Welcome to TechScreen

Welcome to the TechScreen site. This side shall support the exchange of knowledge in the domain of Web Engineering and related aspects. As a side effect, this side is used for research on knowledge management technologies. User can pose challenges in the problem domain and can participate in quizzes. Further a bibliography about arcticles in different related domains is continously extended. Finally, questionnaires on different issues are provided. To be able to participate you need an account and a password from TU Wien's TISS system.

Redirect user to login page using php

If one user logs out from the page he must not be able to access other pages, and must be directed to log in page. How do I redirect one user after log out to the "log_in" page, using php? Solution: In the log_out.php you firstly destroy all sessions, then using a header e.g.: "header('Location: index.php');" you force the user to be redirected to the log_in.php or by " echo <script>window.location.assign('log_in.php')</script>". I have applied the second way

LaTex - adding list of tables to table of contents

 The “List of figures”-table must appear also in the table of contents, and the page numbering should be with roman letters. Solution: "List of Figures" must be a separate section or chapter for it to appear in table of contents. 1. Set the page numbering to roman i.e. \pagenumbering{roman} 2. Create new section i.e.: \section*{} 3. Add manually the "List of Figures" to table of contents i.e.: \addcontentsline{toc}{section}{List of Figures} 4. Create the table for list of figures i.e.: \listoffigures 5.

Establishing trust as a new CTO

Nobody likes change. Nobody likes authority. And even less people like when they are wrong. It is not easy to establish a healthy working environment anywhere, yet alone in IT, where being a sceptic is nowadays almost a matter of fashion (just scroll through all the IT memes). As a new CTO one can quickly find himself in a situation where his ideas and requests are hitting the wall. Developers are those who will actually build the product you are going after, so establishing a trust within that circle is an absolute must if you want to get anywhere.

Running your custom environment on Google cloud

Very often developers have their favourite web application setups. Some like to use Spring, some go after CDI, some use relational databases such as MySQL, while others go after MongoDB... There are countless technologies on the market, and we are still not living in the world where exists such a universal software stack which will cover any architectural and business requirements one might encounter in his development career. But often we have a stack that is highly configurable, and is a combination of multiple tools and libraries that solve most of our needs out of the box.

Transfering documents over web service endpoints

Probably anyone who ever dealt with integration of distributed systems, no matter what the programming language is, came upon a use case where a document, such as .pdf, would need to be sent over a java web service. Usual use case involves feeding data to an isolated module for report generation, and obtaining a generated file as a result. Such transfer is not possible with out-of-the-box technologies. There exists no such "return-type" as File in Java Web Services, nor anywhere else.

Quick workaround for sending prohibited files via FB-chat

When sending files over facebook or other bigger chat- or social media platforms, you may encounter that you are prohibited from sending certain files, for example .exe files. A quick workaround for this problem is to just manually change the file extension to, for example .txt, send it and the receiver just changes the file extension back to .exe.

How to test a mail service without SMTP-server (Java)

To test if a mail was successfully sent using Java you would normally need an SMTP-server to check. If it happens that you don’t have a server available, you can use mailtrap.

Easy POST-requests for testing REST-interface

For a course we had to implement a service composition that communicated over REST interfaces using spring boot. Part of this was to allow not only GET-request, to retrieve information from the service, but also to allow POST-request, which would enable the user to add information to the service. We faced a problem when testing our implementation. While testing the GET-request is very easy, POST-request contain information in the body and we didn’t know how to properly simulate this without a lot of effort. The simple solution for this is the Google Chrome plugin “Postman”.

Nested data table in JSF

After certain period the project manager proposed the change of the fields of an object that should be visible in a Primefaces dataTable. The new introduced field was of the type java.util.List with any number of elements. The representation of the values was not solvable in the dataTable as it does not support nested cells. After unsuccessfully fixing of the problem, I needed to represent data in the panelGrid element.

Angular Application UI Testing

Testing UI of an application can be automated with the Selenium testing framework. The problem by testing of an Angular5 application were random assigned indexes to IDs of HTML elements after each application start (e.g. myid-4), which prevents finding elements by id using Selenium web driver. The finding elements had to be changed and set to finding elements by xpath.


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