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 browser tests is far from obvious with Rails and Docker and may generate some confusion . The short answer is available in this repository on Github. For the long answer keep reading this blog post […]
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 decorate active record objects to make your queries fun again!
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 edge scientific library, or more simply your latest project dependencies are not compatible with your current system setup. Whatever is your situation, follow me in this simple tutorial on how to […]
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. Understanding the basics can help you avoid common pitfalls, better design your experiments, and ultimately do a better job in improving the effectiveness of your website. Please hold tight, and enjoy a pleasant […]
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 risk when done wrong which may terribly bias your accuracy estimate. In this blog post I'll demonstrate - using the Python scikit-learn framework - how to avoid the biggest and […]
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 in R is Dplyr whilst Python relies on Pandas. In this blog post I'll show you the fundamental primitives to manipulate your dataframes using both libraries highlighting their major advantages […]
Why I loved the 2015 Railsconf Keynote
This year Rails 5 will be released and the Railsconf keynote held by DHH - the author of Rails - presents the rationale behind its latest developments. In the following I'll show you why I think we are riding the good Rails and how to apply the right amount of criticism around the Rails' author […]
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 on www.codementor.io was struggling to use JQuery-upload-file to upload a video to a Rails backend. The main reason to use the library was the progress bar feature, something that is […]
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 and running in a matter of minutes.
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 is not immediately available. This is why I wrote underscorejs-fetch.