Facebook chat with Empathy and Ubuntu

This article explains how to configure Empathy under Ubuntu (9.04 Jaunty Jackelope) to interface with Facebook Chat.

On the technical side of things, the indea is to use pidgin-facebookchat – a libpurple plugin – through telepathy-haze – a telepathy connection manager based on libpurple – to establish and maintain the connection. The plugin can be used directly with Pidgin for similar results.

First, we need to install the needed packages (I assume that empathy is installed):

sudo apt-get install pidgin-facebookchat telepathy-haze

As described here and here you then need to do some fiddling. This might change in the future. What you need to do is:

cp /usr/share/telepathy/managers/haze.manager /tmp/
wget https://bugs.freedesktop.org/attachment.cgi?id=20810
sudo mv attachment.cgi?id=20810 /usr/share/telepathy/managers/haze.manager
wget https://bugs.freedesktop.org/attachment.cgi?id=20811
sudo mv attachment.cgi?id=20811 /usr/share/mission-control/profiles/bigbrownchunx-facebookim-haze.profile

Note: The two sudo lines will override any existing files. Since the first file should exist prior to the operation, one should make sure that nothing is removed from it during the operation. Do this by comparing /tmp/haze.manager and /usr/share/telepathy/managers/haze.manager. The latter should be the prior plus a section for the bigbrownchunx-facebookim protocol.

Adding bibliography to the table of contents in LaTeX

By default LaTeX does not display the bibliography section in the table of contents (TOC). This article describes how to add it.

Seemingly random 403 errors on Apache

At some point I realized that apache was giving seemingly random “403 Forbidden” errors. This when under high load and yet, not really high at all. I would be able to trigger it by reloading some page a few times quickly in a row or loading a page with a lot of images.

The problem was mod_evasive, a module designed to protect against DOS attacks. The above usage pattern was being categorised as an attack and rejected. This page explains the details and this page explains how to deal with it in Ubuntu.

I did have to loosen up some settings, namely:

• DOSPageCount 10 (the number of pageviews allowed within DOSPageInterval secs)
• DOSSiteCount 10000 (the number of object requests allowed within DOSSiteInterval secs, that is images, stylesheets, javascrip files ...)

Creating a debian/ubuntu meta package

This article explains how to create a DEB-style meta package.

Creating a personal APT repository

This guide seems to explain it all.

You may run into errors of the form:

$ reprepro -Vb . includedeb jaunty /path/to/package.deb
Error: Distribution jaunty contains an architecture called 'all'.
There have been errors!
$ reprepro -Vb . dumpreferences
Error: Distribution jaunty contains an architecture called 'all'.
There have been errors!
$

In that case, try removing all from the “architectures” line of nano conf/distributions.

Configuring subdomains

This article explains how to set up subdomains. Very easy, at least on Apache …

Swine influenza

Terry Jones has an interesting read on the current swine influenza. Federico Mena Quintero has a spanish translation.

Setup of user privileges in MySQL

MySQL installation, the adding of users, the creation of databases and the assignment of permissions is explained, by example, on this page.

Dealing with AppArmor

Ordinary file-permissions are apparently not sufficient anymore. Ubuntu, and others, therefore uses AppArmor to associate programs with certain permission filters.

One such program is MySQL. When changing the datadir, it will most likely land somewhere outside the permissions granted by AppArmor and as a result fail. I would get errors (from /var/log/syslog) of the form:

Jan 19 00:41:12 asjo kernel: [262573.788599] type=1503 audit(1232322072.553:28): operation="inode_permission" requested_mask="r::" denied_mask="r::" fsuid=116 name="/vol/mysql/" pid=18262 profile="/usr/sbin/mysqld"

Others were having similar problems, as described in this thread among others.

This page solved my problem. Basically, you first put AppArmor in complain-mode regarding the specific program (in this case /usr/sbin/mysqld) by running this command:

sudo aa-complain /usr/sbin/mysqld

This will temporarily turn off the security and log the offending actions. Generate the offending actions by running the program:

sudo /etc/init.d/mysql start

Next you run

sudo aa-logprof

When asked if I wanted to “enable access to the profile repository” I answered L for ‘later’. Next it displays the offending action previously logged, at which point a allow it by answering A. At this point I am asked if I would like to save the changes. S for yes (save).

In order to re-enable security you simply run:

sudo aa-enforce /usr/sbin/mysqld

Pidgin unable to confirm certificate for rsi.hotmail.com

Today pidgin started displaying errors saying that it was unable to confirm the root certificate for rsi.hotmail.com. It turns out to be a missing ‘pem’ file on my Ubuntu Intrepid Ibex (8.10) desktop.

It can easily be fixed by following this guide.

Winter solstice

Today is the shortest day of the year. The event is called the winter solstice and signals the return of the sun. This – of course – will take some time before reaching full effect, but till then one can take rest in knowing that the days are getting longer.

Nikon S60 adds

Nikon has 3 really nice adds for their S60 camera. Watch them here.

Zeitgeist 2008

Google’s Zeitgeist 2008 is here.

Missing sound after resume on Intrepid

After upgrading from Ubuntu Hardy Heron (8.4) to Intrepid Ibex (8.10) my audio has been prone to stop working after resuming from suspend. This is caused by bug #275630. The temporary bugfix is to hit CTRL-ALT-F6 followed by CTRL-ALT-F7.

Return of the broken ACPI laptop disk problem

As reported earlier some laptop disks have a broken bios. The mentioned fix works for Hardy Heron (Ubuntu 8.04), but won’t work for Intrepid Ibex (Ubuntu 8.10). Bug 59695 seems to cover it.

Running this script by hand seems to solve it.

Python introduktion

This post is in danish. Sorry …

For et par år siden skrev jeg en introduktion til Python rettet mod folk med kendskab til imperative sprog. Vi var et par stykker der skulle lære sproget og jeg satte mig for at lave en række repræsentative opgaver. Introduktionen er derfor opbygget som et (fiktivt) kursus. Følgende områder berøres:

• Hello, World
• Arrays (kaldet lister i python)
• Filer og strenge
• Hashes (kaldet dictionaries i python)
• Objekter
• Moduler
• CGI
• .NET
• Client/Server

De afsluttende opgaver bærer præg af, at jeg skulle finde på nogle ekstra opgaver uden – på forhånd – at kende deres svar.

Testing hue performance of screen

X-Rite, who does color calibration, has put up a test designed to show hue weaknesses in display setups. It is not without issues as one has to sort some colors by hand.

We the People versus U.S. Government

The following video is centered around a Boston Legal argument. Full link is http://www.youtube.com/watch?v=1HPLWps7Fqg.

Downloadable lens hoods

This site offers printable lens hoods in PDF format. They are clearly not as nice as real hoods, but they do the trick.

Ken Rockwell facts

There’s a thread at DPReview listing a few lesser known facts about Ken Rockwell. A few picks:

• Ken Rockwell doesn’t adjust his DOF, he changes space-time.
• Ken Rockwell doesn’t wait for the light when he shoots a landscape – the light waits for him.
• Ken Rockwell ordered an L-lens from Nikon, and got one.
• When Ken Rockwell brackets a shot, the three versions of the photo win first place in three different categories.
• Ken Rockwell doesn’t use flash ever since the Nagasaki incident.
• Only Ken Rockwell can take pictures of Ken Rockwell; everyone else would just get their film overexposed by the light of his genius.
• Ken Rockwell’s nudes were fully clothed at the time of exposure.
• On Ken Rockwell’s desktop, the Trash Icon is really a link to National Geographic Magazine.
• For every 10 shots that Ken Rockwell takes, 11 are keepers.
• Ken Rockwell’s digital files consist of 0’s, 1’s AND 2’s.
• Ken Rockwell never focus, everything moves into his DoF.
• Ken Rockwell isn’t the Chuck Norris of photography; Chuck Norris is the Ken Rockwell of martial arts.

This – of course – is a pun on the well known Chuck Norris facts.

The state of the Photo business

Thom Hogan has a nice analysis of the state of the photo business.

Gimp 2.6 released

The Gimp, version 2.6, was just released. Release notes are here.

Guide for installing under Ubuntu Hardy Heron (8.04) here.

Inkscape screencasts

I just came across some video tutorials for Inkscape.

Status of US election

Andrew S. Tanenbaum is running the electoral-vote.com site.

Building UFRaw on Ubuntu

UFRaw is a free converter for RAW images. Like so many others it is based on DCRaw. The latest official release is from late 2007. This is more or less what is provided by Ubuntu.

The current CVS holds a few interesting additions, most noticeable the use of lensfun for doing lens corrections. There is a demo.

The following steps made the CVS compile for me. The result will be placed within the confines of /opt/ufraw-cvs/ and dpkg.

First we need to get the lensfun packages. I found some at this location. Add the following lines to /etc/apt/sources.list (use su to become a privileged user):

# lensfun
deb http://mirror.pcode.nl/ubuntu/ hardy lensfun

Next, install needed deb packages:

sudo apt-get update
sudo apt-get install build-essential
sudo apt-get install lensfun-data lensfun-manual liblensfun0 liblensfun0-dev
sudo apt-get install libgtkimageview-dev libgtkimageview0

In case you don’t have a /opt directory:

sudo mkdir /opt

Then build the programs:

cd /tmp
cvs -d:pserver:anonymous@ufraw.cvs.sourceforge.net:/cvsroot/ufraw login
cvs -z3 -d:pserver:anonymous@ufraw.cvs.sourceforge.net:/cvsroot/ufraw co ufraw
cd ufraw
./autogen.sh
./configure --prefix=/opt/ufraw-cvs
make
sudo make install

And you should then be able to run UFRaw:

/opt/ufraw-cvs/bin/ufraw

Installing Gimp 2.5.2 on Ubuntu

In an earlier post I mentioned a guide to build Gimp 2.5.0 on Ubuntu Hardy Heron. Back then the guide failed on my machine.

With the recent release on Gimp 2.5.2 I decided to give it another try and this time it worked. Below I have listed the specific commands. A few dependencies might be missing.

I case you don’t have the build tools installed (or have no idea if you do):

sudo apt-get install build-essential
sudo apt-get build-dep gimp

Also, to make the commands below work you need to have wget installed:

sudo apt-get install wget

In case you don’t have a /opt directory:

sudo mkdir /opt

In case you have a previous installation, remove this (or move it out of the way):

sudo mv /opt/gimp-2.5 /opt/gimp-2.5.backup

Run the following commands:

export PATH=/opt/gimp-2.5/bin:$PATH
export LD_LIBRARY_PATH=/opt/gimp-2.5/lib
export PKG_CONFIG_PATH=/opt/gimp-2.5/lib/pkgconfig

cd /tmp

svn co http://svn.gnome.org/svn/babl/trunk/ babl
cd babl
./autogen.sh –prefix=/opt/gimp-2.5
make
sudo make install
cd ..

svn co http://svn.gnome.org/svn/gegl/trunk/ gegl
cd gegl
./autogen.sh –prefix=/opt/gimp-2.5
make
sudo make install
cd ..

wget ftp://ftp.gimp.org/pub/gimp/v2.5/gimp-2.5.2.tar.bz2
tar jxvf gimp-2.5.2.tar.bz2
cd gimp-2.5.2
./configure –prefix=/opt/gimp-2.5
make
sudo make install

If everything went well you should be able to start it by running:

/opt/gimp-2.5/bin/gimp-2.5

Converting encoding of a file

Conversion of file encoding can be done easily and in a scriptable fashion using iconv (man page):

iconv -f latin1 -t utf-8 rapport.tex.old >> rapport.tex

The example above converts the file rapport.tex.old from latin1 (ISO-8859-1) to UTF-8. The result is stored in rapport.tex leaving the old file untouched.

Danske Bank og Java

This post is in danish. If you do not read danish you will not find this of interest.

Danske Bank’s netbank benytter Java. Under Ubuntu Hardy Heron betyder det, at man har valget mellem sun-java5-plugin, sun-java6-plugin og de mere eksotiske udgaver. sun-java6-plugin lader kun delvist til at virke og virker ikke de vigtige steder. Eftersom de tidligere har haft problemer med Java er det nok fair at gå ud fra, at de eksotiske implementationer heller ikke virker. Efter at have installeret sun-java5-plugin lader tingene til at virke.

Price of oil

The Oil drum has some, rather technical, insights on the current and future price of the oil barrel. Nothing new really, but graphs are presented.

Installing Gimp 2.5 on Ubuntu

The Gimp has recently begun the process of migrating to the GEGL backend in the 2.5 series. This version has not been packaged by the Ubuntu team.

There is a guide for building GIMP 2.5 on Hardy Heron, but it fails on my system. Somebody did manage to get it working and created a DEB package of the result. This does work for me. Details here.

This installs in parallel with the existing gimp package, so no harm in giving it a try …