check NTP host resolves before updating config

src/config.cpp

@@ -1,4 +1,5 @@
 #include "config.h"
+#include "time.h"
 #include <Arduino.h>
 #include <EEPROM.h>
 
@@ -103,6 +104,7 @@ bool cUWeatherConfig::setNTPHost(const char* buff)
 {
   if (strlen(buff) >= 32) return false;
   strncpy((char*)_data.ntp_host, buff, 32);
+  uweather_time_init(); // restart time
   return true;
 }
 

src/web.cpp

@@ -182,6 +182,11 @@ void handle_config_set(HttpRequest& req, HttpResponse& res)
   } else if (strcmp("mdns_hostname", key) == 0) {
     result = Config.setMDNSHostname(value);
   } else if (strcmp("ntp_host", key) == 0) {
+    IPAddress ntp_host_addr;
+    if (value[0] != '\0' && !WiFi.hostByName(value, ntp_host_addr)) {
+      client_error("Unable to resolve host", res);
+      return;
+    }
     result = Config.setNTPHost(value);
   } else if (strcmp("mqtt_host", key) == 0) {
     result = Config.setMQTTHost(value);