Api Cache

[devmsh]

https://parseplatform.org/Parse-SDK-Android/api/com/parse/ParseQuery.CachePolicy.html

[salahamassi]

Api Cache Proposal:

Suggested Cache Policies:

• cache else network: The query first tries to load from the cache, but if that fails, it loads results from the network.
• cache then network: The query first loads from the cache, then loads from the network.
• network else cache: The query first tries to load from the network, but if that fails, it loads results from the cache.
• network only: The query does not load from the cache, but it will save results to the cache.

I skipped these two policies:

• cache only -> we can simply fetch from Cache directly Cache.get('api/v2/user_profile');
• ignore cache -> we can simply use the DIO normal get method dioClient.get('api/v2/user_profile');

and I and I added one optional policy for the (get post, put and delete) requests:

• cache request on network connection failed: the API client will cache the request and try to perform it again after connecting to the network again

  Api client with cache abilities client:

This is just a pseudo code

enum CachePolicy {
  cacheElseNetwork,
  cacheThenNetwork,
  networkElseCache,
  networkOnly
}

class CachableApiClient {

 final HttpClient _client;
 final CacheDriver _cache;

 CachableApiClient(this._client, this._cache);

  Stream<T> get<T>(
        String path, {
        Map<String, dynamic>? queryParameters,
        Options? options,
        CachePolicy? policy = null,
       bool smartRequestPolicyOnConnectivityFailed = false,
      });

  Stream<T> post<T>(
          String path, {
          Map<String, dynamic>? queryParameters,
          Options? options,
          bool smartRequestPolicyOnConnectivityFailed = false,
        });

  Stream<T> put<T>(
          String path, {
          Map<String, dynamic>? queryParameters,
          Options? options,
         bool smartRequestPolicyOnConnectivityFailed = false,
        }) ;

  Future<T> delete<T>(
          String path, {
          Map<String, dynamic>? queryParameters,
          Options? options,
         bool smartRequestPolicyOnConnectivityFailed = false,
        });
}

most of the methods return stream due to the fact it emits more than one result from multi-data sources (cache and remote) and on else cache policy we can emit an error with the stream to tell the client about the failure of fetch operation from the first data source, then emit the results from the fallback data source.

smartRequestPolicyOnConnectivityFailed, will try to perform the request again directly when the device back to online mode.

How to use:

WIP