Spotify API接口

Question

我正在尝试为spotify API创建一个scala接口。我用它来学习Scala。我的背景大多是蟒蛇。

import dispatch._, Defaults._

trait Request {
  val name: String
  val endpoint: String
}

case class Track(name: String) extends Request {
  override val endpoint = "track.json"
}

case class Album(name: String) extends Request {
  override val endpoint = "album.json"
}

case class Artist(name: String) extends Request {
  override val endpoint = "artist.json"
}

object Spotify {

  def getResponse(req: Request) = {
    val params = Map("q" -> req.name)
    val spotifyUrl = host("ws.spotify.com")

    spotifyUrl / "search"/ "1" / req.endpoint <<? params

  }

  val foo = Album("foo")
  val songs = Http(getResponse(foo) OK as.String)

}

我觉得getResponse应该是请求特性，或者什么的，因为它足够通用，只需要被覆盖的endpoint --但不确定。任何关于这类事情的结构的一般性建议都是有帮助的。

Answer 1

把所有的东西都拆了。

我确信Scala老兵会比我说的更多，并且可能会对我的评论发表评论。

下面是对您的代码的一些更改和相应的注释。

import dispatch._, Defaults._

// decouple from any "master" class.
case class Track(name: String)

case class Album(name: String)

case class Artist(name: String)

// This is called a structural type. We are using a def
// because a val restricts extensibility.
type Named = {def name: String}

// Separate out the endpoints into their own category
object endpointResolver {

  // Use a partial function which you can re-use in order parts
  // of your program. You may use this in your testing as well.
  val endPoints: PartialFunction[Named, String] = {
    case _: Track => "track.json"
    case _: Album => "album.json"
    case _: Artist => "artist.json"
  }

  // use an implicit class. This allows you to add methods
  // to existing classes seamlessly.
  implicit class nrEndpoint(namedRequest: Named) {
    def endpoint: String =
      endPoints apply namedRequest
  }

}

object Spotify {

  // Specify the return type. I was not sure what it was initially.
  def getResponse(req: Named): Req = {

    val params = Map("q" -> req.name)

    val spotifyUrl = host("ws.spotify.com")

    // import and utilise this implicit class
    import endpointResolver.nrEndpoint

    spotifyUrl / "search"/ "1" / req.endpoint <<? params

  }

  val foo = Album("foo")

  // OK is another example of an implicit being used. Use an IDE
  // such as IntelliJ IDEA to navigate through the vast depths
  // of Scala source.
  val songs = Http(getResponse(foo) OK as.String)

}