Module: Historical::MongoMapperEnhancements

Included in:
Historical::Models::AttributeDiff, Historical::Models::ModelVersion, Historical::Models::ModelVersion::Diff, Historical::Models::ModelVersion::Meta
Defined in:
lib/historical/mongo_mapper_enhancements.rb

Overview

Contains some helper methods for better MongoMapper integration.

Instance Method Summary collapse

Instance Method Details

#belongs_to_active_record(name, options = {}) ⇒ Object

Simple ‘belongs_to` relation to an ActiveRecord model.

Parameters:

  • name —

    The name of the relation.

  • options (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (options):

  • :class_name (String) — default: name.classify —

    The class name of the model (if it can’t be guessed from the name)

  • :polymorphic (true, false) — default: false —

    Will create an additional name_type key in the model.



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# File 'lib/historical/mongo_mapper_enhancements.rb', line 10

def belongs_to_active_record(name, options = {})
  ar_id_field   = "#{name}_id"
  ar_type_field = "#{name}_type"
  
  polymorphic   = options.delete(:polymorphic)
  class_name    = options.delete(:class_name)
  model_class   = nil
  
  # classname
  unless polymorphic
    if class_name
      model_class = class_name.is_a?(Class) ? class_name.name : class_name.classify
    else
      model_class = name.to_s.classify
    end
  end
  
  # define the keys
  key ar_id_field,    Integer,  options
  key ar_type_field,  String,   options if polymorphic
  
  # getter
  define_method name do
    if id = send(ar_id_field)
      if polymorphic
        type_class = send(ar_type_field)
        type_class ? type_class.constantize.find(id) : nil
      else
        model_class.constantize.find(id)
      end
    else
      nil
    end
  end
  
  # setter
  define_method "#{name}=" do |val|
    id = type = nil
    
    if val
      raise "expected an instace of ActiveRecord::Base, got: #{val.class.name}" unless val.is_a?(::ActiveRecord::Base)
      type  = val.class.name
      id    = val.id
    end
    
    send("#{ar_id_field}=",   id)
    send("#{ar_type_field}=", type) if polymorphic
  end
end