguments

admin — Fri, 16 Oct 2009 14:12:14 +0000

The python optparse package is really handy for parsing command line arguments. When combining this with an extra main function idiom (to allow interactive usage or use as a module), I ran into a small problem – the following code does not run:

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def main(foo, bar):
print("foo: %s, bar: %s\n" % (foo, bar))
if __name__ == "__main__":
from optparse import OptionParser
parser = OptionParser()
parser.add_option("--foo", dest="foo")
parser.add_option("--bar", dest="bar")
(options, args) = parser.parse_args()
main(**options)

This is the error message:

Traceback (most recent call last):
  File "foobar.py", line 9, in 
    main(**options)
TypeError: main() argument after ** must be a dictionary

The problem here is that the options result from OptionParser is instead of type optparse.Values, which is not derived from dict (huh?!). Quoting the Python language reference:

If the syntax **expression appears in the function call, expression must evaluate to a mapping, the contents of which are treated as additional keyword arguments.

Here are two ways to fix the problem:

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# ...
(options, args) = parser.parse_args()
main(foo=options.foo, bar=options.bar) # Fix (a)
main(**options.__dict__) # Fix (b)

I know I prefer (b), especially if there are many options to pass on. Another work around is used by the pylit project (extending the optparse.Values class).

Reading an arbitrary file as python module source admin — Fri, 20 Feb 2009 16:34:55 +0000 Not sure if anybody will ever need this. I just found out because I did not accept that I can’t load my Subversion pre-commit hook as a module. Of course it is actually quite simple: import imp hook = imp.load_source("hook", "pre-commit") It’s that easy. Now I can test the internal functions from ipython before letting it wreck our repository. Using JFreeChart from Rhino admin — Mon, 21 Jul 2008 23:50:03 +0000 Today I wanted to play around with JFreeChart a bit. As I did not want to repeat the edit-compile-link cycle all the time, I decided that it would be fun to use the Rhino scripting engine for playing around. Unfortunately, this did not seem to work at first: torsten@pulsar:~$ rhino Rhino 1.7 release 1 2008 03 22 js> importClass(org.jfree.chart.JFreeChart) js: "", line 2: Function importClass must be called with a class; had "[JavaPackage org.jfree.chart.JFreeChart]" instead. at :2 Basically, this error tells us that Rhino could not find the JFreeChart classes. The error message is not really helpful though… Anyway, after a bit of looking around, I stumbled across a remark in the older “scripting Java” treatment: [...] simply use the command java -jar js.jar Unfortunately the -jar option to java will overwrite your existing classpath. It turns out that /usr/bin/rhino contains just that command. So to start Rhino with most libraries available, you can just run export CLASSPATH=`echo /usr/share/java/*.jar|tr ' ' :` torsten@pulsar:~$ java org.mozilla.javascript.tools.shell.Main Rhino 1.7 release 1 2008 03 22 js> importClass(org.jfree.chart.JFreeChart) The first command will define the Java class path to contain all the installed .jar files in /usr/share/java. The second command starts the Rhino shell, which has gained lots of power now. Look at the following example: importPackage(org.jfree.chart); importPackage(org.jfree.data.xy); importPackage(org.jfree.chart.plot); importPackage(javax.swing); series = new XYSeries(“First”); for (i = 0; i < 100; i++) series.add(i, i*i); dataset=new XYSeriesCollection(); dataset.addSeries(series); chart = ChartFactory.createXYLineChart(“Line chart”, “X”, “Y”, dataset, PlotOrientation.VERTICAL, true, true, false); frame = new JFrame(“Plot”); chartpanel = new ChartPanel(chart); frame.add(chartpanel); frame.pack(); frame.show(); Hello World! admin — Sat, 05 Jul 2008 17:36:23 +0000 Finally I got around to put something up on http://www.landschoff.net. Often I wanted to get something done “at the weekend”. I always spent the time to look around for good solutions, which would have to be secure, portable, etc. – so I never did it. For a change I now installed Wordpress, even though I don’t really trust it to be secure. Let’s see how this works out, at least it looks great and is a charm to install. Of course I still did it the hard way, so this web server is running on Debian unstable of today, inside an OpenVZ virtual environment. Guess, I’ll set up a Wiki for more permanent content next. Thanks to the OpenVZ and Wordpress developers for creating this cool software, and kudos to my fellow Debian developers for the base.