Zeus promises to make rails development faster

I am talking about development speed. When your application starts growing and you start adding gems, it starts to take really long to start up, be it the server, console or just running a single spec.

Zeus is smart, you don’t have to put it in your Gemfile or run it with Bundler, all you need to do is create a JSON config file via zeus init and then start the server zeus start.

After that, you’re ready to go, all you need to do is prefix every command with zeus. That means rails server becomes zeus server, `rails console…

Andand and SimpleDelegator

The very useful andand gem does not play very nice with Ruby's SimpleDelegator (or vice versa).

This following will not work:

class MyDecorator < SimpleDelegator
  def foo

The reasons are a bit subtle, basically SimpleDelegator will "force" some methods to be delegated, so the andand method is called on the wrapped object, not the delegator.

You can fix it like this:

class Decorator < SimpleDelegator
  def an...

Xfce: How to change the default program for a file extension

This is super stupid:

  • In the Thunar file manager, select the file
  • Go to File / Properties / Open With (WTF!)
  • Select the preferred application from the list and hit "Set default"

This setting will apply to all files with that extension.

How to set the default monospace font on Xfce (Xubuntu)

While you can set your own font in your terminal or other tools, it will not change the default "Monospace" font that some applications use.

To change that, edit ~/.fonts.conf and add settings for the "monospace" family. Here is how it looks on my machine now:


monospace DejaVu Sans Mono

External content

Writing Fast, Memory-Efficient JavaScript

JavaScript engines such as Google’s V8 (Chrome, Node) are specifically designed for the fast execution of large JavaScript applications. As you develop, if you care about memory usage and performance, you should be aware of some of what’s going on in your user’s browser’s JavaScript engine behind the scenes.

Get all associations of an ActiveRecord class

Get the class name by calling class_name, or the type of the association (belongs_to, has_many,…) by calling macro

A jQuery plugin for producing bar charts from tables.

As the title says: this jQuery plugin creates bar charts from HTML tables. It comes in some different flavors.

Check the examples page:

External content

Using sets for many-to-many relationships

A technique to vastly reduce the number of join model records that need to be stored in the database.

The technique is only effective when there is a high redundancy in your data, e.g. combinations of the same 20 tags are used to label thousands of books.

The technique is also limited in that your join models cannot have additional logic, such as attributes or callbacks.

Ther has-many-with-set gem is an implementation of this technique.

How to move a window to the next monitor on Xfce (Xubuntu)

Unfortunately, Compiz does not play nice with Xfce for me and Xfce itself does not offer a way to move a window to the next monitor.

Since I use this a lot in my daily work and there were no scripts working properly for me, I made one myself.
It's actually not bound to Xfce but should work on any window manager (haven't tried it, though).


  1. If you don't yet have xdotool, install it:

    sudo apt-get install xdotool
  2. If you don't yet have wmctrl, install it:

    sudo apt-get install wmctrl
  3. Store the att…

CSS: Vertically center with display: table-cell

Note: We have card with all CSS centering options. You probably want to head over there and get an overview over what techniques are available for your use case and browser requirements.

The classical scenario: There's a parent div element and you want to center some arbitrary child element vertically inside of it. Here's how you do it (also try this jsfiddle).

The children need to be block e…

Rubygems: Rebuild native extensions

Rarely, you might want to rebuild all gems with native extensions, because they might be compiled against outdated system libraries, resulting in some warnings or even segfaults or other ruby errors.

You can do that using

gem pristine --all

This will reset all gems to a pristine state as if you'd reinstall them, and as a side effect, rebuild all native extensions.

The above command will also help you sorting out errors like this after a distribution upgrade: cannot open shared object file: No such fil...
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Subtle Patterns Preview

Ever wanted to preview a pattern from Subtle Patterns on your site without the hassle of swapping out images and modifying CSS?

Subtle Patterns Preview provides a simpler way to do it.

Capybara 2.0 has been released

The gem author Jonas Nicklas highlights in a Google Groups post that the release

  • is not backwards compatible to 1.x versions of Capybara
  • does not support Ruby 1.8.x anymore
  • removes confusion with Rails' built in integration tests (you put capybara rspec integration tests into the spec/feature/... folder) and the :type metadata has been changed from :request to :feature
  • throws exceptions when trying to interact with an element whose identifier is…

uninitialized constant MysqlCompat::MysqlRes (NameError)

If you get a stacktrace complaining about uninitialized constant MysqlCompat::MysqlRes a system library update might broke your gem.

Try fully removing and re-installing the gem:

gem uninstall mysql
gem install mysql

Setup an Ubuntu mirror that enables local release upgrades

Setup the mirror by following the steps described here.

If you want to enable OS upgrades using do-release-upgrade make sure you include $release-proposed packages in the mirror script, e.g., precise-proposed. Additionally, you have to add main/dist-upgrader-all to the $section in your script as debmirror silently ignores some directories.

I attached our modified script to include current releases

Enable Ubuntu release upgrade from the local mirror ————————————–…

Carrierwave: Auto-rotate tagged JPEGs

Modern cameras often produce JPEGs that have a "I should be rotated 90° to the left" flag. If you process such pictures using Carrierwave this will be ignored and you'll end up with a wrongly rotated image.

Fortunately, this is easy to fix:

In your Uploader, add

process :auto_orient # this should go before all other "process" steps

def auto_orient
  manipulate! do |image|

Note: You can add the process :auto_orient outside of all your version blocks and it will apply…

query_diet now support Rails 3

Installation differs slightly from older versions, please check the README.

External content

Keyboard Navigation Plugin for Safari, Chrome and Firefox with a rich feature set

gleeBox is an experimental project that takes a keyboard-centric approach to navigating the web. It provides alternatives to actions that are traditionally performed via the mouse. Some of these are radically more efficient than using a mouse, some not so much. In all cases, they are mostly meant for keyboard and command line lovers.

Gleebox is a terrific plugin that makes navigating through webpages a wink. It even allows for selecting by jQuery selector.

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