From 42fa70c3036a42400be626a38b2eec94b19de1e8 Mon Sep 17 00:00:00 2001
From: Jonathan Green <jonathan@razzard.com>
Date: Wed, 11 Apr 2018 11:37:29 -0300
Subject: [PATCH] Prevent Warning

Error: Call to a member function getTimestamp() on boolean in islandora_view_datastream_cache_check()
---
 includes/datastream.inc | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/includes/datastream.inc b/includes/datastream.inc
index e7547780..ee0f8cc7 100644
--- a/includes/datastream.inc
+++ b/includes/datastream.inc
@@ -161,12 +161,14 @@ function islandora_view_datastream_cache_check(AbstractDatastream $datastream) {
 
   if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
     $modified_since = DateTime::createFromFormat('D, d M Y H:i:s e', $_SERVER['HTTP_IF_MODIFIED_SINCE']);
-    if ($datastream->createdDate->getTimestamp() - $modified_since->getTimestamp() > 0) {
-      // Changed!
-      return $return;
-    }
-    else {
-      $return = 304;
+    if ($modified_since !== FALSE) {
+      if ($datastream->createdDate->getTimestamp() - $modified_since->getTimestamp() > 0) {
+        // Changed!
+        return $return;
+      }
+      else {
+        $return = 304;
+      }
     }
   }
   if ($return === 200 && isset($_SERVER['HTTP_IF_UNMODIFIED_SINCE'])) {