hattr_accessor

Allows you to define attr_accessors that reference members of a hash

Installation

gem install shuber-hattr_accessor --source http://gems.github.com

Usage

The hattr_accessor method requires an option named :attribute which should be name of an attribute which will store the hash. For example:

class DataSource
  hattr_accessor :adapter, :username, :password, :attribute => :credentials
end

The reader and writer methods for :attribute (:credentials in the example above) would be automatically created unless they exist already. You can then use those attributes like normal ones:

@data_source = DataSource.new
@data_source.adapter = 'mysql'
@data_source.username = 'root'
@data_source.credentials # { :adapter => 'mysql', :username => 'root' }

@data_source.credentials = {}
@data_source.adapter # nil

The reader method for :attribute is overwritten with logic to ensure that it returns a hash by default.

@data_source = DataSource.new
@data_source.credentials # {}

You may optionally pass a :type option which will type cast the values when calling their getter methods. This is useful if you're using this gem with rails which will pass values as strings if submitted from a form. For example:

class CustomField::Date < CustomField
  hattr_accessor :offset, :type => :integer, :attribute => :configuration
  hattr_accessor :unit, :reference, :type => :string, :attribute => :configuration
  
  def default_value
    self.offset.send(self.unit.to_sym).send(self.reference.to_sym)
  end
end

@custom_field = CustomField::Date.new(:offset => '5', :unit => 'days', :reference => 'from_now')
@custom_field.offset # 5 (notice it's an integer, not a string)
@custom_field.default_value # evaluates 5.days.from_now 

The current options (email me for suggestions for others) for :type are:

:string
:integer
:float
:boolean

NOTE: Make sure your call define_attribute_methods before calling hattr_accessor when you're using ActiveRecord and your :attribute is a database field.

class CustomField < ActiveRecord::Base
  define_attribute_methods
  
  serialize :configuration, Hash
  
  hattr_accessor :testing, :attribute => :configuration
end

Contact

Problems, comments, and suggestions all welcome: shuber@huberry.com