make httpclient retry

src/main.cpp

@@ -174,6 +174,9 @@ void ICACHE_FLASH_ATTR sendValues() {
   char buffer[500];
   array.printTo(buffer, sizeof(buffer));
 
+  int httpCode = 0;
+  for (int tries=0; tries<3 && httpCode != HTTP_CODE_CREATED; tries++) {
+
     HTTPClient httpclient;
     char url[100];
     sprintf(url, "http://%s/boxes/%s/data", server, SENSEBOX_ID);
@@ -181,7 +184,7 @@ void ICACHE_FLASH_ATTR sendValues() {
     httpclient.begin(url);
     httpclient.addHeader("Content-Type", "application/json");
 
-  int httpCode = httpclient.POST(buffer);
+    httpCode = httpclient.POST(buffer);
 
     if (httpCode > 0) {
       if (httpCode == HTTP_CODE_CREATED) {
@@ -194,6 +197,8 @@ void ICACHE_FLASH_ATTR sendValues() {
 
     httpclient.end();
 
+  }
+
   WiFi.disconnect();
   WiFi.mode(WIFI_OFF);
   WiFi.forceSleepBegin();