LooseAttr

Overview

LooseAttr is ActiveRecord extension module. for the element (column) as defined in the JSON format, can property access.

Installation

Add this line to your application's Gemfile:

gem 'loose_attr'

Usage

Normal

Step1. To prepare the ext_field column. Put the data in JSON format to ext_field.

class CreateAllTables < ActiveRecord::Migration
  def self.up
    create_table(:posts) do |t|
      t.string  :body
      t.string  :category
      t.boolean :actived
      t.text    :ext_field
    end
  end
end

Step2. To define the loose_attr the Model class of ActiceReocrd.

class Post < ActiveRecord::Base
  loose_attr :comment_count,   default_value: 1
  loose_attr :user_name,       default_value: 'noname'
  loose_attr(
    :posted_at,
    cast_type: :date,
    default_value: '2016-01-01 00:00:00',
    option: { format: '%Y-%m-%d %H:%M:%S' }
  )
end

Step3. Call the property defined in loose_attr.

Post.create(
  id: 1,
  body: 'hogefoobar',
  category: :it,
  actived: true,
  ext_field: {
    comment_count: 10,
    user_name: nil,
    posted_at: nil
  }.to_json
)

post = Post.find(1)
puts post.body # hogefoobar
puts post.comment_count # 10
puts post.user_name # noname
puts post.posted_at # 2016-01-01 00:00:00

Extra

If you want to ext_field to ext when, define the modify_loose_attr_column_name.

class CreateAllTables < ActiveRecord::Migration
  def self.up
    create_table(:posts) do |t|
      t.string  :body
      t.string  :category
      t.boolean :actived
      t.text    :ext
    end
  end
end

class Post < ActiveRecord::Base
  modify_loose_attr_column_name 'ext'
  loose_attr :comment_count,   default_value: 1
  loose_attr :user_name,       default_value: 'noname'
  loose_attr(
    :posted_at,
    cast_type: :date,
    default_value: '2016-01-01 00:00:00',
    option: { format: '%Y-%m-%d %H:%M:%S' }
  )
end

loose_attr option property

Propety	Required	Default	Remarks
default_value	×	-	hoge
cast_type	×	-	integer OR string OR boolean OR date
option:format	×	-	cast_type = date only

License

The gem is available as open source under the terms of the MIT License.