Author: Guy

Creating a personal apt repository using `dpkg-scanpackages`

From time to time I build and backport deb packages. Most of them are for my personal use, but sharing them would be nice. Another advantage for setting up a personal repository over directly installing deb files is that you can install dependencies from that repository automatically. Especially useful if one source package builds multiple binary packages which depend on one another.

There is a list of programs ways how to setup such personal repository in the Debian wiki. However, I found most ways to be too cumbersome for my limited requirements. The way I’m describing below is probably the simplest and easiest way to get up and running.

First thing is installing dpkg-dev which provides dpkg-scanpackages.

sudo apt install dpkg-dev

Next put the deb files you created in some local repository such as /usr/local/debian and cd into it.

# dpkg-scanpackages -m . | gzip -c > Packages.gz

will scan all the *.deb files in the directory and create an appropriate Packages.gz file. You need to repeat this step whenever you add new packages to /usr/local/debian.

Finally to enable the new local repository, add the following line to /etc/apt/sources.list:

deb [trusted=yes] file:///usr/local/debian ./

The [trusted=yes] options instruct apt to treat the packages as authenticated. Alternatively, if you want to share it with others, make sure that your webserver serves the directory and point to it

deb https://www.guyrutenberg.com/debian/jessie ./

(You will need the apt-transport-https in order to use https repositories).

Don’t forget to apt update before trying to install packages from the new repository.

Playing Opus Files on Android Marshmallow (6.0)

The Opus codec provides superior audio quality over codecs such as AAC, MP3 and Vorbis. Android has support for Opus since Android 5.0 (Lollipop). However, when I tried playing Opus files on My LG G4, it wouldn’t recognize the file as a media file at all. It turns out, that the default .opus extension is not recognized by Android. The workaround is to change the extension to .ogg. Generally speaking, this is technically correct, as most Opus streams are encapsulated by an Ogg container, however, .opus is the recommended extension (but apparently not for Android).

Fixing HTML Rendering in Wine on Debian Jessie

Some application rely on Internet Explorer to provide HTML rendering capabilities. Wine implements the same functionality based on a custom version of Mozilla’s Gecko rendering engine (the same engine used in Firefox). In Debian Jessie you have a package called libwine-gecko-2.24 (the version is part of the name) which provides this rendering engine for Wine. However, different versions of Wine require different versions of wine-gecko. The package provided in Debian Jessie, matches the Wine version provided by wine-development from the main Jessie repository (1.7.29). Unfortunately wine-development from the jessie-backports if of version 1.9.8 and requires wine-gecko of version 2.44 which is not provided by any Debian repository. This will lead to errors like

Could not load wine-gecko. HTML rendering will be disabled.

and blank spaces where HTML content would be rendered in many applications.

The solution would be to manually install the required version of wine-gecko. We start by downloading the MSI binaries provided by Wine

$ wget https://dl.winehq.org/wine/wine-gecko/2.44/wine_gecko-2.44-x86.msi
$ wget https://dl.winehq.org/wine/wine-gecko/2.44/wine_gecko-2.44-x86_64.msi

Now install the required one, based on whether you are using 32bit or 64bit wine environment:

wine-development msiexec /i wine_gecko-2.44-x86.msi

(be sure the setup the correct $WINEPREFIX if needed).

Greasemonkey: Fix links to PDFs in Bank Hapoalim

This fixes both the links to the PDFs and the embeding in the mailbox. Click on the “View Raw” to install.


// ==UserScript==
// @name Bank Hapoalim
// @description Workaround bugs in Bank Hapoalim website to display pdf messages.
// @author Guy Rutenberg
// @namespace http://www.guyrutenberg.com
// @include https://login.bankhapoalim.co.il/portalserver/mailInbox#/folders/0
// @include https://login.bankhapoalim.co.il/ng1-portals/rb/he/mails#/folders/0
// @run-at document-idle
// @version 1.1
// @grant none
// ==/UserScript==
//
// @include url should be the url of the inner iframe containing the list of mails.
var MutationObserver = window.MutationObserver;
var myObserver = new MutationObserver (mutationHandler);
var obsConfig = {
childList: true, attributes: false,
subtree: true,
};
var target = document.getElementsByTagName('mail-manager')[0];
myObserver.observe (target, obsConfig);
function mutationHandler (mutationRecords) {
console.log('here');
mutationRecords.forEach ( function (mutation) {
for (var item of mutation.addedNodes) {
if (item.tagName == 'PDF-VIEWER') {
var url = 'https://login.bankhapoalim.co.il' + item.getAttribute('pdf-show');
iframe = item.querySelector('iframe');
iframe.src = url;
}
}
});
}

view raw

Bank_Hapoalim.user.js

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Lossless JPEG rotation

JPEG is a lossy format, and naive rotation results in a loss of quality. JPEG does allow some lossless operations, such as rotation by 90 degrees and flipping, on the basic blocks (MCUs) that compromise the image. It also allows re-arranging those blocks. Using this lossless operation, it is possible to preform a lossless JPEG rotation. To do so, the rotated image mus meet some basic criteria like having it size a multiple of the MCU size (usually 16×16).

Not all programs preform a lossless JPEG rotation, so it is useful to be aware which does. I check a couple of commonly used program to see if they indeed preform lossless rotation. The testing procedure was:

  1. Start with the original JPEG photo.
  2. Rotate it once to the right using each program.
  3. Rotate a copy of the rotated photo back to the right using the same program.
  4. Compare using ImageMagick (compare -metric ae) the results.

Results

Gnome’s Image Viewer 3.14.1 is lossless
Digikam (4.4.0) is lossless, however rotating with Digikam’s Image Editor is lossy.
Shotwell (0.20.1) does lossy rotation.

en_IL: English locale for Israel

Update: The new locale was committed to glibc and should be part of glibc-2.24.

Most Israelis are literate in English, and for a large percentage of them, English is also the preferred language when it comes to computers. They prefer English, as it solves right-to-left issues and general inconsistencies (it might be annoying when some programs are translated ands some not). The downside is, that currently, the existing English locales are not suitable for Israel, as there are cultural differences:

  • American English spelling is more common in Israel.
  • The metric system is used, along with the relevant paper sizes (“A4” instead of Letter).
  • Dates are written in dd/mm/YYYY format, unlike in the USA.
  • The first day of week, and also the first workday is Sunday.
  • The currency used is ILS (₪).

So, up until now users had to choose locales such as en_US or en_GB and compromise on some stuff. To solve this issue, and create a truly suitable English locale for Israel, I wrote a localedef file for the en_IL locale.

To install the new locale, copy the en_IL file from the gist below and place under /usr/share/i18n/locales/en_IL (no extension). Next

# echo "en_IL.UTF-8 UTF-8" >> /usr/local/share/i18n/SUPPORTED

Now, complete the installation by running dpkg-reconfigure locales and enable en_IL.UTF-8 from the list, and set it as the default locale.


comment_char %
escape_char /
% This file is part of the GNU C Library and contains locale data.
% The Free Software Foundation does not claim any copyright interest
% in the locale data contained in this file. The foregoing does not
% affect the license of the GNU C Library as a whole. It does not
% exempt you from the conditions of the license if your use would
% otherwise be governed by that license.
% Locale for English locale in Israel
% Contributed by Guy Rutenberg <guyrutenberg@gmail.com>, 2016
LC_IDENTIFICATION
title "English locale for Israel"
source "Free Software Foundation, Inc."
address "http:////www.gnu.org//software//libc//"
contact ""
email "bug-glibc-locales@gnu.org"
tel ""
fax ""
language "English"
territory "Israel"
revision "1.1"
date "2016-04-19"
%
category "i18n:2012";LC_IDENTIFICATION
category "i18n:2012";LC_CTYPE
category "i18n:2012";LC_COLLATE
category "i18n:2012";LC_TIME
category "i18n:2012";LC_NUMERIC
category "i18n:2012";LC_MONETARY
category "i18n:2012";LC_MESSAGES
category "i18n:2012";LC_PAPER
category "i18n:2012";LC_NAME
category "i18n:2012";LC_ADDRESS
category "i18n:2012";LC_TELEPHONE
category "i18n:2012";LC_MEASUREMENT
END LC_IDENTIFICATION
LC_CTYPE
copy "en_GB"
END LC_CTYPE
LC_COLLATE
copy "en_GB"
END LC_COLLATE
LC_MONETARY
copy "he_IL"
END LC_MONETARY
LC_NUMERIC
copy "he_IL"
END LC_NUMERIC
LC_TIME
abday "<U0053><U0075><U006E>";"<U004D><U006F><U006E>";/
"<U0054><U0075><U0065>";"<U0057><U0065><U0064>";/
"<U0054><U0068><U0075>";"<U0046><U0072><U0069>";/
"<U0053><U0061><U0074>"
day "<U0053><U0075><U006E><U0064><U0061><U0079>";/
"<U004D><U006F><U006E><U0064><U0061><U0079>";/
"<U0054><U0075><U0065><U0073><U0064><U0061><U0079>";/
"<U0057><U0065><U0064><U006E><U0065><U0073><U0064><U0061><U0079>";/
"<U0054><U0068><U0075><U0072><U0073><U0064><U0061><U0079>";/
"<U0046><U0072><U0069><U0064><U0061><U0079>";/
"<U0053><U0061><U0074><U0075><U0072><U0064><U0061><U0079>"
abmon "<U004A><U0061><U006E>";"<U0046><U0065><U0062>";/
"<U004D><U0061><U0072>";"<U0041><U0070><U0072>";/
"<U004D><U0061><U0079>";"<U004A><U0075><U006E>";/
"<U004A><U0075><U006C>";"<U0041><U0075><U0067>";/
"<U0053><U0065><U0070>";"<U004F><U0063><U0074>";/
"<U004E><U006F><U0076>";"<U0044><U0065><U0063>"
mon "<U004A><U0061><U006E><U0075><U0061><U0072><U0079>";/
"<U0046><U0065><U0062><U0072><U0075><U0061><U0072><U0079>";/
"<U004D><U0061><U0072><U0063><U0068>";/
"<U0041><U0070><U0072><U0069><U006C>";/
"<U004D><U0061><U0079>";/
"<U004A><U0075><U006E><U0065>";/
"<U004A><U0075><U006C><U0079>";/
"<U0041><U0075><U0067><U0075><U0073><U0074>";/
"<U0053><U0065><U0070><U0074><U0065><U006D><U0062><U0065><U0072>";/
"<U004F><U0063><U0074><U006F><U0062><U0065><U0072>";/
"<U004E><U006F><U0076><U0065><U006D><U0062><U0065><U0072>";/
"<U0044><U0065><U0063><U0065><U006D><U0062><U0065><U0072>"
d_t_fmt "<U0025><U0061><U0020><U0025><U0064><U0020><U0025><U0062><U0020><U0025><U0059><U0020><U0025><U0054><U0020><U0025><U005A>"
d_fmt "<U0025><U0064><U002F><U0025><U006D><U002F><U0025><U0079>"
t_fmt "<U0025><U0054>"
am_pm "";"" % 24-hour clock is used
t_fmt_ampm ""
date_fmt "<U0025><U0061><U0020><U0025><U0065><U0020><U0025><U0062>/
<U0020><U0025><U0048><U003A><U0025><U004D><U003A><U0025><U0053><U0020>/
<U0025><U005A><U0020><U0025><U0059>"
week 7;19971130;1
% In Israel Sunday is a workday.
first_workday 1
END LC_TIME
LC_MESSAGES
copy "en_US"
END LC_MESSAGES
LC_PAPER
copy "he_IL"
END LC_PAPER
LC_NAME
copy "en_US"
END LC_NAME
LC_ADDRESS
postal_fmt "<U0025><U0066><U0025><U004E><U0025><U0061><U0025><U004E>/
<U0025><U0064><U0025><U004E><U0025><U0062><U0025><U004E><U0025><U0073>/
<U0020><U0025><U0068><U0020><U0025><U0065><U0020><U0025><U0072><U0025>/
<U004E><U0025><U007A><U0020><U0025><U0054><U0025>/
<U004E><U0025><U0063><U0025><U004E>"
country_name "<U0049><U0073><U0072><U0061><U0065><U006C>"
country_post "<U0049><U0053><U0052>"
country_ab2 "<U0049><U004C>"
country_ab3 "<U0049><U0053><U0052>"
country_num 376
country_car "<U0049><U004C>"
lang_name "<U0045><U006E><U0067><U006C><U0069><U0073><U0068>"
lang_ab "<U0065><U006E>"
lang_term "<U0065><U006E><U0067>"
lang_lib "<U0065><U006E><U0067>"
END LC_ADDRESS
LC_TELEPHONE
copy "he_IL"
END LC_TELEPHONE
LC_MEASUREMENT
copy "he_IL"
END LC_MEASUREMENT

view raw

en_IL

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nginx and SNI

Server name indication (SNI) allows you serve multiple sites with different TLS/SSL certificates using a single IP address. Nginx has support for SNI for quite some time and actually setting it up is easy, simply add server entries for the corresponding sites. There is one caveat, the server_name entry must come before the server_certificate in order for SNI to be activated:

server {
    listen          443 ssl;
    server_name     www.example.com;
    ssl_certificate www.example.com.crt;
    ...
}

server {
    listen          443 ssl;
    server_name     www.example.org;
    ssl_certificate www.example.org.crt;
    ...
}

is good, but

server {
    listen          443 ssl;
    ssl_certificate www.example.com.crt;
    server_name     www.example.com;
    ...
}

server {
    listen          443 ssl;
    ssl_certificate www.example.org.crt;
    server_name     www.example.org;
    ...
}

will serve the wrong certificate for www.example.org.

WordPress.com Login Loop

Sometimes, when I try to use certain functions on wordpress.com, I get redirected to a login page. After I sign-in, I get redirect again to the same login page. This repeats in an endless loop. It usually doesn’t bother me, as I self-host my blog, but for some things, like the yearly annual report that came in about two weeks ago, it does bother. I looked up into the matter, and the issue turned up to be due to blocking third-party cookies. To resolve the endless login loop, you need to add https://wordpress.com (note the https) to the exception list of accepted third-party cookies (In Firefox it’s under Preferences -> Privacy -> Exceptions).

Skip Updates When Using the Let’s Encrypt `letsencrypt-auto` Client

To use Let’s Encrypt CA to issue free certificates, you need to use their client. The recommended method to install it is to use letsencrypt-auto, a script that automatically fetches and installs all the required dependencies. There is no doubt, that the letsencrypt-auto is the fastest and simplest way to get a Let’s Encrypted client up and running. I’ve used it myself, when I wrote a guide to get Let’s Encrypt up and running easily.

Automatically updating required dependencies, has its downside. As letsencrypt-auto does it every time you run it, it quickly gets annoying. Running a simple ./letsencrypt-auto --help takes a whopping 15 seconds, just figuring out that there are no updates available. Supposing that you know that no update are available, and you wish to save some time, you can run the letsencrypt executable directly, skipping the updating process of lestencrypt-auto:

~/.local/share/letsencrypt/bin/letsencrypt

Most of the actions require you to be root, so you might need to run it with sudo.

You can expect this issue to be resolved in the future. There is already an open issue for it and an active work that will resolve it.

Installing Debian Unstable’s source Packages in Debian Jessie

Sometimes a package that you need is not available for Debian Jessie, but you can find it for Sid (unstable). You may be tempted to try to install it manually, by downloading the binary deb package, but it will most likely fail due to binary incompatibilities with different libraries’ versions you have. The better method will be to get the source package used to build the binary package, and build it yourself. Most of the time the process is not as hard as it sounds.

First, a short preliminary setup is needed Add the following lines to /etc/apt/sources.list:

deb http://http.debian.net/debian jessie-backports main
deb-src http://httpredir.debian.org/debian unstable main contrib

You can replace unstable with testing if you prefer to use packages from testing. Update the lists of packages

sudo apt-get update

Next you need, to get the build dependencies for your package. The example below uses the package lyx:

sudo apt-get build-dep lyx/unstable

Now you are ready to fetch and build the source package:

sudo apt-get source -b lyx/unstable

Finally, you will see in the current directory the resulting DEBs. Simply install them:

sudo gdebi lyx-common_2.1.4-2_all.deb
sudo gdebi lyx_2.1.4-2_amd64.deb

You can later mark the dependecies that you manually installed as automatic:

sudo apt-mark auto lyx-common