Question

I want to customize the error message on a validates_length_of to include the length of the attribute being checked. I know we can do "%{value}" or "%{attribute}" within the message to get those values. Is there a flag we can use to get the length of the attribute? I was hoping to avoid creating a custom validation just to get a pretty message. Additionally, it seems a waste to do count twice on a string when the validator is already doing it.

Here is what I would like:

validates_length_of :a, :b,:c, :d, :e, :maximum => 1000, :message=>"is to long, maximum length is` %{count}, current length is %{actual length here} "

Answer 1

You can use Proc to get the attributes

validates_length_of :a, maximum: 1000,
    message: proc { |p, v| "is to long, " +
                           "maximum length is #{v[:count]}, " +
                           "current length is #{v[:value].length}" }