https://github.com/irgaly/kottage

Kotlin Multiplatform Key-Value Store Local Cache Storage for Single Source of Truth.
https://github.com/irgaly/kottage

cache kotlin kotlin-multiplatform storage

Last synced: 6 days ago
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Kotlin Multiplatform Key-Value Store Local Cache Storage for Single Source of Truth.

• Host: GitHub
• URL: https://github.com/irgaly/kottage
• Owner: irgaly
• License: other
• Created: 2021-04-25T09:27:03.000Z (over 3 years ago)
• Default Branch: main
• Last Pushed: 2024-07-06T08:43:52.000Z (4 months ago)
• Last Synced: 2024-08-02T09:26:29.346Z (3 months ago)
• Topics: cache, kotlin, kotlin-multiplatform, storage
• Language: Kotlin
• Homepage:
• Size: 2.11 MB
• Stars: 59
• Watchers: 3
• Forks: 0
• Open Issues: 4
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • Funding: .github/FUNDING.yml
  • License: LICENSE

Awesome Lists containing this project

• awesome-kotlin-multiplatform - Kottage - Kotlin Multiplatform Key-Value Store Local Cache Storage for Single Source of Truth. (Libraries / Storage)

README

        
# Kottage

Kotlin Multiplatform Key-Value Store Local Cache Storage for Single Source of Truth.

# Features

* A Kotlin Multiplatform library

* Key-Value Store with no schemas, values are stored to SQLite

* Observing events of item updates as Flow

* Cache Expiration

    * Cache Eviction Strategies:

        * Expiration Time

        * FIFO Strategy

        * LRU Strategy

* KVS Cache mode

    * Expired items are evicted automatically

* KVS Storage mode

    * no item expiration

* List structures for Paging are supported

* Support primitive values and `@Serializable` classes

# Requires

* [New memory manager](https://github.com/JetBrains/kotlin/blob/master/kotlin-native/NEW_MM.md)

  enabled with Kotlin/Native platform.

* SQLite3 dynamic link library on runtime environment

    * Windows needs sqlite3.dll on library path or bundled with your application.

        * Download from https://www.sqlite.org/download.html > sqlite-dll-win64-x64-3410200.zip

    * Linux needs sqlite3 package on system.

    * macOS and iOS platform has sqlite3 library, so you don't have to bundle it.

    * Android has SQLiteHelper class, no dynamic libraries are needed.

    * JVM has JDBC SQLite driver, no dynamic libraries are needed.

    * Nodejs bundles SQLite3 binary, no dynamic libraries are needed.

# Usage

## Setup

Add Kottage as gradle dependency.

### Kotlin Multiplatform:

`build.gradle.kts`

```kotlin

// For Kotlin Multiplatform:

plugins {

    kotlin("multiplatform")

}

kotlin {

    sourceSets {

        commonMain {

            implementation("io.github.irgaly.kottage:kottage:1.8.0")

        }

    }

    // ...

}

```

### Android or JVM without Kotlin Multiplatform:

`build.gradle.kts`

```kotlin

// For Kotlin/JVM or Kotlin/Android without Kotlin Multiplatform:

plugins {

    id("com.android.application")

    kotlin("android")

    // kotlin("jvm") // for JVM Application

}

dependencies {

    // You can use as JVM library directly

    implementation("io.github.irgaly.kottage:kottage:1.8.0")

    // ...

}

```

## Use Kottage

Use Kottage as KVS cache or KVS storage.

First, get a Kottage instance. Even though you can use Kottage instance as a singleton, multiple

Kottage instances creation is allowed. Kottage instances and methods are thread safe.

```kotlin

import io.github.irgaly.kottage.platform.contextOf

// directory path string for SQLite file

// For example:

// * Android File Directory: context.getFilesDir().path

// * Android Cache Directory: context.getCacheDir().path

val databaseDirectory: String = ...

val kottageEnvironment: KottageEnvironment = KottageEnvironment(

    context = contextOf(context) // for Android, set a KottageContext with Android Context object

    //context = KottageContext() // for other platforms, set an empty KottageContext

)

// Initialize with Kottage database information.

val kottage: Kottage = Kottage(

    name = "kottage-store-name", // This will be database file name

    directoryPath = databaseDirectory,

    environment = kottageEnvironment,

    scope = scope, // This kottage instance will be automatically close on this CoroutineScope completion

    json = Json.Default // kotlinx.serialization's json object

)

```

Then, use it as KVS Cache.

```kotlin

import kotlin.time.Duration.Companion.days

// Open Kottage database as cache mode

val cache: KottageStorage = kottage.cache("timeline_item_cache") {

    // There are some options

    strategy = KottageFifoStrategy(maxEntryCount = 1000) // default strategy in cache mode

    //strategy = KottageLruStrategy(maxEntryCount = 1000) // LRU cache strategy

    defaultExpireTime = 30.days // cache item expiration time in kotlin.time.Duration

}

// Kottage's data accessing methods (get, put...) are suspending function

// These items will be expired and automatically deleted after 30 days (defaultExpireTime) elapsed

cache.put("item1", "item1 value")

cache.put("item2", 42)

cache.put("item3", true)

val value1: String = cache.get("item1")

val value2: Int = cache.get("item2")

val value3: Boolean = cache.get("item3")

cache.exists("item4") // => false

cache.getOrNull("item4") // => null

// 30 days later... these items are expired

cache.get("item1") // throws NoSuchElementException

cache.getOrNull("item1") // => null

cache.exists("item1") // => false

```

Use it as KVS Storage with no expiration.

```kotlin

// Open Kottage database as storage mode

val storage: KottageStorage = kottage.storage("app_configs")

// Kottage's data accessing methods (get, put...) are suspending function

// These items has no expiration

storage.put("item1", "item1 value")

storage.put("item2", 42)

storage.put("item3", true)

val value1: String = storage.get("item1")

val value2: Int = storage.get("item2")

val value3: Boolean = storage.get("item3")

storage.exists("item4") // => false

storage.getOrNull("item4") // => null

```

### Property Delegation

KottageStorage provides property delegate.

```kotlin

val storage: KottageStorage = kottage.storage("app_configs")

val myConfig: String by storage.property { "default value" }

val myConfigNullable: String? by storage.nullableProperty()

myConfig.write("value")

val config: String = myConfig.read()

```

For example, this is strictly typed data access class:

```kotlin

class AppConfiguration(kottage: Kottage) {

    private val storage: KottageStorage = kottage.storage("app_configs")

    val myConfig: String by storage.property { "default value" }

    val myConfigNullable: String? by storage.nullableProperty()

}

val configuration: AppConfiguration = AppConfiguration(kottage)

configuration.myConfig.write("value")

val config: String = configuration.myConfig.read()

```

### List / Paging

Kottage has a List feature for make Paging UIs and for Single Source of Truth.

```kotlin

import io.github.irgaly.kottage.kottageListValue

val cache: KottageStorage = kottage.cache("timeline_item_cache")

val list: KottageList = cache.list("timeline_list")

// KottageList is an interface of KottageStorage that supports List operations.

// Add List Items

list.add("item_id_1", TimelineItem("item_id_1", ...))

list.addAll(

    listOf(

        kottageListValue("item_id_2", TimelineItem("item_id_2", ...)),

        kottageListValue("item_id_3", TimelineItem("item_id_3", ...)),

        kottageListValue("item_id_4", TimelineItem("item_id_4", ...)),

        kottageListValue("item_id_5", TimelineItem("item_id_5", ...))

    )

)

// The items are stored in "timeline_item_cache" KottageStorage

cache.exists("item_id_1") // => true

// You can update items directly

cache.put("item_id_1", TimelineItem("item_id_1", otherValue = ...))

// Get as Page

val page0: KottageListPage = list.getPageFrom(positionId = null, pageSize = 2)

val page1: KottageListPage = list.getPageFrom(positionId = (page0.nextPositionId), pageSize = 2)

val page2: KottageListPage = list.getPageFrom(positionId = (page1.nextPositionId), pageSize = 2)

page0.items // => List

page0.items.map { it.value() }

  // => [TimelineItem("item_id_1", otherValue = ...), TimelineItem("item_id_2", ...)]

page1.items.map { it.value() }

  // => [TimelineItem("item_id_3", ...), TimelineItem("item_id_4", ...)]

page2.items.map { it.value() }

  // => [TimelineItem("item_id_5", ...)]

page2.hasNext // => false

// KottageList is a Linked List.

val entry1: KottageListEntry? = list.getFirst()

val entry2: KottageListEntry? = list.get(checkNotNull(entry1.nextPositionId))

val entry3: KottageListEntry? = list.get(checkNotNull(entry2.nextPositionId))

// convenience method to get an entry by index

val entry4: KottageListEntry? = list.getByIndex(3)

entry1?.value() // => TimelineItem("item_id_1", otherValue = ...)

```

### Serialization

Kottage can store and restore Serializable classes.

```kotlin

@Serializable

data class MyData(val myValue: Int)

val data: MyData = MyData(42)

val list: List = listOf("item1", "item2") // List is Serializable

val cache: KottageStorage = kottage.cache("my_data_cache")

cache.put("item1", data)

cache.put("item2", list)

val storedData: MyData = cache.get("item1")

val storedList: List = cache.get>("item2")

```

### Type mismatch error

Store and restore works correctly with same type. It throws ClassCastException if restore with wrong

types.

```kotlin

val cache: KottageStorage = kottage.cache("type_items")

cache.put("item1", 0) // Store as Number (= SQLite Number = Long, Int, Short, Byte or Boolean)

cache.put("item2", "strings") // Store as String

cache.get("item1") // throws ClassCastException

cache.get("item2") // throws ClassCastException

```

Serializable types are stored as String. It throws SerializationException if restore with wrong

types.

```kotlin

@Serializable

data class Data(val data: Int)

@Serializable

data class Data2(val data2: Int)

val cache: KottageStorage = kottage.cache("type_items")

cache.put("data", Data(42))

cache.get("data") // => "{\"data\":42}"

cache.get("data") // throws SerializationException

```

### Event Observing

Kottage supports observing events of item updates for implementing Single Source of Truth.

```kotlin

val cache: KottageStorage = kottage.cache("my_item_cache")

val now: Long = ... // Unix Time (UTC) in millis

launch {

    cache.eventFlow(now).collect { event ->

        // receive events from flow

        val eventType: KottageEventType = event.eventType // eventType => KottageEventType.Create

        val updatedValue: String = cache.get(event.itemKey) // updatedValue => "value"

    }

}

cache.put("key", "value")

// get events after time

val events: List = cache.getEvents(now)

val updatedValue: String = cache.get(event.first().itemKey) // updatedValue => "value"

```

An eventFlow (KottageEventFlow) can automatically resume from previous emitted event.

For example, on Android platform, collect events while Lifecycle is at least STARTED.

```kotlin

val cache = kottage.cache("my_item_cache")

val now = ... // Unix Time (UTC) in millis

val eventFlow = cache.eventFlow(now)

...

override fun onCreate(...) { // for example: onCreate

    ...

    lifecycleScope.launch {

        repeatOnLifecycle(Lifecycle.State.STARTED) {

            eventFlow.collect { event ->

                // eventFlow starts dispatching events from last emitted event on previous subscription.

            }

        }

    }

}

```

# Encryption

User defined encryption are supported. **Only KVS value part is encrypted**, while other part (KVS

key, storage name...) remains plain data.

| part                         | stored data |

|------------------------------|-------------|

| KVS value                    | encrypted   |

| KVS key                      | plain       |

| Kottage name (SQL file name) | plain       |

| Kottage Storage name         | plain       |

| Kottage List name            | plain       |

| KottageListMetaData          | plain       |

| KottageEvent                 | plain       |

```kotlin

val storage: KottageStorage = kottage.storage("encrypted_storage") {

    encoder = object : KottageEncoder {

        override fun encode(value: ByteArray): ByteArray {

            // Your encoding logic (plain ByteArray to encrypted ByteArray) here

            return ...

        }

        override fun decode(encoded: ByteArray): ByteArray {

            // Your decoding logic (encrypted ByteArray to plain ByteArray) here

            return ...

        }

    }

}

// storage's values are encrypted

storage.put("long_value", 100L)

storage.put("string_value", "value")

val longValue: Long = storage.get("long_value") // => 100L

val stringValue: String = storage.get("long_value") // => "value"

```

* Recommendation: [Krypto](https://docs.korge.org/krypto/) is a cool library to use encryption

  feature in Kotlin Multiplatform.

# Supporting Data Types

* Primitives: `Double`, `Float`, `Long`, `Int`, `Short`, `Byte`, `Boolean`

* Bytes: `ByteArray`

* Texts: `String`

* Serializable: kotlinx.serialization's `@Serializable` classes

# Multiplatform

Kottage is a Kotlin Multiplatform library. Please feel free to report a issue if it doesn't

work correctly on these platforms.

| Platform                          | Target                                                                               | Status                                                        |

|-----------------------------------|--------------------------------------------------------------------------------------|---------------------------------------------------------------|

| Kotlin/JVM on Linux/macOS/Windows | jvm                                                                                  | :white_check_mark: Tested                                     |

| Kotlin/JS on Linux/macOS/Windows  | browser, nodejs                                                                      | :white_check_mark: Tested
browser on macOS Chrome, Safari |

| Kotlin/Android                    | android                                                                              | :white_check_mark: Tested                                     |

| Kotlin/Native iOS                 | iosArm64
iosX64(simulator)
iosSimulatorArm64                                   | :white_check_mark: Tested (by iosSimulatorArm64 only)         |

| Kotlin/Native watchOS             | watchosArm64
watchosDeviceArm64
watchosX64(simulator)
watchosSimulatorArm64 | :white_check_mark: (Tested as iosSimulatorArm64)              |

| Kotlin/Native tvOS                | tvosArm64
tvosX64(simulator)
tvosSimulatorArm64                                | :white_check_mark: (Tested as iosSimulatorArm64)              |

| Kotlin/Native macOS               | macosArm64
macosX64                                                               | :white_check_mark: Tested (by macosArm64 only)                |

| Kotlin/Native Linux               | linuxX64
linuxArm64                                                               | :white_check_mark: Tested (by linuxX64 only)                  |

| Kotlin/Native Windows             | mingwX64                                                                             | :white_check_mark: Tested                                     |

There is also [Kottage for SwiftPM](https://github.com/irgaly/kottage-package) that is **just for

experimental** build.

## Kotlin/JS (browser/nodejs) Support

Kottage supports Kottage/JS browser and nodejs. Kottage on browser uses IndexedDB as persistent

database instead of SQLite. Kottage on nodejs uses SQLite.

| Kotlin/JS type | Database  |

|----------------|-----------|

| browser        | IndexedDB |

| nodejs         | SQLite    |

Browsers will clear IndexedDB data when user's disk storage gets low disk space.

You can request browsers your IndexedDB's data not to be cleared by using `StorageManager.persist()`

.

See [Web API documents](https://developer.mozilla.org/en-US/docs/Web/API/StorageManager/persist) for

more details.

### Kotlin/JS browser Setup

Kotlin/JS's library contains both of implementations for browser and for nodejs, so additional

Webpack config is required for browser to use Kottage.

When you run `jsBrowserRun` (jsBrowserDevelopmentRun or jsBrowserProductionRun), some Webpack Errors

occurs:

```shell

Compiled with problems:X

WARNING in ../../node_modules/better-sqlite3/lib/database.js 50:10-81

Critical dependency: the request of a dependency is an expression

ERROR in ../../node_modules/better-sqlite3/lib/database.js 2:11-24

Module not found: Error: Can't resolve 'fs' in '(projectdir)/build/js/node_modules/better-sqlite3/lib'

ERROR in ../../node_modules/better-sqlite3/lib/database.js 3:13-28

Module not found: Error: Can't resolve 'path' in '(projectdir)/build/js/node_modules/better-sqlite3/lib'

BREAKING CHANGE: webpack < 5 used to include polyfills for node.js core modules by default.

This is no longer the case. Verify if you need this module and configure a polyfill for it.

If you want to include a polyfill, you need to:

	- add a fallback 'resolve.fallback: { "path": require.resolve("path-browserify") }'

	- install 'path-browserify'

If you don't want to include a polyfill, you can use an empty module like this:

	resolve.fallback: { "path": false }

...

```

all error's text:

```shell

Compiled with problems:X

WARNING in ../../node_modules/better-sqlite3/lib/database.js 50:10-81

Critical dependency: the request of a dependency is an expression

ERROR in ../../node_modules/better-sqlite3/lib/database.js 2:11-24

Module not found: Error: Can't resolve 'fs' in '(projectdir)/build/js/node_modules/better-sqlite3/lib'

ERROR in ../../node_modules/better-sqlite3/lib/database.js 3:13-28

Module not found: Error: Can't resolve 'path' in '(projectdir)/build/js/node_modules/better-sqlite3/lib'

BREAKING CHANGE: webpack < 5 used to include polyfills for node.js core modules by default.

This is no longer the case. Verify if you need this module and configure a polyfill for it.

If you want to include a polyfill, you need to:

	- add a fallback 'resolve.fallback: { "path": require.resolve("path-browserify") }'

	- install 'path-browserify'

If you don't want to include a polyfill, you can use an empty module like this:

	resolve.fallback: { "path": false }

ERROR in ../../node_modules/better-sqlite3/lib/methods/backup.js 2:11-24

Module not found: Error: Can't resolve 'fs' in '(projectdir)/build/js/node_modules/better-sqlite3/lib/methods'

ERROR in ../../node_modules/better-sqlite3/lib/methods/backup.js 3:13-28

Module not found: Error: Can't resolve 'path' in '(projectdir)/build/js/node_modules/better-sqlite3/lib/methods'

BREAKING CHANGE: webpack < 5 used to include polyfills for node.js core modules by default.

This is no longer the case. Verify if you need this module and configure a polyfill for it.

If you want to include a polyfill, you need to:

	- add a fallback 'resolve.fallback: { "path": require.resolve("path-browserify") }'

	- install 'path-browserify'

If you don't want to include a polyfill, you can use an empty module like this:

	resolve.fallback: { "path": false }

ERROR in ../../node_modules/better-sqlite3/lib/methods/backup.js 4:22-37

Module not found: Error: Can't resolve 'util' in '(projectdir)/build/js/node_modules/better-sqlite3/lib/methods'

BREAKING CHANGE: webpack < 5 used to include polyfills for node.js core modules by default.

This is no longer the case. Verify if you need this module and configure a polyfill for it.

If you want to include a polyfill, you need to:

	- add a fallback 'resolve.fallback: { "util": require.resolve("util/") }'

	- install 'util'

If you don't want to include a polyfill, you can use an empty module like this:

	resolve.fallback: { "util": false }

ERROR in ../../node_modules/bindings/bindings.js 5:9-22

Module not found: Error: Can't resolve 'fs' in '(projectdir)/build/js/node_modules/bindings'

ERROR in ../../node_modules/bindings/bindings.js 6:9-24

Module not found: Error: Can't resolve 'path' in '(projectdir)/build/js/node_modules/bindings'

BREAKING CHANGE: webpack < 5 used to include polyfills for node.js core modules by default.

This is no longer the case. Verify if you need this module and configure a polyfill for it.

If you want to include a polyfill, you need to:

	- add a fallback 'resolve.fallback: { "path": require.resolve("path-browserify") }'

	- install 'path-browserify'

If you don't want to include a polyfill, you can use an empty module like this:

	resolve.fallback: { "path": false }

ERROR in ../../node_modules/file-uri-to-path/index.js 6:10-29

Module not found: Error: Can't resolve 'path' in '(projectdir)/build/js/node_modules/file-uri-to-path'

BREAKING CHANGE: webpack < 5 used to include polyfills for node.js core modules by default.

This is no longer the case. Verify if you need this module and configure a polyfill for it.

If you want to include a polyfill, you need to:

	- add a fallback 'resolve.fallback: { "path": require.resolve("path-browserify") }'

	- install 'path-browserify'

If you don't want to include a polyfill, you can use an empty module like this:

	resolve.fallback: { "path": false }

Compiled with problems:X

ERROR in ./kotlin/kottage-project-core.js 72:11-24

Module not found: Error: Can't resolve 'fs' in '(projectdir)/build/js/packages/kottage-project-js-browser/kotlin'

```

To suppress this errors, add Webpack config file to project directory. This config will ignore

better-sqlite3 module that is not needed in browser application, and exclude packed files.

`{youar application module path}/webpack.config.d/kottage.webpack.config.js`:

```javascript

config.resolve.fallback = {

    ...config.resolve.fallback,

    fs: false,

    os: false

}

config.externals = {

    ...config.externals,

    "better-sqlite3": "better-sqlite3"

}

```

Sample application project is available in [sample/js-browser](sample/js-browser).

### Kotlin/JS nodejs Setup

Kottage uses [better-sqlite3](https://github.com/WiseLibs/better-sqlite3) on nodejs.

better-sqlite3 requires sqlite3 FFI file `better_sqlite3.node` on runtime environment.

If there is no FFI file, `Could not locate the bindings file` error occurred:

```shell

CoroutinesInternalError: Fatal exception in coroutines machinery for AwaitContinuation(DispatchedContinuation[NodeDispatcher@1, [object Object]]){Completed}@2. Please read KDoc to 'handleFatalException' method and report this incident to maintainers

    at AwaitContinuation.DispatchedTask.handleFatalException_56zdfo_k$ ((projectdir)/DispatchedTask.kt:144:22)

    at AwaitContinuation.DispatchedTask.run_mw4iiu_k$ ((projectdir)/DispatchedTask.kt:115:13)

    at ScheduledMessageQueue.MessageQueue.process_mza50i_k$ ((projectdir)/JSDispatcher.kt:153:25)

    at (projectdir)/JSDispatcher.kt:19:48

    at processTicksAndRejections (node:internal/process/task_queues:77:11) {

  cause: Error: Could not locate the bindings file. Tried:

   → (projectdir)/build/js/node_modules/better-sqlite3/build/better_sqlite3.node

   → (projectdir)/build/js/node_modules/better-sqlite3/build/Debug/better_sqlite3.node

   → (projectdir)/build/js/node_modules/better-sqlite3/build/Release/better_sqlite3.node

   → (projectdir)/build/js/node_modules/better-sqlite3/out/Debug/better_sqlite3.node

...

```

all error's text:

```shell

CoroutinesInternalError: Fatal exception in coroutines machinery for AwaitContinuation(DispatchedContinuation[NodeDispatcher@1, [object Object]]){Completed}@2. Please read KDoc to 'handleFatalException' method and report this incident to maintainers

    at AwaitContinuation.DispatchedTask.handleFatalException_56zdfo_k$ ((projectdir)/DispatchedTask.kt:144:22)

    at AwaitContinuation.DispatchedTask.run_mw4iiu_k$ ((projectdir)/DispatchedTask.kt:115:13)

    at ScheduledMessageQueue.MessageQueue.process_mza50i_k$ ((projectdir)/JSDispatcher.kt:153:25)

    at (projectdir)/JSDispatcher.kt:19:48

    at processTicksAndRejections (node:internal/process/task_queues:77:11) {

  cause: Error: Could not locate the bindings file. Tried:

   → (projectdir)/build/js/node_modules/better-sqlite3/build/better_sqlite3.node

   → (projectdir)/build/js/node_modules/better-sqlite3/build/Debug/better_sqlite3.node

   → (projectdir)/build/js/node_modules/better-sqlite3/build/Release/better_sqlite3.node

   → (projectdir)/build/js/node_modules/better-sqlite3/out/Debug/better_sqlite3.node

   → (projectdir)/build/js/node_modules/better-sqlite3/Debug/better_sqlite3.node

   → (projectdir)/build/js/node_modules/better-sqlite3/out/Release/better_sqlite3.node

   → (projectdir)/build/js/node_modules/better-sqlite3/Release/better_sqlite3.node

   → (projectdir)/build/js/node_modules/better-sqlite3/build/default/better_sqlite3.node

   → (projectdir)/build/js/node_modules/better-sqlite3/compiled/18.11.0/darwin/arm64/better_sqlite3.node

   → (projectdir)/build/js/node_modules/better-sqlite3/addon-build/release/install-root/better_sqlite3.node

   → (projectdir)/build/js/node_modules/better-sqlite3/addon-build/debug/install-root/better_sqlite3.node

   → (projectdir)/build/js/node_modules/better-sqlite3/addon-build/default/install-root/better_sqlite3.node

   → (projectdir)/build/js/node_modules/better-sqlite3/lib/binding/node-v108-darwin-arm64/better_sqlite3.node

      at bindings ((projectdir)/build/js/node_modules/bindings/bindings.js:126:9)

      at new Database ((projectdir)/build/js/node_modules/better-sqlite3/lib/database.js:48:64)

      at Database ((projectdir)/build/js/node_modules/better-sqlite3/lib/database.js:11:10)

      at $createDriverCOROUTINE$0.doResume_5yljmg_k$ ((projectdir)/DriverFactory.kt:35:13)

      at DriverFactory.createDriver_qrqvgc_k$ ((projectdir)/DriverFactory.kt:15:20)

      at createDriver ((projectdir)/DriverFactory.kt:32:12)

      at createDriver$default ((projectdir)/DriverFactory.kt:27:9)

      at SqliteDatabaseConnectionFactory$createDatabaseConnection$slambda.doResume_5yljmg_k$ ((projectdir)/SqliteDatabaseConnectionFactory.kt:28:15)

      at SqliteDatabaseConnectionFactory$createDatabaseConnection$slambda.invoke_uw69q_k$ ((projectdir)/SqliteDatabaseConnectionFactory.kt:21:41)

      at SqliteDatabaseConnection.l [as sqlDriverProvider_1] ((projectdir)/build/js/packages/kottage-project-js-nodejs/kotlin/kottage-project-kottage.js:28289:16) {

    tries: [

      '(projectdir)/build/js/node_modules/better-sqlite3/build/better_sqlite3.node',

      '(projectdir)/build/js/node_modules/better-sqlite3/build/Debug/better_sqlite3.node',

      '(projectdir)/build/js/node_modules/better-sqlite3/build/Release/better_sqlite3.node',

      '(projectdir)/build/js/node_modules/better-sqlite3/out/Debug/better_sqlite3.node',

      '(projectdir)/build/js/node_modules/better-sqlite3/Debug/better_sqlite3.node',

      '(projectdir)/build/js/node_modules/better-sqlite3/out/Release/better_sqlite3.node',

      '(projectdir)/build/js/node_modules/better-sqlite3/Release/better_sqlite3.node',

      '(projectdir)/build/js/node_modules/better-sqlite3/build/default/better_sqlite3.node',

      '(projectdir)/build/js/node_modules/better-sqlite3/compiled/18.11.0/darwin/arm64/better_sqlite3.node',

      '(projectdir)/build/js/node_modules/better-sqlite3/addon-build/release/install-root/better_sqlite3.node',

      '(projectdir)/build/js/node_modules/better-sqlite3/addon-build/debug/install-root/better_sqlite3.node',

      '(projectdir)/build/js/node_modules/better-sqlite3/addon-build/default/install-root/better_sqlite3.node',

      '(projectdir)/build/js/node_modules/better-sqlite3/lib/binding/node-v108-darwin-arm64/better_sqlite3.node'

    ]

  }

}

```

To prevent this error, you should build FFI file with a custom Gradle Task.

* Make sure your machine environment has `python3`.

* Register `installBetterSqlite3` task. This task will

  make `{rootProject}/build/js/node_modules/better-sqlite3/build/Release/better_sqlite3.node`.

`{rootProject}/build.gradle.kts` ([sample build.gradle.kts is here](build.gradle.kts))

```kotlin

import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsRootExtension

import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsRootPlugin

import org.jetbrains.kotlin.gradle.targets.js.npm.tasks.KotlinNpmInstallTask

...

plugins.withType {

    extensions.configure {

        // Choose any version you want to use from https://nodejs.org/en/download/releases/

        nodeVersion = "19.9.0"

        val installBetterSqlite3 by tasks.registering(Exec::class) {

            val nodeExtension = this@configure

            val nodeEnv = nodeExtension.requireConfigured()

            val node = nodeEnv.nodeExecutable.replace(File.separator, "/")

            val nodeDir = nodeEnv.nodeDir.path.replace(File.separator, "/")

            val nodeBinDir = nodeEnv.nodeBinDir.path.replace(File.separator, "/")

            val npmCli = if (OperatingSystem.current().isWindows) {

                "$nodeDir/node_modules/npm/bin/npm-cli.js"

            } else {

                "$nodeDir/lib/node_modules/npm/bin/npm-cli.js"

            }

            val npm = "\"$node\" \"$npmCli\""

            val betterSqlite3 = buildDir.resolve("js/node_modules/better-sqlite3")

            dependsOn(tasks.withType())

            inputs.files(betterSqlite3.resolve("package.json"))

            inputs.property("node-version", nodeVersion)

            outputs.files(betterSqlite3.resolve("build/Release/better_sqlite3.node"))

            outputs.cacheIf { true }

            workingDir = betterSqlite3

            commandLine = if (OperatingSystem.current().isWindows) {

                listOf(

                    "sh",

                    "-c",

                    // use pwd command to convert C:/... -> /c/...

                    "PATH=\$(cd $nodeBinDir;pwd):\$PATH $npm run install --verbose"

                )

            } else {

                listOf(

                    "sh",

                    "-c",

                    "PATH=\"$nodeBinDir:\$PATH\" $npm run install --verbose"

                )

            }

        }

    }

}

...

```

* Add NodeJsExec Task's dependency

  setting. ([sample sample/js-nodejs/build.gradle.kts is here](sample/js-nodejs/build.gradle.kts))

`{nodejs project}/build.gradle.kts`

```kotlin

plugins {

    kotlin("multiplatform")

}

kotlin {

    js(IR) {

        ...

    }

    ...

}

...

tasks.withType().configureEach {

    dependsOn(rootProject.tasks.named("installBetterSqlite3"))

}

...

```

* Then, execute `jsNodeRun` (jsNodeDevelopmentRun or jsNodeProductionRun) task. There are no FFI

  errors.

# Kottage Internals

TBA: I'll write details of library here.

* Lazy item expiration.

* Automated clean up of expired item.

* Limit item counts.