fix: paginated aggregation with empty response

Author: QuadStingray

package.json

@@ -1,7 +1,7 @@
 {
   "name" : "mongodb-driver",
   "organization" : "dev.mongocamp",
-  "version" : "2.6.3.snapshot",
+  "version" : "2.6.3",
   "author" : "[email protected]",
   "license" : "Apache-2.0",
   "repository" : {

src/main/scala/dev/mongocamp/driver/mongodb/pagination/MongoPaginatedAggregation.scala

@@ -40,9 +40,17 @@ case class MongoPaginatedAggregation[A <: Any](
 
     val dbResponse = dao.Raw.findAggregated(pipeline, allowDiskUse).result(maxWait)
 
-    val count: Long = dbResponse.get(AggregationKeyMetaData).get.asArray().get(0).asDocument().get(AggregationKeyMetaDataTotal).asNumber().longValue()
-    val allPages    = Math.ceil(count.toDouble / rows).toInt
-    val list        = dbResponse.get("data").get.asArray().asScala.map(_.asDocument()).map(bdoc => Document(bdoc))
+    val count: Long = dbResponse
+      .get(AggregationKeyMetaData)
+      .get
+      .asArray()
+      .asScala
+      .headOption
+      .map(v => v.asDocument().get(AggregationKeyMetaDataTotal).asNumber().longValue())
+      .getOrElse(0)
+
+    val allPages = Math.ceil(count.toDouble / rows).toInt
+    val list     = dbResponse.get("data").get.asArray().asScala.map(_.asDocument()).map(bdoc => Document(bdoc))
     PaginationResult(list.toList, PaginationInfo(count, rows, page, allPages))
   }
 
@@ -53,8 +61,16 @@ case class MongoPaginatedAggregation[A <: Any](
     val pipeline = aggregationPipeline ++ List(
       Aggregates.facet(new Facet(AggregationKeyMetaData, listOfMetaData.asJava), new Facet(AggregationKeyData, listOfPaging.asJava))
     )
-    val dbResponse  = dao.Raw.findAggregated(pipeline, allowDiskUse).result(maxWait)
-    val count: Long = dbResponse.get(AggregationKeyMetaData).get.asArray().get(0).asDocument().get(AggregationKeyMetaDataTotal).asNumber().longValue()
+    val dbResponse = dao.Raw.findAggregated(pipeline, allowDiskUse).result(maxWait)
+    val count: Long = dbResponse
+      .get(AggregationKeyMetaData)
+      .get
+      .asArray()
+      .asScala
+      .headOption
+      .map(v => v.asDocument().get(AggregationKeyMetaDataTotal).asNumber().longValue())
+      .getOrElse(0)
+
     count
   }
 

src/test/scala/dev/mongocamp/driver/mongodb/pagination/PaginationAggregationSpec.scala

@@ -7,8 +7,8 @@ import dev.mongocamp.driver.mongodb.dao.PersonSpecification
 
 import dev.mongocamp.driver.mongodb.test.TestDatabase._
 import org.mongodb.scala.bson.conversions.Bson
-import org.mongodb.scala.model.Aggregates.{filter, group, sort}
-import org.mongodb.scala.model.Filters.{and, equal}
+import org.mongodb.scala.model.Aggregates.{ filter, group, sort }
+import org.mongodb.scala.model.Filters.{ and, equal }
 
 class PaginationAggregationSpec extends PersonSpecification {
 
@@ -65,6 +65,24 @@ class PaginationAggregationSpec extends PersonSpecification {
 
     }
 
+    "aggregation with empty response" in {
+      val pipeline = List(filter(and(equal("unknown", "filter"))), groupStage, sortStage)
+
+      val pagination = MongoPaginatedAggregation(PersonDAO, pipeline, allowDiskUse = true)
+
+      val page = pagination.paginate(1, 10)
+
+      (pagination.countResult must be).equalTo(0)
+
+      (page.paginationInfo.allCount must be).equalTo(0)
+
+      (page.paginationInfo.pagesCount must be).equalTo(0)
+
+      (page.databaseObjects.size must be).equalTo(0)
+
+
+    }
+
   }
 
 }