diff --git a/akka-http-core/src/main/scala/akka/http/impl/util/StreamUtils.scala b/akka-http-core/src/main/scala/akka/http/impl/util/StreamUtils.scala
index 3007330cd0..83277829e9 100644
--- a/akka-http-core/src/main/scala/akka/http/impl/util/StreamUtils.scala
+++ b/akka-http-core/src/main/scala/akka/http/impl/util/StreamUtils.scala
@@ -173,38 +173,6 @@ private[http] object StreamUtils {
   def mapEntityError(f: Throwable ⇒ Throwable): RequestEntity ⇒ RequestEntity =
     _.transformDataBytes(mapErrorTransformer(f))
 
-  /**
-   * Simple blocking Source backed by an InputStream.
-   *
-   * FIXME: should be provided by akka-stream, see #15588
-   */
-  def fromInputStreamSource(inputStream: InputStream,
-                            fileIODispatcher: String,
-                            defaultChunkSize: Int = 65536): Source[ByteString, Unit] = {
-    val onlyOnceFlag = new AtomicBoolean(false)
-
-    val iterator = new Iterator[ByteString] {
-      var finished = false
-      if (onlyOnceFlag.get() || !onlyOnceFlag.compareAndSet(false, true))
-        throw new IllegalStateException("One time source can only be instantiated once")
-
-      def hasNext: Boolean = !finished
-
-      def next(): ByteString =
-        if (!finished) {
-          val buffer = new Array[Byte](defaultChunkSize)
-          val read = inputStream.read(buffer)
-          if (read < 0) {
-            finished = true
-            inputStream.close()
-            ByteString.empty
-          } else ByteString.fromArray(buffer, 0, read)
-        } else ByteString.empty
-    }
-
-    Source(() ⇒ iterator).withAttributes(ActorAttributes.dispatcher(fileIODispatcher))
-  }
-
   /**
    * Returns a source that can only be used once for testing purposes.
    */
diff --git a/akka-http/src/main/scala/akka/http/scaladsl/server/directives/FileAndResourceDirectives.scala b/akka-http/src/main/scala/akka/http/scaladsl/server/directives/FileAndResourceDirectives.scala
index 3405295164..0420f9050d 100644
--- a/akka-http/src/main/scala/akka/http/scaladsl/server/directives/FileAndResourceDirectives.scala
+++ b/akka-http/src/main/scala/akka/http/scaladsl/server/directives/FileAndResourceDirectives.scala
@@ -5,8 +5,11 @@
 package akka.http.scaladsl.server
 package directives
 
-import java.io.{ File, FileInputStream }
-import java.net.URL
+import java.io.File
+import java.net.{ URI, URL }
+
+import akka.stream.ActorAttributes
+import akka.stream.io.{ InputStreamSource, SynchronousFileSource }
 
 import scala.annotation.tailrec
 import akka.actor.ActorSystem
@@ -51,7 +54,8 @@ trait FileAndResourceDirectives {
             extractSettings { settings ⇒
               complete {
                 HttpEntity.Default(contentType, file.length,
-                  StreamUtils.fromInputStreamSource(new FileInputStream(file), settings.fileIODispatcher))
+                  SynchronousFileSource(file)
+                    .withAttributes(ActorAttributes.dispatcher(settings.fileIODispatcher)))
               }
             }
           }
@@ -88,7 +92,8 @@ trait FileAndResourceDirectives {
                 extractSettings { settings ⇒
                   complete {
                     HttpEntity.Default(contentType, length,
-                      StreamUtils.fromInputStreamSource(url.openStream(), settings.fileIODispatcher))
+                      InputStreamSource(() ⇒ url.openStream())
+                        .withAttributes(ActorAttributes.dispatcher(settings.fileIODispatcher)))
                   }
                 }
               }