Add Cache-Control headers to responses

okserver.go

@@ -17,12 +17,18 @@ func main() {
 	// Create a very simple HTTP server with two endpoints: one
 	// that just replies "OK", and one that dumps the incoming
 	// request back to the client.
+	//
+	// The OK handler answers with a cachable response, while the
+	// dynamic one sets cache-busting headers.
 	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
 		switch r.URL.Path {
 		case "/echo":
 			w.Header().Set("Content-Type", "text/plain")
+			w.Header().Set("Expires", "-1")
+			w.Header().Set("Cache-Control", "no-store")
 			r.Write(w)
 		case "/", "/health":
+			w.Header().Set("Cache-Control", "max-age=86400")
 			io.WriteString(w, "OK\n")
 		default:
 			http.NotFound(w, r)