Symbolize attribute values in ActiveRecord (e.g. for nicer enums)

This plugin introduces an easy way to use symbols for values of ActiveRecord attributes. Symbolized attributes return a ruby symbol (or nil) as their value and can be set using symbols.

About

Since ActiveRecord does not natively support database column types of ENUM or SET, you’ll usually use a string attribute and restrict it to certain values with validations. Using this plugin, the values of such pseudo-enums are symbols, which look more ruby-style than strings.

Simply add “symbolize :attr_name” to your model class, and the specified attribute will return symbol values and can be set using smbols (setting string values will still work, which is important when using forms).

An attribute to symbolize should be a string (varchar) column in the database.

Blog: zargony.com/ Github: github.com/zargony/activerecord_symbolize

Install

Gem:

gem install gemcutter
gem tumble
gem install symbolize
config.gem "symbolize", :source => 'http://gemcutter.org'

Plugin:

./script/plugin install git://github.com/nofxx/activerecord_symbolize.git

Usage

Add “symbolize :attr_name” to your model class. You may also want to add validates_inclusion_of to restrict the possible values (just like an enum).

  class User < ActiveRecord::Base
    symbolize :gender, :in => [:female, :male], :scopes => true
    symbolize :so, :in => {
      :linux   => "Linux",
      :mac     => "Mac OS X"
    }, :scopes => true
    symbolize :gui, , :in => [:gnome, :kde, :xfce], :allow_blank => true
    symbolize :browser, :in => [:firefox, :opera], :i18n => false, :methods => true
    symbolize :angry, :in => [true, false], :scopes => true
end

in/within

The values allowed on the enum field, you can provide a hash with => “Human text” or an array of keys to be i18n eval (or not). Booleans are also supported. See below.

allow_(blank|nil): What you expect.

i18n

If you don`t provide a hash with values, it will try i18n:

activerecord:
  attributes:
    user:
      enums:
        gui:
          gnome: Gnome Desktop Enviroment
          kde: K Desktop Enviroment
          xfce: XFCE4
        gender:
          female: Girl
          male: Boy

You can skip i18n lookup with :i18n => false

symbolize :gender, :in => [:female, :male], :i18n => false

method

If you provide the method option, some fancy boolean methods will be added: In our User example, browser has this option, so you can do:

@user.firefox?
@user.opera?

Booleans

Its possible to use boolean fields also.

symbolize :switch, :in => [true, false]

...
  switch:
    "true": On
    "false": Off
    "nil": Unknown

scopes (BETA)

If you provide the scopes option, some fancy named scopes will be added: In our User example, gender has this option, so you can do:

User.female => User.find(:all, :conditions => { :gender => :female })

You can chain named scopes as well:

User.female.mac => User.find(:all, :conditions => { :gender => :female, :so => :mac })

For boolean colums you can use

User.angry     => User.find(:all, :conditions => { :angry => true })
User.not_angry => User.find(:all, :conditions => { :angry => false })

( or with_[attribute] and without_[attribute] )

Examples

u = User.find_by_name('Anna')   # => #<User Anna>
u.gender                        # => :female

u = User.find_by_gender(:male)  # => #<User Bob>
u.gender                        # => :male

u = User.find(:all, :conditions => { :gender => :female })
u = User.female

u = User.new(:name => 'ET', :gender => :unknown)
u.save                          # => validation fails

Examples Helpers

<% form_for @user do |f| %>
  <%= f.radio_sym "gender" %>
  <!-- Alphabetic order -->
  <%= f.select_sym "so" %>
  <!-- Fixed order -->
  <%= f.select_sym "office" %>
<% end %>

output:

<form action="users/1" method="post">
  <div style="margin:0;padding:0">...</div>
  <label>Female <input id="user_gender_female" name="user[gender]" type="radio" value="female"></label>
  <label>Male <input checked="checked" id="user_gender_male" name="user[gender]" type="radio" value="male" ></label>
  <!-- Alphabetic order -->
  <select id="user_so" name="post[so]">
    <option value="linux" selected="selected">Linux</option>
    <option value="mac">Mac OS X</option>
    <option value="windows">Windows XP</option>
  </select>
  <!-- Fixed order -->
  <select id="user_office" name="post[office]">
    <option value="kde" selected="selected">Koffice</option>
    <option value="ms">Microsoft Office</option>
    <option value="open">Open Office</option>
  </select>
</form>

Notes

This fork: github.com/nofxx/symbolize

Forked from: github.com/nuxlli/activerecord_symbolize

Initial work: I’ve been using this for quite some time and made it a rails plugin now. More background iinformation can be found at zargony.com/2007/09/07/symbolize-attribute-values-in-activerecord