From be17040f9dbc2d7632e0252e8e8f8a065c68fa2d Mon Sep 17 00:00:00 2001
From: Ivica Ceraj <iceraj@gmail.com>
Date: Tue, 12 Aug 2014 08:30:33 -0400
Subject: [PATCH] Fix for empty imsx_messageIdentifier

---
 AUTHORS                                  | 1 +
 common/lib/xmodule/xmodule/lti_module.py | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/AUTHORS b/AUTHORS
index 3e96b5759c..96bca29d4a 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -168,3 +168,4 @@ Juanan Pereira <juanan.pereira@ehu.es>
 Clinton Blackburn <cblackburn@edx.org>
 Dennis Jen <djen@edx.org>
 Filippo Valsorda <hi@filippo.io>
+Ivica Ceraj <ceraj@mit.edu>
diff --git a/common/lib/xmodule/xmodule/lti_module.py b/common/lib/xmodule/xmodule/lti_module.py
index 297cfae2ca..c5e8458f0f 100644
--- a/common/lib/xmodule/xmodule/lti_module.py
+++ b/common/lib/xmodule/xmodule/lti_module.py
@@ -694,7 +694,7 @@ oauth_consumer_key="", oauth_signature="frVp4JuvT1mVXlxktiAUjQ7%2F1cw%3D"'}
         parser = etree.XMLParser(ns_clean=True, recover=True, encoding='utf-8')
         root = etree.fromstring(data, parser=parser)
 
-        imsx_messageIdentifier = root.xpath("//def:imsx_messageIdentifier", namespaces=namespaces)[0].text
+        imsx_messageIdentifier = root.xpath("//def:imsx_messageIdentifier", namespaces=namespaces)[0].text or ''
         sourcedId = root.xpath("//def:sourcedId", namespaces=namespaces)[0].text
         score = root.xpath("//def:textString", namespaces=namespaces)[0].text
         action = root.xpath("//def:imsx_POXBody", namespaces=namespaces)[0].getchildren()[0].tag.replace('{'+lti_spec_namespace+'}', '')