A simple web scraping with Kotlin

Skrotlin.kt

// Crawler.kt

import kotlinx.coroutines.*
import org.json.JSONObject
import org.jsoup.Jsoup
import org.jsoup.nodes.Document
import org.jsoup.nodes.Element
import org.jsoup.select.Elements

class Crawler {
    suspend fun pipeline(urls: List<String>, selector: String): List<Elements> = coroutineScope {
        retrieveAllHtmlDocumentAsync(urls).awaitAll().map { parse(it, selector) }
    }

    private fun parse(document: Document, selector: String): Elements {
        return document.select(selector)
    }

    private suspend fun retrieveAllHtmlDocumentAsync(urls: List<String>): List<Deferred<Document>> = coroutineScope {
        urls.map { url ->
            async {
                Jsoup.parse(khttp.get(url).text)
            }
        }
    }

    private fun toJson(element: Element): JSONObject {
        return JSONObject(element)
    }

}

// Skrotlin.kt - main
import kotlin.system.measureTimeMillis

suspend fun main(args: Array<String>) {
    val vanDelay = "http://slowwly.robertomurray.co.uk/delay/3000/url"
    val totalTime = measureTimeMillis {
        val crawler = Crawler()
        val result = crawler.pipeline(listOf("$vanDelay/https://http.cat",
                "$vanDelay/https://httpstatusdogs.com/",
                "$vanDelay/https://gympass.com",
                "$vanDelay/https://google.com",
                "$vanDelay/https://stackoverflow.com"), "div")
        println(result)
        println(result.size)
    }

    println("total time: $totalTime")
}