Naively decode an arbitrary URI encoded string

naiveuridecode.scala

#!/usr/bin/env amm

import $ivy.`org.typelevel::cats-core:1.4.0`
import cats.implicits._

import java.net.{URLEncoder, URLDecoder}
import scala.util.{Try, Success}

val charsets = List("utf-8", "x-windows-949")

/**
 * Note that not all charsets can round-trip for every character
 */
def roundtrip(str: String)(charsetName: String): Option[String] =
    Try(URLDecoder.decode(str, charsetName)).toOption.flatMap { decoded =>
      Try(URLEncoder.encode(decoded, charsetName)) match {
        case Success(`str`) => Some(decoded)
        case _ => None
      }
    } 

def naiveDecodeUriComponent(str: String): Option[String] =
  charsets.collectFirstSome(roundtrip(str))

println(naiveDecodeUriComponent("%ED%85%8C%EC%8A%A4%ED%8A%B8")) // Some("테스트")
println(naiveDecodeUriComponent("%C5%D7%BD%BA%C6%AE")) // Some("테스트")