Flutter: How to Refresh token when token expires to call？

Question

我是flutter新手，我正在使用http包进行网络呼叫。如果请求200的响应码，我想刷新令牌并再次调用请求。如何使用http包获取此信息？我听说过dio包，但它对我来说很复杂。

User getUser(){

   final response = http.post(Uri.https(BASE_URL, '/api/user'), 
    headers: {'Authorization: Bearer $token'});

    if(response.statusCode == 200){
       return User.fromJson(jsonDecode(response.body)['user']);
    }
    else if(response.statusCode == 401){
      //refresh token and call getUser again     
    }

}

Answer 1

您可以使用刷新标记，如下所示：

User getUser(){

   final response = http.post(Uri.https(BASE_URL, '/api/user'), 
    headers: {'Authorization: Bearer $token'});

    if(response.statusCode == 200){
       return User.fromJson(jsonDecode(response.body)['user']);
    }
    else if(response.statusCode == 401){
      //refresh token and call getUser again
      final response = http.post(Uri.https(BASE_URL, '/api/[YourAuthorizationEndpoint]'), 
    headers: {'grant_type': 'refresh_token', 'refresh_token': '$refresh_token'});
      token = jsonDecode(response.body)['token'];
      refresh_token = jsonDecode(response.body)['refresh_token'];
      return getUser();
    }

}

Answer 2

您可以使用dart的http/retry包：

import 'package:http/http.dart' as http;
import 'package:http_retry/http_retry.dart';

final client = RetryClient(
   http.Client(), 
   retries: 1,
   when: (response) {
    return response.statusCode == 401 ? true : false;
   },
   onRetry: (req, res, retryCount) {
     if (retryCount == 0 && res?.statusCode == 401) {
        // refresh token
     }  
   },
);

try {
  final response = await client.get('http://www.example.com');
} finally {
  client.close();
}