Better stack trace on import

src/main/scala/se/nimsa/sbx/app/routing/ImportRoutes.scala

@@ -120,6 +120,7 @@ trait ImportRoutes {
               complete((httpStatus, metaData.image))
             }
           case Failure(failure) =>
+            failure.printStackTrace()
             val status = failure match {
               case _: DicomStreamException => BadRequest
               case _ => InternalServerError

src/main/scala/se/nimsa/sbx/dicom/streams/DicomStreamOps.scala

@@ -107,7 +107,13 @@ trait DicomStreamOps {
               scheduleTask(30.seconds) {
                 storage.deleteByName(Seq(tempPath)) // delete temp file once file system has released handle
               }
-              if (!t.isInstanceOf[DicomStreamException]) throw new DicomStreamException(t.getMessage) else throw t
+
+              // The actual cause of failure, in the case of DICOM exceptions, may be hidden deep in the stack trace. Find the deepest such element. If not return the top one.
+              def linearize(t: Throwable): List[Throwable] = if (t.getCause == null || t == t.getCause) t :: Nil else t :: linearize(t.getCause)
+              throw linearize(t)
+                .filter(_.isInstanceOf[DicomStreamException])
+                .lastOption
+                .getOrElse(new DicomStreamException(t.getMessage))
           }
       }
   }