Category: Ruby

Can Sphinx and foxy fixtures place nicely together? Due to the way Sphinx indexing works, foxy fixtures will often slow down the indexing process drastically. This article explains how to overcome this limitation.

<% @categories.in_groups_of(2).each do |group| %>
  <tr>
  <% group.each do |category| %>
    <td><%=h category.name %></td>
  <% end %>
  </tr>
<% end %>

What are you staring at? Move along, move along.

Many Rails plugins require that certain files like images, CSS, and JavaScript get copied to the public folder during installation. The typical way to do this is add code to install.rb, which then gets executed when you first install the plugin in your Rails project. What happens when the assets in a plugin you’re using change, though? You end up having to manually copy files around anytime the plugin gets updated, which is an extremely error-prone process.

I extracted asset_copier from an existing Terralien project. It fixes this problem beautifully. Once installed, it keeps the assets in your Rails project synchronized with your plugin. It even deletes assets from the Rails project that have been removed in the plugin.

To learn more, check out this post. If instant gratification is more your thing, install the gem directly and apply it to your target plugin:

sudo gem install pelargir-asset_copier --source=http://gems.github.com
cd ~/some_rails_project
script/generate asset_copier some_plugin

I’m in the middle of developing a Radiant extension for Terralien. Radius is the tagging language for Radiant, and today I figured out how to use a route from inside a custom tag class.

A typical Radius tag class might look like this:

module AwesomeTags
  include Radiant::Taggable

  tag "session:logout" do |tag|
    "Logout"
  end
end

You can see that the hard-coded URL isn’t exactly DRY. I’ve already defined a route for it. Why should I have to hard code it here? The solution:

module AwesomeTags
  include Radiant::Taggable
  include ActionController::UrlWriter  
  default_url_options[:host] = REGISTRY[:host]

  tag "session:logout" do |tag|
    "Logout"
  end
end

Note that UrlWriter needs to know the host name to base its URLs off of. The host name gets set using the registry pattern. It will be different depending on whether the app is running in development or production mode.

The same method can be used to reference routes from inside ActiveRecord models.

I just released a new gem on GitHub that provides some common validation expectations to rspec. Instead of writing specs to verify that your models are handling validation correctly, these expectations simply check that the validation is getting declared correctly in your model. For example:

describe User do
  it_should_validate_presence_of :first_name, :last_name, :email
  it_should_validate_numericality_of :zip
  it_should_validate_uniqueness_of :email
end

Since the expectations never hit the database, they are also faster than testing the traditional way. It’s dead simple to install on Rails 2.1 or later:

script/plugin install git://github.com/pelargir/rspec_validation_expectations.git

The expectations become available to your specs immediately.

I’m at the Ruby Hoedown in Huntsville this weekend. Being around so many brilliant geeks encouraged me to release a gem I’ve had sitting in the hopper for several weeks.

finder_filter encapsulates a pattern I find myself using quite frequently in Rails. Namely, looking up an instance variable before an action. For example:

class UsersController < ActionController::Base
  before_filter :find_user, :only => [:show, :edit]
  
  def show
    # do something with @user
  end
  
  def edit
    # do something with @user
  end
  
  def find_user
    @user = User.find(params[:id)
  end
end

Sticking the finder in a before filter keeps the code DRY, but it still takes several lines to do this. finder_filter reduces this to a single line of code:

class UsersController < ActionController::Base
  finder_filter :only => [:show, :edit]
  
  def show; end
  def edit; end
end

There are other options to customize the column and param used in the lookup. Check out the README for full details.

To install the gem as a plugin in your Rails project:

sudo gem install pelargir-finder_filter --source=http://gems.github.com

Then open environment.rb in your Rails app and add the gem as a dependency in your initializer block:

Rails::Initializer.run do |config| 
  config.gem "pelargir-finder_filter"
  ...
end

If you have any comments or suggestions, I’d love to hear from you. Contact me through the finder_filter project on GitHub.