如何过滤rails中的参数?

Rails has built in log filtering so you don't log passwords and credit cards. Works great for that but when you want to trigger a custom log (like to email) and send your own params or other data along with it, the parameters are obviously not auto-filtered. I have been digging and trying to find this in the rails source but have had no luck so far.Rails has built in log filtering so you don't l