Try extractors instead

Trying to implement this pattern in Actix 3 I banged my head for awhile trying to use middleware, basically making a guard and then figuring out how to pass data from the middleware into the handler. It was painful and eventually I realized that I was working against Actix rather than with it.

Finally I learned out that the way to get information to a handler is to create a struct (AuthedUser, perhaps?) and implement the FromRequest trait on that struct.

Then every handler that asks for an AuthedUser in the function signature will be auth gated and if the user is logged in will have any user information you attach to AuthedUser in the FromRequest::from_request method.

Actix refers to these structs that implement FromRequest as extractors. It’s a bit of magic that could use more attention in the guide.