Custom Storage

The SDK persists two internal keys: a first-launch flag (Detour_firstEntranceFlag) and an analytics device identifier (Detour_deviceId). Left unset, DetourConfig.storage is null and the SDK falls back to its own SharedPreferences-based store. To use encrypted storage, DataStore or another persistence layer, pass a DetourStorage implementation instead.

Values must persist across restarts

Both keys have to persist across app restarts. A storage adapter that loses them makes the SDK re-run the deferred flow and generate a new analytics device id.

Storage interface

interface DetourStorage {
    suspend fun getItem(key: String): String?
    suspend fun setItem(key: String, value: String)
    suspend fun removeItem(key: String) { }
}

Examples

The adapter below wraps EncryptedSharedPreferences. Any class that implements DetourStorage works, so use it as a starting point for DataStore or another persistence layer.

EncryptedSharedPreferences

import android.content.Context
import androidx.security.crypto.EncryptedSharedPreferences
import androidx.security.crypto.MasterKey
import com.swmansion.detour.storage.DetourStorage
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.withContext

class EncryptedStorageProvider(context: Context) : DetourStorage {
    private val masterKey = MasterKey.Builder(context)
        .setKeyScheme(MasterKey.KeyScheme.AES256_GCM)
        .build()

    private val prefs = EncryptedSharedPreferences.create(
        context,
        "DetourSecureStorage",
        masterKey,
        EncryptedSharedPreferences.PrefKeyEncryptionScheme.AES256_SIV,
        EncryptedSharedPreferences.PrefValueEncryptionScheme.AES256_GCM
    )

    override suspend fun getItem(key: String): String? = withContext(Dispatchers.IO) {
        prefs.getString(key, null)
    }

    override suspend fun setItem(key: String, value: String) = withContext(Dispatchers.IO) {
        prefs.edit().putString(key, value).apply()
    }
}

val config = DetourConfig(
    apiKey = BuildConfig.DETOUR_API_KEY,
    appId = BuildConfig.DETOUR_APP_ID,
    storage = EncryptedStorageProvider(this)
)

Related pages

• Usage
• API Reference