Fixed: update in example/lib/queued_interceptor_csrftoken.dart

dio/README.md

@@ -444,28 +444,41 @@ Because of security reasons, we need all the requests to set up a csrfToken in t
   //  dio instance to request token
   var tokenDio = Dio();
   String? csrfToken;
-  dio.options.baseUrl = 'http://www.dtworkroom.com/doris/1/2.0.0/';
+  dio.options.baseUrl = 'https://seunghwanlytest.mocklab.io/';
   tokenDio.options = dio.options;
   dio.interceptors.add(QueuedInterceptorsWrapper(
-    onRequest: (options, handler) {
+    onRequest: (options, handler) async {
       print('send request：path:${options.path}，baseURL:${options.baseUrl}');
+
       if (csrfToken == null) {
         print('no token，request token firstly...');
-        tokenDio.get('/token').then((d) {
-          options.headers['csrfToken'] = csrfToken = d.data['data']['token'];
-          print('request token succeed, value: ' + d.data['data']['token']);
-          print(
-              'continue to perform request：path:${options.path}，baseURL:${options.path}');
-          handler.next(options);
-        }).catchError((error, stackTrace) {
-          handler.reject(error, true);
-        });
-      } else {
-        options.headers['csrfToken'] = csrfToken;
-        return handler.next(options);
+
+        final result = await tokenDio.get('/token');
+
+        if (result.hasSucceed) {
+          /// assume `token` is in response body
+          final body = jsonDecode(result.data) as Map<String, dynamic>?;
+
+          if (body != null && body.containsKey('data')) {
+            options.headers['csrfToken'] = csrfToken = body['data']['token'];
+            print('request token succeed, value: $csrfToken');
+            print(
+              'continue to perform request：path:${options.path}，baseURL:${options.path}',
+            );
+            return handler.next(options);
+          }
+        }
+
+        return handler.reject(
+          DioError(requestOptions: result.requestOptions),
+          true,
+        );
       }
+
+      options.headers['csrfToken'] = csrfToken;
+      return handler.next(options);
     },
-   ); 
+  );
 ```
 
 You can clean the waiting queue by calling `clear()`;

dio/lib/src/response.dart

@@ -32,6 +32,16 @@ class Response<T> {
   /// Http status code.
   int? statusCode;
 
+  /// Returns if the response has an error
+  ///
+  /// `hasError` is true when status code is not between 200 and 299
+  bool get hasError => statusCode != null && statusCode! ~/ 100 != 2;
+
+  /// Returns if the response has succeed
+  ///
+  /// `hasSucceed` is true when status code is between 200 and 299
+  bool get hasSucceed => !hasError;
+
   /// Returns the reason phrase associated with the status code.
   /// The reason phrase must be set before the body is written
   /// to. Setting the reason phrase after writing to the body.

example/lib/queued_interceptor_crsftoken.dart

@@ -1,4 +1,5 @@
 import 'dart:async';
+import 'dart:convert';
 
 import 'package:dio/dio.dart';
 
@@ -7,57 +8,70 @@ void main() async {
   //  dio instance to request token
   var tokenDio = Dio();
   String? csrfToken;
-  dio.options.baseUrl = 'http://www.dtworkroom.com/doris/1/2.0.0/';
+  dio.options.baseUrl = 'https://seunghwanlytest.mocklab.io/';
   tokenDio.options = dio.options;
   dio.interceptors.add(QueuedInterceptorsWrapper(
-    onRequest: (options, handler) {
+    onRequest: (options, handler) async {
       print('send request：path:${options.path}，baseURL:${options.baseUrl}');
+
       if (csrfToken == null) {
         print('no token，request token firstly...');
-        tokenDio.get('/token').then((d) {
-          options.headers['csrfToken'] = csrfToken = d.data['data']['token'];
-          print('request token succeed, value: ' + d.data['data']['token']);
-          print(
-              'continue to perform request：path:${options.path}，baseURL:${options.path}');
-          handler.next(options);
-        }).catchError((error, stackTrace) {
-          handler.reject(error, true);
-        });
-      } else {
-        options.headers['csrfToken'] = csrfToken;
-        return handler.next(options);
+
+        final result = await tokenDio.get('/token');
+
+        if (result.hasSucceed) {
+          /// assume `token` is in response body
+          final body = jsonDecode(result.data) as Map<String, dynamic>?;
+
+          if (body != null && body.containsKey('data')) {
+            options.headers['csrfToken'] = csrfToken = body['data']['token'];
+            print('request token succeed, value: $csrfToken');
+            print(
+              'continue to perform request：path:${options.path}，baseURL:${options.path}',
+            );
+            return handler.next(options);
+          }
+        }
+
+        return handler.reject(
+          DioError(requestOptions: result.requestOptions),
+          true,
+        );
       }
+
+      options.headers['csrfToken'] = csrfToken;
+      return handler.next(options);
     },
-    onError: (error, handler) {
-      //print(error);
-      // Assume 401 stands for token expired
+    onError: (error, handler) async {
+      /// Assume 401 stands for token expired
       if (error.response?.statusCode == 401) {
-        var options = error.response!.requestOptions;
-        // If the token has been updated, repeat directly.
-        if (csrfToken != options.headers['csrfToken']) {
-          options.headers['csrfToken'] = csrfToken;
-          //repeat
-          dio.fetch(options).then(
-            (r) => handler.resolve(r),
-            onError: (e) {
-              handler.reject(e);
-            },
-          );
-          return;
+        print('the token has expired, need to receive new token');
+        final options = error.response!.requestOptions;
+
+        /// assume receiving the token has no errors
+        /// to check `null-safety` and error handling
+        /// please check inside the [onRequest] closure
+        final tokenResult = await tokenDio.get('/token');
+
+        /// update [csrfToken]
+        /// assume `token` is in response body
+        final body = jsonDecode(tokenResult.data) as Map<String, dynamic>?;
+        options.headers['csrfToken'] = csrfToken = body!['data']['token'];
+
+        if (options.headers['csrfToken'] != null) {
+          print('the token has been updated');
+
+          /// since the api has no state, force to pass the 401 error
+          /// by adding query parameter
+          final originResult = await dio.fetch(options..path += '&pass=true');
+          if (originResult.hasSucceed) {
+            return handler.resolve(originResult);
+          }
         }
-        tokenDio.get('/token').then((d) {
-          //update csrfToken
-          options.headers['csrfToken'] = csrfToken = d.data['data']['token'];
-        }).then((e) {
-          //repeat
-          dio.fetch(options).then(
-            (r) => handler.resolve(r),
-            onError: (e) {
-              handler.reject(e);
-            },
-          );
-        });
-        return;
+        print('the token has not been updated');
+        return handler.reject(
+          DioError(requestOptions: options),
+        );
       }
       return handler.next(error);
     },
@@ -67,9 +81,9 @@ void main() async {
     print('request ok!');
   }
 
-  await Future.wait([
-    dio.get('/test?tag=1').then(_onResult),
-    dio.get('/test?tag=2').then(_onResult),
-    dio.get('/test?tag=3').then(_onResult)
-  ]);
+  /// assume `/test?tag=2` path occurs the authorization error (401)
+  /// and token to be updated
+  await dio.get('/test?tag=1').then(_onResult);
+  await dio.get('/test?tag=2').then(_onResult);
+  await dio.get('/test?tag=3').then(_onResult);
 }