Class: HasHelpers::BaseConstructor

Inherits:
SimpleDelegator
  • Object
show all
Defined in:
app/constructors/has_helpers/base_constructor.rb

Class Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Class Attribute Details

.has_many_ids_associations ⇒ Object (readonly)

Returns the value of attribute has_many_ids_associations.



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# File 'app/constructors/has_helpers/base_constructor.rb', line 9

def has_many_ids_associations
  @has_many_ids_associations
end

Class Method Details

.has_many_ids(*associations) ⇒ Object

Sets up the constructor to handle [association_ids] attributes, without immediately executing the database statements, which is the Rails default.

Example

Class Report::Constructor < :HasHelpersBaseConstructor

class Report has an association: has_many :users, through: :shares

has_many_ids :users end

The example above will allow report[user_ids] attribute to be set and build the associated objects in memory. In this case, if report[user_ids] = [1], it will execute report.shares.build(user_id: 1) Any existing objects with the ids not included in this parameter will be marked for destruction.



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# File 'app/constructors/has_helpers/base_constructor.rb', line 25

def has_many_ids(*associations)
  @has_many_ids_associations ||= []
  @has_many_ids_associations.concat associations
end

Instance Method Details

#assign_attributes(object_attrs) ⇒ Object 



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# File 'app/constructors/has_helpers/base_constructor.rb', line 31

def assign_attributes(object_attrs)
  attrs = object_attrs.dup

  # Build/destroy has_many objects from "object_ids" params
  self.class.has_many_ids_associations.each do |association_name|
    association = object.class.reflect_on_association(association_name)
    association_key = association.foreign_key.to_s.pluralize
    association_to_build = association.through_reflection

    if attrs[association_key]
      association_primary_key = association.association_primary_key.to_s
      type_caster = association.klass.type_caster

      # Get ids from parameters, casting them to their correct type for the database.
      object_ids = attrs.delete(association_key).select(&:present?).map { |val| type_caster.type_cast_for_database(association_primary_key, val) }
      persisted_object_ids = object.send(association.name).map(&:id)

      # Mark for destruction any object that's not included in the attributes.
      object.send(association_to_build.name).reject do |assc_object|
        # skip any object that doesn't have this foreign key set.
        assc_object.send(association.foreign_key).blank? || object_ids.include?(assc_object.send(association.foreign_key))
      end.each(&:mark_for_destruction)
      (object_ids - persisted_object_ids).each do |new_object_id|
        object.send(association_to_build.name).build(association.foreign_key => new_object_id)
      end
    end
  end

  object.assign_attributes(attrs)
end