Fetching contributors…
Cannot retrieve contributors at this time
114 lines (82 sloc) 3.93 KB


A simple Model mixin with adapters for various ORM frameworks such as ActiveRecord, DataMapper and MongoMapper. Sencha::Model was originally created as part of the gem extjs-mvc to assist with auto-generating ExtJS Stores ( However, it can be useful for a variety of Javascript frameworks for rendering data on the client.


% sudo gem install gemcutter % sudo gem install sencha-model

An ORM Model mixin: Sencha::Model

sencha-model contains Model mixin named Sencha::Model which works for three popular ORM frameworks, ActiveRecord, DataMapper and MongoMapper. The API for each framework is identical and an adapter can be created for just about any ORM in about an hour.

Simply include the mixin into your model. Use the class-method sencha_fields to specify those fields with will be used to render a record to Hash for later JSON-encoding.

class User < ActiveRecord::Base
  include Sencha::Model

  sencha_fields :exclude => [:password, :password_confirmation]

  # OR 
  sencha_fields :name, :description

  # OR
  sencha_fields :only => [:name, :description] # actually the same as above

  # OR
  sencha_fields :additional => [:computed] # includes all database columns and an additional computed field

  # OR define a column as a Hash
  sencha_fields :description, :name => {"sortDir" => "ASC"}, :created_at => {"dateFormat" => "c"}

  # OR render associations, association-fields will have their "mapping" property set automatically
  sencha_fields :name, :description, :company => [:name, :description]

  def computed
    name.blank? ? login : name

After including the model mixin Sencha::Model, try typing the following in irb console:

>> User.sencha_schema
=> { :idProperty=>"id", :fields=>[
     {:type=>'int', :allowBlank=>true, :name=>"id"},
     {:type=>'string', :allowBlank=>false, :name=>"first", :defaultValue => nil},
     {:type=>'string', :allowBlank=>false, :name=>"last", :defaultValue => nil},
     {:type=>'string', :allowBlank=>false, :name=>"email", :defaultValue => nil}

An auto-generated schema. This field-names were originally designed to be consumed by an from the Ext JS Framework. TODO: make the field-names configurable.

You can also define different sets of fields for different representations of your model.

E.g. with the following definition:

class User < ActiveRecord::Base include ExtJS::Model

sencha_fieldset :grid, [ :name,


{:company => [:name, :description]} ]

sencha_fieldset :combo, [:full_name] ## # computed field # def full_name “#{first_name} #{name}” end end

You can get store configs for both representations with




And the corresponding data for the representations with




A Testing Mixin: Sencha::TestMacros

The sencha Gem includes a small set of testing macros to help unit-test models. Using this macro requires the 'Shoulda' gem from thoughtbot


In individual model unit tests:

class ModelTest < ActiveSupport::TestCase
  should_have_sencha_fields_for_fieldset :fieldset_name, [:name, :email, :city]
  #other tests

Note on Patches/Pull Requests

  • Fork the project.

  • Make your feature addition or bug fix.

  • Add tests for it. This is important so I don't break it in a future version unintentionally.

  • Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)

  • Send me a pull request. Bonus points for topic branches.


Copyright © 2009 Chris Scott. See LICENSE for details.