diff --git a/apps/workflowengine/lib/Check/FileSize.php b/apps/workflowengine/lib/Check/FileSize.php
index c1ee1d85ae965..41c8f0d8b570b 100644
--- a/apps/workflowengine/lib/Check/FileSize.php
+++ b/apps/workflowengine/lib/Check/FileSize.php
@@ -75,7 +75,9 @@ protected function getFileSizeFromHeader() {
 
 		$size = $this->request->getHeader('OC-Total-Length');
 		if ($size === '') {
-			if (in_array($this->request->getMethod(), ['POST', 'PUT'])) {
+			// Try fallback for upload methods
+			$method = $this->request->getMethod();
+			if (in_array($method, ['POST', 'PUT'], true)) {
 				$size = $this->request->getHeader('Content-Length');
 			}
 		}