make httpclient retry

src/main.cpp

@@ -174,25 +174,30 @@ void ICACHE_FLASH_ATTR sendValues() {
   char buffer[500];
   array.printTo(buffer, sizeof(buffer));
 
-  HTTPClient httpclient;
-  char url[100];
-  sprintf(url, "http://%s/boxes/%s/data", server, SENSEBOX_ID);
+  int httpCode = 0;
+  for (int tries=0; tries<3 && httpCode != HTTP_CODE_CREATED; tries++) {
 
-  httpclient.begin(url);
-  httpclient.addHeader("Content-Type", "application/json");
+    HTTPClient httpclient;
+    char url[100];
+    sprintf(url, "http://%s/boxes/%s/data", server, SENSEBOX_ID);
 
-  int httpCode = httpclient.POST(buffer);
+    httpclient.begin(url);
+    httpclient.addHeader("Content-Type", "application/json");
 
-  if (httpCode > 0) {
-    if (httpCode == HTTP_CODE_CREATED) {
-      httpclient.writeToStream(&Serial);
-      Serial.println();
-    } else {
-      Serial.printf("[HTTP] POST... failed, error: %s\n", httpclient.errorToString(httpCode).c_str());
+    httpCode = httpclient.POST(buffer);
+
+    if (httpCode > 0) {
+      if (httpCode == HTTP_CODE_CREATED) {
+        httpclient.writeToStream(&Serial);
+        Serial.println();
+      } else {
+        Serial.printf("[HTTP] POST... failed, error: %s\n", httpclient.errorToString(httpCode).c_str());
+      }
     }
-  }
 
-  httpclient.end();
+    httpclient.end();
+
+  }
 
   WiFi.disconnect();
   WiFi.mode(WIFI_OFF);