Is it safe to open multiple stores?

[Prn-Ice]

This is a question

Currently I have an app with multiple repositories

• each repository handles its local data source
• previously I had a custom HiveLocalDataSource base class that was implemented by all local data sources
• I'd like to replace this current system with stash

For example my new local data source for my account_repository will look like this.

final accountStore = await newObjectboxLocalCacheStore(
    fromEncodable: (json) => Account.fromJson(json),
  );

  // Creates a cache with a capacity of 10 from the previously created store
  final cache = await accountStore.cache<Account>(
    name: 'cache1',
    maxEntries: 10,
    eventListenerMode: EventListenerMode.synchronous,
  );

Is it safe to do this in all my repositories or is it more efficient to have one store shared through the entire app?

[ivoleitao]

In my honest opinion it’s probably more performant and memory efficient to use just one store However it all depends on your app constraints as it could make sense to separate. I wouldn’t do it though without a strong reason. This is valid mostly for persistent backends something like memory is very light

For example I have one app where I use a vault just to store assets ( images / binaries etc ) and a custom database for the metadata.

It all depends on your scenario but I don’t see any technical constraints to do not do it

[Prn-Ice]

If I did use one store wouldn't i loose the automatic deserialization?

[ivoleitao]

Ha I see it’s different types ? Meaning you need different fromEncodable functions per store ?

If thats the case yes you will need different stores. I have to say that this is a limitation of the library itself as in theory I should be able to allow the configuration of multiple fromEncodable functions per store name ( partitions ). I will consider the implications of doing that, seems a nice feature to add.

Answering directly with the current implementation, you need multiple stores if you are storing different object types. Bear in mind that even on a scenario where I hypothetically support multiple fromEncodable functions per store partition you would always loose the generic option as you will not be able to specify a type (as you can have multiple underneath ) when creating a vault/cache or a store

[Prn-Ice]

I see, so should I keep the issue open till then?

[ivoleitao]

Yes let met look at this as it seems fairly easy to do. However something tells me that at some point in time I had already looked at this but for some reason I didn't implemented it.

Let me look at it on this weekend to see if there's any blocker for this work

[ivoleitao]

Hi from what I was able to investigate this is possible to do. I will add this feature at vault / cache creation. I still need a couple of days to do this due to the number places that I have to change

[Prn-Ice]

That's awesome news, I'll be ready to test anytime.

[ivoleitao]

Hi, development is completed. This will unfortunately bring a small breaking change but honestly it was a miss and having this makes the library much better. Find a complete example bellow and notice that the fromEncodable function is configured per partition and not per store as previously

```dart
import 'dart:io';

import 'package:stash/stash_api.dart';
import 'package:stash_file/stash_file.dart';

class Task {
  final int id;
  final String title;
  final bool completed;

  Task({required this.id, required this.title, this.completed = false});

  /// Creates a [Task] from json map
  factory Task.fromJson(Map<String, dynamic> json) => Task(
      id: json['id'] as int,
      title: json['title'] as String,
      completed: json['completed'] as bool);

  /// Creates a json map from a [Task]
  Map<String, dynamic> toJson() =>
      <String, dynamic>{'id': id, 'title': title, 'completed': completed};

  @override
  String toString() {
    return 'Task $id, "$title" is ${completed ? "completed" : "not completed"}';
  }
}

class Contact {
  final int id;
  final String name;

  Contact({required this.id, required this.name});

  /// Creates a [Contact] from json map
  factory Contact.fromJson(Map<String, dynamic> json) =>
      Contact(id: json['id'] as int, name: json['name'] as String);

  /// Creates a json map from a [Contact]
  Map<String, dynamic> toJson() => <String, dynamic>{'id': id, 'name': name};

  @override
  String toString() {
    return 'Contact $id, "$name"';
  }
}

void main() async {
  // Temporary directory
  final path = Directory.systemTemp.path;

  // Creates a store
  final store = await newFileLocalVaultStore(path: path);

  // Creates a vault that stores Tasks from the previously created store
  final taskVault = await store.vault<Task>(
      name: 'taskVault',
      fromEncodable: (json) => Task.fromJson(json),
      eventListenerMode: EventListenerMode.synchronous)
    ..on<VaultEntryCreatedEvent<Task>>().listen(
        (event) => print('Key "${event.entry.key}" added to the task vault'));

  // Creates a vault that stores Contacts from the previously created store
  final contactVault = await store.vault<Contact>(
      name: 'contactVault',
      fromEncodable: (json) => Contact.fromJson(json),
      eventListenerMode: EventListenerMode.synchronous)
    ..on<VaultEntryCreatedEvent<Contact>>().listen((event) =>
        print('Key "${event.entry.key}" added to the contact vault'));

  // Adds a task with key 'task1' to the vault
  await taskVault.put('task1',
      Task(id: 1, title: 'Run task vault store example', completed: true));

  // Adds a contact with key 'contact1' to the vault
  await contactVault.put(
      'contact1', Contact(id: 1, name: 'Run contact vault store example'));

  // Retrieves the value from the task vault
  print(await taskVault.get('task1'));

  // Retrieves the value from the contact vault
  print(await contactVault.get('contact1'));
}

I will release it today.

Note: I didn't had time to develop automatic unit tests for this feature as the existing ones are per type and this needs to test multi-types. I will add it later

[Prn-Ice]

Thanks, currently on holiday, will test tomorrow

[Prn-Ice]

Seems to work just fine, want me to leave the issue open until you find time to add those tests?

[ivoleitao]

Thanks you can close it. I will try to add it in a future release