From d35c4826120752709b33f492f2e451bac0972c8b Mon Sep 17 00:00:00 2001
From: Adam Vessey <adam@discoverygarden.ca>
Date: Thu, 16 Jan 2014 20:12:00 +0000
Subject: [PATCH] Avoid adding on duplicate extensions.

As we often use filenames for datastream labels, and then use the labels
to generate file names for download, we were ending up with file
extensions being doubled up.
---
 includes/datastream.inc | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/includes/datastream.inc b/includes/datastream.inc
index 72a86c5f..26a7a8d5 100644
--- a/includes/datastream.inc
+++ b/includes/datastream.inc
@@ -53,8 +53,16 @@ function islandora_view_datastream(AbstractDatastream $datastream, $download = F
   if ($download) {
     // Browsers will not append all extensions.
     $mime_detect = new MimeDetect();
-    $extension = $mime_detect->getExtension($datastream->mimetype);
-    $filename = $datastream->label . '.' . $extension;
+    $extension = '.' . $mime_detect->getExtension($datastream->mimetype);
+
+    // Prevent adding on a duplicate extension.
+    $extension_length = strlen($extension);
+    $duplicate_extension_position = strripos($datastream->label, $extension, -$extension_length);
+    $filename = $datastream->label;
+    if ($duplicate_extension_position === FALSE) {
+      $filename .= $extension;
+    }
+
     header("Content-Disposition: attachment; filename=\"$filename\"");
   }