restapi（6）- do it the functional way, 重温函数式编程 - Scala

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restapi（6）- do it the functional way, 重温函数式编程(二)

2019-09-03 03:40:13 【大中小】浏览:280次

; parameters('pid,'desc.?,'width.as[Int].?,'heigth.as[Int].?)) { (pid, optDesc, optWid, optHgh) => withoutSizeLimit { decodeRequest { extractDataBytes { bytes => val futBytes = bytes.runFold(ByteString()) { case (hd, bs) => hd ++ bs } val futSeqno = for { cnt <- repository.count(pid).toFuture barr <- futBytes _ <- addPicuture(pid, cnt, optDesc, optWid, optHgh, barr.toArray).toFuture } yield cnt complete(futSeqno.map(_.toString)) } }

现在是不是变得简单易明了？如果你觉着这样看起来更加容易理解，那么我建议你现在开始多点接触了解函数式编程。

接着用同样方式把整个项目重新实现一次。修改后的源代码如下：

MongoRepo.scala

package com.datatech.rest.mongo
import org.mongodb.scala._
import org.bson.conversions.Bson
import org.mongodb.scala.result._
import com.datatech.sdp.mongo.engine._
import MGOClasses._
import MGOEngine._
import MGOCommands._
import com.datatech.sdp.result.DBOResult.DBOResult

object MongoRepo {

  class MongoRepo[R](db:String, coll: String, converter: Option[Document => R])(implicit client: MongoClient) {
    def getAll[R](next:Option[String],sort:Option[String],fields:Option[String],top:Option[Int]): DBOResult[Seq[R]] = {
      var res = Seq[ResultOptions]()
      next.foreach {b => res = res :+ ResultOptions(FOD_TYPE.FOD_FILTER,Some(Document(b)))}
      sort.foreach {b => res = res :+ ResultOptions(FOD_TYPE.FOD_SORT,Some(Document(b)))}
      fields.foreach {b => res = res :+ ResultOptions(FOD_TYPE.FOD_PROJECTION,Some(Document(b)))}
      top.foreach {b => res = res :+ ResultOptions(FOD_TYPE.FOD_LIMIT,None,b)}

      val ctxFind = MGOContext(dbName = db,collName=coll)
        .setActionType(MGO_ACTION_TYPE.MGO_QUERY)
        .setCommand(Find(andThen = res))
      mgoQuery[Seq[R]](ctxFind,converter)
    }

    def query[R](filtr: Bson, next:Option[String]=None,sort:Option[String]=None,fields:Option[String]=None,top:Option[Int]=None): DBOResult[Seq[R]] = {
      var res = Seq[ResultOptions]()
      next.foreach {b => res = res :+ ResultOptions(FOD_TYPE.FOD_FILTER,Some(Document(b)))}
      sort.foreach {b => res = res :+ ResultOptions(FOD_TYPE.FOD_SORT,Some(Document(b)))}
      fields.foreach {b => res = res :+ ResultOptions(FOD_TYPE.FOD_PROJECTION,Some(Document(b)))}
      top.foreach {b => res = res :+ ResultOptions(FOD_TYPE.FOD_LIMIT,None,b)}
      val ctxFind = MGOContext(dbName = db,collName=coll)
        .setActionType(MGO_ACTION_TYPE.MGO_QUERY)
        .setCommand(Find(filter = Some(filtr),andThen = res))
      mgoQuery[Seq[R]](ctxFind,converter)
    }

    import org.mongodb.scala.model.Filters._
    def count(pid: String):DBOResult[Int] = {
      val ctxCount = MGOContext(dbName = db,collName=coll)
        .setActionType(MGO_ACTION_TYPE.MGO_QUERY)
        .setCommand(Count(filter=Some(equal("pid",pid))))
      mgoQuery[Int](ctxCount,None)
    }

    def getOneDocument(filtr: Bson): DBOResult[Document] = {
      val ctxFind = MGOContext(dbName = db,collName=coll)
        .setActionType(MGO_ACTION_TYPE.MGO_QUERY)
        .setCommand(Find(filter = Some(filtr),firstOnly = true))
      mgoQuery[Document](ctxFind,None)
    }
    def getOnePicture[R](pid: String, seqno: Int): DBOResult[R] = {
      val ctxFind = MGOContext(dbName = db, collName = coll)
        .setActionType(MGO_ACTION_TYPE.MGO_QUERY)
        .setCommand(Find(filter = Some(and(equal("pid",pid),equal("seqno",seqno))), firstOnly = true))
      mgoQuery[R](ctxFind, c

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