Ruby Cardstream Payment Gateway code

cardstream_ruby.rb

require "net/https"
require "uri"
require "cgi"
require "digest"

class Cardstream
  def initialize(post_data)
    url_params = escape_params(post_data)
    @post_data = hash_post_data(url_params)
  end

  def post
    uri = URI.parse("https://gateway.cardstream.com/direct/")
    http = Net::HTTP.new(uri.host, uri.port)
    http.use_ssl = true
    http.verify_mode = OpenSSL::SSL::VERIFY_NONE

    request = Net::HTTP::Post.new uri
    request.add_field('Content-Type', 'application/x-www-form-urlencoded')
    request.add_field('Content-Length', @post_data.size)
    request.body = @post_data

    response = http.request request
    return CGI::parse(response.body)
  end

  private

  def escape_params(post_data)
    post_data
      .sort.to_h
      .map { |k, v| "#{k}=#{CGI::escape(v.to_s)}" }
      .reduce { |acc, v| "#{acc}&#{v}" }
      .gsub(/\(/, "%28")
      .gsub(/\)/, "%29")
      .gsub(/%20/, "+")
  end

  def hash_post_data(url_params)
    url_params + '&signature=' + Digest::SHA2.new(512).hexdigest("#{url_params}#{SIG_KEY}")
  end
end


post_data = {
  action: 'REFUND',
  amount: 4900,
  merchantID: 12345678,
  type: 1,
  xref: '1234567'
}

Cardstream::SIG_KEY = 'mysigkey'
cs = Cardstream.new(post_data)
response = cs.post
puts response