http response tooling written

internal/site/cookie.go

@@ -2,10 +2,10 @@ package site
 
 import "net/http"
 
-func deleteCookieInResponse(w http.ResponseWriter, name string) {
-	w.Header().Set("Set-Cookie", (&http.Cookie{
+func getExpiredCookie(name string) http.Cookie {
+	return http.Cookie{
 		Name:   name,
 		Path:   "/",
 		MaxAge: -1, // expire the cookie
-	}).String())
+	}
 }