Flatpaking of Paperwork: Issues with locale-specific files and scanner drivers

[Jerome Flesch]

12 octobre 2017 13:45 "Alexander Larsson" <alexl at redhat.com> a écrit:

> On Wed, 2017-10-11 at 20:34 +0000, Jerome Flesch wrote:
> 
>> Hello,
>> 
>> I'm trying to package Paperwork ( https://openpaper.work | https://g
>> ithub.com/openpaperwork/paperwork ), and I've hit two issues:
>> 
>> - Paperwork uses Tesseract for OCR, and Tesseract requires specific
>> data files for each language ( https://github.com/tesseract-ocr/tessd
>> ata/ ). All the data files for all the languages take about 600MB.
>> Most users will use at most 2 or 3 languages, so bundling them all
>> with Paperwork would be pretty overkill.
> 
> Flatpak splits out locale data into a separate extension called
> org.my.App.Locale, and when you install the app only parts of the
> locale extension is installed, depending on exactly what languages are
> configured. For example, if you only use "sv" then only the /sv
> directory of the locale extension is installed.
> 
> This can be used to add locale-specific data files. For instance, the
> freedesktop.org platform recently grew dictionary data, which are
> placed in the locale extension. This means you only get the
> dictionaries for your installed languages.
> 
> Exactly how the locales work has changed a bit over time. For the
> longest time it only installed the languages that were the current
> language when you installed, but at some point per-installation
> configuration option was added, and some changes in what is installed
> by default. In fact, only yesterday i did some work on this in master.
> 
> Here is the current behaviour:
> There is a new command "flatpak config" which lets you set the set of
> languages to install:
> flatpak config --set language sv;en;de
> (or with --user to set the per-user config)
> This is then used whenever you install/update apps.
> If this is not configured then the default is used. For --user installs
> the default is the current languages as defined by various locale env
> vars. For system defaults we ask AccountServices for all users
> configured languages and combine those as the list. If AccountServices
> is not there, or some user has no language set we install all
> languages.
> 
Thank you for your explanation. Are there any documentations or examples showing how to manage these locale extensions with flatpak-builder (if possible at all) ?


>> - Paperwork uses Sane to access scanners. However, Sane only has
>> user-land drivers (most uses libusb I guess). Most users don't have
>> saned (Sane daemon) enabled on their system. Therefore, libsane
>> usually access directly the scanner(s) using the user-land drivers
>> bundled with it. I can easily package all the open-source drivers of
>> sane-backends with Paperwork, but some people have scanners requiring
>> proprietary drivers. For instance, my Brother scanner is installed
>> using a shell script provided by Brother, and this shell script
>> download and install .deb files.
> 
> You can make an app extension point for this, then people can package
> drivers either as flatpaks, or by using "unmanaged extensions" which
> are just a correctly named directory on the host acting as an
> extension.
> 
> --
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> Alexander Larsson Red Hat, Inc
> alexl at redhat.com alexander.larsson at gmail.com
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