Class: Perry::Processors::PreloadAssociations

Inherits:
Object
  • Object
show all
Defined in:
lib/perry/processors/preload_associations.rb

Overview

Perry::Processors::PreloadAssociations

This adapter processor will allow associations to be eager loaded after the original records are fetched. Any associations specified in an :includes option will be loaded for all records in the query (each association in a single request).

Configuration Options:

None

Modifiers:

None

Instance Method Summary collapse

Constructor Details

#initialize(adapter, config = {}) ⇒ PreloadAssociations

Returns a new instance of PreloadAssociations.



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# File 'lib/perry/processors/preload_associations.rb', line 20

def initialize(adapter, config={})
  @adapter = adapter
  @config = config
end

Instance Method Details

#call(options) ⇒ Object 



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# File 'lib/perry/processors/preload_associations.rb', line 25

def call(options)
  results = @adapter.call(options)

  if results && !results.empty?
    relation = options[:relation]
    (includes = relation.to_hash[:includes] || {}).keys.each do |association_id|
      association = relation.klass.defined_associations[association_id.to_sym]
      raise Perry::AssociationNotFound, "unknown association #{association_id}" unless association
      eager_records = association.scope(results).includes(includes[association_id]).all(:modifiers => options[:relation].modifiers_value)

      results.each do |result|
        scope = association.scope(result)
        case association.type
        when :has_one, :has_many
          scope.records = eager_records.select do |record|
            record.send(association.foreign_key) == result.send(association.primary_key)
          end
          if association.collection?
            result.send("#{association.id}=", scope)
          else
            result.send("#{association.id}=", scope.records.first)
          end
        when :belongs_to
          scope.records = eager_records.select do |record|
            record.send(association.primary_key) == result.send(association.foreign_key)
          end
          result.send("#{association.id}=", scope.records.first)
        end
      end
    end
  end

  results
end