Client.kt

package http;

import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
import com.fasterxml.jackson.module.kotlin.readValue
import okhttp3.OkHttpClient
import okhttp3.Request
import reactor.core.publisher.Mono

class Client(val httpClient: OkHttpClient = OkHttpClient(), val mapper: ObjectMapper = jacksonObjectMapper()) {
    inline fun <reified T : Any> request(req: Request): Mono<T> {
        return Mono.just(httpClient.newCall(req).execute())
            .doOnSuccess {
                if (!it.isSuccessful) {
                    throw Exception("request error.", it)
                }
            }.map {
                mapper.readValue<T>(response.body()?.string() ?: "")
            }
    }
}