Class: ApiMaker::PreloaderThrough

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

Instance Method Summary collapse

Constructor Details

#initialize(collection:, reflection:) ⇒ PreloaderThrough

Returns a new instance of PreloaderThrough.



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# File 'lib/api_maker/preloader_through.rb', line 2

def initialize(collection:, reflection:)
  @collection = collection
  @reflection = reflection
end

Instance Method Details

#append_name_for_current_reflection(current_reflection) ⇒ Object 



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# File 'lib/api_maker/preloader_through.rb', line 55

def append_name_for_current_reflection(current_reflection)
  singular_name = current_reflection.__send__(:inverse_name)&.to_s || current_reflection.active_record.model_name.param_key
  return singular_name.to_sym if @reflection.klass.reflections.key?(singular_name)

  plural_name = singular_name.pluralize
  return plural_name.to_sym if @reflection.klass.reflections.key?(plural_name)

  raise "Couldn't find a reflection name #{singular_name} or #{plural_name} on #{@reflection.klass.name}"
end

#joins_array_to_hash(array) ⇒ Object 



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# File 'lib/api_maker/preloader_through.rb', line 65

def joins_array_to_hash(array)
  array = array.clone

  result = {}
  work_result = result

  while array.any?
    element = array.pop

    if array.length == 1
      work_result[element] = array.pop
    else
      work_result[element] = {}
    end

    work_result = work_result[element]
  end

  result
end

#joins_for_reflection(current_reflection) ⇒ Object 



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# File 'lib/api_maker/preloader_through.rb', line 24

def joins_for_reflection(current_reflection)
  joins = []

  loop do
    # Resolve if the through relationship is through multiple other through relationships
    current_reflection = resolve_through(current_reflection)

    macro = current_reflection.through_reflection.macro
    inverse_name = current_reflection.through_reflection.__send__(:inverse_name)

    if inverse_name
      joins << inverse_name
    elsif macro == :has_many
      joins << current_reflection.through_reflection.name
    elsif macro == :belongs_to || macro == :has_one
      joins << current_reflection.through_reflection.active_record.model_name.plural.to_sym
    else
      raise "Unknown class: #{current_reflection.through_reflection.class.name}"
    end

    current_reflection = next_reflection_for(current_reflection)

    unless current_reflection.is_a?(ActiveRecord::Reflection::ThroughReflection)
      joins.append(append_name_for_current_reflection(current_reflection))
      break
    end
  end

  joins
end

#models_query_through_reflection ⇒ Object 



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# File 'lib/api_maker/preloader_through.rb', line 7

def models_query_through_reflection
  last_reflection = @reflection.through_reflection.inverse_of

  if last_reflection
    table_name = last_reflection.table_name
    primary_key = last_reflection.klass.primary_key
  else
    table_name = @reflection.through_reflection.active_record.model_name.plural
    primary_key = @reflection.through_reflection.active_record.primary_key
  end

  joins_hash = joins_array_to_hash(joins_for_reflection(@reflection))

  @reflection.klass.joins(joins_hash)
    .where(table_name => {primary_key => @collection.map(&:id)})
end

#next_reflection_for(current_reflection) ⇒ Object 



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# File 'lib/api_maker/preloader_through.rb', line 86

def next_reflection_for(current_reflection)
  reflection_name = (current_reflection.source_reflection_name || @reflection.name).to_s

  new_reflection = current_reflection.through_reflection.klass.reflections[reflection_name.pluralize]
  new_reflection ||= current_reflection.through_reflection.klass.reflections[reflection_name.singularize]

  raise "No such reflection: #{current_reflection.through_reflection.klass.name}##{reflection_name}" unless new_reflection

  new_reflection
end

#resolve_through(current_reflection) ⇒ Object 



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# File 'lib/api_maker/preloader_through.rb', line 97

def resolve_through(current_reflection)
  current_reflection = current_reflection.through_reflection while current_reflection.through_reflection.is_a?(ActiveRecord::Reflection::ThroughReflection)
  current_reflection
end