A working proxy exists.

server/main.go

@@ -30,7 +30,6 @@ func main() {
 }
 
 func handle(w http.ResponseWriter, r *http.Request) {
-	log.Infoln("handle")
 	if r.Method != http.MethodPost {
 		http.Error(w, "Unsupported method", http.StatusMethodNotAllowed)
 
@@ -56,6 +55,8 @@ func handle(w http.ResponseWriter, r *http.Request) {
 		response = handlePrintJob(request, r.Body)
 	case ipp.GetJobs:
 		response = handleGetJobs(request)
+	case ipp.ValidateJob:
+		response = handleValidateJob(request)
 	default:
 		response = ipp.NewResponse(ipp.ClientErrorBadRequest, request.RequestID())
 	}