Vincenzo Mantova - Software

LaTeX in Empathy and Adium

Vincenzo Mantova — Tue, 26 Mar 2013 17:25:51 +0000

This is a little tutorial on how to embed MathJax in Empathy's and Adium's chat windows, making it possible to use LaTeX formulas in chats without resorting to plugins or calling external scripts.

I tested this change only in Empathy 3.6 on Ubuntu 12.10 with the "Ubuntu" message style, and other configurations may require different changes. Do not forget to make a backup of the files you are going to modify.

TO DO: call "Typeset" on the new fragment only, attach a screenshot (Nvidia's fault).

Embedding MathJax into an AdiumMessageStyle

Empathy and Adium use HTML+Javascript templates to display the content of the chat windows. Since they actually use Gecko and Webkit, it is possible to embed pretty much any code you like.

MathJax is a handy Javascript library that converts LaTeX formulas inside $$ ... $$ and \[ ... \] into MathML or images, depending on the configuration. In order to enable the MathJax library inside an Empathy chat window it is enough to do the following.

Install the MathJax library somewhere (either via your package manager or downloading it), copy/extract your favourite message style into the folder ~/.local/share/adium/message-styles/ and modify its Template.html in the following way:

add the line <script type="text/javascript" src="/~mantova/io/%3Cstrong%3E%5Blocation%20of%20MathJax%5D%3C/strong%3E/MathJax.js?config=default"></script> just before the first <script> tag; this will import MathJax in the message style;
add the line MathJax.Hub.Queue(["Typeset", MathJax.Hub]); inside the body of the appendMessage, near the end of the function, after the new message has been added to the page but before any other formatting commands (e.g., a call to alignChat); this tells MathJax to look for new LaTeX code every time a new message is displayed on the screen;
repeat the last step inside the body of the function appendMessageNext, unless the function calls appendMessage.

I suggest to modify the file Info.plist as well appending a "+ MathJax" to the style name.

Instructions for Ubuntu 12.10

If you use Ubuntu 12.10 and the "Ubuntu" message style in Empathy, you can use the attached patch.

Download the attached ubuntu-message-style+mathjax.patch
Install libjs-mathjax:
sudo apt-get install libjs-mathjax
Create a directory in your home folder to host the new message style:
mkdir -p ~/.local/share/adium/message-styles
Copy the default Ubuntu message style to your home folder:
cp -r /usr/share/adium/message-styles/ubuntu.AdiumMessageStyle ~/.local/share/adium/message-styles/ubuntu+mathjax.AdiumMessageStyle
Go inside the directory of the new message style:
cd ~/.local/share/adium/message-styles/ubuntu+mathjax.AdiumMessageStyle
Apply the patch:
patch -p1 < [location of the downloaded patch]
Choose the new theme "Ubuntu + MathJax" in Empathy's preferences.
Open a new chat tab and write some LaTeX code inside $$ ... $$ or \[ ... \]
Enjoy!

Attachments

ubuntu-message-style+mathjax.patch

PAM SASL authentication module

Vincenzo Mantova — Tue, 15 Feb 2011 18:55:35 +0000

A PAM module for SASL password authentication.

The source code is hosted on SourceForge.
Packages for Ubuntu can be downloaded from the official PPA.

Usage case

This module is useful when combined with the saslauthd service, if you want to let some low privilege process, such as gnome-screensaver, to be able to authenticate the user using information not accessible to the process, e.g., to the system Kerberos keytab /etc/krb5.keytab or the LDAP password stored in /etc/ldap.conf.

Example with `gnome-screensaver`

This example is modelled around Debian, Ubuntu and other similar distributions.
We will configure gnome-screensaver so that the user can unlock the screen even if he has no privileges to read some necessary files.

First, you have to install the module and the service saslauthd (in Debian/Ubuntu, it is contained in the sasl2-bin package).

Modify the system files in the following way:

/etc/pam.d/gnome-screensaver

auth    required    pam_sasl.so
auth    optional    pam_gnome_keyring.so

/etc/pam.d/sasl-gnome-screensaver

@include common-auth

/etc/sasl/sasl-gnome-screensaver.conf

pwcheck_method: saslauthd

/etc/default/saslauthd

[...]
# Should saslauthd run automatically on startup? (default: no)
START=yes

[...]
# Example: MECHANISMS="pam"
MECHANISMS="pam"

[...]

/etc/security/group.conf

[...]
#xsh; tty* ;sword;!Wk0900-1800;sound, play
#xsh; tty* ;*;Al0900-1800;floppy

login;*;*;Al0000-2400;cdrom,audio,video,sasl
gdm;*;*;Al0000-2400;cdrom,audio,video,sasl

[...]

Under this configuration, when the user tries to unlock the screen the following happens:

gnome-screensaver gives the password to the module pam_sasl.so
pam_sasl.so reads the configuration file /etc/sasl/sasl-gnome-screensaver.conf, and decides to use the saslauthd service
pam_sasl.so contacts the saslauthd service through a socket accessible only to members of the sasl group (hence the configuration of /etc/security/group.conf)
saslauthd is configured to use the PAM library, so it checks the password using the modules configured in /etc/pam.d/sasl-gnome-screensaver
the password is finally checked in the same way as it was before installing pam_sasl, but this time the check is done by the saslauthd daemon which runs as root.

YouTube Adium plugin

Vincenzo Mantova — Tue, 15 Feb 2011 18:54:51 +0000

A plugin to show YouTube videos right inside the chat window of Adium.
The plugin can be found at Adium - Xtras.
The source code and the binary releases are hosted on SourceForge.

Known Issues

The video cannot be resized.
There is no localization support (i.e. the video controls will always appear in English and the "close" link will always be "close").
The video will move together with the text! You'll have to stay quiet till the end.
The plugin only works with links beginning with http://www.youtube.com/watch?v=.
It can be used only with version 4 message styles (those provided with Adium are ok).