KI-AGENT: Persistente App-Sessions mit Refresh-Tokens ergänzen

2026-07-20 22:01:08 +02:00
parent d8273e794d
commit 657a4f9e85
11 changed files with 405 additions and 60 deletions
--- a/backend/db/migrations/0056_auth_refresh_tokens.sql
+++ b/backend/db/migrations/0056_auth_refresh_tokens.sql
@@ -0,0 +1,21 @@
+CREATE TABLE IF NOT EXISTS "auth_refresh_tokens" (
+    "id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+    "user_id" uuid NOT NULL,
+    "tenant_id" bigint,
+    "token_hash" text NOT NULL,
+    "created_at" timestamp with time zone DEFAULT now() NOT NULL,
+    "expires_at" timestamp with time zone NOT NULL,
+    "revoked_at" timestamp with time zone,
+    CONSTRAINT "auth_refresh_tokens_token_hash_unique" UNIQUE("token_hash"),
+    CONSTRAINT "auth_refresh_tokens_user_id_auth_users_id_fk"
+        FOREIGN KEY ("user_id") REFERENCES "public"."auth_users"("id")
+        ON DELETE cascade ON UPDATE cascade,
+    CONSTRAINT "auth_refresh_tokens_tenant_id_tenants_id_fk"
+        FOREIGN KEY ("tenant_id") REFERENCES "public"."tenants"("id")
+        ON DELETE set null ON UPDATE cascade
+);
+
+CREATE INDEX IF NOT EXISTS "auth_refresh_tokens_user_id_idx"
+    ON "auth_refresh_tokens" ("user_id");
+CREATE INDEX IF NOT EXISTS "auth_refresh_tokens_expires_at_idx"
+    ON "auth_refresh_tokens" ("expires_at");
--- a/backend/db/migrations/meta/_journal.json
+++ b/backend/db/migrations/meta/_journal.json
@@ -372,6 +372,13 @@
      "when": 1784021669805,
      "tag": "0055_tenant_export_maintenance_lock",
      "breakpoints": true
+    },
+    {
+      "idx": 53,
+      "version": "7",
+      "when": 1784548800000,
+      "tag": "0056_auth_refresh_tokens",
+      "breakpoints": true
    }
  ]
 }
--- a/backend/db/schema/auth_refresh_tokens.ts
+++ b/backend/db/schema/auth_refresh_tokens.ts
@@ -0,0 +1,20 @@
+import { pgTable, text, timestamp, uuid, bigint } from "drizzle-orm/pg-core"
+
+import { authUsers } from "./auth_users"
+import { tenants } from "./tenants"
+
+export const authRefreshTokens = pgTable("auth_refresh_tokens", {
+    id: uuid("id").primaryKey().defaultRandom(),
+    userId: uuid("user_id")
+        .notNull()
+        .references(() => authUsers.id, { onDelete: "cascade", onUpdate: "cascade" }),
+    tenantId: bigint("tenant_id", { mode: "number" })
+        .references(() => tenants.id, { onDelete: "set null", onUpdate: "cascade" }),
+    tokenHash: text("token_hash").notNull().unique(),
+    createdAt: timestamp("created_at", { withTimezone: true }).notNull().defaultNow(),
+    expiresAt: timestamp("expires_at", { withTimezone: true }).notNull(),
+    revokedAt: timestamp("revoked_at", { withTimezone: true }),
+})
+
+export type AuthRefreshToken = typeof authRefreshTokens.$inferSelect
+export type NewAuthRefreshToken = typeof authRefreshTokens.$inferInsert
--- a/backend/db/schema/index.ts
+++ b/backend/db/schema/index.ts
@@ -7,6 +7,7 @@ export * from "./auth_roles"
 export * from "./auth_tenant_users"
 export * from "./auth_user_roles"
 export * from "./auth_users"
+export * from "./auth_refresh_tokens"
 export * from "./bankaccounts"
 export * from "./bankrequisitions"
 export * from "./bankstatements"
--- a/backend/src/routes/auth/auth.ts
+++ b/backend/src/routes/auth/auth.ts
@@ -1,14 +1,18 @@
 import { FastifyInstance } from "fastify";
 import bcrypt from "bcrypt";
-import jwt from "jsonwebtoken";
 import { generateRandomPassword, hashPassword } from "../../utils/password";
 import { sendMail } from "../../utils/mailer";
-import { secrets } from "../../utils/secrets";

 import { authUsers } from "../../../db/schema";
 import { authTenantUsers } from "../../../db/schema";
 import { tenants } from "../../../db/schema";
-import { eq, and } from "drizzle-orm";
+import { eq } from "drizzle-orm";
+import {
+    createAccessToken,
+    issueRefreshToken,
+    revokeRefreshToken,
+    rotateRefreshToken,
+} from "../../utils/authTokens";

 export default async function authRoutes(server: FastifyInstance) {

@@ -122,15 +126,9 @@ export default async function authRoutes(server: FastifyInstance) {
            return reply.code(401).send({ error: "Invalid credentials" });
        }

-        const token = jwt.sign(
-            {
-                user_id: user.id,
-                email: user.email,
-                tenant_id: req.tenant?.id ?? null,
-            },
-            secrets.JWT_SECRET!,
-            { expiresIn: "6h" }
-        );
+        const tenantId = req.tenant?.id ? Number(req.tenant.id) : null;
+        const token = createAccessToken(user, tenantId);
+        const refreshToken = await issueRefreshToken(server, user.id, tenantId);

        reply.setCookie("token", token, {
            path: "/",
@@ -140,9 +138,31 @@ export default async function authRoutes(server: FastifyInstance) {
            maxAge: 60 * 60 * 6,
        });

-        return { token };
+        return { token, refreshToken };
    });

+    server.post("/auth/refresh", {
+        schema: {
+            tags: ["Auth"],
+            summary: "Refresh a persistent session",
+            body: {
+                type: "object",
+                required: ["refreshToken"],
+                properties: {
+                    refreshToken: { type: "string" },
+                },
+            },
+        },
+    }, async (req, reply) => {
+        const { refreshToken } = req.body as { refreshToken: string };
+        const refreshed = await rotateRefreshToken(server, refreshToken);
+
+        if (!refreshed) {
+            return reply.code(401).send({ error: "Invalid or expired refresh token" });
+        }
+
+        return refreshed;
+    });

    // -----------------------------------------------------
    // LOGOUT
@@ -153,6 +173,10 @@ export default async function authRoutes(server: FastifyInstance) {
            summary: "Logout User"
        }
    }, async (req, reply) => {
+        const refreshToken = (req.body as { refreshToken?: string } | undefined)?.refreshToken;
+        if (refreshToken) {
+            await revokeRefreshToken(server, refreshToken);
+        }
        reply.clearCookie("token", {
            path: "/",
            httpOnly: true,
--- a/backend/src/routes/tenant.ts
+++ b/backend/src/routes/tenant.ts
@@ -14,6 +14,7 @@ import {
 import {and, desc, eq, inArray} from "drizzle-orm"
 import { enrichProfilesWithBranches } from "../utils/profileBranches"
 import { enrichProfilesWithTeams } from "../utils/profileTeams"
+import { rotateRefreshToken } from "../utils/authTokens"


 export default async function tenantRoutes(server: FastifyInstance) {
@@ -65,7 +66,7 @@ export default async function tenantRoutes(server: FastifyInstance) {
                return reply.code(401).send({ error: "Unauthorized" })
            }

-            const { tenant_id } = req.body as { tenant_id: string }
+            const { tenant_id, refreshToken } = req.body as { tenant_id: string; refreshToken?: string }
            if (!tenant_id) return reply.code(400).send({ error: "tenant_id required" })

            // prüfen ob der User zu diesem Tenant gehört
@@ -81,7 +82,22 @@ export default async function tenantRoutes(server: FastifyInstance) {
                return reply.code(403).send({ error: "Not a member of this tenant" })
            }

-            // JWT neu erzeugen
+            if (refreshToken) {
+                const session = await rotateRefreshToken(
+                    server,
+                    refreshToken,
+                    Number(tenant_id),
+                    req.user.user_id
+                )
+
+                if (!session) {
+                    return reply.code(401).send({ error: "Invalid or expired refresh token" })
+                }
+
+                return session
+            }
+
+            // Abwärtskompatibilität für Clients ohne persistente Session
            const token = jwt.sign(
                {
                    user_id: req.user.user_id,
--- a/backend/src/utils/authTokens.ts
+++ b/backend/src/utils/authTokens.ts
@@ -0,0 +1,93 @@
+import { createHash, randomBytes } from "node:crypto"
+import jwt from "jsonwebtoken"
+import { FastifyInstance } from "fastify"
+import { and, eq, gt, isNull } from "drizzle-orm"
+
+import { authRefreshTokens, authUsers } from "../../db/schema"
+import { secrets } from "./secrets"
+
+const ACCESS_TOKEN_TTL_SECONDS = 60 * 60 * 6
+const REFRESH_TOKEN_TTL_DAYS = 90
+
+export function createAccessToken(user: { id: string; email: string }, tenantId: number | null) {
+    return jwt.sign(
+        {
+            user_id: user.id,
+            email: user.email,
+            tenant_id: tenantId,
+        },
+        secrets.JWT_SECRET!,
+        { expiresIn: ACCESS_TOKEN_TTL_SECONDS }
+    )
+}
+
+export function hashRefreshToken(token: string) {
+    return createHash("sha256").update(token, "utf8").digest("hex")
+}
+
+export async function issueRefreshToken(
+    server: FastifyInstance,
+    userId: string,
+    tenantId: number | null
+) {
+    const token = randomBytes(48).toString("base64url")
+    const expiresAt = new Date(Date.now() + REFRESH_TOKEN_TTL_DAYS * 24 * 60 * 60 * 1000)
+
+    await server.db.insert(authRefreshTokens).values({
+        userId,
+        tenantId,
+        tokenHash: hashRefreshToken(token),
+        expiresAt,
+    })
+
+    return token
+}
+
+export async function rotateRefreshToken(
+    server: FastifyInstance,
+    token: string,
+    tenantOverride?: number | null,
+    expectedUserId?: string
+) {
+    const tokenHash = hashRefreshToken(token)
+    const [session] = await server.db
+        .update(authRefreshTokens)
+        .set({ revokedAt: new Date() })
+        .where(and(
+            eq(authRefreshTokens.tokenHash, tokenHash),
+            isNull(authRefreshTokens.revokedAt),
+            gt(authRefreshTokens.expiresAt, new Date())
+        ))
+        .returning({
+            id: authRefreshTokens.id,
+            userId: authRefreshTokens.userId,
+            tenantId: authRefreshTokens.tenantId,
+        })
+
+    if (!session) return null
+    if (expectedUserId && session.userId !== expectedUserId) return null
+
+    const [user] = await server.db
+        .select({ id: authUsers.id, email: authUsers.email })
+        .from(authUsers)
+        .where(eq(authUsers.id, session.userId))
+        .limit(1)
+
+    if (!user) return null
+
+    const tenantId = tenantOverride === undefined ? session.tenantId : tenantOverride
+    const refreshToken = await issueRefreshToken(server, session.userId, tenantId)
+    const accessToken = createAccessToken(user, tenantId)
+
+    return { token: accessToken, refreshToken }
+}
+
+export async function revokeRefreshToken(server: FastifyInstance, token: string) {
+    await server.db
+        .update(authRefreshTokens)
+        .set({ revokedAt: new Date() })
+        .where(and(
+            eq(authRefreshTokens.tokenHash, hashRefreshToken(token)),
+            isNull(authRefreshTokens.revokedAt)
+        ))
+}
--- a/mobile/app/login.tsx
+++ b/mobile/app/login.tsx
@@ -33,6 +33,7 @@ export default function LoginScreen() {

  const [email, setEmail] = useState('');
  const [password, setPassword] = useState('');
+  const [isPasswordVisible, setIsPasswordVisible] = useState(false);
  const [apiBaseUrl, setApiBaseUrl] = useState(getApiBaseUrlSync());
  const [serverInput, setServerInput] = useState(getApiBaseUrlSync());
  const [showServerModal, setShowServerModal] = useState(false);
@@ -141,14 +142,23 @@ export default function LoginScreen() {
        />

        <Text style={styles.label}>Passwort</Text>
+        <View style={styles.passwordRow}>
          <TextInput
-          secureTextEntry
+            secureTextEntry={!isPasswordVisible}
            placeholder="••••••••"
            placeholderTextColor="#9ca3af"
-          style={styles.input}
+            style={styles.passwordInput}
            value={password}
            onChangeText={setPassword}
          />
+          <Pressable
+            accessibilityRole="button"
+            accessibilityLabel={isPasswordVisible ? 'Passwort ausblenden' : 'Passwort einblenden'}
+            style={styles.passwordToggle}
+            onPress={() => setIsPasswordVisible((visible) => !visible)}>
+            <Text style={styles.passwordToggleText}>{isPasswordVisible ? 'Ausblenden' : 'Anzeigen'}</Text>
+          </Pressable>
+        </View>

        {error ? <Text style={styles.error}>{error}</Text> : null}

@@ -251,6 +261,30 @@ const styles = StyleSheet.create({
    fontSize: 16,
    color: '#111827',
  },
+  passwordRow: {
+    flexDirection: 'row',
+    alignItems: 'center',
+    borderWidth: 1,
+    borderColor: '#d1d5db',
+    borderRadius: 10,
+  },
+  passwordInput: {
+    flex: 1,
+    paddingHorizontal: 12,
+    paddingVertical: 10,
+    fontSize: 16,
+    color: '#111827',
+  },
+  passwordToggle: {
+    alignSelf: 'stretch',
+    justifyContent: 'center',
+    paddingHorizontal: 12,
+  },
+  passwordToggleText: {
+    color: PRIMARY,
+    fontSize: 13,
+    fontWeight: '600',
+  },
  button: {
    marginTop: 6,
    backgroundColor: PRIMARY,
--- a/mobile/src/lib/api.ts
+++ b/mobile/src/lib/api.ts
@@ -131,6 +131,11 @@ export type MeResponse = {
  permissions: string[];
 };

+export type AuthSession = {
+  token: string;
+  refreshToken: string;
+};
+
 export type EncodedLabelRow = {
  dataType: 'pixels' | 'void' | 'check';
  rowNumber: number;
@@ -199,6 +204,20 @@ type RequestOptions = {
  timeoutMs?: number;
 };

+export class ApiError extends Error {
+  constructor(
+    message: string,
+    public readonly status: number
+  ) {
+    super(message);
+    this.name = 'ApiError';
+  }
+}
+
+export function isAuthenticationError(error: unknown): boolean {
+  return error instanceof ApiError && error.status === 401;
+}
+
 export type MatrixStatus = {
  enabled?: boolean;
  ready?: boolean;
@@ -363,7 +382,7 @@ export async function apiRequest<T>(path: string, options: RequestOptions = {}):
      (payload as { message?: string; error?: string } | null)?.message ||
      (payload as { message?: string; error?: string } | null)?.error ||
      `Request failed (${response.status}) for ${path}`;
-    throw new Error(message);
+    throw new ApiError(message, response.status);
  }

  return payload as T;
@@ -399,7 +418,7 @@ async function apiFormRequest<T>(path: string, token: string, formData: FormData
      (payload as { message?: string; error?: string } | null)?.message ||
      (payload as { message?: string; error?: string } | null)?.error ||
      `Request failed (${response.status}) for ${path}`;
-    throw new Error(message);
+    throw new ApiError(message, response.status);
  }

  return payload as T;
@@ -629,17 +648,37 @@ export async function renderPrintLabel(
  });
 }

-export async function loginWithEmailPassword(email: string, password: string): Promise<string> {
-  const payload = await apiRequest<{ token?: string }>('/auth/login', {
+function requireAuthSession(payload: Partial<AuthSession>, action: string): AuthSession {
+  if (!payload?.token || !payload?.refreshToken) {
+    throw new Error(`${action} did not return a complete session.`);
+  }
+
+  return { token: payload.token, refreshToken: payload.refreshToken };
+}
+
+export async function loginWithEmailPassword(email: string, password: string): Promise<AuthSession> {
+  const payload = await apiRequest<Partial<AuthSession>>('/auth/login', {
    method: 'POST',
    body: { email, password },
  });

-  if (!payload?.token) {
-    throw new Error('Login did not return a token.');
+  return requireAuthSession(payload, 'Login');
 }

-  return payload.token;
+export async function refreshAuthSession(refreshToken: string): Promise<AuthSession> {
+  const payload = await apiRequest<Partial<AuthSession>>('/auth/refresh', {
+    method: 'POST',
+    body: { refreshToken },
+  });
+
+  return requireAuthSession(payload, 'Session refresh');
+}
+
+export async function logoutSession(refreshToken: string): Promise<void> {
+  await apiRequest('/auth/logout', {
+    method: 'POST',
+    body: { refreshToken },
+  });
 }

 export async function fetchMe(token: string): Promise<MeResponse> {
@@ -666,18 +705,18 @@ export async function sendMobileTestPush(token: string): Promise<{ accepted: num
  });
 }

-export async function switchTenantRequest(tenantId: number, token: string): Promise<string> {
-  const payload = await apiRequest<{ token?: string }>('/api/tenant/switch', {
+export async function switchTenantRequest(
+  tenantId: number,
+  token: string,
+  refreshToken: string
+): Promise<AuthSession> {
+  const payload = await apiRequest<Partial<AuthSession>>('/api/tenant/switch', {
    method: 'POST',
    token,
-    body: { tenant_id: String(tenantId) },
+    body: { tenant_id: String(tenantId), refreshToken },
  });

-  if (!payload?.token) {
-    throw new Error('Tenant switch did not return a token.');
-  }
-
-  return payload.token;
+  return requireAuthSession(payload, 'Tenant switch');
 }

 export async function fetchTasks(token: string): Promise<Task[]> {
--- a/mobile/src/lib/token-storage.ts
+++ b/mobile/src/lib/token-storage.ts
@@ -1,8 +1,15 @@
 import * as SecureStore from 'expo-secure-store';

 const TOKEN_KEY = 'fedeo.mobile.auth.token';
+const REFRESH_TOKEN_KEY = 'fedeo.mobile.auth.refresh-token';

 let memoryToken: string | null = null;
+let memoryRefreshToken: string | null = null;
+
+export type StoredSession = {
+  token: string;
+  refreshToken: string;
+};

 async function hasSecureStore(): Promise<boolean> {
  try {
@@ -30,11 +37,41 @@ export async function setStoredToken(token: string): Promise<void> {
  }
 }

-export async function clearStoredToken(): Promise<void> {
-  memoryToken = null;
+export async function getStoredSession(): Promise<StoredSession | null> {
+  if (await hasSecureStore()) {
+    const [token, refreshToken] = await Promise.all([
+      SecureStore.getItemAsync(TOKEN_KEY),
+      SecureStore.getItemAsync(REFRESH_TOKEN_KEY),
+    ]);
+    memoryToken = token;
+    memoryRefreshToken = refreshToken;
+  }
+
+  if (!memoryToken || !memoryRefreshToken) return null;
+  return { token: memoryToken, refreshToken: memoryRefreshToken };
+}
+
+export async function setStoredSession(session: StoredSession): Promise<void> {
+  memoryToken = session.token;
+  memoryRefreshToken = session.refreshToken;

  if (await hasSecureStore()) {
-    await SecureStore.deleteItemAsync(TOKEN_KEY);
+    await Promise.all([
+      SecureStore.setItemAsync(TOKEN_KEY, session.token),
+      SecureStore.setItemAsync(REFRESH_TOKEN_KEY, session.refreshToken),
+    ]);
+  }
+}
+
+export async function clearStoredToken(): Promise<void> {
+  memoryToken = null;
+  memoryRefreshToken = null;
+
+  if (await hasSecureStore()) {
+    await Promise.all([
+      SecureStore.deleteItemAsync(TOKEN_KEY),
+      SecureStore.deleteItemAsync(REFRESH_TOKEN_KEY),
+    ]);
  }
 }

--- a/mobile/src/providers/auth-provider.tsx
+++ b/mobile/src/providers/auth-provider.tsx
@@ -1,8 +1,22 @@
 import { createContext, useCallback, useContext, useEffect, useMemo, useRef, useState } from 'react';

-import { fetchMe, loginWithEmailPassword, MeResponse, switchTenantRequest, Tenant } from '@/src/lib/api';
+import {
+  fetchMe,
+  loginWithEmailPassword,
+  logoutSession,
+  MeResponse,
+  isAuthenticationError,
+  refreshAuthSession,
+  switchTenantRequest,
+  Tenant,
+} from '@/src/lib/api';
 import { hydrateApiBaseUrl } from '@/src/lib/server-config';
-import { clearStoredToken, getStoredToken, setStoredToken, tokenStorageInfo } from '@/src/lib/token-storage';
+import {
+  clearStoredToken,
+  getStoredSession,
+  setStoredSession,
+  tokenStorageInfo,
+} from '@/src/lib/token-storage';

 export type AuthUser = MeResponse['user'];

@@ -27,6 +41,7 @@ type AuthContextValue = {

 const AuthContext = createContext<AuthContextValue | undefined>(undefined);
 const BOOTSTRAP_TIMEOUT_MS = 20000;
+const SESSION_REFRESH_INTERVAL_MS = 5 * 60 * 60 * 1000;

 function normalizeTenantId(value: number | string | null | undefined): number | null {
  if (value === null || value === undefined || value === '') {
@@ -52,6 +67,7 @@ export function AuthProvider({ children }: { children: React.ReactNode }) {
  const [isBootstrapping, setIsBootstrapping] = useState(true);
  const [bootstrapError, setBootstrapError] = useState<string | null>(null);
  const [token, setToken] = useState<string | null>(null);
+  const [refreshToken, setRefreshToken] = useState<string | null>(null);
  const [user, setUser] = useState<AuthUser | null>(null);
  const [tenants, setTenants] = useState<Tenant[]>([]);
  const [activeTenantId, setActiveTenantId] = useState<number | null>(null);
@@ -80,11 +96,15 @@ export function AuthProvider({ children }: { children: React.ReactNode }) {
  );

  const logout = useCallback(async () => {
+    if (refreshToken) {
+      void logoutSession(refreshToken).catch(() => undefined);
+    }
    await clearStoredToken();
    setToken(null);
+    setRefreshToken(null);
    setBootstrapError(null);
    resetSession();
-  }, [resetSession]);
+  }, [refreshToken, resetSession]);

  const refreshUser = useCallback(async () => {
    if (!token) {
@@ -101,6 +121,7 @@ export function AuthProvider({ children }: { children: React.ReactNode }) {

  const resetLocalSession = useCallback(async () => {
    setToken(null);
+    setRefreshToken(null);
    setBootstrapError(null);
    setIsBootstrapping(false);
    resetSession();
@@ -117,19 +138,27 @@ export function AuthProvider({ children }: { children: React.ReactNode }) {
      await withTimeout(
        (async () => {
          await hydrateApiBaseUrl();
-          const storedToken = await getStoredToken();
+          const storedSession = await getStoredSession();

-          if (!storedToken) {
+          if (!storedSession) {
            if (bootstrapRunRef.current !== runId) return;
            setToken(null);
            resetSession();
            return;
          }

-          await hydrateSession(storedToken);
+          let activeSession = storedSession;
+          try {
+            await hydrateSession(activeSession.token);
+          } catch {
+            activeSession = await refreshAuthSession(activeSession.refreshToken);
+            await setStoredSession(activeSession);
+            await hydrateSession(activeSession.token);
+          }

          if (bootstrapRunRef.current !== runId) return;
-          setToken(storedToken);
+          setToken(activeSession.token);
+          setRefreshToken(activeSession.refreshToken);
        })(),
        BOOTSTRAP_TIMEOUT_MS,
        'Die mobile Session konnte nicht rechtzeitig initialisiert werden.'
@@ -137,10 +166,13 @@ export function AuthProvider({ children }: { children: React.ReactNode }) {
    } catch (err) {
      if (bootstrapRunRef.current === runId) {
        setToken(null);
+        setRefreshToken(null);
        resetSession();
        setBootstrapError(err instanceof Error ? err.message : 'Die mobile Session konnte nicht initialisiert werden.');
+        if (isAuthenticationError(err)) {
          void clearStoredToken().catch(() => undefined);
        }
+      }
    } finally {
      if (bootstrapRunRef.current === runId) {
        setIsBootstrapping(false);
@@ -154,28 +186,49 @@ export function AuthProvider({ children }: { children: React.ReactNode }) {

  const login = useCallback(
    async (email: string, password: string) => {
-      const nextToken = await loginWithEmailPassword(email, password);
-      await setStoredToken(nextToken);
-      await hydrateSession(nextToken);
-      setToken(nextToken);
+      const session = await loginWithEmailPassword(email, password);
+      await setStoredSession(session);
+      await hydrateSession(session.token);
+      setToken(session.token);
+      setRefreshToken(session.refreshToken);
    },
    [hydrateSession]
  );

  const switchTenant = useCallback(
    async (tenantId: number) => {
-      if (!token) {
+      if (!token || !refreshToken) {
        throw new Error('No active session found.');
      }

-      const nextToken = await switchTenantRequest(tenantId, token);
-      await setStoredToken(nextToken);
-      await hydrateSession(nextToken);
-      setToken(nextToken);
+      const session = await switchTenantRequest(tenantId, token, refreshToken);
+      await setStoredSession(session);
+      await hydrateSession(session.token);
+      setToken(session.token);
+      setRefreshToken(session.refreshToken);
    },
-    [token, hydrateSession]
+    [token, refreshToken, hydrateSession]
  );

+  useEffect(() => {
+    if (!refreshToken) return;
+
+    const interval = setInterval(() => {
+      void (async () => {
+        try {
+          const session = await refreshAuthSession(refreshToken);
+          await setStoredSession(session);
+          setToken(session.token);
+          setRefreshToken(session.refreshToken);
+        } catch {
+          // Bei einem temporären Netzfehler bleibt die gespeicherte Session erhalten.
+        }
+      })();
+    }, SESSION_REFRESH_INTERVAL_MS);
+
+    return () => clearInterval(interval);
+  }, [refreshToken]);
+
  const activeTenant = useMemo(
    () => tenants.find((tenant) => Number(tenant.id) === activeTenantId) || null,
    [activeTenantId, tenants]