Axlsx is an incredible gem to generate "Office Open XML" spreadsheet files (XLSX). Does not break on large spreadsheets and supports a ton of features like graphs.

API looks mature and existing code is easy to migrate when coming from the spreadsheet gem.
The documentation of some methods is a bit out of date, but you'll find your way around the gem's code.

No support for reading files, however. :( If you want to open XLSX spreadsheets (for example to confirm your output in tests), you can use [roo](h...

jquery-timing is a very useful jquery plugin that helps to remove lots of nested anonymous functions. It's API provides you some methods that help you to write readable and understandable method chains. See yourself:

Example

// before
$('.some').show().children().doThat();
window.setTimeout(function(){
  $('some').children().doSomething().hide(function() {
    window.setTimeout(function() {
      otherStuffToDo();
    }, 1000);
  });
}, 500);

// after
$('.some').s...

The bash offers control over the behavior of autocompletion.

The most primitive example is this (just run it in your bash; if you want it available everywhere, put the complete ... line into your .bashrc):

> complete -W "list of all words for an automatic completion" command_to_be_completed
> command_to_be_completed a<TAB>
all an automatic

With complete you define how the specified command shall be completed. For basic needs, -W (as in "word list") should be enough, but you may also specify a function, a glob patte...

When searching for text in a MySQL table, you have two choices:

• The LIKE operator
• FULLTEXT indexes (which currently only work on MyISAM tables, but will one day work on InnoDB tables. The workaround right now is to extract your search text to a separate MyISAM table, so your main table can remain InnoDB.)

I always wondered how those two methods would scale as the number of records incr...

If - for whatever reason - you have to render stylesheets dynamically, the following snippet might be of help. It emulates what "sprockets" would to when precompiling your assets, and give your stylesheets access to all the regular bells and whistles (like asset_path, proper @imports etc):

class DynamicStylesheetsController < ApplicationController

    def show
      logical_path = RELATIVE_PATH_TO_YOUR_TEMPLATE
      path = File.join(Rails.root, logical_path)
      template = Sass::Rails::SassTemplate.new(path)
      environment = ...

Our old solution for cronjobs, the "craken" plugin, is no longer maintained and does not work on Rails 3.2+.

We will instead use the whenever gem.

"Whenever" works just like "craken", by putting your rake tasks into the server's cron table. Everything seems to work just like we need it.

Installation for new projects

1. Add "whenever" to your Gemfile:

    group :deploy do
      gem 'whenever', require: false
    end
   

2. Add it to your config/deploy.rb:
   ...

For two years we've been using SearchableTrait which gives models the ability to process Googlesque queries like this:

Contact.search('a mix of words "and phrases" and qualified:fields')

This trait used to be a huge blob of code without tests and documentation, so I made a gem out of it. Check out https://github.com/makandra/dusen for code, tests, and a huge README.

You should use the Dusen gem and delete SearchableTrait in all future projects.

Note that the syntax to define query proc...

If you can now longer hear or record sounds after upgrading Ubuntu, you probably need to re-tell Ubuntu which devices to use for playback/recording.

Fix sound output

• Open the PulseAudio Volume Control (pavucontrol). If you don't have that application, install it with sudo apt-get install pavucontrol.
• Start playback of an MP3 so you can see when changes take effect.
• Under "Output devices" use the "Mute" buttons to figure our which output device is the correct one. When you found it, also set it as the fallback dev...

In Rails 2, when calling instance_eval or instance_exec on a scope, the scope will fetch its records from the database.

This has been fixed in Rails 3+.

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.

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).

Installation

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 attached file in some place that's in your PATH.
   The cool kids use ~/bin/.

4. Make it executable: `chmod +x ~/bin/move-to-next-mo...

When you have two models in a has_many, has_one or belongs_to association, the :inverse_of option in Rails tells ActiveRecord that they're two sides of the same association.

Example with a has_many / belongs_to association:

class Forum < ActiveRecord::Base
  has_many :posts, inverse_of: :forum
end

class Post < ActiveRecord::Base
  belongs_to :forum, inverse_of: :posts
end

Knowing the other side of the same association Rails can optimize object loading so forum and forum.posts[0].forum will reference the same o...

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.

Icon fonts like Font Awesome are infinitely scalable, look great on high-DPI displays and will give your app a modern look.

However, icon fonts can be very awkward to use compared to raster icons. Elements are given icons by giving them a special class like icon-plus or icon-home:

<span class="icon-plus">Create</span>

The icon font's stylesheet will then recognize this class and insert the icon as the element's :before style.

In practic...

url = 'http://www.foocorp.com/foo/bar'
URI.parse(url).host
# => www.foocorp.com

Note that this will raise an error if the given argument is not a URL.

If you need the host's full URL without path, query, fragment etc., use URI.join with a clever twist:

url = 'http://www.foocorp.com:33546/foo/bar?query=foobar#hash'
URI.join url, '/'
# => http://www.foocorp.com:33546/

In theory you can take any scope and extend it with additional joins or conditions. We call this chaining scopes.

In practice chaining becomes problematic when scope chains grow more complex. In particular having JOINs in your scope will reduce the scope's ability to be chained with additional JOINs without crashes or side effects. This is because ActiveRecord doesn't really "understand" your scope chain, it only mashes together strings that mostly happen to look like a MySQL query in the end.

**I don't generally advice against u...

ActiveModel::Errors is used to handle validation errors on Rails objects. If you inspect an instance, it feels like a hash (to be more precise, it inherits from Hash):

errors = ActiveModel::Errors.new(Object.new)
=> {}
>> 
?> errors.add(:base, "foo")
=> ["foo"]
>> errors.add(:base, "bar")
=> ["foo", "bar"]
>> 
?> errors
=> {:base=>["foo", "bar"]}

If you need to hack anything with these errors, beware that it behaves in a special way. If you iterate over the errors it will decompose arrays.
For ...

In a nutshell:

If you require your Rails models manually, pay attention to the path you use. Unless you have to, don't do it at all.

Background

Consider these classes:

# app/models/user.rb

class User < ActiveRecord::Base
  validate :magic

  def magic
    errors.add_to_base('failed') if bad_things?
  end
end

^
# app/models/foo.rb

require 'user'

class Foo
  # something happens here
end

Now, when your environment is booted, Rails will automatically load your models, like User...

“Fat models” cause maintenance issues in large apps. Only incrementally better than cluttering controllers with domain logic, they usually represent a failure to apply the Single Responsibility Principle (SRP). “Anything related to what a user does” is not a single responsibility.

Early on, SRP is easier to apply. ActiveRecord classes handle persistence, associations and not much else. But bit-by-bit, they grow. Objects that are inherently responsible for persistence become the de facto owner of all business logic as well. And a year or tw...