Question: is it possible to have:

`before_filter :authenticate_user! || :authenticate_admin!`

Answer: 
```
before_filter {authenticate_user! || authenticate_admin!}

```

Passing in a proc to the before\_filter method, would be the closest to what you have provided in you question.
```
before_filter :do_authentication

def do_authentication
  authenticate_user! || authenticate_admin!
end

```