added assignment 8 ex 2

src/Assignment8/Ex2.scala

@@ -0,0 +1,62 @@
+package Assignment8
+
+import net.liftweb.json
+import net.liftweb.json.DefaultFormats
+
+import java.net.URI
+import scala.concurrent.duration.Duration
+import scala.concurrent.{Await, Future}
+import scala.sys.process._
+import scala.util.{Failure, Success}
+
+object Ex2 extends App {
+  implicit val ec: scala.concurrent.ExecutionContext = scala.concurrent.ExecutionContext.global
+  implicit val formats: DefaultFormats.type = DefaultFormats
+
+  case class Coin(id: String, icon: String, name: String, symbol: String, rank: Int, price: Double, priceBtc: Double, volume: Double, marketCap: Double, availableSupply: Double, totalSupply: Double, fullyDilutedValuation: Double, priceChange1h: Double, priceChange1d: Double, priceChange1w: Double, redditUrl: String, websiteUrl: String, twitterUrl: String, explorers: List[String])
+  case class Currency(name: String, rate: Double, symbol: String, imageUrl: String)
+
+  val BITCOIN_TO_USD: String = "https://openapiv1.coinstats.app/coins/bitcoin"
+  val USD_TO_CHF: String = "https://openapiv1.coinstats.app/fiats"
+  private val API_KEY: String = sys.env.getOrElse("OPENAPI_KEY", "")
+
+  def getUrl(url: String): Future[String] = {
+    Future {
+      val uri: URI = new URI(url)
+      val cmd: String = "curl -s -H 'X-API-KEY: " + API_KEY + "' " + uri.toString
+      cmd.!!
+    }
+  }
+
+  def extractBitcoinToUSDRate(jsonStr: String): Double = {
+    val data: Coin = json.parse(jsonStr).extract[Coin]
+    return data.price
+  }
+
+  def extractUSDToCHFRate(jsonStr: String): Double = {
+    val data: List[Currency] = json.parse(jsonStr).extract[List[Currency]]
+    return data.find(currency => currency.name == "CHF")
+               .map(currency => currency.rate)
+               .get
+  }
+
+  def getBitcoinToUSD: Future[Double] = {
+    getUrl(BITCOIN_TO_USD) map extractBitcoinToUSDRate
+  }
+
+  def getUSDToCHF: Future[Double] = {
+    getUrl(USD_TO_CHF) map extractUSDToCHFRate
+  }
+
+  val f: Future[Double] = for {
+    btc2usd <- getBitcoinToUSD
+    usd2chf <- getUSDToCHF
+  } yield btc2usd * usd2chf
+
+  f onComplete {
+    case Success(value) => println(s"1 BTC == $value CHF")
+    case Failure(e) => println(s"An error occurred: $e")
+  }
+
+  Await.ready(f, Duration.Inf)
+}