轉譯 \t \r \n 以外的 Unicode 控制字元成 \uxxxx 的形式

escape_unicode_control_characters.rb

class String
  # Escape Unicode control characters except \t \r \n
  def escape_unicode_control_characters
    gsub(/(?<unicode_control_characters>[\p{C}&&[^\t\r\n]]+)/u) do |_match|
      Regexp.last_match[:unicode_control_characters].unpack('U*').map { |i| '\u' + i.to_s(16).rjust(4, '0') }.join
    end
  end
end

require 'json'
bad_json = "{\"text\":\"String contain unicode \u00008 characters\"}"
JSON.parse(bad_json) # JSON::ParserError: 784: unexpected token at '{"text":"String contain unicode ' ...
JSON.parse(bad_json.escape_unicode_control_characters) # {"text"=>"String contain unicode \u00008 characters"}