Pacecar

Pacecar adds scope methods and other common functionality to ActiveRecord classes via database column introspection.

Pacecar automatically includes the Pacecar::Helpers module into all ActiveRecord::Base classes.

To get all Pacecar functionality, you need to "include Pacecar" in your class.

class User < ActiveRecord::Base
  include Pacecar
end

To get some subset (for example, only the state functionality), you can do something like "include Pacecar::State" to get only the module(s) you want.

class Post < ActiveRecord::Base
  include Pacecar::State
end

Pacecar supports mysql, postgres and sqlite database drivers, and is compatible with Rails 4.x versions.

Installation

Just include in your Gemfile:

gem 'pacecar'

Usage

Assuming a database schema:

class CreateSchema < ActiveRecord::Migration
  def self.up
    create_table :users, :force => true do |t|
      t.boolean :admin, :default => false, :null => false
      t.datetime :approved_at
      t.datetime :rejected_at
      t.string :first_name
      t.string :last_name
      t.text :description
      t.timestamps
    end
    create_table :posts, :force => true do |t|
      t.string :owner_type
      t.integer :owner_id
      t.string :publication_state
      t.string :post_type
      t.timestamps
    end
    create_table :comments, :force => true do |t|
      t.integer :user_id
      t.text :description
      t.integer :rating
      t.timestamps
    end
  end
end

And some basic model declarations:

class User < ActiveRecord::Base
  include Pacecar
  has_many :posts, as: :owner
  has_many :comments
  has_many :articles
end

class Post < ActiveRecord::Base
  include Pacecar
  PUBLICATION_STATES = %w(Draft Submitted Rejected Accepted)
  TYPES = %w(Free Open Private Anonymous PostModern)
  belongs_to :owner, polymorphic: true
  has_state :publication_state
  has_state :post_type, with: TYPES
  has_polymorph :owner
end

class Comment < ActiveRecord::Base
  include Pacecar
  belongs_to :user
end

class Article < ActiveRecord::Base
  belongs_to :user
end

All columns

Records where approved_at is not null, or where it is null:

User.approved_at_present
User.approved_at_missing

Records where first_name is not null, or where it is null:

User.first_name_present
User.first_name_missing

Records ordered by first_name (default to 'asc', can specify to override):

User.by_first_name
User.by_first_name(:asc)
User.by_first_name(:desc)

Records where an attribute matches exactly a term:

User.first_name_equals('John')

Boolean columns

Records that are all admins or non-admins:

User.admin
User.not_admin

Polymorphic relationships

Records which have an owner_type of User:

Post.for_owner_type(User)

State columns

Records which are in a particular state, or not in a state:

Post.publication_state_draft
Post.post_type_not_open

Query methods on instances to check state:

Post.first.publication_state_draft?
Post.last.post_type_not_open?

Limits

First x records:

User.limited(10)

Named scopes

Because these are all scope, you can combine them.

To get all users that have a first_name set, who are admins:

User.first_name_present.admin

Supported Databases

• MySQL
• SQLite
• Postgres

Credits

Pacecar is maintained and funded by thoughtbot, inc

Thank you to all the contributors!

The names and logos for thoughtbot are trademarks of thoughtbot, inc.

License

Pacecar is Copyright © 2008-2013 thoughtbot. It is free software, and may be redistributed under the terms specified in the MIT-LICENSE file.