控制器上的类型开关

Question

I'm implementing a simple interceptor using revel, who's sole responsibility is to ensure that a user is authenticated and redirect to auth page if not. I have something to the effect of

func setUser(c *revel.Controller) revel.Result {
    switch interface{}(c.Type).(type) {
    case controllers.Auth:
        return nil
    }
    return c.Redirect(controllers.Auth.Index)
}

The type case controllers.Auth is never encountered, effectively resulting in an infinite loop. I'm assuming there's something obvious I'm missing, but while I figure out how to run a revel app through gdb to try and debug this, figured I'd ask here.

Answer 1

I believe for your switch you need a base case. You end up in it infinitely because c's type is not controllers.Auth and you have no other cases. But, in your use case, there is no reason to use a switch and I personally wouldn't. It's binary, so just type assert on controllers.Auth , if it's not that then you redirect.

func setUser(c *revel.Controller) revel.Result {
    if _, ok := c.(controllers.Auth); ok {
             return c.Redirect(controllers.Auth.Index)   
    }
    return nil
}