From https://github.com/typhoeus/typhoeus
You need to do the get before the response body is available.
EDIT: Here is an operable solution. It doesn't use your website, which I couldn't access even manually. But, this returns response code 200 and the response_body. Running this in my debugger showed the complete response, which you could see using "puts response.inspect".
class TyphoeusTry
require 'typhoeus'
request = Typhoeus::Request.new("http://www.google.com",
method: :get,
userpwd: "test_user:test_password",
headers: { ContentType: "application/json"})
response = request.run
puts response.response_body
end