olpa, OSS developer

Here are a few links which helped me to understand what to use to mock microservices with REST API. Just for a case, I’ve choosen wiremock because I need Java and saboteur functionality.

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Selenium is a web browser automation software. In Ubuntu 16.04 it doesn’t work out of the box, and external components should be installed. In this post I note how to install them locally without affecting the system.

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I’ve seriously tried TDD in a real project, writing tests before code and following the red-green-refactor cycle. Short summary:

* I believe in TDD now;
* training and practice are required to learn TDD, reading books is not enough;
* the initial time investment is big.

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Rviz A 3d visualization environment for robots. Sounds intriguing and useful, but the first steps in it are painful. In particular, moving anything is surprisingly a very hard task for a novice who doesn’t know about the right way. Now I have enough experience to describe what to do: Moving things in rviz.

The Linux command line and other software based on readline library support vi editing mode. After I worked on a new system with the default settings for a while, I noticed that I miss this mode very much.

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Based on the article How to Run Your Own Git Server, I’ve constructed a small list for fast git setup for temporary projects.

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I was a speaker at the TeX users meeting in Wuppertal, with the talk “Erfahrung und Vorhersagen für automatisches XML-nach-PDF-Publizieren mit TeX” (experience and prediction for automatical from-XML-to-PDF publishing using TeX).

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python libxml2 dita

For correct transformation of DITA files (XML-standard for modular documentation), it is necessary to pull information from DTD (document type definition). In my python code, sometimes I did get this information and sometimes not. Now I’ve tracked the source of instability and corrected the code.

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The PDF is of some non-standard landscape layout, the printer is an usual A4 printer, the software can’t handle the mix correctly. The solution is to tune the dimensions of the PDF pages manually.

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For XML to DocBook to .docx conversion, I found that “le-tex transpect” framework has solved many technical issues already, so I overcame the “not invented here syndrome” and decided to rely on this tool. To tune the stylesheets for own needs, I created a github copy of the repository: docxtools. To run the stylesheets outside the framework, a special setup is required. The setup is described in the folder “doc/hello-world“.

In theory, changing content of an Excel file is easy:

* Parse XML from the zip-file
* Change XML
* Save XML into the zip

In practice I got the error: >>Von Excel wurde unlesbares Inhalt in … gefunden. Möchten Sie den Inhalt dieser Arbeitsmappe wiederherstellen?< < (English: "Excel found unreadable content...") Read the rest of this entry »

In the year 2001 I started to experiment with GUI applications in Python. The experience was summarized and published in the article “A complete Python Tkinter sample application for a long operation“. Now, in the year 2015, a programmer have sent me an updated code. With the minimal changes, which mostly are update of the names of Tkinter modules, the code works.

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Sometimes I want to read a web page without its design “improvements”. In many case it is enough to switch off css, and in firefox this functionality is built-in. Shift+F7 to get the developer tools. Thanks stackoverflow for the hint.

After upgrading the local Linux system, my python paramiko (ssh protocol implementation) program stopped working, with the error message:

CTR mode needs counter parameter, not IV

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GNU FriBidi is an implementation of the Unicode Bidirectional Algorithm (bidi). There is a Python binding PyFribidi, but it is not complete. What I need is not a visual presentation of a string, but information where direction is changing. This function is not provided by the binding, therefore I’ve made an alternative using ctypes.

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My advice: do use the “second shot” option. At least, I failed to pass the first attempt and had to try again. What was wrong:

* I needed time to adapt myself to the testing interface, and probably made something wrong in several first exercises.
* A few tasks are a bit unusual and I spent too much time on them. You should remember them and do homework.
* I work bad under under time pressure.

The best preparation resource I found is this youtube transcript: https://www.youtube.com/watch?v=7mm31GLUiNE. It is in French, but everything is clear, especially after the first certification attempt.

On the second attempt, passed. 918 out of 1000 is more than enough.

I’ve tried to install a TeX package and got the error message:

tlmgr: The TeX Live versions supported by the repository
http://ftp.fernuni-hagen.de/ftp-dir/pub/mirrors/www.ctan.org/systems/texlive/tlnet
  (2014--2014)
do not include the version of the local installation
  (2013)

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By me, vmware doesn’t start without twicks. A normal rum produces something like:

process 3954: Attempt to remove filter function 0xb6ad0690 user data 0xb7896048, but no such filter has been added
D-Bus not built with -rdynamic so unable to print a backtrace

In my case the solution is to start HAL daemon before running vmware.

HTML is the main output format for XML transformations. Every XSLT-processor, including libxslt/libxml2, supports it. But if you transform a libxml2 tree manually, you are in trouble. You can save XML only as XML, not as HTML. A solution is required. My version is not elegant, but works.

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The number (and dates) in Excel are float numbers. How these numbers are displyed to an user — as an integer, or with two digits after a point, etc — are defined by the cell format. Unfortunately, xlrd does not support number formatting. It is your task to interpret the format and display the number as expected. My code can probably help. Download xlrd-format-excel-number

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