Module: JitPreloadExtension

Defined in:
lib/jit_preloader/active_record/base.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#jit_n_plus_one_tracking ⇒ Object

Returns the value of attribute jit_n_plus_one_tracking.



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# File 'lib/jit_preloader/active_record/base.rb', line 3

def jit_n_plus_one_tracking
  @jit_n_plus_one_tracking
end

#jit_preload_aggregates ⇒ Object

Returns the value of attribute jit_preload_aggregates.



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# File 'lib/jit_preloader/active_record/base.rb', line 4

def jit_preload_aggregates
  @jit_preload_aggregates
end

#jit_preload_scoped_relations ⇒ Object

Returns the value of attribute jit_preload_scoped_relations.



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# File 'lib/jit_preloader/active_record/base.rb', line 5

def jit_preload_scoped_relations
  @jit_preload_scoped_relations
end

#jit_preloader ⇒ Object

Returns the value of attribute jit_preloader.



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# File 'lib/jit_preloader/active_record/base.rb', line 2

def jit_preloader
  @jit_preloader
end

Class Method Details

.prepended(base) ⇒ Object 



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# File 'lib/jit_preloader/active_record/base.rb', line 54

def self.prepended(base)
  class << base
    delegate :jit_preload, to: :all

    def has_many_aggregate(assoc, name, aggregate, field, table_alias_name: nil, default: 0)
      method_name = "#{assoc}_#{name}"

      define_method(method_name) do |conditions={}|
        self.jit_preload_aggregates ||= {}

        key = "#{method_name}|#{conditions.sort.hash}"
        return jit_preload_aggregates[key] if jit_preload_aggregates.key?(key)
        if jit_preloader
          reflection = association(assoc).reflection
          primary_ids = jit_preloader.records.collect{|r| r[reflection.active_record_primary_key] }
          klass = reflection.klass

          aggregate_association = reflection
          while aggregate_association.through_reflection
            aggregate_association = aggregate_association.through_reflection
          end

          association_scope = klass.all.merge(association(assoc).scope).unscope(where: aggregate_association.foreign_key)
          association_scope = association_scope.instance_exec(&reflection.scope).reorder(nil) if reflection.scope

          # If the query uses an alias for the association, use that instead of the table name
          table_reference = table_alias_name
          table_reference ||= association_scope.references_values.first || aggregate_association.table_name

          conditions[table_reference] = { aggregate_association.foreign_key => primary_ids }

          # If the association is a STI child model, specify its type in the condition so that it
          # doesn't include results from other child models
          parent_is_base_class = aggregate_association.klass.superclass.abstract_class? || aggregate_association.klass.superclass == ActiveRecord::Base
          has_type_column = aggregate_association.klass.column_names.include?(aggregate_association.klass.inheritance_column)
          is_child_sti_model = !parent_is_base_class && has_type_column
          if is_child_sti_model
            conditions[table_reference].merge!({ aggregate_association.klass.inheritance_column => aggregate_association.klass.sti_name })
          end

          if reflection.type.present?
            conditions[reflection.type] = self.class.name
          end
          group_by = "#{table_reference}.#{aggregate_association.foreign_key}"

          preloaded_data = Hash[association_scope
            .where(conditions)
            .group(group_by)
            .send(aggregate, field)
          ]

          jit_preloader.records.each do |record|
            record.jit_preload_aggregates ||= {}
            record.jit_preload_aggregates[key] = preloaded_data[record.id] || default
          end
        else
          self.jit_preload_aggregates[key] = send(assoc).where(conditions).send(aggregate, field) || default
        end
        jit_preload_aggregates[key]
      end
    end
  end
end

Instance Method Details

#clear_jit_preloader! ⇒ Object 



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# File 'lib/jit_preloader/active_record/base.rb', line 12

def clear_jit_preloader!
  self.jit_preload_aggregates = {}
  self.jit_preload_scoped_relations = {}
  if jit_preloader
    jit_preloader.records.delete(self)
    self.jit_preloader = nil
  end
end

#preload_scoped_relation(name:, base_association:, preload_scope: nil) ⇒ Object 



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# File 'lib/jit_preloader/active_record/base.rb', line 21

def preload_scoped_relation(name:, base_association:, preload_scope: nil)
  return jit_preload_scoped_relations[name] if jit_preload_scoped_relations&.key?(name)

  records = jit_preloader&.records || [self]
  previous_association_values = {}

  records.each do |record|
    association = record.association(base_association)
    if association.loaded?
      previous_association_values[record] = association.target
      association.reset
    end
  end

  ActiveRecord::Associations::Preloader.new.preload(
    records,
    base_association,
    preload_scope
  )

  records.each do |record|
    record.jit_preload_scoped_relations ||= {}
    association = record.association(base_association)
    record.jit_preload_scoped_relations[name] = association.target
    association.reset
    if previous_association_values.key?(record)
      association.target = previous_association_values[record]
    end
  end

  jit_preload_scoped_relations[name]
end

#reload(*args) ⇒ Object 



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# File 'lib/jit_preloader/active_record/base.rb', line 7

def reload(*args)
  clear_jit_preloader!
  super
end