Case-Sensitive Captcha Support

[rautniraj]

First of all, thank you for providing such a cool and easy-to-use library! Setting it up was seamless by following the GitHub repository and Ruby gem documentation.

I noticed that the library does not support case-sensitive captcha validation. While the captcha image displays text in uppercase, submitting the answer in lowercase is still accepted. After going through the code, I saw that the text is manually converted to lowercase before matching.

Could you clarify the reasoning behind this design choice? Additionally, is there a way to enable case-sensitive validation, or could this be added as an option?

Thanks in advance!

Niraj Raut
Love from 🇮🇳

[rautniraj]

 def generate
      length = config.length

      raise RuCaptcha::Errors::Configuration, "length config error, value must in 3..7" unless length.in?(3..7)

      result = RuCaptchaCore.create(length, config.difficulty || 5, config.line, config.noise, config.format)
      [result[0].downcase, result[1].pack("c*")]
    end

def verify_rucaptcha?(_resource = nil, opts = {})
      opts ||= {}

      store_info = RuCaptcha.cache.read(rucaptcha_sesion_key_key)
      # make sure move used key
      RuCaptcha.cache.delete(rucaptcha_sesion_key_key) unless opts[:keep_session]

      # Make sure session exist
      return add_rucaptcha_validation_error if store_info.blank?

      # Make sure not expire
      return add_rucaptcha_validation_error if (Time.now.to_i - store_info[:time]) > RuCaptcha.config.expires_in

      # Make sure parama have captcha
      captcha = (opts[:captcha] || params[:_rucaptcha] || "").downcase.strip
      return add_rucaptcha_validation_error if captcha.blank?

      return add_rucaptcha_validation_error if captcha != store_info[:code]

      true
    end

In both the code i observe you are doing manual downcase, so will it work if i remove this downcase and try to match captcha keeping casesensitive in consideration ?

Before trying out anything i want to know will this break the code in any way based on what design you have followed ?

Thank You
Niraj Raut

[huacnlee]

This is by design. Case-In sensitive is used for reduce wrongs.

With 5 Alphabetical characters, it's enough.

[rautniraj]

Thank you for your insights.

Our requirement is to maintain a case-sensitive match with a length of four characters, including noise, at a medium difficulty level. However, the current design does not support this.

Can I modify the code to remove the .downcase usage? Will this change be sufficient, or could it cause issues elsewhere?

If this modification works, I will test it in my project. Additionally, I would like to contribute to your project by adding a configuration parameter that allows users to choose between case-sensitive and case-insensitive matching.