Rack middleware to prevent cookies coming in or out except on POST

cookieblind.rb

class Cookieblind
  def initialize(app)
    @app = app
  end
  
  def call(env)
    request = Rack::Request.new(env)
    unless request.post?
      env.delete("HTTP_COOKIE")
    end
    status, headers, body = @app.call(env)
    response = Rack::Response.new(body, status, headers)
    unless request.post?
      response.header['Set-Cookie'] = "";
    end
    response.finish
  end
end