Class: GraphQL::Dataloader::ActiveRecordAssociationSource

Inherits:
Source
  • Object
show all
Defined in:
lib/graphql/dataloader/active_record_association_source.rb

Constant Summary collapse

RECORD_SOURCE_CLASS = 
ActiveRecordSource

Constants inherited from Source

Source::MAX_ITERATIONS

Instance Attribute Summary

Attributes inherited from Source

#dataloader, #pending, #results

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Source

#clear_cache, #load_all, #merge, #normalize_fetch_key, #pending?, #request, #request_all, #result_key_for, #run_pending_keys, #setup, #sync

Constructor Details

#initialize(association, scope = nil) ⇒ ActiveRecordAssociationSource 



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# File 'lib/graphql/dataloader/active_record_association_source.rb', line 10

def initialize(association, scope = nil)
  @association = association
  @scope = scope
end

Class Method Details

.batch_key_for(association, scope = nil) ⇒ Object 



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# File 'lib/graphql/dataloader/active_record_association_source.rb', line 15

def self.batch_key_for(association, scope = nil)
  if scope
    [association, scope.to_sql]
  else
    [association]
  end
end

Instance Method Details

#fetch(records) ⇒ Object 



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# File 'lib/graphql/dataloader/active_record_association_source.rb', line 31

def fetch(records)
  record_classes = Set.new.compare_by_identity
  associated_classes = Set.new.compare_by_identity
  scoped_fetch = !@scope.nil?
  records.each do |record|
    if scoped_fetch
      assoc = record.association(@association)
      assoc.reset
    end
    if record_classes.add?(record.class)
      reflection = record.class.reflect_on_association(@association)
      if !reflection.polymorphic? && reflection.klass
        associated_classes.add(reflection.klass)
      end
    end
  end

  available_records = []
  associated_classes.each do |assoc_class|
    already_loaded_records = dataloader.with(RECORD_SOURCE_CLASS, assoc_class).results.values
    available_records.concat(already_loaded_records)
  end

  ::ActiveRecord::Associations::Preloader.new(records: records, associations: @association, available_records: available_records, scope: @scope).call

  loaded_associated_records = records.map { |r|
    assoc = r.association(@association)
    lar = assoc.target
    if scoped_fetch
      assoc.reset
    end
    lar
  }

  if !scoped_fetch
    # Don't cache records loaded via scope because they might have reduced `SELECT`s
    # Could check .select_values here?
    records_by_model = {}
    loaded_associated_records.flatten.each do |record|
      if record
        updates = records_by_model[record.class] ||= {}
        updates[record.id] = record
      end
    end
    records_by_model.each do |model_class, updates|
      dataloader.with(RECORD_SOURCE_CLASS, model_class).merge(updates)
    end
  end

  loaded_associated_records
end

#load(record) ⇒ Object 



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# File 'lib/graphql/dataloader/active_record_association_source.rb', line 23

def load(record)
  if (assoc = record.association(@association)).loaded?
    assoc.target
  else
    super
  end
end