feat(dart): remove the access_token if is expired (#19)

Author: simeng-li

lib/src/modules/token_storage.dart

@@ -87,13 +87,37 @@ class TokenStorage {
       [String? resource, List<String>? scopes]) async {
     final key = _buildAccessTokenKey(resource, scopes);
 
-    if (_accessTokenMap != null) {
-      return _accessTokenMap![key];
+    _accessTokenMap ??= await _getAccessTokenMapFromStorage();
+
+    final accessToken = _accessTokenMap?[key];
+
+    // remove the access token if expired and return null
+    if (accessToken?.isExpired == true) {
+      await _deleteAccessToken(key);
+      return null;
     }
 
-    _accessTokenMap = await _getAccessTokenMapFromStorage();
+    return accessToken;
+  }
+
+  Future<void> _deleteAccessToken(String accessTokenKey) async {
+    final Map<String, AccessToken> tempAccessTokenMap =
+        Map.from(_accessTokenMap ?? {});
+
+    final value = tempAccessTokenMap.remove(accessTokenKey);
+
+    // Do not update the storage if target accessToken does not exist
+    if (value == null) return;
+
+    // clean up the storage if is empty
+    if (tempAccessTokenMap.isEmpty) {
+      await _storage.delete(key: _TokenStorageKeys.accessTokenKey);
+      _accessTokenMap = null;
+      return;
+    }
 
-    return _accessTokenMap?[key];
+    await _saveAccessTokenMapToStorage(tempAccessTokenMap);
+    _accessTokenMap = tempAccessTokenMap;
   }
 
   Future<void> _saveAccessTokenMapToStorage(

test/modules/token_storage_test.dart

@@ -59,12 +59,19 @@ void main() {
           equals(tokenStorage?.expiresAt.toIso8601String()));
     });
 
-    test('access token should expires properly', () async {
-      await sut.setAccessToken(accessToken, expiresIn: 1);
+    test('should remove the expired access token and return null', () async {
+      await sut.setAccessToken(accessToken,
+          resource: resource, scopes: scope.split(' '), expiresIn: 1);
+
+      final tokenStorage = await sut.getAccessToken(resource, scope.split(' '));
+      expect(tokenStorage?.token, accessToken);
 
       await Future.delayed(const Duration(seconds: 2), () async {
-        final token = await sut.getAccessToken();
-        expect(token?.isExpired, true);
+        final token = await sut.getAccessToken(resource, scope.split(' '));
+        expect(token, isNull);
+        expect(
+            await storageStrategy.read(key: _TokenStorageKeys.accessTokenKey),
+            isNull);
       });
     });