Paginated DFP Ad Unit PQL request

grab_ad_units.scala

import com.google.api.ads.dfp.axis.factory.DfpServices
import com.google.api.ads.dfp.axis.utils.v201608.{DateTimes, StatementBuilder}
import com.google.api.ads.dfp.axis.v201608.{AdUnitPage, InventoryServiceInterface}

def run(dfpSession: DfpSession): Unit = {
    // Construct DFP Services
    val dfpServices = new DfpServices
    val adUnitService: InventoryServiceInterface = dfpServices.get(dfpSession, classOf[InventoryServiceInterface])

    @tailrec
    def processPage(query: StatementBuilder, contents: List[String] = Nil): List[String] = {
      val page: AdUnitPage = adUnitService.getAdUnitsByStatement(query.toStatement)

      val pageContents: List[String] = Option(page.getResults) match {
                          case None => Logger.info(s"No results found!"); Nil
                          case Some(results) => results.toList.map(r => Json.toJson(r).toString)
                        }

      query.increaseOffsetBy(StatementBuilder.SUGGESTED_PAGE_LIMIT)
      val contentsSoFar = contents ++ pageContents

      if (query.getOffset < page.getTotalResultSetSize){
        processPage(query, contentsSoFar)
      } else {
        contentsSoFar
      }
    }
    
    val statementForEverything: StatementBuilder =
      new StatementBuilder()
        .orderBy("lastModifiedDateTime ASC")
        .limit(StatementBuilder.SUGGESTED_PAGE_LIMIT)

    val contents: List[String] = processPage(statementForEverything)
    Logger.info(s"Processed ${contents.size} Ad Units")