assignable_values now lets you define a secondary default that is only used if the primary default value is not assignable:

class Song < ActiveRecord::Base
  assignable_values_for :year, :default => 1999, :secondary_default => lambda { Date.today.year } do
    (Date.today.year - 2) .. Date.today.year
  end
end

If called in 2013 the code above will fall back to:

Song.new.year # => 2013

This is especially useful in authorization scenarios with [Consul](https://github....

paper_trail is an excellent gem to track record versions and changes.

You almost never want to reimplement something like it yourself. If you need to log some extra information, you can add them on top.

It comes with a really good README file that holds lots of examples. I'll show you only some of its features here:

• Setting up a model to track changes

  Just add has_paper_trail to it:
  class User < ActiveRecord::Base
  has_paper_trail
  end

• Accessing a previous version

  Saying user.previous_version gi...

The will_paginate gem will show a default of 30 records per page.
If you want to test pagination in a Cucumber feature, you don't want to create 31 records just for that.

Instead, you probably want to modify the number of items shown, by saying something like this:

Given we paginate after 2 users

Using the following step definition, you now can! :)

require 'cucumber/rspec/doubles'

Given /^paginate after (\d+) (.*)$/ do |per_page, model_name|
  model = model_name.singularize.gsub(/...

Unless you changed the default, this will be 16 MB:

mysql> SHOW VARIABLES WHERE Variable_name="max_allowed_packet";
+--------------------+----------+
| Variable_name      | Value    |
+--------------------+----------+
| max_allowed_packet | 16777216 |
+--------------------+----------+

Sometimes, you may want to open up a second database connection, to a read slave or another database. When doing that, you must make sure you don't overwrite an existing connection.

The problem

While this may look good, it will actually cause all kinds of trouble:

def with_other_database
  ActiveRecord::Base.establish_connection(slave_settings)
  yield
ensure
  ActiveRecord::Base.establish_connection(master_settings)
end

Putting aside that you are setting the general connection here (not generally a ...

This will make MySQL log all received queries so you can see for yourself what happens on the database level.

Don't switch this on for production machines!

1. Edit your my.cnf:
   sudo vim /etc/mysql/my.cnf
2. In the [mysqld] section, add:
   log=/var/log/mysql.log
3. Restart your MySQL daemon. On Ubuntu:
   sudo service mysql restart

Note that your MySQL performance will suffer. But when you need to enable query logging for a debug fest, you probably don't care about that.

I highly recommend that you make use of RubyMine's feature to pin tabs.

When you pin all "important" files, you can follow method definitions, wildly open files from search results and have a ton of open tabs -- without the problem of finding the stuff you were working on before.

Guide

1. Pin the tabs of files that are currently in the focus of your work (important models, specs, etc):
   • Right-click a tab and select "Pin tab"
   • Or use a shortcut (see below)
2. Work as usual.
3. Once you opened other tabs because you searched ...

In Rails 3.1+, instead of defining a separate up and down method you can define a single method change:

class AddComparisonFieldsToReport < ActiveRecord::Migration
  def change
    add_column :reports, :compare, :boolean
    update "UPDATE reports SET compare = #{quoted_false}"
    add_column :reports, :compare_start_date, :date
    add_column :reports, :compare_end_date, :date
  end
end

Migrating up works as expected:

b rake db:migrate
==  AddComparisonFieldsToReport: migrating ====================================
-- ad...

I ported the initializer to Rails 3.

If you upgrade to the mysql2 gem, you will run into the problem that the server's database.yml (which is usually not under version control) needs to change exactly on deploy.

You can however make your database.yml work for mysql and mysql2 at the same time. Simpy do this

production:
   adapter: <%= defined?(Mysql2) ? 'mysql2' : 'mysql' %>
   #...

The linked article describes how to use a Firefox addon "Flash-Aid" to install a better build of Flash and apply some optimizations.

With this I can now properly watch fullscreen HD videos under Ubuntu.

This script loads a dump into your development database.

You can provide the full path to you database dump like this:

load-dump path/to/my.dump

When you call load-dump without any arguments it will show a menu with all dumps in your ~/dumps/ folder.

load-dump

This script is part of our geordi gem on github.

The problem

When using the asset pipeline your assets (images, javascripts, stylesheets, fonts) live in folders inside app:

app/assets/fonts
app/assets/images
app/assets/javascripts
app/assets/stylesheets

With the asset pipeline, you can use the full power of Ruby to generate assets. E.g. you can have ERB tags in your Javascript. Or you can have an ERB template which generates Haml which generates HTML. You can chain as many preprocessors as you want.

When you deploy, Rails runs assets:precompile...

Some advice for bulk loading many records into InnoDB and finishing before the sun burns out. Use with care.

Building CSS mobile-first is the way forward, because blah blah blah progressive enhancement blah. Problem is, Internet Explorer prior to 9 ignores anything within media query blocks, leaving those browsers with mobile styles.

Not all of us can get away with that, but thankfully, as Chris Eppstein points out, Sass 3.2 (not yet released) can generate a separate stylesheet with everything it needs to create a "desktop" look.

This page was built mobile-first where smaller width devices get a single column layout, but IE8 and below still get a...

Probably was in the repository once and got deleted in a commit that you pulled.

Geoffrey Grosenbach has created Gruff for easily plotting graphs. It is written in pure Ruby and integrates with Rails applications.

It provides features as automatic sizing of dots and lines (the more values, the thinner the graph's elements), custom or predefined themes, different styles (bar, line, dot and many more) and multiple graphs in one chart.

Installation

In your Gemfile:

gem 'rmagick', :require => false
gem 'gruff'

Then run bundle install (and don't forget to restart your development server.)

Usage

This i...

If you need a gem for a certain purpose, be sure to check this site.

The rankings are determined by counting up the number of forks and watchers of various github projects, so I'd view it less as "this is what I should be using," and more as "these are some things I should check out." At the very least, they're all likely to be under active development and fairly up to date, and it's very useful to see groups of gems broken down by category.

Localizing a non-trivial application can be a huge undertaking. This card will give you an overview over the many components that are affected.

When you are asked to give an estimate for the effort involved, go through the list below and check which points are covered by your requirements. Work with a developer who has done a full-app localization before and assign an hour estimate to each of these points.

Static text

• Static strings and template text in app must be translated: Screens, mailer templates, PDF templates, helpe...

There is now a solution.

MySQL version 5.1 comes with an alternative, faster InnoDB implementation (called "InnoDB Plugin").

Switching is easy:

• Stop your mysqld with sudo stop mysql
• Add the following lines to your /etc/mysql/my.cnf under the [mysqld] section
  ignore-builtin-innodb
  plugin-load=innodb=ha_innodb_plugin.so
• Start your mysqld with sudo start mysql

The file format has not changed, your tables should survive this.

Note: This is not necessary in MySQL 5.5, where the new implementation is the default.

When requests arrive at the application servers simultaneously, weird things can happen. Sometimes, this can also happen if a user double-clicks on a button, for example.

This often leads to problems, as two object instances are modified in parallel maybe by different code and one of the requests writes the results to the database.

In case you want to make sure that only one of the requests "wins", i.e. one of the requests is fully executed and completed while the other one at least has to wait for the first request to be completed, you ha...

Using beginning_of_day or end_of_day on Date or DateTime objects in Rails 2.x applications will never respect time zones, which is horrible.\
This is fixed in Rails 3, though.

Even when using Date.current or DateTime.current you will get regular Time or DateTime objects:

>> Date.current.beginning_of_day.class
=> Time # not a ActiveSupport::TimeWithZone as expected
>> DateTime.current.beginning_of_day.class
=> DateTime ...