Class: BatchAgg::AssocMagic

Inherits:
Object
  • Object
show all
Defined in:
lib/batchagg.rb

Instance Method Summary collapse

Constructor Details

#initialize(model, outer_table) ⇒ AssocMagic

Returns a new instance of AssocMagic.



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# File 'lib/batchagg.rb', line 13

def initialize(model, outer_table)
  @model = model
  @outer_table = outer_table
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(name, *args) ⇒ Object 



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# File 'lib/batchagg.rb', line 18

def method_missing(name, *args, &)
  reflection = @model.reflect_on_association(name)
  if reflection
    target = reflection.klass
    if reflection.through_reflection
      # has_many :through
      through = reflection.through_reflection
      source = reflection.source_reflection
      final_target = reflection.klass.arel_table
      through_table = through.klass.arel_table

      cond1 = if source.macro == :belongs_to
                through_table[source.foreign_key].eq(final_target[source.association_primary_key])
              else
                final_target[source.foreign_key].eq(through_table[source.active_record_primary_key])
              end

      cond2 = if through.macro == :belongs_to
                @outer_table[through.foreign_key].eq(through_table[through.association_primary_key])
              else
                through_table[through.foreign_key].eq(@outer_table[through.active_record_primary_key])
              end

      subquery = through_table.project(Arel.sql("1")).where(cond1.and(cond2))
      target.where(subquery.exists)
    elsif reflection.macro == :belongs_to
      target.where(target.arel_table[reflection.association_primary_key].eq(@outer_table[reflection.foreign_key]))
    else
      target.where(target.arel_table[reflection.foreign_key].eq(@outer_table[reflection.active_record_primary_key]))
    end
  else
    super
  end
end

Instance Method Details

#respond_to_missing?(name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/batchagg.rb', line 53

def respond_to_missing?(name, *)
  @model.reflect_on_association(name) || super
end