No errors but Go app still doesn't work properly - http

Question

I'm working on a web chat application and I experienced an issue that shouldn't be happening.
In the main.go I have this function:
http.Handle("/chat", MustAuth(&templateHandler{filename: "chat.html"}))
and I've just built an authentication file (auth.go, still in progress) with a cookie, here it is:
package main
import "net/http"
type authHandler struct {
next http.Handler
}
func (h *authHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
_, err := r.Cookie("auth")
if err == http.ErrNoCookie {
//not authenticated
w.Header().Set("Location", "/login")
w.WriteHeader(http.StatusTemporaryRedirect)
return
}
if err != nil {
//some other error
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
//success - call the next handler
h.next.ServeHTTP(w, r)
}
func MustAuth(handler http.Handler) http.Handler {
return &authHandler{next: handler}
}
The problem is that when I run it and open the localhost page, the cookie doesn't work how it should and doesn't redirect me to the login page as it should.

Answer 1

I have made a fully compiling example out of the code you provided - however it does work for me: lolcalhost:8080/chat redirects me to localhost:8080/login
I suspect your browser may have a cookie "auth" already set.
You can press STRG+SHIFT+I and go to the networking tab to see what is transmitted.
Check there really is no cookie set for you.
Code I tried:
package main
import "net/http"
type authHandler struct {
next http.Handler
}
func ServeHTTP(w http.ResponseWriter, r *http.Request) {
_, err := r.Cookie("auth")
if err == http.ErrNoCookie {
//not authenticated
w.Header().Set("Location", "/login")
w.WriteHeader(http.StatusTemporaryRedirect)
return
}
if err != nil {
//some other error
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
//success - call the next handler
//h.next.ServeHTTP(w, r)
w.Write([]byte("Hi"))
}
func main() {
http.HandleFunc("/chat", ServeHTTP)
http.ListenAndServe(":8080", nil)
}