ruby on rails - How to validate the input value of text_area is JSON format? -

i using rails 4.2 ruby 2.1.5

here description model:

class description < activerecord::base   validates :value, presence: true   belongs_to :api end 

what can validate input of value json format?

add custom validate method parse value. rescue exception , add error if fails parsing.

validate :validate_json_format  private  def validate_json_format   return if value.blank?    json.parse(value)  rescue json::parsererror   errors.add(:value, 'invalid json format') end