TheStorage

A fast and secure storage library for Flutter.

Features

• Fast and efficient storage operations
• Secure data encryption
• Easy-to-use API

Getting started

To use this package, add the_storage as a dependency in your pubspec.yaml file.

Usage

Import the package:

import 'package:the_storage/the_storage.dart';

Get an instance of the storage and initialize it:

TheStorage.i().init();

TheStorage is a singleton, so you can get the same instance anywhere in your app:

final instance = TheStorage.i();

You can specify file name for storage:

TheStorage.i().init(dbName: 'my_storage.db');

This should be done as early as possible in your app, and only once. Before calling init() second time, you should call dispose() method.

To write key-value pair to storage, use the set() method:

TheStorage.i().set('myKey', 'myValue');

To read value from storage, use the get() method:

final value = await TheStorage.i().get('myKey');

You can use domains to separate your data. To write key-value pair to storage with domain, use the domain argument:

await TheStorage.i().set('myKey', 'myValue', domain: 'myDomain');
final data = await TheStorage.i().get('myKey', domain: 'myDomain');

Additionally you can delete key-value pair from storage:

await TheStorage.i().delete(
  'myKey',
  domain: 'myDomain',
);

Also you can use batch operations to write multiple key-value pairs in domain, specify domain and whether to overwrite existing values:

await TheStorage.i().setDomain(
  {
    'myKey': 'myValue',
    'myKey2': 'myValue2',
  },
  domain: 'myDomain',
  overwrite: false,
);

Read all key-value pairs or only keys from domain:

final domain = await TheStorage.i().getDomain(
  domain: 'myDomain',
);

final domainKeys = await TheStorage.i().getDomainKeys(
  domain: 'myDomain',
);

And delete data from domain:

await TheStorage.i().deleteDomain(
  [
    'myKey',
    'myKey2',
  ],
  domain: 'myDomain',
);

You can clear all data from storage:

await TheStorage.i().clear();

For debugging purposes you can reset storage, it will delete storage file and dispose storage instance. So, you should call init() method again after reset:

await TheStorage.i().reset();

Reactiveness

TheStorage provides a reactive way to listen to changes in storage. You can use stream versions of get, getDomain and getDomainKeys methods to listen to changes in storage:

final valueStream = await TheStorage.i().subscribe('myKey', domain: 'myDomain');
final domainStream = await TheStorage.i().subscribeDomain('myDomain');
final domainKeysStream = await TheStorage.i().subscribeDomainKeys('myDomain');

These methods have the same arguments as their non-stream versions plus boolean keepAlive which specifies whether to keep the stream alive the last subscriber unsubscribes, so the data will stay in memory instead of being reacquired from the storage when a new subscriber subscribes. In other hand this can cause more memory usage. By default, keepAlive is true.

Encryption

TheStorage stores key and initial vector using flutter_secure_storage package. Every record key is encrypted using AES with 256-bit key and 128-bit initial vector. To encrypt the record data, the same 256-bit key and a unique (for each record) 128-bit seed vector are used, which is stored with the encrypted data. So, every record has its own initial vector. This approach makes impossible replay attacks by comparing encrypted data with already known source data.

Storage

TheStorage uses sqflite package to store data. This is a fast and reliable solution for storing data on the device. TheStorage uses a single table to store all data and indexes to speed up data search.

Testing

This package includes several unit tests for its features. To run the tests, use the following command:

flutter test