void handleSaveMac() { if (server.hasArg("mac")) { // Extract the string from the POST request String data = server.arg("mac"); // Open the file in write mode File file = LittleFS.open(DB_PATH, "w"); if (!file) { server.send(500, "text/plain", "Failed to open file for writing"); return; } // Write the string data to the file file.print(data); file.close(); sendOK(); } else { server.send(400, "text/plain", "No string provided in the request"); } } void handleGetMac() { // Open the file in read mode File file = LittleFS.open(DB_PATH, "r"); if (!file) { server.send(500, "text/plain", "Failed to open file for reading"); return; } // Read the string data from the file String data = file.readString(); file.close(); // Send the string data as the json resp server.send(200, "application/json", data); }