Module: Mongoid::Factory

Extended by:
Factory
Included in:
Factory
Defined in:
lib/mongoid/factory.rb

Overview

Instantiates documents that came from the database.

Constant Summary collapse

TYPE =
Deprecated. 
"_type".freeze

Instance Method Summary collapse

Instance Method Details

#build(klass, attributes = nil) ⇒ Document

Builds a new Document from the supplied attributes.

This method either instantiats klass or a descendant of klass if the attributes include klass’ discriminator key.

If the attributes contain the discriminator key (which is _type by default) and the discriminator value does not correspond to a descendant of klass then this method would create an instance of klass.

Examples:

Build the document.

Mongoid::Factory.build(Person, { "name" => "Durran" })

Parameters:

  • klass (Class) —

    The class to instantiate from if _type is not present.

  • attributes (Hash) (defaults to: nil) —

    The document attributes.

Returns:

  • (Document) —

    The instantiated document.



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# File 'lib/mongoid/factory.rb', line 29

def build(klass, attributes = nil)
  attributes ||= {}
  dvalue = attributes[klass.discriminator_key] || attributes[klass.discriminator_key.to_sym]
  type = klass.get_discriminator_mapping(dvalue)
  if type
    type.new(attributes)
  else
    klass.new(attributes)
  end
end

#from_db(klass, attributes = nil, criteria = nil, selected_fields = nil) ⇒ Document

Builds a new Document from the supplied attributes loaded from the database.

If the attributes contain the discriminator key (which is _type by default) and the discriminator value does not correspond to a descendant of klass then this method raises an UnknownModel error.

If a criteria object is given, it is used in two ways:

  1. If the criteria has a list of fields specified via #only, only those fields are populated in the returned document.

  2. If the criteria has a referencing association (i.e., this document is being instantiated as an association of another document), the other document is also populated in the returned document’s reverse association, if one exists.

Examples:

Build the document.

Mongoid::Factory.from_db(Person, { "name" => "Durran" })

Parameters:

  • klass (Class) —

    The class to instantiate from if _type is not present.

  • attributes (Hash) (defaults to: nil) —

    The document attributes.

  • criteria (Criteria) (defaults to: nil) —

    Optional criteria object.

  • selected_fields (Hash) (defaults to: nil) —

    Fields which were retrieved via #only. If selected_fields are specified, fields not listed in it will not be accessible in the returned document.

Returns:

  • (Document) —

    The instantiated document.



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# File 'lib/mongoid/factory.rb', line 66

def from_db(klass, attributes = nil, criteria = nil, selected_fields = nil)
  if criteria
    selected_fields ||= criteria.options[:fields]
  end
  type = (attributes || {})[klass.discriminator_key]
  if type.blank?
    obj = klass.instantiate(attributes, selected_fields)
    if criteria && criteria.association && criteria.parent_document
      obj.set_relation(criteria.association.inverse, criteria.parent_document)
    end
    obj
  else
    constantized = klass.get_discriminator_mapping(type)

    unless constantized
      camelized = type.camelize

      # Check if the class exists
      begin
        constantized = camelized.constantize
      rescue NameError
        raise Errors::UnknownModel.new(camelized, type)
      end
    end

    # Check if the class is a Document class
    if !constantized.respond_to?(:instantiate)
      raise Errors::UnknownModel.new(camelized, type)
    end

    constantized.instantiate(attributes, selected_fields)
  end
end