Adding onError() method to the interceptor

[kwado-tech]

Thanks for this awesome package. My use case involves re-authorization using refreshToken and this can be done if an error-code is intercepted and a new token request. This feature would be greatly appreciated. Thanks

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[CodingAleCR]

Hey, this sounds like an awesome idea, I will add it to the work I've got pending. Thank you very much 🙌🏼

[kwado-tech]

That's great can wait for the feature

On Wed, Jan 15, 2020, 3:22 PM Alejandro Ulate notifications@github.com wrote:

Hey, this sounds like an awesome idea, I will add it to the work I've got pending. Thank you very much 🙌🏼

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[CodingAleCR]

Hey, I was thinking about this a bit longer and well.. you can currently use this through an interceptor, maybe you can share some of your code so I can help to guide you in the right direction.

[alienriquebm]

Hi my friend. I see it this question and i think i can ask here my own...

I have this code trying to intercept any error on the responses, but doesn't work. Can you help me @CodingAleCR ? Thanks!

import 'dart:convert';

import 'package:flutter/material.dart';

import '../models/http_exception.dart';
import 'package:flutter_secure_storage/flutter_secure_storage.dart';
import 'package:http_interceptor/http_interceptor.dart';

class ApiInterceptor with ChangeNotifier implements InterceptorContract  {
  final storage = new FlutterSecureStorage();
  @override
  Future<RequestData> interceptRequest({RequestData data}) async {
    try {
      data.headers["Content-Type"] = "application/json";
      String token = await storage.read(key: 'token');
      if (token != null) {
        data.headers["Authorization"] = "Bearer $token";
      }
    } catch (e) {
      print(e);
    }
    return data;
  }

  @override
  Future<ResponseData> interceptResponse({ResponseData data}) async {
    print('DATA HEREEEEEEEEEEEEEEEEEEEEEe');
    print(data);
    try {
      final decodedResponse = json.decode(data.body);
      if (data.statusCode >= 400) {
        throw HttpException(decodedResponse['error']);
      }
    } catch (error) {
      if (error.toString().contains('Connection refused')) {
        throw HttpException(
            'Error de conexión al servidor, por favor reintente más tarde.');
      }
    }

    return data;
  }
}

[CodingAleCR]

Hi, I will try to get a look in detail, are you sure the API you are doing requests to is returning with a status code of 400 or more, and then if it does, are you getting any information on it or is the project crashing? Also, You might want to add limitations so that the status code is between 400 and 499 since 500+ is used for Server errors.

[CodingAleCR]

Hi, I was able to take a quick look to this today, so here's what is happening.

Request/Response Flow:

1. You send a request to a server.
2. Server responds with a status code >= 400.
3. Your interceptor takes it, and it throws the exception you created.
4. The plugin transmits the exception to the next in line listening. This means that you should have a try-catch block when you are using the HttpClientWithInterceptor or the HttpWithInterceptor.

For example, here's how it would look in the library's example:

class WeatherApiInterceptor implements InterceptorContract {
  @override
  Future<RequestData> interceptRequest({RequestData data}) async {
    try {
      data.params['appid'] = OPEN_WEATHER_API_KEY;
      data.params['units'] = 'metric';
      data.headers["Content-Type"] = "application/json";
    } catch (e) {
      print(e);
    }
    return data;
  }

  @override
  Future<ResponseData> interceptResponse({ResponseData data}) async {
    try {
      final decodedResponse = json.decode(data.body);
      if (data.statusCode >= 400) {
        throw Exception("Error while fetching: ${decodedResponse['error']}");
      }
    } catch (error) {
      if (error.toString().contains('Connection refused')) {
        throw Exception("Error while fetching: ${error.toString()}");
      }
    }

    return data;
  }
}

class WeatherRepository {
  HttpClientWithInterceptor client;

  WeatherRepository(this.client);

  Future<Map<String, dynamic>> fetchCityWeather(int id) async {
    var parsedWeather;
    try {
      final response =
          await client.get("$baseUrl/weather", params: {'id': "$id"});
      if (response.statusCode == 200) {
        parsedWeather = json.decode(response.body);
      } else {
        print("Error: ${response.body}");
        return Future.error(
          "Error while fetching.",
          StackTrace.fromString("${response.body}"),
        );
      }
    } catch (e) {
      print(e);
    }
    return parsedWeather;
  }
}