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在仓储后封装 API

对调用方隐藏 Ktor 和序列化细节

在仓储后封装 API 是 CoddyKit 上的免费 Kotlin Multiplatform Academy 课时。这是第 2 节课，共 4 节。你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。这是 Kotlin Multiplatform Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Kotlin Multiplatform Academy 课程共包含 4 节课。

本课时的部分内容尚未翻译，以英文显示。

Now Build the Real Thing

With the interface set, you write a concrete implementation that actually fetches data behind the scenes.

Implement the Interface

Create a class that uses implements the repository interface, promising to fulfill every method it declares.

class UserRepositoryImpl : UserRepository

Inject the Ktor Client

Pass the HttpClient into the constructor instead of creating it inside, so it can be shared and replaced in tests.

class UserRepositoryImpl(private val client: HttpClient) : UserRepository

Hide the Network Call

Inside each method, make the Ktor request and return the result. Callers see clean data, never the request itself.

override suspend fun getUsers() = client.get(url).body<List<User>>()

Keep URLs Inside

Store base URLs and paths within the implementation. The rest of the app stays blissfully unaware of any endpoint.

One Place to Change

If the API path changes, you edit only this class. The interface and every caller stay untouched.

Serialization Stays Hidden

The body call turns JSON into models here, so serialization never leaks out to the UI layer.

val user: User = client.get(url).body()

Same Code, Both Apps

This implementation lives in commonMain, so the same fetching code powers Android and iOS identically.

Swap Without Breaking Callers

Because it satisfies the interface, you can replace it with a caching version later and no caller changes.

Wire It With DI

A dependency injection setup hands callers this implementation through the interface type, keeping things loosely coupled.

single<UserRepository> { UserRepositoryImpl(get()) }

The Full Wrapper

Here is the complete wrapper: it takes a client, hides the request, and returns plain domain models.

class UserRepositoryImpl(
    private val client: HttpClient
) : UserRepository {
    override suspend fun getUsers() =
        client.get("/users").body<List<User>>()
}

Quick Check

What is the main job of the repository implementation?

Recap

The implementation takes an HttpClient, performs the request, and returns domain models, keeping all networking sealed off from callers.

常见问题解答

「在仓储后封装 API」课时是免费的吗？

是的 — 「在仓储后封装 API」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Kotlin Multiplatform Academy 课程的其余内容，请升级到 CoddyKit PRO。 Kotlin Multiplatform Academy 课程共包含 4 节课。

「在仓储后封装 API」这节课中我会学到什么？

对调用方隐藏 Ktor 和序列化细节你通过在浏览器中直接运行的动手代码来练习 Kotlin Multiplatform Academy，全天候 AI 导师会在你学习这节课的过程中回答你的问题。

学习 Kotlin Multiplatform Academy 需要有经验吗？

无需任何先前经验。CoddyKit 上的 Kotlin Multiplatform Academy 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。这是第 2 节课，共 4 节。

「在仓储后封装 API」课时需要多长时间？

大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。

我能在这节 Kotlin Multiplatform Academy 课中编写并运行代码吗？

能。每节 Kotlin Multiplatform Academy 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。

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