I love this feature to persist the value on the Bloc. However shared preferences dependency makes it Flutter only package (maybe it is fine for now). In case of Bloc pattern, it should not know anything about Flutter, because we could use that Bloc on AngularDart for example. Probably Hummingbird will make AngularDart obsolete but not sure when that can happen.

I think this package can go to Dart-only and provide flutter (shared preference, etc.) overrides, also will give any other future storage mechanisms (Firebase for example).

Suggestion: AbstractHydrate with methods to override: Fetches from a storage by a key (current HydrateSubject could override this with SharedPreferences use)

T fetch() {
}

Stores value (serializes if needed/supported) and current HydrateSubject can override this with current implementation.

store(T val) {
}

This would allow to have the hydrate package Dart only, and 'flutter_hydrate' (or other name) for example use SharedPreferences. In future more "plugin" packages can be created to serialize or store to DB or store to file, even Firebase.

Just idea, see my https://pub.dartlang.org/packages/flutter_fimber and https://pub.dartlang.org/packages/fimber packages that follows that logic.

Now common code is in AbstractHydratedSubject.

When creating a custom HydratedSubject, you just need to override hydrate/_persistValue and implement the constructors. HydratedSetup also helps will some common code needed in the constructors.

I tried to use the package but requires rxdart 0.20. I don't think I have something that can benefit from 0.21 but would be ok to update the package to 0.21. Thanks

Hello, I'm a flutter newbee.

I'm storing a token using this and it's working like a charm. Now I would like to know how to store a list of houses.

I have a list of favorite houses in my bloc. Like this:

...
BehaviorSubject<List<House>> _favoritesController = BehaviorSubject<List<House>>(seedValue: <House>[]);
Stream<List<House>> get favorites => _favoritesController.stream;
...

Is it possible to persist this list?

Thank you.

I do not know if it's an issue, but when I installed it, there was a compatibility error, because there is a new version shared_preferences, which was in my project previously

Resolves #23

While working on the PR, I realized that the generic persistence can be done for basically any persistent data storage, not only the key-value one.

Resolves #23 Alternative to #26

Abstracts away only the key-value store. The persistence key and also the hydrate and persist callbacks are kept in the HydratedSubject class, avoiding breaking changes.

Right now I am using streambuilder to fetch user data to show it in drawer menu. Every time user see drawer screen future are taking time to interact with network call and render the data. Can I use hydrated package to store user data whenever he logins ?

thank you.

To avoid ambiguity it is best to keep the persistence test first. This has already caused a problem in a project of mine where I use it within a class with

Use cases:

1. Custom wrappers over SharedPreferences -- some projects abstract away from persistence, making this package a bad choice for them, since we only support stock SharedPreferences.
2. Secure storage -- while iOS should be good to go, sharedpreferences on Android is not the most secure way to store data. Adding a generic interface should give the user freedom of choice when it comes to choosing the layer which does the actual key/value persistence.

In general the idea is to abstract away from details on how we do persistence, and turn this package into a generic reactive extension for a keyed storage.

[VERBOSE-2:shell.cc(186)] Dart Error: Unhandled exception:
Invalid argument(s): The source must not be null
#0      int.parse (dart:core/runtime/libintegers_patch.dart:51:25)
#1      new AdvertisingService.<anonymous closure> (package:when_coin/services/advertising.dart:41:62)
#2      HydratedSubject._hydrateSubject (package:hydrated/hydrated.dart:140:18)
<asynchronous suspension>
#3      new HydratedSubject._ (package:hydrated/hydrated.dart:58:5)
#4      new HydratedSubject (package:hydrated/hydrated.dart:89:16)
#5      new AdvertisingService (package:when_coin/services/advertising.dart:39:30)
#6      main (package:when_coin/main.dart:5:16)
#7      _startIsolate.<anonymous closure> (dart:isolate/runtime/libisolate_patch.dart:289:19)
#8      _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:171:12)

As pointed out by @solid-vovabeloded: Currently if we use HydratedSubject with a primitive type, custom persist and hydrate callbacks won't be invoked, or used at all:

The idea is to change the check order in the above method to use the custom callbacks, if they were provided, and then fall back to standard handling.