Class: Object

Inherits:
BasicObject
Defined in:
lib/safe_object_as_json.rb

Instance Method Summary collapse

Instance Method Details

#as_json(options = nil) ⇒ Object

Converts any object to JSON by creating a hash out of it’s instance variables. If there is a circular reference within an object hierarchy, then duplicate objects will be omitted in order to avoid infinite recursion.



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# File 'lib/safe_object_as_json.rb', line 16

def as_json(options = nil)
  if respond_to?(:to_hash)
    to_hash.as_json(options)
  else
    # The default as_json serializer serializes the instance variables as name value pairs.
    # In order to prevent infinite recursion, we keep track of the object already used
    # in the serialization and omit them if they are included recursively.
    references = (Thread.current[:object_as_json_references] || Set.new)
    begin
      Thread.current[:object_as_json_references] = references if references.empty?
      references << object_id
      hash = {}

      # Apply :only and :except filter from the options to the hash of instance variables.
      values = instance_values
      if options && SafeObjectAsJson::SUPPORT_FILTERING
        only_attr = options[:only]
        if only_attr
          values = values.slice(*Array(only_attr).map(&:to_s))
        else
          except_attr = options[:except]
          if except_attr
            values = values.except(*Array(except_attr).map(&:to_s))
          end
        end
      end

      values.each do |name, value|
        unless references.include?(value.object_id) || value.is_a?(Proc) || value.is_a?(IO)
          references << value
          hash[name] = (options.nil? ? value.as_json : value.as_json(options.dup))
        end
      end
      hash
    ensure
      references.delete(object_id)
      Thread.current[:object_as_json_references] = nil if references.empty?
    end
  end
end