class HTTP::Cookie

def set_cookie_value

origin before calling this method.
missing, RuntimeError is raised. It is always the best to set an
information like a path or domain (when `for_domain` is set) is
Returns a string for use in the Set-Cookie header. If necessary 
def set_cookie_value
  string = cookie_value
  if @for_domain
    if @domain
      string << "; Domain=#{@domain}"
    else
      raise "for_domain is specified but domain is unknown"
    end
  end
  if @path
    if !@origin || (@origin + './').path != @path
      string << "; Path=#{@path}"
    end
  else
    raise "path is unknown"
  end
  if @max_age
    string << "; Max-Age=#{@max_age}"
  elsif @expires
    string << "; Expires=#{@expires.httpdate}"
  end
  if @httponly
    string << "; HttpOnly"
  end
  if @secure
    string << "; Secure"
  end
  string
end