Defining a Virtual Attribute

[quyen91]

https://www.safaribooksonline.com/library/view/ruby-cookbook/0596523696/ch08s07.html

[quyen91]

when using tag. It is better to using callback. like that

attr_accessor :tag_names
    after_save :assign_tags

    private
    def assign_tags
        if @tag_names
            self.tags = @tag_names.split(",").map do |name|
                # Tag.find_or_create_by_name(name)
                Tag.where(name: name.strip).first_or_create!
            end
        end
    end
    def list_tags
        self.tags.map(&:name).join(", ")
    end

it means that we only save tags if post is saved successfully.

[quyen91]

other of after_save style

after_save do function_name
    # code here
end