SymmetricalDataSecurity: Volbx – Qt-based spreadsheet app for data manipulation

Monday, December 28, 2020

Volbx – Qt-based spreadsheet app for data manipulation

Table of content

Example view

Description

Volbx is a graphical tool used for data manipulation written in C++/Qt. User can:

load data - opens xlsx and ods spreadsheet files,
filter data - filters panel can be used to define data range on each column,
select data - user can select rows on main data table,
visualize data - multiple types of built in diagrams (histogram, grouping, linear regression, quantiles) which adjusts dynamically according to user actions,
order data - each column can be ordered ascending or descending,
export data - selected set of data, together with linked plots, can be exported to xlsx spreadsheet file or CSV.

History

Tool was originally created for real estate appraisal as it gives possibility, for people working in that area, to estimate past, current and future value of analyzed properties. When project/start-up was dropped, I've decided to release less specialized application as open source project. Most advanced and dedicated for real estates functionalities were cut out, basic and intermediate ones stayed.

Used tools and libs

Tool	Windows	Lubuntu
OS version	10 v1909	20.04
GCC	7.3.0	9.3.0
Cmake	3.14	3.17
Git	2.20	2.25
Svn	1.11.1	1.13.0
Qt	5.12.6	5.12.7
QtCreator	4.12.0	4.13.0
Qwt	6.1.4	6.1.4
QuaZip	0.9	0.9
Zlib	1.2.11	1.2.11
Eible	master	master
QwtBle	master	master
Wble	master	master

Compilation and installation

Use directly Cmake or QtCreator. Cmake should:

configure everything automatically,
download dependencies using Git (QuaZip, Zlib, Eible, Wble, Qwtble) and SVN (Qwt),
build dependencies,
compile Volbx and create binaries.

This is of course happy path...

TIPS: set CMAKE_PREFIX_PATH env variable (should point to Qt) and add qmake location to PATH variable (QWT building expects it).

Licensing

Volbx is published using LGPLv3 license.

Project uses following software and licenses:

Qt, Qwt, QuaZip, Eible, Wble and Qwtble libraries - LGPL licences (more on qt-project.org, quazip.sourceforge.net, qwt.sourceforge.net and github.com/przemek83),
Zlib - Zlib license (can be found on zlib.net).

Updater

Build target VersionCheck.
Run VersionCheck.
Following window should be shown:

Setup update server

Get a domain and hosting :)
Create simple .php file which contains something similar to this:

<?
echo("Volbx-Update-Info\n");

echo("1.10");

chdir("current/");
foreach (glob("*") as $filename) {
    echo "\n$filename;" . filesize($filename);
}
?>

Copy .php file to hosting.
Create folder current in directory where .php file is located.
Add new/other version of Volbx and/or updater in current directory.
Change code of Networking namespace in Volbx to point to proper address. Look for QNetworkRequest Networking::getCurrentVersionRequest() and QNetworkRequest Networking::getDownloadFileRequest(const QString& file)
Compile VersionChecker and run it.
Application should connect to given address and download content of current folder.

Remarks:

Updater is doing correctness checks using file sizes. Checksums should be used instead.
When I've created VersionChecker I've decided to use simplest known by me solution. I do not know if it is safe and 'proper' enough but it worked for me. I'm not web developer ;)
Windows needs admin rights (as of ~2012) to execute files having in name strings like "update", "install" or "setup". I've picked name VersionChecker to workaround that problem.
On Windows OS updater cannot overwrite file which are being used (as of ~2012). There is a special mechanism in place for replacing used/locked files:
- close Volbx,
- run updater,
- download files,
- change not used binaries/libs,
- on next run of Volbx replace automatically used/blocked ones.