Latest Posts

Setting up Rabbit MQ Server

Posted on June 8, 2022 by Peter Andersson

Here are some quick notes that I refer to when installing Rabbit MQ server on Linux. Installation Read and follow: https://www.rabbitmq.com/download.html Quickstart Make sure the […]

Development

A simple JWT example with NodeJS and Python (part 1)

Posted on June 6, 2022 by Peter Andersson

The following example is built using a Python Flask backend, a CURL-script to test it, and a simple React frontend that logs in, gets an […]

Development, Javascript, Linux, Node, Python

How to “forget” a file tracked in Git

Posted on May 13, 2022 by Peter Andersson

I often do this: I hurry creating a git repository, do a quick “git add .” and commits. Afterworth, after a few more commits, I […]

Development, Git

Adding a million rows from CSV file to a Mysql database table using Python and Pandas!

Posted on April 17, 2022 by Peter Andersson

Do you have a lot of CSV files, with sometimes many rows of data that you need to import to a Mysql database? You could […]

Development, Python

Where do you add initialization code in a Spring Boot application.

Posted on February 15, 2022 by Peter Andersson

Some people think Spring and Spring Boot adds to much “magic” to a Java app, and to some extend I agree. Have they gone too […]

Development, Java, Spring Boot

Multiproject builds in Gradle

Posted on February 12, 2022 by Peter Andersson

Gradle is a beast! Having a background in simpler build systems like Makefile and Ant, Gradles DSL confused me initially. Gradle has sections that basically […]

Gradle

Using annotated Spring Boot entities in a Library

Posted on February 12, 2022 by Peter Andersson

When I moved a bunch of classes from a rather large Spring Boot application into a separate library (se more about that process here), I […]

Development, Spring Boot

The last Police interview with Stig Engström

Posted on February 11, 2022 by Peter Andersson

One of my interests which are not computer related, is the murder of Olof Palme, Feb 28 1986. Here is the last interview with Stig […]

Palmemordet

Why Windows Suck

Posted on October 14, 2021 by Peter Andersson

Why it sucks? The TL;DR is “It’s not Linux”. I really want to like Windows. And God knows I have tried. A couple of times […]

Development, Linux, Microsoft, Thoughts, Web

Installing a certificate using LetsEncrypt on a Ubuntu server with Apache (New version 2022-08-15)

Posted on October 14, 2021 by Peter Andersson

Running webservers on own hardware I develop a lot of websites, and I run them on my own hardware (a Ubuntu Server). When developing (on […]

Apache, Development, Ruby on Rails, Web

Creating a bigger swap file on Linux Mint

Posted on January 5, 2021 by Peter Andersson

For some reason, Linux Mint (and other variants probably?) creates a measily 2GB swap file, which is too small IMHO when you have 16GB or […]

Linux

PATH

Posted on December 1, 2020 by Peter Andersson

How the system path is set is quite complicated, depending on your system and shell setup. But for the most common one (Linux Mint/Bash in […]

bash, Development, Linux

Massuploading pictures using ActiveStorage

Posted on December 1, 2020 by Peter Andersson

ActiveStorage is a gem, I really think so. Before AS, whenevener I needed to attach a “blob” (image or other document) to a model it […]

Development, HTML and CSS, Ruby, Ruby on Rails

Detecting colors in a webcam feed

Posted on November 26, 2020 by Peter Andersson

A friend asked me to help debug an app that tried to detect three different colors. It was written in Python and used three precreated […]

Development, Imaging, Python, Video

Great color themes for your Linux terminal

Posted on October 25, 2020 by Peter Andersson

The major difference between Linux and Windows is the quality of the terminal. I would say the comparison is like comparing a with a But […]

Development, Linux

Fixing CUPS error on Linux Mint

Posted on August 18, 2020 by Peter Andersson

I had terrible problems connecting to my Wifi printer Canon MG5450. It worked perfectly from my Imac, but from my Linux Box I got “server-error-internal-error” […]

Linux

Solution to pyenv problem

Posted on July 17, 2020 by Peter Andersson

If you get this (or similar) error when running: /home/peter/.pyenv/versions/3.8.3/lib/python3.8/site-packages/pandas/compat/__init__.py:117: UserWarning: Could not import the lzma module. Your installed Python is incomplete. Attempting to use […]

Python

Creating a Desktop shortcut in Linux Mint

Posted on June 30, 2020 by Peter Andersson

In ~/Desktop, create a file named Eclipse.desktop with content: [Desktop Entry] Version=x.y Name=ProgramName Comment=This is my comment Exec=/home/peter/Documents/exec.sh Icon=/home/peter/Pictures/icon.png Terminal=false Type=Application Categories=Utility;Application; if you need […]

Development

The amazing power of Python and the Pandas framework!

Posted on April 11, 2020 by Peter Andersson

This code connects to a Mysql database, reads ths content of a table and imports it into a Dataframe. From there you can twist and […]

Development, Python

Avoiding relative imports in a React app

Posted on March 14, 2020 by Peter Andersson

Even with a moderately large React app, you try to structure your modules and end up here in the end: import ../../../components/dialogs/enter.jsx WTF?? Good luck […]

Development, Javascript, React, Visual Studio Code

Ruby and Rails development environment

Posted on March 6, 2020 by Peter Andersson

How do you setup VS Code, which is a great code editor, for Ruby development? Well you start by installing these gems: gem install solargraph […]

Development, Ruby on Rails, Visual Studio Code

Removing Mysql completely!

Posted on January 21, 2020 by Peter Andersson

It’s not as straightforward as you might think to completely remove MySQL from your linux box. Here are the details: Use apt to uninstall and […]

Development

Writing a websocket server using Ruby

Posted on November 27, 2019 by Peter Andersson

I just found this amazing article about the finer details of Websockets, and how to implement a WS server using Ruby. I just had to […]

Development, Network, Ruby

Monitoring using iotop

Posted on November 20, 2019 by Peter Andersson

iotop is installed via sudo apt install iotop and is a great tool for monitoring I/O in your box. Here are a few tips […]

Linux

Customizing a new Linux Mint setup

Posted on November 17, 2019 by Peter Andersson

So it finally happened. After years of usage I managed to f**k up my linux boot. I suspect the HDD was about to give up […]

Git, Linux

A few console.log gems you didn’t know about

Posted on November 14, 2019 by Peter Andersson

Top 10 javascript console tips! Tip #0 console.assert() Tip #1 console.trace() Tip #2 console.time() && console.timeEnd() Tip #3 console.memory Tip #4 console.profile(‘profileName’) & console.profileEnd(‘profileName’) Tip […]

Development, Javascript, Node

Adding Redux to your React project

Posted on November 14, 2019 by Peter Andersson

Installation Add the necessary modules yarn add react-redux yarn add redux Fix the component import {connect} from ‘react-redux’; // definition of DummyComponent here… const mapStateToProps […]

Development, Javascript, React

Configuring the Spring Boot Actuator

Posted on October 25, 2019 by Peter Andersson

The Actuator is a great tool. The documentation and history of changed configuration and implementation is however a big big mess. To cut a LONG […]

Development, Java, Linux

A simple but complete Highcharts example

Posted on October 19, 2019 by Peter Andersson

This is how you can test the excellent Highcharts library. Make sure you have JQuery added first. <link rel=”stylesheet” href=”https://cdnjs.cloudflare.com/ajax/libs/highstock/6.0.2/css/highcharts.css” integrity=”sha256-ji+33kRPEXS0+FM/AbApEs8n5kT2UBiGyk36zs1F9gE=” crossorigin=”anonymous” /> Also include […]

Ajax, Development, HTML and CSS, Javascript

Rubys magic language

Posted on September 30, 2019 by Peter Andersson

This is a piece of code I keep to remind me of the magic in Ruby. class Main # you can dynamically define methods with […]

Development, Ruby, Ruby on Rails

TWS API Resources

Posted on August 9, 2019 by Peter Andersson

If you, like me, often code applications against the TWS API from Interactive Brokers, you will have good use of the following resources: The official […]

Development

Awesome Ruby

Posted on July 25, 2019 by Peter Andersson

Yes it’s awesome, I know! But even more so, is the list of tools, gems and frameworks that are available for Ruby programmers. Here is […]

Development

Setting up Python for development

Posted on June 13, 2019 by Peter Andersson

Perfecting your Python development setup by RealPython Perfect Your Python Development Setup (Learning Path) – Real Python Optimize your Python development setup with this learning […]

Development, Python

The Top Command

Posted on May 12, 2019 by Peter Andersson

You now the command top? The one you use when you want to see if there is one process hogging all the CPU? But there […]

Linux

Managing multiple Python versions with multiple virtual environments

Posted on May 3, 2019 by Peter Andersson

Since I was used to use rvm to handle multiple ruby versions, and a .ruby-version file which automatically switched version for me, of course I […]

Development, Python

Updating dyndns automatically from Linux

Posted on May 2, 2019 by Peter Andersson

If you have an account at the eminent service dyndns.com, you can update it automatically from your host by using this method: Start by installing […]

Development, Network

Download EOD data from Yahoo Finance to a Python Pandas Dataframe

Posted on April 17, 2019 by Peter Andersson

If you use the Pandas DataReader and get this message: pandas_datareader.exceptions.ImmediateDeprecationError: Google finance has been immediately deprecated due to large breaks in the API without […]

Development, Python, Trading

Slack shortcuts and commands

Posted on April 12, 2019 by Peter Andersson

I can’t stand long articles so here’s a short bullet list: Searching in:channelname, in:name, from:username, from:me, has:link, has:star, has:emojiname, before, after, on, during Commands /remind […]

Development, Network

Creating a child theme in WordPress

Posted on April 6, 2019 by Peter Andersson

This is a no-nonsense instruction of how to create a child theme in WordPress. We create it from the existing theme “twentynineteen” 1. Create a […]

Development, HTML and CSS, PHP, Wordpress

Multiple select listboxes in Rails

Posted on March 29, 2019 by Peter Andersson

Since I think the documentation is lacking and I always have to rely on Stackoverflow every time I want to use it, I keep this […]

Development, Ruby on Rails

Creating your own tag helper in Rails

Posted on March 29, 2019 by Peter Andersson

Lets say you get sick and tired of writing this in your views: <div class=”field”> <%=form.label :location %> <%=form.text_field :location %> </div> and instead you […]

Development, Ruby, Ruby on Rails

Elegant menu transition in Bootstrap

Posted on March 27, 2019 by Peter Andersson

I like the fixed menu, that stays in place when your scroll the content, but I have seen a few websites do a cool transition […]

Development, HTML and CSS, Javascript

Setting up Apache with Letsencrypt certificates

Posted on March 25, 2019 by Peter Andersson

Since you need a domain name, and I almost always use dynamic domain services, I recommend setting up ddclient so that the dynamic DNS is […]

Apache, Development, Linux, Network

No thank you!

Posted on March 12, 2019 by Peter Andersson

Putting a server on the internet is today similar to walking alone at night in a part of the city you know nothing about, where […]

Development, Linux, Network

A standard HTML header

Posted on February 28, 2019 by Peter Andersson

You should specify a lot of things in your HTML header nowadays. Previously it was enough with some CSS and JS script includes. Now we […]

Development, HTML and CSS, Wordpress

Creating a DSL in Ruby

Posted on February 14, 2019 by Peter Andersson

Creating a Domain Specific Language has been on my TODO-list for a long time! Ruby is the perfect language for this task I have collected […]

Development, Ruby on Rails

Pythons argparse for dummies

Posted on January 11, 2019 by Peter Andersson

Python is a great language, but sometimes it makes life more complicated than necessary. I don’t know if this is because it’s heritage (C) or […]

Development, Python

Administrate your Linux system using your web browser

Posted on December 13, 2018 by Peter Andersson

Linux is great, but granted, sometime it can feel a little complicated. Installing and configuring software always start with a Google: “howto install XXX Ubuntu […]

Linux, Network

Make your own Rails View helpers

Posted on November 14, 2018 by Peter Andersson

Rails helpers like image_url, link_to, form_with, fields_for etc are nifty little “macros” that makes your Rails code smaller and clearer. I mean, who doesn’t prefer […]

Development, HTML and CSS, Ruby on Rails

Asymmetric Key Cryptography

Posted on October 26, 2018 by Peter Andersson

I know, it’s a mouthful! I never thought I’d understand asymmetric cryptography, partly because I tend to stay away from REALLY complicated stuff, and partly […]

Development, Linux, Math

Bringing some order in your data files

Posted on October 8, 2018 by Peter Andersson

Lots of harddisk space leads to…. lots of files. Why throw stuff away when keeping it is so cheap? I always end up with a […]

Development, Linux, OSX, Video

Roadmap for 2018/2019

Posted on September 25, 2018 by Peter Andersson

Too many frameworks? Check. Too many tools? Check. Too many crossroads? Then use this roadmap. It will help you decide which path to take in […]

Ajax, Development, Git, HTML and CSS, Javascript, React, Tankar, Thoughts, Vue

Installing OpenCV 3.4.1 using Python 3 on Raspbian Stretch

Posted on September 11, 2018 by Peter Andersson

UPDATED OCT 2020 See this link for a much better procedure: https://medium.com/@aadeshshah/pre-installed-and-pre-configured-raspbian-with-opencv-4-1-0-for-raspberry-pi-3-model-b-b-9c307b9a993a This is left for archiving purposes: As usual, I will keep this […]

Development, Python, Raspberry Pi

Array is an instance of class Class

Posted on September 3, 2018 by Peter Andersson

If the title to this post seems impossible to understand, please read this conversation between Gavin Sinclair and Martin de Mello. Something that was really […]

Development, Ruby, Ruby on Rails

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