Get Current User from JWT Authentication on Mux - go

Question

I'm beginner with Go, ruby my previous language. I started with Mux for build an API. Now I'm learning authentication using JWT to protect the API. Firstly I try to handle authentication in a function with single file main.go
func ListPosts(w http.ResponseWriter, r *http.Request){
// verify authentication here
// other stuff to get list of posts by a user authentication here
}
func handleRequests() {
myRouter := mux.NewRouter().StrictSlash(true)
myRouter.HandleFunc("/posts", ListPosts).Methods("GET")
log.Fatal(http.ListenAndServe(":8081", myRouter))
}
func main() {
handleRequests()
}
Everything is working well, the above implementation is repeating the authentication every I create a new endpoint, so I'm trying to make it DRY
Here is my main.go now :
func handleRequests() {
myRouter := mux.NewRouter().StrictSlash(true)
myRouter.HandleFunc("/posts", jwt.Authenticate(controllers.ListPosts)).Methods("GET")
log.Fatal(http.ListenAndServe(":8081", myRouter))
}
func main() {
handleRequests()
}
this is the jwt package I have made :
package jwt
func Authenticate(handler http.HandlerFunc) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
// checking header Authorization here
token, err := ValidateToken(r)
if err != nil {
// checking signature invalid here
// checking expire token here
// response error here
}
if !token.Valid {
// response error here
}
getClaim := token.Claims.(*Token)
// I'm using https://github.com/Kamva/mgm (mongo)
user := &models.User{}
coll := mgm.Coll(user)
// Find and decode the doc to a user model here
handler.ServeHTTP(w, r)
return
}
}
The authentication is working well, and now I want to get a user authentication in controllers package, do I need to put an UID of user on header and find a user with it? I believe that make a redudant, because I have find a user on Authenticate function.
package controllers
func ListPosts(w http.ResponseWriter, r *http.Request) {
// should I find a user with r.Header["UID"] here ?
w.WriteHeader(http.StatusOK)
_ = json.NewEncoder(w).Encode({})
}