Helper methods for getting/applying request params

ParamReader.scala

trait Request {
  def getParam(key: String): String
  def getCommaParamList(key: String): Seq[String]
  
  def paramOpt[T](key: String)(implicit reader: ParamReader[T]): Option[T] = Option(getParam(key)).map(reader.read)
  def paramOpt[T](key: String, op: T => _)(implicit reader: ParamReader[T]): Unit = paramOpt(key).foreach(op)
  def param[T](key: String)(implicit reader: ParamReader[T]): T = reader.read(getParam(key))
  def param[T](key: String, op: T => _)(implicit reader: ParamReader[T]): Unit = op(param(key))
  def paramExists(key: String): Boolean = getParam(key) != null
  def paramExists(key: String, op: Boolean => _): Unit = op(paramExists(key))
  def paramZipAll[A, B](keyA: String, keyB: String)(implicit readerA: ParamReader[A], readerB: ParamReader[B]): Iterable[(A, B)] = {
    val as = getCommaParamList(keyA)
    val bs = getCommaParamList(keyB)
    require(as.length == bs.length)
    as.view.zip(bs.view).map {
      case (a, b) =>
        (readerA.read(a), readerB.read(b))
    }
  }
  def paramZipAll[A, B](keyA: String, keyB: String, op: (A, B) => _)(implicit readerA: ParamReader[A], readerB: ParamReader[B]): Unit = {
    paramZipAll[A, B](keyA, keyB).foreach {
      case (a, b) => op(a, b)
    }
  }
}


trait ParamReader[T] {
  def read(value: String): T
}

object ParamReader {
  implicit val stringReader = new ParamReader[String] {
    def read(value: String) = value
  }
  implicit val intReader = new ParamReader[Int] {
    def read(value: String) = value.toInt
  }
  implicit val longReader = new ParamReader[Long] {
    def read(value: String) = value.toLong
  }
  implicit val doubleReader = new ParamReader[Double] {
    def read(value: String) = value.toDouble
  }
  implicit val boolReader = new ParamReader[Boolean] {
    def read(value: String) = value == "true" || value == "1"
  }
}