tested

client/libs/caching/src/ram_caching.cpp

@@ -68,7 +68,7 @@ void RtcMemory::get_host_mac(uint8_t* destination, bool open){
 
 void RtcMemory::store_mac_address(uint8_t* mac){
     preferences.begin("config", false);
-    if(preferences.putBytes("host", mac, sizeof(mac)) > 0){
+    if(preferences.putBytes("host", mac, sizeof(uint8_t) * 6) > 0){
         ESP_LOGI(TAG, "Host MAC address saved to flash %02X:%02X:%02X:%02X:%02X:%02X", mac[0],
         mac[1],mac[2],mac[3],mac[4],mac[5]);
         }

client/libs/caching/src/ram_caching.hpp

@@ -29,7 +29,6 @@ class RtcMemory {
 
     private:
         RtcMemory(){}
-        // used for data storage
         // used for MAC storage
         Preferences preferences;
         uint8_t BROADCAST_MAC[6] = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};

client/libs/espnow/src/ESPNow.cpp

@@ -15,18 +15,6 @@ bool was_msg_received(){
 	return false;
 }
 
-void get_host_mac(uint8_t *destination)
-{
-	preferences.begin("config", true);
-	if (preferences.isKey("host")) {
-		preferences.getBytes("host", destination, sizeof(uint8_t) * 6);
-	} else {
-		memcpy(destination, BROADCAST_MAC, sizeof(BROADCAST_MAC));
-		ESP_LOGI(TAG, "Backup MAC address used");
-	}
-	preferences.end();
-}
-
 esp_err_t add_host_to_peers(config received){
 	esp_now_peer_info_t host;
 	memset(&host, 0, sizeof(host));
@@ -56,6 +44,7 @@ void on_data_recv(const uint8_t *mac, const uint8_t *incomingData, int len)
 														  // you can also set your own MAC https://randomnerdtutorials.com/get-change-esp32-esp8266-mac-address-arduino/
 	switch (received_msg.type){
 		case hostChange:{
+			msg_recv = true;
 			ESP_LOGI(TAG, "hostChange received");
 			Time::getInstance().setTime(received_msg.epoch_seconds);
 			
@@ -71,22 +60,17 @@ void on_data_recv(const uint8_t *mac, const uint8_t *incomingData, int len)
 			add_host_to_peers(received_msg);
 		}
 		case dataAck:{
+			msg_recv = true;
 			ESP_LOGI(TAG, "dataAck received.");
 			Time::getInstance().setTime(
 			received_msg.epoch_seconds); // see https://www.esp32.com/viewtopic.php?t=9965, maybe this needs an offset
 			ESP_LOGI(TAG, "Timestamp received: %ld", Time::getInstance().getEpochSeconds());
-			if(RtcMemory::getInstance().does_host_exist()){
-				RtcMemory::getInstance().store_mac_address(received_msg.host);
-				add_host_to_peers(received_msg);
-			}
-			// add host to peers
 		}
 			// delay(50);
 		
 		default:{
 			break;
 		}
-		msg_recv = true;
 	}
 }
 
@@ -102,7 +86,7 @@ esp_err_t espnow_setup()
 		return result; // not sure about this
 	}
 
-	get_host_mac(hostInfo.peer_addr); // check if there is a host saved in flash mem, broadcast otherwise
+	RtcMemory::getInstance().get_host_mac(hostInfo.peer_addr); // check if there is a host saved in flash mem, broadcast otherwise
 
 	hostInfo.channel = 0;
 

client/libs/espnow/src/Message.cpp

@@ -30,11 +30,11 @@ std::string Message::getMessageAsMinifiedJsonString() const
 Message::Message(ClientDataPackage data) : clientDataPackage(std::move(data))
 {
 	// check for existing host mac address, use broadcast otherwise
-	get_host_mac(recipient);
+	RtcMemory::getInstance().get_host_mac(recipient);
 }
 Message::Message(MeasurementData const &data, const SensorInformation &information, unsigned long timestamp)
     : clientDataPackage(data, information, timestamp)
 {
 	// check for existing host mac address, use broadcast otherwise
-	get_host_mac(recipient);
+	RtcMemory::getInstance().get_host_mac(recipient);
 }

host/host_central_mast/src/main.cpp

@@ -132,19 +132,13 @@ void syncUTCTimeToRTC();
 void on_data_recv(const uint8_t *mac, const uint8_t *incomingData, int len)
 {
 	response response = {};
-	response.type = dataAck;
+	// send a host change msg if client is new, simplifies client
+	response.type = esp_now_is_peer_exist(mac) ? dataAck : hostChange; 
 	esp_read_mac(response.mac, ESP_MAC_WIFI_STA);
 	response.time = rtc.getEpoch();
-	esp_err_t success = esp_now_send(mac, (uint8_t*) &response, sizeof(response));
-	esp_log_write(ESP_LOG_DEBUG, TAG_ESPNOW.c_str(), 
-		(success == ESP_OK) ? "Response sent\n" : "Failed to respond\n");
-		
-	esp_log_write(ESP_LOG_INFO, TAG_ESPNOW.c_str(), "Message recieved\n");
-	// copy received data to a char array
-	char data[len];
-	memcpy(data, incomingData, len);
-	esp_log_write(ESP_LOG_DEBUG, TAG_ESPNOW.c_str(), "Raw received Data: %s\n", data);
 
+	// this block needs to happen before we send the message, as it's not possible to
+	// send a message to an unregistered peer (i.e. new client)
 	if(!esp_now_is_peer_exist(mac)){
 		esp_now_peer_info_t client = {};
 		memcpy(client.peer_addr, mac, sizeof(uint8_t) * 6);
@@ -157,6 +151,17 @@ void on_data_recv(const uint8_t *mac, const uint8_t *incomingData, int len)
 		}
 	}
 
+	esp_err_t success = esp_now_send(mac, (uint8_t*) &response, sizeof(response));
+	esp_log_write(ESP_LOG_DEBUG, TAG_ESPNOW.c_str(), 
+		(success == ESP_OK) ? "Response sent\n" : "Failed to respond\n");
+
+		
+	esp_log_write(ESP_LOG_INFO, TAG_ESPNOW.c_str(), "Message recieved\n");
+	// copy received data to a char array
+	char data[len];
+	memcpy(data, incomingData, len);
+	esp_log_write(ESP_LOG_DEBUG, TAG_ESPNOW.c_str(), "Raw received Data: %s\n", data);
+
 	DynamicJsonDocument doc = parseReceivedJsonData(data);
 
 	String macAddress = getMacAddressAsString(mac);
@@ -179,13 +184,6 @@ void on_data_recv(const uint8_t *mac, const uint8_t *incomingData, int len)
 	queue.push(lineData);
 	xSemaphoreGive(xMutex);
 
-	response response = {};
-	response.type = dataAck;
-	esp_read_mac(response.mac, ESP_MAC_WIFI_STA);
-	response.time = rtc.getEpoch();
-	esp_err_t success = esp_now_send(mac, (uint8_t*) &response, sizeof(response));
-	esp_log_write(ESP_LOG_DEBUG, TAG_ESPNOW.c_str(), 
-		(success == ESP_OK) ? "Response sent\n" : "Failed to respond\n");
 }
 
 String documentToLineProtocolString(const DynamicJsonDocument &doc)