Module: JsonSerialize::ClassMethods

Defined in:
lib/json_serialize.rb

Instance Method Summary collapse

Instance Method Details

#json_serialize(field, ..., fields_with_default_values) ⇒ Object

Marks one or more fields as JSON-serialized. These fields are stored in the database as JSON and encoded/decoded automatically upon read/write.

Parameters:

  • field (Symbol) —

    The database field to JSON-serialize.

  • fields_with_default_values (Hash<Symbol, Object>) —

    A map of additional fields to JSON-serialize, with the default value that should be given if the field is ‘NULL`.



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# File 'lib/json_serialize.rb', line 21

def json_serialize(*fields)
  @fields_with_defaults = fields.extract_options!
  fields.each do |field|
    @fields_with_defaults[field] = nil
  end

  @fields_with_defaults.each do |field, default_value|
    define_method field do
      if instance_variable_defined?(field_ivar(field)) then
        instance_variable_get field_ivar(field)
      else
        encoded = read_attribute(field)
        default = default_value.kind_of?(Proc) ? default_value.call : (default_value.duplicable? ? default_value.dup : default_value)
        decoded = encoded.nil? ? default : ActiveSupport::JSON.decode(encoded)
        instance_variable_set field_ivar(field), decoded
        decoded
      end
    end

    define_method :"#{field}=" do |value|
      write_attribute field, (value.nil? ? nil : ActiveSupport::JSON.encode(value))
      instance_variable_set field_ivar(field), value
    end
  end

  define_method :serialize_json_values do
    self.class.instance_variable_get(:@fields_with_defaults).keys.each do |field|
      if instance_variable_defined?(field_ivar(field)) then
        send :"#{field}=", instance_variable_get(field_ivar(field))
      end
    end
  end

  before_validation :serialize_json_values
  prepend WithRefreshJSONIvars
end