Modular object storage framework offering key/value storage with automatic key derivation. Features include various serialization methods, secure and file-based storage, and value transformation capabilities.
A modular object storage framework for Kotlin multiplatform projects.
ObjectStore provides a simple key/value storage interface which by default uses Type details to derive the Key
automatically. To create an ObjectStore you need two things:
ObjectStoreWriter: Providers the persistence mechanism to store data for later access.ObjectStoreSerializer: Provides the serialization mechanism to transform objects for storage.val store = ObjectStore(
storeWriter = SharedPreferencesStoreWriter("prefs", context),
storeSerializer = JsonStoreSerializer()
)
// Store an object
store.put(User("username", , ...))
user: User? = store.getOrNull<User>()
user: User = store.<User>()
user: User = store.(default = User(...))
userFlow: StateFlow<User?> = store.getFlow<User>()
userFlow.collect { println(it) }
store.keys()
store.remove<User>()
store.clear()
When storing basic types such as String, Boolean, etc. you must provide a key for the record.
store.put(false, key = "my_key")
store.get<Boolean>(default = false, key = "my_key")
NOTE: When targeting Javascript, all classes used with ObjectStore must be annotated with @Serializable.
This is used to derive class and parameter name based keys, other platforms do not use the Kotlinx.serialization library in objectstore-core.
Turning objects into data suitable for storage requires a ObjectStoreSerializer implementation.
The following modules provide serialization capabilities using the matching
Kotlinx.serialization module.
objectstore-cbor: CborStoreSerializer()objectstore-json: JsonStoreSerializer()objectstore-protobuf: ProtoBufStoreSerializer()Storing object data requires a ObjectStoreWriter implementation.
The following Writers are provided in the objectstore-core module:
SharedPreferencesStoreWriter("prefs_name", context)UserDefaultsStoreWriter()LocalStorageStoreWriter()InMemoryStoreWriter()The objectstore-fs provides file based storage using okio.
All targets are supported except iosArm32 and jsBrowser.
val store = ObjectStore(
storeWriter = FileStoreWriter("/storage-directory")
)
The provided path must not exist or be an existing directory where files can be stored. Each value will be stored in a separate file using the hex encoded key as the filename.
To store data in a secure way, the objectstore-secure module provides Writers which encrypt data when stored on disk.
KeychainStoreWritre("com.service.name", "com.service.group")EncryptedSharedPreferencesStoreWriter("prefs_name", context)The ValueTransformingStoreWriter provides a hook to encode/decode values before they are written to disk.
The transform methods are defined as (type: KType, value: T) -> T, when unhandled you must return the original value.
val storeWriter = InMemoryStoreWriter().transformValue(
transformGet = { _, value -> (value as? String)?.base64Decoded() ?: value },
transformSet = { _, value -> (value as? String)?.base64Encoded() ?: value }
)
The MemCachedStoreWriter provides lazy in-memory caching around any ObjectStoreWriter implementation.
val storeWriter = FileStoreWriter("/data").memCached()
repositories {
mavenCentral()
// Or snapshots
maven("https://s01.oss.sonatype.org/content/repositories/snapshots/")
}
dependencies {
implementation("org.drewcarlson:objectstore-core:$VERSION")
// Serializers
implementation("org.drewcarlson:objectstore-cbor:$VERSION")
implementation("org.drewcarlson:objectstore-json:$VERSION")
implementation()
implementation()
implementation()
}
This project is licensed under Apache-2.0, found in LICENSE.
[versions]
objectstore = "1.0.0-SNAPSHOT"
[libraries]
objectstore-core = { module = "org.drewcarlson:objectstore-core", version.ref = "objectstore" }
objectstore-fs = { module = "org.drewcarlson:objectstore-fs", version.ref = "objectstore" }
objectstore-cbor = { module = "org.drewcarlson:objectstore-cbor", version.ref = "objectstore" }
objectstore-json = { module = "org.drewcarlson:objectstore-json", version.ref = "objectstore" }
objectstore-protobuf = { module = "org.drewcarlson:objectstore-protobuf", version.ref = "objectstore" }
objectstore-secure = { module = "org.drewcarlson:objectstore-secure", version.ref = "objectstore" }
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