private void doFileDelivery(UserRequest ureq, String taskFile) {
OlatRootFolderImpl forumContainer = new OlatRootFolderImpl(TACourseNode.getTaskFolderPathRelToFolderRoot(courseEnv, node), null);
VFSItem item = forumContainer.resolve(taskFile);
if (item instanceof VFSLeaf) {
VFSLeaf leaf = (VFSLeaf)item;
ureq.getDispatchResult().setResultingMediaResource(new VFSMediaResource(leaf));
} else if (item==null) {
Tracing.logWarn("Can not cast to VFSLeaf. item==null, taskFile=" + taskFile,null, TaskController.class);
} else {
Tracing.logWarn("Can not cast to VFSLeaf. item.class.name=" + item.getClass().getName() + ", taskFile="+taskFile,null, TaskController.class);
}