as_json

# File activesupport/lib/active_support/json/encoding.rb, line 280
  def as_json(options = nil) #:nodoc:
    # create a subset of the hash by applying :only or :except
    subset = if options
      if attrs = options[:only]
        slice(*Array(attrs))
      elsif attrs = options[:except]
        except(*Array(attrs))
      else
        self
      end
    else
      self
    end

    # use encoder as a proxy to call as_json on all values in the subset, to protect from circular references
    encoder = options && options[:encoder] || ActiveSupport::JSON::Encoding::Encoder.new(options)
    Hash[subset.map { |k, v| [k.to_s, encoder.as_json(v, options)] }]
  end