MDL-14561 fixed https issue in IE

diff --git a/grade/export/txt/grade_export_txt.php b/grade/export/txt/grade_export_txt.php
index c38e1f28e2f23d2ec017d58dfaa7eff8722b9968..962b5217c09ddd6736a08d852818d926ae6de63b 100755 (executable)
--- a/grade/export/txt/grade_export_txt.php
+++ b/grade/export/txt/grade_export_txt.php
@@ -65,9 +65,15 @@ class grade_export_txt extends grade_export {
         }
 
         /// Print header to force download
-        @header('Cache-Control: private, must-revalidate, pre-check=0, post-check=0, max-age=0');
-        @header('Expires: '. gmdate('D, d M Y H:i:s', 0) .' GMT');
-        @header('Pragma: no-cache');
+        if (strpos($CFG->wwwroot, 'https://') === 0) { //https sites - watch out for IE! KB812935 and KB316431
+            @header('Cache-Control: max-age=10');
+            @header('Expires: '. gmdate('D, d M Y H:i:s', 0) .' GMT');
+            @header('Pragma: ');
+        } else { //normal http - prevent caching at all cost
+            @header('Cache-Control: private, must-revalidate, pre-check=0, post-check=0, max-age=0');
+            @header('Expires: '. gmdate('D, d M Y H:i:s', 0) .' GMT');
+            @header('Pragma: no-cache');
+        }
         header("Content-Type: application/download\n");
         $downloadfilename = clean_filename("{$this->course->shortname} $strgrades");
         header("Content-Disposition: attachment; filename=\"$downloadfilename.txt\"");