has_magic_columns
Allows the addition of custom "magic" columns and attributes on a per-model or per-parent-model basis. This is useful for situations where custom fields are required for a specific model or for multi-user, multi-account environments where accounts can customize attributes for subordinate models.
NOTE: This plugin is probably not production-ready. While all the described features work, not all features have been tested. It was originally a Rails 2 plugin written by Brandon Keene and has been updated to a gem with Rails 3 support.
Installation
Add to your Gemfile:
gem "has_magic_columns"
Create the migrations for MagicColumns and migrate:
rails g has_magic_columns:install
rake db:migrate
Usage
Model
Sprinkle a little magic into an existing model:
class Person < ActiveRecord::Base
has_magic_columns
end
Add magic columns to your model:
@charlie = Person.create(:email => "[email protected]")
@charlie.magic_columns.create(:name => "first_name")
Supply additional options if you have more specific requirements for your columns:
@charlie.magic_columns.create(:name => "last_name", :is_required => true)
@charlie.magic_columns.create(:name => "birthday", :datatype => :date)
@charlie.magic_columns.create(:name => "salary", :default => "40000", :pretty_name => "Yearly Salary")
The :datatype option supports :check_box_boolean, :date, :datetime, or :integer.
Use your new columns just like you would with any other ActiveRecord attribute:
@charlie.first_name = "Charlie"
@charlie.last_name = "Magic!"
@charlie.birthday = Date.today
@charlie.save
Find @charlie and inspect him:
@charlie = User.find(@charlie.id)
@charlie.first_name #=> "Charlie"
@charlie.last_name #=> "Magic!"
@charlie.birthday #=> #<Date: 4908497/2,0,2299161>
@charlie.salary #=> "40000", this is from :salary having a :default
Inherited Model
A child can inherit magic columns from a parent. To do this, declare the parent as having magic columns:
class Account < ActiveRecord::Base
has_many :users
has_magic_columns
end
@account = Account.create(:name => "BobCorp")
And declare the child as having magic columns :through the parent.
class User < ActiveRecord::Base
belongs_to :account
has_magic_columns :through => :account
end
@alice = User.create(:name => "alice", :account => @account)
To see all the magic columns available for a child from its parent:
@alice.magic_columns #=> [#<MagicColumn>,...]
@account.magic_columns #=> [#<MagicColumn>,...]
@alice.account.magic_columns #=> [#<MagicColumn>,...]
To add magic columns, go through the parent or child:
@alice.magic_columns.create(...)
@account.magic_columns.create(...)
All children for a given parent will have access to the same magic columns:
@alice.magic_columns.create(:name => "salary")
@alice.salary = "40000"
@bob = User.create(:name => "bob", :account => @account)
# Magic! No need to add the column again!
@bob.salary = "50000"
To Do
Here's a short list of things that need to be done to polish up this gem:
- Test other parts of the data model (e.g. magic_attributes, magic_options)
- Benchmark and optimize
Maintainers
Contribute
See the CONTRIBUTORS guide.
Credits
- Thank you to Brandon Keene for his original work making this plugin.
- Thank you to the will_paginate gem for iinspiration and code examples for how to test a Rails plugin.