So you got this error, even though your Gemfile bundles mysql2:

!!! Missing the mysql2 gem. Add it to your Gemfile: gem 'mysql2'

or

Please install the mysql adapter: `gem install activerecord-mysql-adapter` (mysql is not part of the bundle. Add it to Gemfile.)

The reason for this confusing error message is probably that your Gemfile says mysql2, but your database.yml still uses the mysql adapter. Change it to use the mysql2 adapter:

development:
  adapter: mysql2
  database: myproject_developm...

Our rspec_candy gem now gives you three matchers:

be_same_number_as

Tests if the given number is the "same" as the receiving number, regardless of whether you're comparing Fixnums (integers), Floats and BigDecimals:

100.should be_same_number_as(100.0)
50.4.should be_same_number_as(BigDecimal('50.4'))

Note that "same" means "same for your purposes". Internally the matcher compares normalized results of #to_s.

be_same_second_as

...

The behaviour of browsers is very inconsistent when an Ajax request is answered with a redirect. Highlights are:

• IE 9 will follow a DELETE request with a second DELETE. You never want that.
• Firefox will follow a POST request with a GET, as you might expect. If a PUT is redirected however, you will get a confirmation dialog, where you can choose to follow with a second PUT or simply abort. You don't want that either.

See some workarounds here.

A number of issues concerning Sass/SCSS autocompletion and syntax highlighting were submitted as a feedback for RubyMine 4.5. Web development with Rails can’t do without Sass/SCSS code writing so we’ve decided to fix the most annoying bugs as soon as possible.

The next version of MySQL will include a built-in memcached daemon. This daemon can quickly get and set key/value pairs from and to InnoDB tables while completely bypassing the parsing and planning overhead of SQL.

This could potentially be very awesome because we would then have a distributed key/value store that stores data in a way it can also be queried with complex SQL queries.

For custom Rake tasks, you shouldn't need to modify them after the original definition. However, if you want to add behavior to some vendor tasks (such as those defined with Rails), this blog post will cover how to do that.

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....

You can use String#demodulize from ActiveSupport:

"ActiveRecord::CoreExtensions::String::Inflections".demodulize # => "Inflections"
"Inflections".demodulize                                       # => "Inflections"

When you develop a gem and you have a Gemfile in your project directory, you might be surprised that your gem dependencies aren't already required in your specs. Here is some info that should help you out:

• Bundler actually doesn't automatically require anything. You need to call Bundler.require(:default, :your_custom_group1, ...) for that. The reason why you never had to write this line is that Rails does this for you when it boots the environment.
• That also means that if you have an embedded Rails app in your spec folder (like [h...

Consul 0.4.0 comes with some new features.

Dependencies

• Consul no longer requires assignable_values, it's optional for when you want to use the authorize_values_for macro.
• Consul no longer uses ActiveSupport::Memoizable because that's deprecated in newer Railses. Consul now uses Memoizer for this.

Temporarily change the current power

When you set Power.current to a power in an RS...

The usage shares of your site highly depends on your target audience. E.g. no Internet Explorer has ever seen hollyapp.com, but that's because of its tech-savvy audience. Distribution will also differ by other factors, such as region. See this Wikipedia article for details.

If you don't know your audience, you can use the stats of tracking tools, which see a lot of traffic go by a wide variety of sites. Some of these are:

• [W3Counter](http://www.w3counter...

Don't say is_a?(ActiveRecord::NamedScope::Scope) because that is no longer true in Rails 3 and also doesn't match unscoped ActiveRecord classes themselves (which we consider scopes for all practical purposes).

A good way is to say this instead:

object.respond_to?(:scoped)

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...

When we looked at this card together a year ago, we were no longer sure if unquote is actually useful. I now found a good example for when you need unquote, and rewrote the card accordingly.

You've always been able to access the humanized version for the current value like this:

song = Song.new(:genre => 'pop')
song.humanized_genre # => 'Pop music'

You can now also retrieve the humanized version of any given value by passing it as an argument:

song.humanized_genre('rock') # => 'Rock music'

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 |
+--------------------+----------+

Rake (like make) allows you to add dependencies to a task after you've initially declared it. Indeed it allows you to continue to talk about a task in multiple places. This way I can decide to add dependencies close to the pre-requisite task.

... you probably have a time zone issue.

When you get

Timecop.travel(Date.parse("2011-11-11 00:00") do
  Time.current  # Thu, 10 Nov 2011 23:00:01 UTC +00:00
  Time.now      # Fri Nov 11 00:00:02 +0100 2011
  Date.today    # Fri, 11 Nov 2011
  Date.tomorrow # Fri, 11 Nov 2011
end

you probably haven't defined a zime zone yet.

So might fix this by adding the following lines to your application.rb:

class Application < Rails::Application
  config.time_zone = 'Berlin' # or whatever your time zone
end

It se...

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 ...

Take care in queries where multiple AND or OR operators are used. In doubt, always use braces to enforce precedence.

The asset pipeline from Rails 3.1 packported to 2.3. By Michael Grosser from parallel_tests fame.

The facebook API allows up to 600 requests per 600 seconds.
If you poll more often, you'll get no or malformed answers.