Overview
Virtual Attributes is a Ruby gem and an ActiveRecord extension that allows you to create advanced and structered serialized attributes.
To install it, add this line to you Gemfile and bundle install.
source 'https://rubygems.org'
gem 'virtual-attributes'
# ...Virtual Attributes offers:
- Built-in type cast ;
- Default values ;
- Executable default values (impossible with migrations!) ;
- Validations ;
- Migration like syntax.
Usage
You can use it on your models exactly like a Ruby on Rails migration !
class Client < ActiveRecord::Base
serialize :contact do |t|
t.string :firstname, :lastname
t.date :birthdate, default: Date.new(1980, 1, 1)
t.integer :gender, default: 0
t.integer :country_id
t.string :phone
t.boolean :show_phone, default: proc{ Configuration.show_phone_by_default }
end
endOn your forms you can use it with fields_for :
<%= form_for @client do |f| %>
<fieldset id="contact" class="">
<legend>Contact</legend>
<%= f.fields_for :contact, f.object.contact do |ff| %>
<dl>
<dt>Firstname </dt><dd><%= ff.text_field :firstname %></dd>
<dt>Lastname </dt><dd><%= ff.text_field :lastname %></dd>
<dt>Birthdate </dt><dd><%= ff.date_field :birthdate %></dd>
<dt>Gender </dt><dd><%= ff.select :gender, [[:male, 0], [:female, 1]] %></dd>
<dt>Country </dt><dd><%= ff.select :country_id, [["Algeria", 1], ["France", 2]] %></dd>
<dt>Phone </dt><dd><%= ff.text_field :phone %></dd>
<dt>Show phone?</dt><dd><%= ff.check_box :show_phone %></dd>
</dl>
<% end %>
</fieldset>
<dl>
<dt>Company name</dt> <dd><%= f.text_field :name %></dd>
<dt>Email</dt> <dd><%= f.text_field :email %></dd>
</dl>
<p>
<%= f.submit "Submit", :disable_with => 'Submiting...' %>
</p>
<% end %>And that's it! Virtual Attributes will convert the controller parameters to an instance of a dynamically created class named Client::ContactVirtualAttributes.
Then, it will cast, validate and do all the magic for you.
Outside of ActiveRecord
You can use Virtual Attributes outside of ActiveRecord, by inheriting your classes from VirtualAttributes::Base.
class ClientContact < VirtualAttributes::Base
string :fullname, default: ""
string :login, default: ->(e){ e.fullname.reverse }
date :birthdate, default: "1963/11/22"
boolean :rockstar, default: false
integer :age
validates_presence_of :fullname, :login, :age
endirb(main):011:0> a = ClientContact.new
=> #<ClientContact:0x007ff3b4078640>
irb(main):012:0> a.fullname = "John Doe"
=> "John Doe"
irb(main):013:0> a.login
=> "eoD nhoJ"
irb(main):014:0> a.birthdate
=> Fri, 22 Nov 1963
irb(main):015:0> a.rockstar
=> false
irb(main):016:0> a.valid?
=> false
irb(main):017:0> a.errors
=> #<ActiveModel::Errors:0x007ff3ab3130e8 @base=#<ClientContact:0x007ff3b4078640 @fullname="John Doe", @validation_context=nil, @errors=#<ActiveModel::Errors:0x007ff3ab3130e8 ...>>, @messages={:age=>["doit être rempli(e)"]}>
irb(main):018:0> a.errors.full_messages
=> ["Age doit être rempli(e)"]However, VirtualAttributes internals rely on ActiveRecord and has it as a mandatory dependancy.
License
Virtual Attributes is Copyright©2015 Arity Labs, inc. It is free software, and may be redistributed under the terms specified in the MIT-LICENSE file.
En français
Ce gem est produit à partir d'un tutoriel didactic en français, publié sur le blog Arity Labs.