MoshiDatastore.kt

@Module
@InstallIn(SingletonComponent::class)
internal object DataStoreModule {
  
    @Provides
    @Singleton
    fun provideMyCacheDataStore(
        @ApplicationContext context: Context,
        moshi: Moshi,
    ): DataStore<MyCachedDataClass> {
        return DataStoreFactory.create(
            produceFile = { context.dataStoreFile("MY_CACHE_DATA_SOURCE.json") },
            serializer = DataStoreJsonSerializer(
                defaultValue = MyCachedDataClass(),
                provideJsonAdapter = { moshi.adapter(MyCachedDataClass::class.java) },
            ),
            corruptionHandler = ReplaceFileCorruptionHandler { MyCachedDataClass() },
        )
    }
}
    
class DataStoreJsonSerializer<T>(
    override val defaultValue: T,
    // use function to provide moshi adapter to prevent initiating on main thread
    private val provideJsonAdapter: () -> JsonAdapter<T>,
) : Serializer<T> {

    override suspend fun readFrom(input: InputStream): T {
        return try {
            input.source().buffer().use {
                checkNotNull(provideJsonAdapter().fromJson(it))
            }
        } catch (e: Exception) {
            logInfo(e) { "Unable to read datastore" }
            throw CorruptionException("Unable to read datastore", e) // handled by corruptionHandler
        }
    }

    override suspend fun writeTo(t: T, output: OutputStream) {
        try {
            output.sink().buffer().use {
                provideJsonAdapter().toJson(it, t)
            }
        } catch (e: Exception) {
            logError(e) { "Unable to write to datastore" }
        }
    }
}