activerecord-endoscope

Endoscope enables scope to apply to model instance

Example

class User < ActiveRecord::Base
  extend ActiveRecord::Endoscope # add this before using scope
  scope :admin, -> {
    where(role: 'admin')
  }
  scope :not_admin, -> {
    where.not(role: 'admin')
  }
  scope :admin_or_manager, -> {
    where(role: ['admin', 'manager'])
  }
  scope :minor, -> {
    where(age: 0..19)
  }
  scope :aged, ->(age) {
    where(age: age)
  }
  scope :have_no_email, -> {
    where(email: nil)
  }
  scope :have_email, -> {
    where.not(email: nil).where.not(email: '')
  }
end

Then these methods are defined automatically:

u = User.new(role: 'ordinary', age: 20, email: '[email protected]')
u.admin?            # => false
u.not_admin?        # => true
u.admin_or_manager? # => false
u.minor?            # => false
u.aged?(20)         # => true
u.has_no_email?     # => false
u.has_email?        # => true

With NO SQL execution.

Restriction

Limited queries have been supported yet.

SQL literal such as where('email IS NOT NULL') is not supported.

Supported queries are shown in: https://github.com/tkawa/arel_ruby/blob/master/lib/arel/visitors/ruby.rb

If your query is not supported, you can override the method manually.

Installation

Add these lines to your application's Gemfile:

gem 'activerecord-endoscope'
gem 'arel_ruby', github: 'tkawa/arel_ruby'

And then execute:

$ bundle

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request

Acknowledgment

The features of this gem almost depend on arel_ruby.

https://github.com/amatsuda/arel_ruby

Thanks @amatsuda!