Enumerations

Rails plugin for enumerations in ActiveRecord models.

Installation

Inside your Gemfile add the following:

gem 'enumerations'

Usage

Defining enumerations

Create a model for your enumerations:

class Status < Enumerations::Base
  values draft:           { id: 1, name: 'Draft' },
         review_pending:  { id: 2, name: 'Review pending' },
         published:       { id: 3, name: 'Published' }
end

Or you can use value method for defining your enumerations:

class Status < Enumerations::Base
  value :draft,           id: 1, name: 'Draft'
  value :review_pending,  id: 2, name: 'Review pending'
  value :published,       id: 3, name: 'Published'
end

Include enumerations for integer fields in other models:

class Post < ActiveRecord::Base
  enumeration :status

  validates :status, presence: true           # You can validate either :status or :status_id
end

You can pass attributes to specify which enumeration and which column to use:

class Post < ActiveRecord::Base
  enumeration :status,
              foreign_key: :post_status_id,   # specifies which column to use
              class_name: Post::Status        # specifies the class of the enumerator

  validates :post_status, presence: true
end

Attribute foreign_key you can pass as a String or a Symbol. Attribute class_name can be set as a String, a Symbol or a String.

Setting enumeration value to objects

Set enumerations, find enumerations by symbol:

@post = Post.first
@post.status = Status.find(:draft)
@post.save

Or you can set enumerations on this way:

@post.status = Status.draft

Also, you can set enumeration value like this:

@post.status_draft!

When you include enumerations into your model, you'll get methods for setting each enumeration value. Each method name is consists from enumeration name and enumeration value name with ! at the end. Examples:

class Post < ActiveRecord::Base
  enumeration :status
end

@post.status_draft!

class User < ActiveRecord::Base
  enumeration :role
end

@user.role_admin!

class User < ActiveRecord::Base
  enumeration :type, class_name: Role
end

@user.type_editor!

Finder methods

Find enumerations by id:

@post.status = Status.find(2)                 # => Review pending
@post.save

Other finding methods:

# Find by id as a String
Status.find('2')                              # => Review pending

# Find by symbol as a String
Status.find('draft')                          # => Draft

# Find by multiple attributes
Status.find_by(name: 'None', visible: true)   # => None

Compare enumerations:

@post.status == :published                    # => true
@post.status == 3                             # => true
@post.status == Status.find(:published)       # => true
@post.status.published?                       # => true

Get all enumerations:

Status.all

Filtering methods

Enumerations can be filtered with where method, similar to ActiveRecord::QueryMethods#where.

Role.where(admin: true)                       # => [Role.admin, Role.editor]
Role.where(admin: true, active: true)         # => [Role.admin]

Scopes on model

With enumerations, you'll get scope for each enumeration value in the following format:

with_#{enumeration_name}_#{enumeration_value_name}

Examples:

class Post < ActiveRecord::Base
  enumeration :status
end

Post.with_status_draft                        # => <#ActiveRecord::Relation []>
Post.with_status_review_pending               # => <#ActiveRecord::Relation []>

class Post < ActiveRecord::Base
  enumeration :my_status, class_name: Status
end

Post.with_my_status_draft                      # => <#ActiveRecord::Relation []>
Post.with_my_status_review_pending             # => <#ActiveRecord::Relation []>

Each scope returns all records with specified enumeration value.

Forms usage

Use in forms:

%p
  = f.label :status_id
  %br
  = f.collection_select :status_id, Status.all, :id, :name

Advance Usage

Except id and name you can specify other attributes to your enumerations:

class Status < Enumerations::Base
  value :draft,           id: 1, name: 'Draft'
  value :review_pending,  id: 2, name: 'Review pending', description: 'Some description...'
  value :published,       id: 3, name: 'Published'
end

Every enumeration has id, name and description methods. If you call method that is not in attribute list for enumeration, it will return nil.

Status.review_pending.description              # => 'Some description...'
Status.draft.description                       # => nil

Translations

Enumerations uses power of I18n API to enable you to create a locale file for enumerations like this:

---
en:
  enumerations:
    status:
      draft:
        name: Draft
        description: Article draft...
        ...
    role:
      admin:
        name: Administrator

You can separate enumerations locales into a separate *.yml files. Then you should add locale file paths to I18n load path:

# config/initializers/locale.rb

# Where the I18n library should search for translation files (e.g.):
I18n.load_path += Dir[Rails.root.join('config', 'locales', 'enumerations', '*.yml')]

Author

Copyright © 2010 Tomislav Car, Infinum Ltd.