Dockerized Rails Capybara tests on top of Selenium
If you use Docker to deploy your Rails application you may want to use the same infrastructure to run your tests. However the setup of your Selenium …
How to isolate complex queries in an object oriented fashion
Building complex queries in ruby can make your code quite difficult to read, manage and reuse. In this blog post I’ll present a simple method to …
Create isolated Jupyter ipython kernels with pyenv and virtualenv
Everyone loves isolation. Makes our life easier and our systems much more robust. Isolating Jupyter notebooks makes no exception. Maybe you want to try some cutting …
A/B Testing, from scratch
If you work in a diligent web development business you probably know what an A/B test is. However, its fascinating statistical theory is usually left behind. …
Cross Validation done wrong
Cross validation is an essential tool in statistical learning to estimate the accuracy of your algorithm. Despite its great power it also exposes some fundamental …
Data manipulation primitives in R and Python
Both R and Python are incredibly good tools to manipulate your data and their integration is becoming increasingly important. The latest tool for data manipulation …
Upload video files with progress bar using Rails, Paperclip and Javascript
Rails does not help much when dealing with AJAX uploads by means of external JS libraries. I recently came across a case where a user …
Understanding the Resque internals – Resque::DirtyExit unveiled
If your Resque jobs fail because of a mysterious Resque::DirtyExit a quick tour of the Resque internals will help you fix the issue and be back up …
Bringing Ruby fetch to the Javascript world
If you are a Rubyist you are probably comfortable using the fetch method on a day-to-day basis but when you are developing in Javascript this sweetness …
Refactoring a complex Javascript calendar
Frontend components are hard to implement and more often than not the code reflects this complexity. In this blog post I will show you how …