AWS S3 added listObjects endpoint including common prefixes for a delimiter

docs/src/main/paradox/s3.md

@@ -85,6 +85,17 @@ Scala
 Java
 : @@snip [snip](/s3/src/test/java/docs/javadsl/S3Test.java) { #list-bucket }
 
+## List bucket contents and common prefixes
+
+To get a list of the contents and common prefixes for one hierarchy level using a delimiter, use @scala[@scaladoc[S3.listBucketAndCommonPrefixes](akka.stream.alpakka.s3.scaladsl.S3$)]@java[@scaladoc[S3.listBucketAndCommonPrefixes](akka.stream.alpakka.s3.javadsl.S3$)].
+When run, this will give a tuple stream of (Seq[@scaladoc[ListBucketResultContents](akka.stream.alpakka.s3.ListBucketResultContents)], Seq[@scaladoc[ListBucketResultCommonPrefixes](akka.stream.alpakka.s3.ListBucketResultCommonPrefixes)]).
+
+Scala
+: @@snip [snip](/s3/src/test/scala/docs/scaladsl/S3SourceSpec.scala) { #list-bucket-and-common-prefixes }
+
+Java
+: @@snip [snip](/s3/src/test/java/docs/javadsl/S3Test.java) { #list-bucket-and-common-prefixes }
+
 ## Copy upload (multi part)
 
 Copy an S3 object from source bucket to target bucket using @scala[@scaladoc[S3.multipartCopy](akka.stream.alpakka.s3.scaladsl.S3$)]@java[@scaladoc[S3.multipartCopy](akka.stream.alpakka.s3.javadsl.S3$)].

s3/src/main/scala/akka/stream/alpakka/s3/impl/HttpRequests.scala

@@ -30,6 +30,7 @@ import scala.concurrent.{ExecutionContext, Future}
       bucket: String,
       prefix: Option[String] = None,
       continuationToken: Option[String] = None,
+      delimiter: Option[String] = None,
       headers: Seq[HttpHeader] = Nil
   )(implicit conf: S3Settings): HttpRequest = {
 
@@ -42,6 +43,7 @@ import scala.concurrent.{ExecutionContext, Future}
       Seq(
         "list-type" -> listType,
         "prefix" -> prefix,
+        "delimiter" -> delimiter,
         continuationTokenName -> continuationToken
       ).collect { case (k, Some(v)) => k -> v }.toMap
     )

s3/src/main/scala/akka/stream/alpakka/s3/impl/Marshalling.scala

@@ -11,7 +11,7 @@ import akka.annotation.InternalApi
 import akka.http.scaladsl.marshallers.xml.ScalaXmlSupport
 import akka.http.scaladsl.model.{ContentTypes, HttpCharsets, MediaTypes, Uri}
 import akka.http.scaladsl.unmarshalling.{FromEntityUnmarshaller, Unmarshaller}
-import akka.stream.alpakka.s3.ListBucketResultContents
+import akka.stream.alpakka.s3.{ListBucketResultCommonPrefixes, ListBucketResultContents}
 
 import scala.util.Try
 import scala.xml.NodeSeq
@@ -70,6 +70,12 @@ import scala.xml.NodeSeq
               Instant.parse((c \ "LastModified").text),
               (c \ "StorageClass").text
             )
+          },
+          (x \\ "CommonPrefixes").map { c =>
+            ListBucketResultCommonPrefixes(
+              (x \ "Name").text,
+              (c \ "Prefix").text
+            )
           }
         )
     }

s3/src/main/scala/akka/stream/alpakka/s3/impl/S3Stream.scala

@@ -35,6 +35,8 @@ import akka.stream.alpakka.s3.headers.ServerSideEncryption
 import akka.stream.scaladsl.{Flow, Keep, RunnableGraph, Sink, Source}
 import akka.util.ByteString
 
+import scala.collection.immutable
+
 /** Internal Api */
 @InternalApi private[s3] final case class S3Location(bucket: String, key: String)
 
@@ -70,7 +72,8 @@ import akka.util.ByteString
 /** Internal Api */
 @InternalApi private[impl] final case class ListBucketResult(isTruncated: Boolean,
                                                              continuationToken: Option[String],
-                                                             contents: Seq[ListBucketResultContents])
+                                                             contents: Seq[ListBucketResultContents],
+                                                             commonPrefixes: Seq[ListBucketResultCommonPrefixes])
 
 /** Internal Api */
 @InternalApi private[impl] final case class CopyPartResult(lastModified: Instant, eTag: String)
@@ -126,31 +129,40 @@ import akka.util.ByteString
       }
   }.mapMaterializedValue(_ => NotUsed)
 
+  sealed trait ListBucketState
+  case object Starting extends ListBucketState
+  case class Running(continuationToken: String) extends ListBucketState
+  case object Finished extends ListBucketState
+
+  def listBucketCall[T](
+      bucket: String,
+      prefix: Option[String],
+      delimiter: Option[String],
+      s3Headers: S3Headers,
+      token: Option[String],
+      resultTransformer: ListBucketResult => T
+  )(implicit mat: ActorMaterializer, attr: Attributes): Future[Option[(ListBucketState, T)]] = {
+    import mat.executionContext
+    implicit val conf = resolveSettings(attr, mat.system)
+
+    signAndGetAs[ListBucketResult](
+      HttpRequests.listBucket(bucket, prefix, token, delimiter, s3Headers.headersFor(ListBucket))
+    ).map { (res: ListBucketResult) =>
+      Some(
+        res.continuationToken
+          .fold[(ListBucketState, T)]((Finished, resultTransformer(res)))(
+            t => (Running(t), resultTransformer(res))
+          )
+      )
+    }
+  }
+
   def listBucket(bucket: String,
                  prefix: Option[String] = None,
                  s3Headers: S3Headers): Source[ListBucketResultContents, NotUsed] = {
-    sealed trait ListBucketState
-    case object Starting extends ListBucketState
-    case class Running(continuationToken: String) extends ListBucketState
-    case object Finished extends ListBucketState
-
-    def listBucketCall(
-        token: Option[String]
-    )(implicit mat: ActorMaterializer,
-      attr: Attributes): Future[Option[(ListBucketState, Seq[ListBucketResultContents])]] = {
-      import mat.executionContext
-      implicit val conf = resolveSettings(attr, mat.system)
-
-      signAndGetAs[ListBucketResult](HttpRequests.listBucket(bucket, prefix, token, s3Headers.headersFor(ListBucket)))
-        .map { (res: ListBucketResult) =>
-          Some(
-            res.continuationToken
-              .fold[(ListBucketState, Seq[ListBucketResultContents])]((Finished, res.contents))(
-                t => (Running(t), res.contents)
-              )
-          )
-        }
-    }
+
+    def listBucketCallOnlyContents(token: Option[String])(implicit mat: ActorMaterializer, attr: Attributes) =
+      listBucketCall(bucket, prefix, None, s3Headers, token, _.contents)
 
     Source
       .setup { (mat, attr) =>
@@ -159,14 +171,44 @@ import akka.util.ByteString
         Source
           .unfoldAsync[ListBucketState, Seq[ListBucketResultContents]](Starting) {
             case Finished => Future.successful(None)
-            case Starting => listBucketCall(None)
-            case Running(token) => listBucketCall(Some(token))
+            case Starting => listBucketCallOnlyContents(None)
+            case Running(token) => listBucketCallOnlyContents(Some(token))
           }
           .mapConcat(identity)
       }
       .mapMaterializedValue(_ => NotUsed)
   }
 
+  def listBucketAndCommonPrefixes(
+      bucket: String,
+      delimiter: String,
+      prefix: Option[String] = None,
+      s3Headers: S3Headers
+  ): Source[(immutable.Seq[ListBucketResultContents], immutable.Seq[ListBucketResultCommonPrefixes]), NotUsed] = {
+
+    def listBucketCallContentsAndCommonPrefixes(token: Option[String])(implicit mat: ActorMaterializer,
+                                                                       attr: Attributes) =
+      listBucketCall(bucket,
+                     prefix,
+                     Some(delimiter),
+                     s3Headers,
+                     token,
+                     listBucketResult => (listBucketResult.contents, listBucketResult.commonPrefixes))
+
+    Source
+      .setup { (mat, attr) =>
+        implicit val materializer = mat
+        implicit val attributes = attr
+        Source
+          .unfoldAsync[ListBucketState, (Seq[ListBucketResultContents], Seq[ListBucketResultCommonPrefixes])](Starting) {
+            case Finished => Future.successful(None)
+            case Starting => listBucketCallContentsAndCommonPrefixes(None)
+            case Running(token) => listBucketCallContentsAndCommonPrefixes(Some(token))
+          }
+      }
+      .mapMaterializedValue(_ => NotUsed)
+  }
+
   def getObjectMetadata(bucket: String,
                         key: String,
                         versionId: Option[String],