Scalaの練習。SlideshareのAPI叩いてみた

Main.scala

// 使用例

import com.taroid.slideshare4s.{SortOrder, SlideShare, Query}

object Main {
  def main(args: Array[String]) {
    val apiKey = System.getenv("SLIDESHARE_API_KEY")
    val sharedSecret = System.getenv("SLIDESHARE_SHARED_SECRET")
    val ss = SlideShare(apiKey, sharedSecret)
    val query = Query(words = "kotlin", itemsPerPage = 10, language = "ja", sortOrder = SortOrder.LATEST)
    ss.searchSlideshow(query).foreach(println)
  }
}

Query.scala

package com.taroid.slideshare4s

import com.taroid.slideshare4s.SortOrder.SortOrder

case class Query(
  words: String,
  page: Int = 1,
  itemsPerPage: Int = 12,
  language: String = "**",
  sortOrder: SortOrder = SortOrder.RELEVANCE
) {
  require(words != null)
  require(words.size > 0)
  require(language != null)
  require(sortOrder != null)
}

SlideShare.scala

package com.taroid.slideshare4s

trait SlideShare {
  def apiKey: String
  def sharedSecret: String

  protected def currentTimeSeconds: Long = System.currentTimeMillis / 1000
  protected def hash: String = Utils.toSha1Hex(sharedSecret + currentTimeSeconds)

  def searchSlideshow(query: Query): Seq[Slideshow]
}

object SlideShare {
  def apply(apiKey: String, sharedSecret: String): SlideShare = {
    require(apiKey != null)
    require(apiKey.size > 0)
    require(sharedSecret != null)
    require(sharedSecret.size > 0)

    return new SlideShareImpl(apiKey, sharedSecret)
  }
}

SlideShareImpl.scala

package com.taroid.slideshare4s

import java.text.SimpleDateFormat
import scala.xml.XML

private class SlideShareImpl(val apiKey: String, val sharedSecret: String) extends SlideShare {
  assert(apiKey != null)
  assert(apiKey.size > 0)
  assert(sharedSecret != null)
  assert(sharedSecret.size > 0)

  override def searchSlideshow(query: Query): Seq[Slideshow] = {
    require(query != null)

    import SlideShareImpl._

    val url = Utils.createUrlWithParams(Urls.SEARCH,
      "api_key" -> apiKey,
      "ts" -> currentTimeSeconds,
      "hash" -> hash,
      "q" -> query.words,
      "page" -> query.page,
      "items_per_page" -> query.itemsPerPage,
      "lang" -> query.language,
      "sort" -> query.sortOrder
    )

    val dateFormat = new SimpleDateFormat("EEE MMM dd HH:mm:ss Z yyyy")

    return (XML.load(url) \ Tags.SLIDESHOW) map { e =>
      Slideshow(
        id = (e \ Tags.ID).text.toLong,
        title = (e \ Tags.TITLE).text,
        username = (e \ Tags.USERNAME).text,
        description = (e \ Tags.DESC).text,
        url = (e \ Tags.URL).text,
        thumbnailUrl = (e \ Tags.THUMB_URL).text,
        created = dateFormat.parse((e \ Tags.CREATED).text),
        updated = dateFormat.parse((e \ Tags.UPDATED).text),
        language = (e \ Tags.LANG).text
      )
    }
  }
}

private object SlideShareImpl {
  private object Urls {
    private val BASE = "https://www.slideshare.net/api/2/"
    val SEARCH = BASE + "search_slideshows"
  }

  private object Tags {
    val SLIDESHOW = "Slideshow"
    val ID = "ID"
    val TITLE = "Title"
    val USERNAME = "Username"
    val DESC = "Description"
    val URL = "URL"
    val THUMB_URL = "ThumbnailURL"
    val CREATED = "Created"
    val UPDATED = "Updated"
    val LANG = "Language"
  }
}

Slideshow.scala

package com.taroid.slideshare4s

import java.util.Date

case class Slideshow(
  id: Long,
  title: String,
  username: String,
  description: String,
  url: String,
  thumbnailUrl: String,
  created: Date,
  updated: Date,
  language: String
) {
  require(title != null)
  require(username != null)
  require(description != null)
  require(url != null)
  require(thumbnailUrl != null)
  require(created != null)
  require(updated != null)
  require(language != null)
}

SortOrder.scala

package com.taroid.slideshare4s

object SortOrder extends Enumeration {
  type SortOrder = Value

  val RELEVANCE = Value("relevance")
  val MOSTVIEWED = Value("mostviewd")
  val MOSTDOWNLOADED = Value("mostdownloaded")
  val LATEST = Value("latest")
}

Utils.scala

package com.taroid.slideshare4s

import java.security.MessageDigest

private object Utils {

  def toSha1Hex(str: String): String = {
    require(str != null)

    val messageDigest = MessageDigest.getInstance("SHA-1")
    messageDigest.update(str.getBytes)
    return messageDigest.digest.map("%02x".format(_)).mkString
  }

  def createUrlWithParams(url: String, params: (String, Any)*): String = {
    require(url != null)
    require(params.forall(_ != null))

    val builder = params.foldLeft(new StringBuilder(url).append("?")) {
      (b, p) => b.append(p._1).append("=").append(p._2.toString).append("&")
    }

    return builder.substring(0, builder.size - 1)
  }
}