修复用户端令牌失效后的登录恢复

apps/user_app/lib/data/services/api_client.dart

@@ -1,5 +1,5 @@
 // 功能描述：封装用户端 HTTP 请求，并将服务端错误转换为安全、可读的中文提示。
-// 版本：1.1.0
+// 版本：1.2.0
 import 'dart:convert';
 import 'dart:typed_data';
 
@@ -84,12 +84,21 @@ class ApiException implements Exception {
   String toString() => message;
 }
 
+/// 表示鉴权会话已经失效；页面层应等待路由跳转，不再展示普通网络错误。
+class SessionExpiredException extends ApiException {
+  const SessionExpiredException() : super(401, '登录状态已失效，请重新登录');
+}
+
+/// 接收被服务端拒绝的请求令牌，用于安全地失效对应会话。
+typedef UnauthorizedCallback = void Function(String rejectedToken);
+
 /// 负责用户端统一 HTTP 请求、鉴权头和响应解析。
 class ApiClient {
   ApiClient(
     this._tokenProvider, {
     http.Client? client,
     String? baseUrl,
+    this.onUnauthorized,
   }) : _client = client ?? http.Client(),
        baseUrl =
            baseUrl ??
@@ -101,6 +110,7 @@ class ApiClient {
   final String baseUrl;
   final String Function() _tokenProvider;
   final http.Client _client;
+  final UnauthorizedCallback? onUnauthorized;
 
   Future<Object?> get(String path, {bool authenticated = true}) =>
       _send('GET', path, authenticated: authenticated);
@@ -112,6 +122,13 @@ class ApiClient {
     final token = _tokenProvider();
     if (token.isNotEmpty) request.headers['authorization'] = token;
     final response = await _sendRequest(request);
+    if (response.statusCode == 401 && token.isNotEmpty) {
+      _rejectSession(token);
+    }
+    final responseCode = _jsonResponseCode(response);
+    if (token.isNotEmpty && responseCode != null && _isAuthenticationFailure(responseCode)) {
+      _rejectSession(token);
+    }
     if (response.statusCode == 404) return null;
     if (response.statusCode < 200 || response.statusCode >= 300) {
       throw ApiException(response.statusCode, '头像加载失败');
@@ -138,16 +155,21 @@ class ApiClient {
   }) async {
     final request = http.Request(method, Uri.parse('$baseUrl$path'));
     request.headers['accept'] = 'application/json';
+    var requestToken = '';
     if (authenticated) {
-      final token = _tokenProvider();
-      if (token.isNotEmpty) request.headers['authorization'] = token;
+      requestToken = _tokenProvider();
+      if (requestToken.isNotEmpty) request.headers['authorization'] = requestToken;
     }
     if (body != null) {
       request.headers['content-type'] = 'application/json; charset=UTF-8';
       request.body = jsonEncode(body);
     }
     final response = await _sendRequest(request);
-    return _decode(response);
+    return _decode(
+      response,
+      authenticated: authenticated,
+      requestToken: requestToken,
+    );
   }
 
   /// 发送请求并统一处理网络连接异常。
@@ -160,7 +182,14 @@ class ApiClient {
   }
 
   /// 解析统一响应结构，并按错误码生成中文提示。
-  Object? _decode(http.Response response) {
+  Object? _decode(
+    http.Response response, {
+    required bool authenticated,
+    required String requestToken,
+  }) {
+    if (authenticated && response.statusCode == 401 && requestToken.isNotEmpty) {
+      _rejectSession(requestToken);
+    }
     if (response.statusCode < 200 || response.statusCode >= 300) {
       throw ApiException(response.statusCode, '网络请求失败（${response.statusCode}）');
     }
@@ -175,6 +204,9 @@ class ApiClient {
     }
     final code = (decoded['code'] as num?)?.toInt() ?? 500;
     if (code != 0) {
+      if (authenticated && requestToken.isNotEmpty && _isAuthenticationFailure(code)) {
+        _rejectSession(requestToken);
+      }
       throw ApiException(
         code,
         localizeApiErrorMessage(code, decoded['message'] as String?),
@@ -182,8 +214,37 @@ class ApiClient {
     }
     return decoded['details'];
   }
+
+  /// 通知会话层并抛出专用异常，避免页面把鉴权失败误报为网络问题。
+  Never _rejectSession(String rejectedToken) {
+    onUnauthorized?.call(rejectedToken);
+    throw const SessionExpiredException();
+  }
+
+  /// 尝试从二进制接口返回的 JSON 错误体中提取业务码。
+  int? _jsonResponseCode(http.Response response) {
+    final contentType = response.headers['content-type'] ?? '';
+    int? firstContentByte;
+    for (final byte in response.bodyBytes) {
+      if (byte == 0x20 || byte == 0x09 || byte == 0x0a || byte == 0x0d) continue;
+      firstContentByte = byte;
+      break;
+    }
+    if (!contentType.contains('json') && firstContentByte != 0x7b) {
+      return null;
+    }
+    try {
+      final decoded = jsonDecode(response.body);
+      return decoded is Map ? (decoded['code'] as num?)?.toInt() : null;
+    } on FormatException {
+      return null;
+    }
+  }
 }
 
+/// 判断服务端稳定错误码是否表示登录会话无效。
+bool _isAuthenticationFailure(int code) => (code >= 1301 && code <= 1314) || code == 1715;
+
 Map<String, Object?> jsonMap(Object? value) {
   if (value is Map<String, Object?>) return value;
   if (value is Map) return value.map((key, item) => MapEntry(key.toString(), item));