I have a KMP Ktor client API lib written in Common. The consumer can set a config for a httpclient. ...

# ktor

[MV]

I have a KMP Ktor client API lib written in Common. The consumer can set a config for a httpclient. Currently I have this as

object API {
    var defaultClient = HttpClient {}
    fun <T : HttpClientEngineConfig> setDefaultClientConfig(block: HttpClientConfig<T>.() -> Unit) {
          defaultClient = defaultClient.config(block as HttpClientConfig<*>.() -> Unit)
    }
}

Is there a way to achieve this without doing an unchecked cast?

[MV]

This is so that I can specify concrete client config depending on the target.

For example in JVM

The consumer can do this now.

API.setDefaultClientConfig<OkHttpConfig> {
   install(UserAgent) {
     agent = "MyAgent"
   }

  engine {
    preconfigured = okHttpClient()
    addNetworkInterceptor(DownloadProgressInterceptor(...))
  }
}

[AdamW]

A consumer wouldn’t necessarily know which engine HttpClient { } defaults to here in case there are multiple engines in the classpath. To do this without an unchecked cast, the engine also needs to be provided by a consumer. But overall that’s a dangerous looking pattern in API

[MV]

Yes, I wanted to avoid that, I have made them typed for each target. But it is still a unchecked cast

fun API.setDefaultClientConfig(block: HttpClientConfig<OkHttpConfig>.() -> Unit){
    @Suppress("UNCHECKED_CAST")
    defaultClient = defaultClient.config(block as HttpClientConfig<*>.() -> Unit)
}

[andylamax]

I think is better if your API should accept a HttpClient instead of the config block