I am trying to create a custom ApiClient class that I can inject as a dependency (with get_it package) to be used in the data layer of my application. In order not to worry about access tokens throughout the presentation/application/domain layers of my app, I'd like to have a field, accessToken, that keeps track of the accessToken inside the ApiClient (singleton) class.
The ApiClient class would be used all throughout my data layer to handle requests to my server for data. It should have a method that allows me to add my own requests to it for unique routes. Then, if those routes require access tokens, it will add the accessToken field from the class along with the request. If that access token is invalid (expired/tampered with), then I would use the refresh token from the device's storage and send a request to the server to get a new access token, then try the original request again. It would "retry" the request at maximum once. Then, if there's still an error, it just returns that to be handled.
I am really struggling with how to implement this. My current attempt is below. Any help would be amazing!
class ApiClient {
final String baseUrl;
final Dio dio;
final NetworkInfo networkInfo;
final FlutterSecureStorage secureStorage;
ApiClient(
{required this.baseUrl,
required this.dio,
required this.networkInfo,
required this.secureStorage}) {
dio.interceptors.add(RefreshInvalidTokenInterceptor(networkInfo, dio, secureStorage));
}
}
class RefreshInvalidTokenInterceptor extends QueuedInterceptor {
final NetworkInfo networkInfo;
final Dio dio;
final FlutterSecureStorage secureStorage;
String? accessToken;
RefreshInvalidTokenInterceptor(this.networkInfo, this.dio, this.secureStorage);
#override
Future onError(DioError err, ErrorInterceptorHandler handler) async {
if (_shouldRetry(err) && await networkInfo.isConnected) {
try {
// access token request (using refresh token from flutter_secure_storage)
final refreshToken = await secureStorage.read(key: "refreshToken");
final response = await dio.post(
"$kDomain/api/user/token",
queryParameters: {"token": refreshToken},
);
accessToken = response.data["accessToken"];
return err;
} on DioError catch (e) {
handler.next(e);
} catch (e) {
handler.next(err);
}
} else {
handler.next(err);
}
}
bool _shouldRetry(DioError err) =>
(err.response!.statusCode == 403 || err.response!.statusCode == 401);
}
There are similar questions online, but none seem to answer my question! :)
EDIT: I've gotten a working solution (almost), with just 1 error. This works (except in the function retryRequest() I'm hardcoding the request to be a post request):
<imports removed for simplicity>
class ApiClient {
final Dio dio;
final NetworkInfo networkInfo;
final FlutterSecureStorage secureStorage;
String? accessToken;
ApiClient({
required this.dio,
required this.networkInfo,
required this.secureStorage,
}) {
dio.options = BaseOptions(
connectTimeout: 5000,
receiveTimeout: 3000,
receiveDataWhenStatusError: true,
followRedirects: true,
headers: {"content-Type": "application/json"},
);
dio.interceptors.add(QueuedInterceptorsWrapper(
//! ON REQUEST
onRequest: (options, handler) {
handler.next(options);
},
//! ON RESPONSE
onResponse: (response, handler) {
print("onResponse...");
handler.next(response);
},
//! ON ERROR
onError: (error, handler) async {
print("onError...");
if (tokenInvalid(error)) {
print("token invalid: retrying");
print("header before: ${dio.options.headers}");
await getAccessTokenAndSetToHeader(dio);
print("header after: ${dio.options.headers}");
final response = await retryRequest(error, handler);
handler.resolve(response);
print("here-1");
} else {
handler.reject(error);
}
print("here-2");
print("here-3");
},
));
}
Future<String?> getRefreshToken() async => await secureStorage.read(key: "refreshToken");
Future<void> getAccessTokenAndSetToHeader(Dio dio) async {
final refreshToken = await secureStorage.read(key: "refreshToken");
if (refreshToken == null || refreshToken.isEmpty) {
print("NO REFRESH TOKEN ERROR; LOGOUT!!!");
throw ServerException();
} else {
final response = await dio.post(
"$kDomain/api/user/token",
data: {"token": refreshToken},
);
dio.options.headers["authorization"] = "Bearer ${response.data["accessToken"]}";
}
}
// This function has the hardcoded post
Future<Response> retryRequest(DioError error, ErrorInterceptorHandler handler) async {
print("retry called, headers: ${dio.options.headers}");
final retryResponse = await dio.post(error.requestOptions.path);
print("retry results: $retryResponse");
return retryResponse;
}
bool tokenInvalid(DioError error) =>
error.response?.statusCode == 403 || error.response?.statusCode == 401;
Future<void> refreshToken() async {}
bool validStatusCode(Response response) =>
response.statusCode == 200 || response.statusCode == 201;
}
However, if I change the hardcoded post request to:
final retryResponse =
await dio.request(error.requestOptions.path, data: error.requestOptions.data);
the code no longer works... anyone know why? Having it dynamic based on whatever the failed request was, lets me re-use this class.
package:dio already include the BaseOptions which you can use to add some basic configuration like the baseUrl.
After that, you could use interceptors to add the accessToken to every request. To do this depending on your state management solution you can update the accessToken when the user authentication state changes.
And finally regarding the token refresh you can checkout package:fresh_dio.
Figured it out! (code + how to use below)
Here is my entire ApiClient class (imports hidden for simplicity). It acts as an HTTP client using dio:
class ApiClient {
final Dio dio;
final NetworkInfo networkInfo;
final FlutterSecureStorage secureStorage;
String? accessToken;
/// The base options for all requests with this Dio client.
final BaseOptions baseOptions = BaseOptions(
connectTimeout: 5000,
receiveTimeout: 3000,
receiveDataWhenStatusError: true,
followRedirects: true,
headers: {"content-Type": "application/json"},
baseUrl: kDomain, // Domain constant (base path).
);
/// Is the current access token valid? Checks if it's null, empty, or expired.
bool get validToken {
if (accessToken == null || accessToken!.isEmpty || Jwt.isExpired(accessToken!)) return false;
return true;
}
ApiClient({
required this.dio,
required this.networkInfo,
required this.secureStorage,
}) {
dio.options = baseOptions;
dio.interceptors.add(QueuedInterceptorsWrapper(
// Runs before a request happens. If there's no valid access token, it'll
// get a new one before running the request.
onRequest: (options, handler) async {
if (!validToken) {
await getAndSetAccessTokenVariable(dio);
}
setHeader(options);
handler.next(options);
},
// Runs on an error. If this error is a token error (401 or 403), then the access token
// is refreshed and the request is re-run.
onError: (error, handler) async {
if (tokenInvalidResponse(error)) {
await refreshAndRedoRequest(error, handler);
} else {
// Other error occurs (non-token issue).
handler.reject(error);
}
},
));
}
/// Sets the current [accessToken] to request header.
void setHeader(RequestOptions options) =>
options.headers["authorization"] = "Bearer $accessToken";
/// Refreshes access token, sets it to header, and resolves cloned request of the original.
Future<void> refreshAndRedoRequest(DioError error, ErrorInterceptorHandler handler) async {
await getAndSetAccessTokenVariable(dio);
setHeader(error.requestOptions);
handler.resolve(await dio.post(error.requestOptions.path,
data: error.requestOptions.data, options: Options(method: error.requestOptions.method)));
}
/// Gets new access token using the device's refresh token and sets it to [accessToken] class field.
///
/// If the refresh token from the device's storage is null or empty, an [EmptyTokenException] is thrown.
/// This should be handled with care. This means the user has somehow been logged out!
Future<void> getAndSetAccessTokenVariable(Dio dio) async {
final refreshToken = await secureStorage.read(key: "refreshToken");
if (refreshToken == null || refreshToken.isEmpty) {
// User is no longer logged in!
throw EmptyTokenException();
} else {
// New DIO instance so it doesn't get blocked by QueuedInterceptorsWrapper.
// Refreshes token from endpoint.
try {
final response = await Dio(baseOptions).post(
"/api/user/token",
data: {"token": refreshToken},
);
// If refresh fails, throw a custom exception.
if (!validStatusCode(response)) {
throw ServerException();
}
accessToken = response.data["accessToken"];
} on DioError catch (e) {
// Based on the different dio errors, throw custom exception classes.
switch (e.type) {
case DioErrorType.sendTimeout:
throw ConnectionException();
case DioErrorType.connectTimeout:
throw ConnectionException();
case DioErrorType.receiveTimeout:
throw ConnectionException();
case DioErrorType.response:
throw ServerException();
default:
throw ServerException();
}
}
}
}
bool tokenInvalidResponse(DioError error) =>
error.response?.statusCode == 403 || error.response?.statusCode == 401;
bool validStatusCode(Response response) =>
response.statusCode == 200 || response.statusCode == 201;
}
It should be injected as a singleton to your project so there's one instance of it (for the sake of keeping the state of its accessToken field). I used get_it like so:
// Registers the custom ApiClient class.
sl.registerLazySingleton(() => ApiClient(dio: sl(), networkInfo: sl(), secureStorage: sl()));
Then, inside your data layer (or wherever you call APIs from), you can use it by passing it through the constructor:
class MyDatasource implements IMyDatasource {
final ApiClient apiClient;
late Dio api;
FeedDatasource({required this.client, required this.apiClient}) {
api = apiClient.dio;
}
// Logic for your class here.
}
I simplified it to api so I wouldn't have to go apiClient.dio... every call (optional).
Then, you can use it in one of your class' methods like so:
#override
Future<List<SomeData>> fetchSomeDataFromApi() async {
try {
final response = await api.post("/api/data/whatYouWant");
throw ServerException();
} catch (e) {
throw ServerException();
}
}
Now, for this request, if your class has a valid access token (non-null, non-empty, non-expired), it will call normally. However, if your token isn't valid, it'll refresh it first, then proceed with your call. Even if the call fails after the token originally passed the validation check (token somehow expires during the call for example), it will still be refreshed, and the call re-executed.
Note: I use a lot of custom exceptions, this is optional.
Hopefully this helps someone else!
I want to know dio post request how perform interceptor 'onrequest' in response 'onerror'
Above code in 'onerror' request refresh token not working interceptor also any other way
Future getlist() async{
final dio = Dio();
Final storage=Fluttersecurestorage();
String accesstoken =await storage.read('accesstoken');
final response= await dio.post(
url,
data: loginData,
options: Options(headers: {"authorization": 'Bearer $accesstoken'}),
dio.interceptors.clear();
dio.interceptors.add(
InterceptorsWrapper(
onRequest: (request, handler) {
},
onError: (err, handler) async {
if (err.response?.statusCode == 401) {
//request refresh token}
}
}
));
I have declared a class to make api requests using flutter Dio as follows.
class DioUtil {
static Dio _instance;
static Dio getInstance() {
if (_instance == null) {
_instance = createDio();
}
return _instance;
}
static Dio createDio() {
var dio = Dio();
dio.interceptors.add(InterceptorsWrapper(onRequest: (options, handler) {
// Do something before request is sent
return handler.next(options); //continue
}, onResponse: (response, handler) {
// Do something with response data
return handler.next(response); // continue
}, onError: (DioError e, handler) async {
if (e.response != null) {
if (e.response.statusCode == 401) {
var dio = DioUtil.getInstance();
dio.interceptors.requestLock.lock();
dio.interceptors.responseLock.lock();
RequestOptions requestOptions = e.requestOptions;
await refreshToken();
Repository repository = Repository();
var accessToken = await repository.readData("accessToken");
final opts = new Options(
method: requestOptions.method
);
dio.options.headers["Authorization"] = "Bearer " + accessToken;
dio.interceptors.requestLock.unlock();
dio.interceptors.responseLock.unlock();
dio.request(requestOptions.path,
options: opts,
data: requestOptions.data,
queryParameters: requestOptions.queryParameters);
}//TODO: handle else clause
}
}));
return dio;
}
static refreshToken() async {
Response response;
Repository repository = Repository();
var dio = Dio();
final Uri apiUrl = Uri.parse(BASE_PATH + "auth/reIssueAccessToken");
var refreshToken = await repository.readData("refreshToken");
dio.options.headers["Authorization"] = "Bearer " + refreshToken;
response = await dio.postUri(apiUrl);
if (response.statusCode == 200) {
LoginResponse loginResponse =
LoginResponse.fromJson(jsonDecode(response.toString()));
repository.addValue('accessToken', loginResponse.data.accessToken);
repository.addValue('refreshToken', loginResponse.data.refreshToken);
} else {
print(response.toString());
}
}
}
and I use flutter bloc pattern and my bloc is as follows.
class OurClassBloc extends Bloc<OurClassEvent, OurClassState> {
OurClassBloc(OurClassState initialState) : super(initialState);
Repository repository = Repository();
#override
Stream<OurClassState> mapEventToState(
OurClassEvent event,
) async* {
if (event is GetClasses) {
yield* _getClassCategories(event);
}
}
Stream<OurClassState> _getClassCategories(GetClasses event) async* {
Response response;
var dio = DioUtil.getInstance();
final String apiUrl = (BASE_PATH + "classCategories");
var accessToken = await repository.readData("accessToken");
Map<String, dynamic> map = {"active": event.active};
dio.options.headers["Authorization"] = "Bearer " + accessToken;
dio.options.headers["Accept"] = "*/*";
try {
response = await dio.get(apiUrl, queryParameters: map);
if (response.statusCode == 200) {
OurClassResponse loginResponse =
OurClassResponse.fromJson(jsonDecode(response.toString()));
yield OurClassSuccess(loginResponse);
}
if (response.statusCode >= 400) {
yield OurClassFailed();
}
} catch (e) {
yield OurClassFailed();
}
}
}
When I make the requests with valid access token, I get 200 status code in bloc class and api works fine.when the token is expired, the dio class correctly gets the new token, make the same api call with new token successfully and inside the below callback I get the correct response also.
onResponse: (response, handler) {
return handler.next(response);
}
but response doesn't comes to bloc class. Though it returned the response by calling return handler.next(response);,it is not coming to response variable inside _getClassCategories method.I expect the correct response should come to the response variable in bloc class for both scenarios:
makes the api call with valid token.
makes the api call with expired token.
but only scenario 1 is working in my code and hope someone here can help me to fix this.
EDIT- this works fine with dio previous version(3.0.10) - code
dio.request(requestOptions.path,
options: opts,
data: requestOptions.data,
queryParameters: requestOptions.queryParameters);
This line creates a new request with no relation to the original one. If the request succeeds, there is no code listening for a response. If you want the original caller to receive anything, you will need to forward the response to the original handler:
try {
final response = await dio.request(requestOptions.path,
options: opts,
data: requestOptions.data,
queryParameters: requestOptions.queryParameters);
handler.resolve(response);
} on DioError catch (error) {
handler.next(error); // or handler.reject(error);
}
Also, be sure to forward the error to the handler in non-401 cases as well. Dio 4.0.0 interceptors don't automatically forward anything.
So I was having issues with flutter http package when it came to making a post request so I used dart HttpClient. I made a post request according to what was described somewhere but I am having issues getting response. Here is my code
Future<HttpClientResponse> submit() async {
print('start');
Map<String, dynamic> data = { 'title' : 'My first post' };
String jsonString = json.encode(data); // encode map to json
String paramName = 'param'; // give the post param a name
String formBody = paramName + '=' + Uri.encodeQueryComponent(jsonString);
List<int> bodyBytes = utf8.encode(formBody); // utf8 encode
HttpClientRequest request =
await HttpClient().postUrl(Uri.parse('https://jsonplaceholder.typicode.com/posts'));
// it's polite to send the body length to the server
request.headers.set('Content-Length', bodyBytes.length.toString());
request.headers.set('Content-Type', 'application/json');
request.add(bodyBytes);
print('done');
return await (request.close());
}
How do I get the response from this request?
HttpClientResponse response = await request.close();
response.transform(utf8.decoder).listen((contents) {
print(data); // <- response content is here
});
This will return HttpCLientResponse, more info https://api.dartlang.org/stable/2.6.1/dart-io/HttpClient-class.html
I have found this from the docs
new HttpClient().get('localhost', 80, '/file.txt')
.then((HttpClientRequest request) => request.close())
.then((HttpClientResponse response) {
response.transform(utf8.decoder).listen((contents) {
// handle data
});
});
Or Use http library
I have create a common method which can handle all get Request,
Future<String> getRequest([var endpoints, var queryParameters]) async {
var uri = Uri.https(NetworkUrl.BASE_URL_1, endpoints, queryParameters);
uri.replace(queryParameters: queryParameters);
var response =
await http.get(Uri.encodeFull(uri.toString()));
//Retrun reponse here
if (response.statusCode == 200) return response.body;
}
To get a response from the above method,
Future<String> deletePostApi() async {
await NetworkRepository()
.getRequest(NetworkUrl.deletePost + '${widget.mFeedData.post_id}')
.then((value) {// <=value is json respone
var dataConvertedToJSON = json.decode(value);
print("checkEmailResp" + dataConvertedToJSON.toString());
});
}
I have problem with canceling requests using Dio api client.
final cancelToken = CancelToken();
final request = host.request(path,
data: data,
queryParameters: query,
options: Options(method: describeEnum(method)),
cancelToken: cancelToken);
final cancelableRequest = CancelableOperation.fromFuture(request, onCancel: () {
cancelToken.cancel();
});
When cancelToken.cancel(); is called I receive DioErrorType.CANCEL but request is not canceled (checked in Charles web proxy). I have tried throttling request but it always waits for response.
Try to write this way to cancel Dio api calling
CancelToken cancelToken = CancelToken();
Request request = host.request(path,
data: data,
queryParameters: query,
options: Options(method: describeEnum(method)),
cancelToken: cancelToken);
// cancel the requests with "cancelled" message.
final cancelableRequest = CancelableOperation.fromFuture(request, onCancel: token.cancel("cancelled"));