Module: PortableModel::ClassMethods

Defined in:
lib/portable_model.rb

Instance Method Summary collapse

Instance Method Details

#excluded_export_attrs ⇒ Object 



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# File 'lib/portable_model.rb', line 189

def excluded_export_attrs
  @excluded_export_attrs ||= Set.new
end

#import_from_hash(record_hash) ⇒ Object

Import a record from a hash.

Raises:

  • (ArgumentError) 


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# File 'lib/portable_model.rb', line 87

def import_from_hash(record_hash)
  raise ArgumentError.new('specified argument is not a hash') unless record_hash.is_a?(Hash)

  # Override any necessary attributes before importing.
  record_hash.merge!(overridden_import_attrs)

  if (columns_hash.include?(inheritance_column) &&
      (record_type_name = record_hash[inheritance_column.to_s]) &&
      !record_type_name.blank? &&
      record_type_name != sti_name)
    # The model implements STI and the record type points to a different
    # class; call the method in that class instead.
    compute_type(record_type_name).import_from_hash(record_hash)
  else
    start_importing do |imported_records|
      # If the hash had already been imported during the current session,
      # use the result of that previous import.
      record = imported_records[record_hash.object_id]

      unless record
        transaction do
          # First split out the attributes that correspond to portable
          # associations.
          assoc_attrs = portable_associations.inject({}) do |hash, assoc_name|
            hash[assoc_name] = record_hash.delete(assoc_name) if record_hash.has_key?(assoc_name)
            hash
          end

          # Create a new record.
          record = create!(record_hash.merge(:importing_record => true))

          # Import each of the record's associations into the record.
          assoc_attrs.each do |assoc_name, assoc_value|
            record.import_into_association(assoc_name, assoc_value)
          end
        end

        imported_records[record_hash.object_id] = record
      end

      record
    end
  end
end

#import_from_yml(filename, additional_attrs = {}) ⇒ Object

Export a record from a YAML file.



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# File 'lib/portable_model.rb', line 134

def import_from_yml(filename, additional_attrs = {})
  record_hash = YAML::load_file(filename)
  import_from_hash(record_hash.merge(additional_attrs))
end

#included_association_keys ⇒ Object 



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# File 'lib/portable_model.rb', line 185

def included_association_keys
  @included_association_keys ||= Set.new
end

#overridden_export_attrs ⇒ Object 



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# File 'lib/portable_model.rb', line 193

def overridden_export_attrs
  @overridden_export_attrs ||= {}
end

#overridden_import_attrs ⇒ Object 



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# File 'lib/portable_model.rb', line 197

def overridden_import_attrs
  @overridden_import_attrs ||= {}
end

#portable_associations ⇒ Object

Returns names of portable associations, which are has_one and has_many associations that do not go through other associations and that also include PortableModel.

Because has_and_belongs_to_many associations are bi-directional, they are not portable.



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# File 'lib/portable_model.rb', line 177

def portable_associations
  reflect_on_all_associations.select do |assoc_reflection|
    assoc_reflection.macro.in?([:has_one, :has_many]) &&
      !assoc_reflection.is_a?(ActiveRecord::Reflection::ThroughReflection) &&
      assoc_reflection.klass.include?(PortableModel)
  end.map(&:name).map(&:to_s)
end

#portable_attributes ⇒ Object

Returns the names of portable attributes, which are any attributes that are not primary or foreign keys.



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# File 'lib/portable_model.rb', line 156

def portable_attributes
  columns.reject do |column|
    # TODO: Consider rejecting counter_cache columns as well; this will involve retrieving a has_many association's corresponding belongs_to association to retrieve its counter_cache_column.
    (
      column.primary ||
      column.name.in?(excluded_export_attrs) && !overridden_export_attrs.has_key?(column.name) ||
      (
        column.name.in?(reflect_on_all_associations(:belongs_to).map(&:association_foreign_key)) &&
        !column.name.in?(included_association_keys)
      )
    )
  end.map(&:name).map(&:to_s)
end

#start_exporting(&block) ⇒ Object

Starts an export session and yields a hash of currently exported records in the session to the specified block.



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# File 'lib/portable_model.rb', line 142

def start_exporting(&block)
  start_porting(:exported_records, &block)
end

#start_importing(&block) ⇒ Object

Starts an import session and yields a hash of currently imported records in the session to the specified block.



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# File 'lib/portable_model.rb', line 149

def start_importing(&block)
  start_porting(:imported_records, &block)
end