Flutter Cache JSON response using http response header

Question

I'm trying to create and use a cache for a server JSON response.

something like volley response caching does. https://stackoverflow.com/a/32022946/1993001 in Android

I am using DIO for network operations.

Answer 1

You can you create your own cache with Interceptors on top of Dio requests.

You can create in on your own:

import 'package:dio/dio.dart';

class CacheInterceptor extends Interceptor {
  CacheInterceptor();

  var _cache = new Map<Uri, Response>();

  @override
  onRequest(RequestOptions options) async {
    return options;
  }

  @override
  onResponse(Response response) async {
    _cache[response.request.uri] = response;
  }

  @override
  onError(DioError e) async{
    print('onError: $e');
    if (e.type == DioErrorType.CONNECT_TIMEOUT || e.type == DioErrorType.DEFAULT) {
      var cachedResponse = _cache[e.request.uri];
      if (cachedResponse != null) {
        return cachedResponse;
      }
    }
    return e;
  }
}

and then use it with:

final dio = Dio()..interceptors.add(CacheInterceptor());   

or just check the library: https://pub.dev/packages/dio_cache