RFID message ins backend geht, websocket fürs frontend

src/databasebackend.h

@@ -1,3 +1,4 @@
+#pragma once
 #include <Arduino.h>
 #include <HTTPClient.h>
 #include "master.h"
@@ -17,34 +18,76 @@ bool backendOnline() {
     http.addHeader("Authorization", String("Bearer ") + BACKEND_TOKEN);
     
     int httpCode = http.GET();
+    bool isOnline = (httpCode == HTTP_CODE_OK);
     
-    if (httpCode == HTTP_CODE_OK) {
-        return true;
+    if (isOnline) {
         Serial.println("Database server connection successful");
     } else {
-        return false;
         Serial.printf("Database server connection failed, error: %d\n", httpCode);
     }
     
     http.end();
+    return isOnline;
 }
 
-bool userExists(const String& userId) {
+struct UserData {
+    String uid;
+    String firstname;
+    String lastname;
+    int alter;
+    bool exists;
+};
+
+// UserData checkUser(const String& uid) is defined only once to avoid redefinition errors.
+UserData checkUser(const String& uid) {
+
+    UserData userData = {"", "", "", 0, false};
+    
     if (!backendOnline()) {
-        Serial.println("No internet connection, cannot check user existence.");
-        return false;
+        Serial.println("No internet connection, cannot check user.");
+        return userData;
     }
 
     HTTPClient http;
-    http.begin(String(BACKEND_SERVER) + "/api/users/" + userId);
+    http.begin(String(BACKEND_SERVER) + "/api/users/find");
+    http.addHeader("Content-Type", "application/json");
     http.addHeader("Authorization", String("Bearer ") + BACKEND_TOKEN);
     
-    //Post request to check if user exists
-    int httpCode = http.POST("");
+    // Create JSON payload
+    StaticJsonDocument<200> requestDoc;
+    requestDoc["uid"] = uid;
+    String requestBody;
+    serializeJson(requestDoc, requestBody);
+    
+    int httpCode = http.POST(requestBody);
+    
+    if (httpCode == HTTP_CODE_OK) {
+        String payload = http.getString();
+        StaticJsonDocument<512> responseDoc;
+        DeserializationError error = deserializeJson(responseDoc, payload);
+        
+        if (!error) {
+            userData.uid = responseDoc["uid"].as<String>();
+            userData.firstname = responseDoc["firstname"].as<String>();
+            userData.lastname = responseDoc["lastname"].as<String>();
+            userData.alter = responseDoc["alter"] | 0;
+            userData.exists = true;
+        }
+    } else {
+        Serial.printf("User check failed, HTTP code: %d\n", httpCode);
+    }
+    
+    http.end();
+    return userData;
+}
 
+// Keep this for backward compatibility
+bool userExists(const String& uid) {
+    return checkUser(uid).exists;
 }
 
 void setupBackendRoutes(AsyncWebServer& server) {
+    
     server.on("/api/health", HTTP_GET, [](AsyncWebServerRequest *request) {
         
         DynamicJsonDocument doc(64);