Deprecation Notice

The Rails 5.0 Attributes API provides a default option that makes this gem unnecessary.

ActiveRecord::SafeInitialize

Safely initialize an ActiveRecord attribute with respect to missing columns.

Installation

Add this line to your application's Gemfile:

gem 'activerecord-safe_initialize'

And then execute:

$ bundle

Or install it yourself as:

$ gem install activerecord-safe_initialize

Usage

If you want to select subsets of SQL tables, you have to use after_initialize with care:

class Post < ActiveRecord::Base
  after_initialize { self.category ||= 'Default' }
end

Post.select([:title, :body, :published_at]).first # => ActiveModel::MissingAttributeError

To do this safely you must write:

class Post < ActiveRecord::Base
  after_initialize { self.category ||= 'Default' if has_attribute?(:category) }
end

With safe_initialize you can write:

class Post < ActiveRecord::Base
  safe_initialize :category, with: 'Default'
end

If with is a Symbol, safe_initialize will send it to self to get the value:

class Post < ActiveRecord::Base
  safe_initialize :uuid, with: :generate_uuid

private

  def generate_uuid
    SecureRandom.uuid
  end
end

If with is callable, it will instance_exec it to get the value:

class Post < ActiveRecord::Base
  safe_initialize :uuid, with: ->{ SecureRandom.uuid }
end

You can set a default for multiple attributes at once:

class Employee < ActiveRecord::Base
  safe_initialize :pay_rate, :holiday_rate, with: 0.0
end

Options are passed through to after_initialize:

safe_initialize :uuid, with: ->{ SecureRandom.uuid }, :if => :new_record?

A block can be used instead of :with

safe_initialize :uuid, :if => :new_record? do
  SecureRandom.uuid
end

Contributing

1. Fork it ( https://github.com/lyconic/activerecord-safe_initialize/fork )
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 a new Pull Request