Handling cache with client only

Handling cache with client only

The package won't handle any specific rule, so you will most likely have to make your own. Here's a few samples to achieve correct behaviour with client only.

The samples below assume to add an interceptor before DioCacheInterceptor to control your own rules.

Return cache if the response is aged less than 5 minutes.

dioInstance..interceptors.add(InterceptorsWrapper(
  onRequest: (RequestOptions options, handler) {
    final key = cacheOptions.defaultCacheKeyBuilder(request);

    final cache = await store.get(key);
    if (cache != null && DateTime.now().difference(cache.responseDate).inMinutes < 5) {
      return handler.resolve(cache.toResponse(options, fromNetwork: false));
    }

    return handler.next(options);
  },
));

Store specific URLs only.

dioInstance..interceptors.add(InterceptorsWrapper(
  onRequest: (RequestOptions options, handler) {
    if (options.uri.toString().contains('<uri_to_cache_here>')) {
      final cacheOptions = CacheOptions.fromExtra(options)!;
      options.extra = cacheOptions.copyWith(policy: CachePolicy.forceCache).toExtra();
      return handler.next(options);
    }

    return handler.next(options);
  },
));

maxStale: postponing or not

// Global options
final options = const CacheOptions(
  store: MemCacheStore(),
  policy: CachePolicy.forceCache,
  maxStale: const Duration(days: 1),
);

// ...

// Each time, this request will postpone maxStale from current date time + maxStale
// from global options
final response = await dio.get('https://www.foo.com');

// ...

// This request will not modify maxStale
// Response will stale after 1 day and origin server will be called
final response = await dio.get('https://www.foo.com',
  options: options.copyWith(maxStale: Nullable(null)).toOptions(),
);