Use chat settings when deciding whether to render

Only render the chat widget if both the site has enabled it in the
`MITX_FEATURES` and if the course has enabled it. In addition, fail
gracefully with a log warning if the `JABBER_DOMAIN` is not set, and
do not try to render the widget. However, do go ahead and render the
rest of the courseware.

lms/djangoapps/courseware/views.py

@@ -238,21 +238,27 @@ def chat_settings(course, user):
     Returns a dict containing the settings required to connect to a
     Jabber chat server and room.
     """
+    domain = getattr(settings, "JABBER_DOMAIN", None)
+    if domain is None:
+        log.warning('You must set JABBER_DOMAIN in the settings to '
+                    'enable the chat widget')
+        return None
+
     return {
-        'domain': settings.JABBER_DOMAIN,
+        'domain': domain,
 
         # Jabber doesn't like slashes, so replace with dashes
         'room': "{ID}_class".format(ID=course.id.replace('/', '-')),
 
         'username': "{USER}@{DOMAIN}".format(
-            USER=user.username, DOMAIN=settings.JABBER_DOMAIN
+            USER=user.username, DOMAIN=domain
         ),
 
         # TODO: clearly this needs to be something other than the username
         #       should also be something that's not necessarily tied to a
         #       particular course
         'password': "{USER}@{DOMAIN}".format(
-            USER=user.username, DOMAIN=settings.JABBER_DOMAIN
+            USER=user.username, DOMAIN=domain
         ),
     }
 
@@ -321,8 +327,17 @@ def index(request, course_id, chapter=None, section=None,
             'xqa_server': settings.MITX_FEATURES.get('USE_XQA_SERVER', 'http://xqa:server@content-qa.mitx.mit.edu/xqa')
             }
 
-        if course.show_chat:
+        # Only show the chat if it's enabled by the course and in the
+        # settings.
+        show_chat = course.show_chat and settings.MITX_FEATURES['ENABLE_CHAT']
+        if show_chat:
             context['chat'] = chat_settings(course, user)
+            # If we couldn't load the chat settings, then don't show
+            # the widget in the courseware.
+            if context['chat'] is None:
+                show_chat = False
+
+        context['show_chat'] = show_chat
 
         chapter_descriptor = course.get_child_by(lambda m: m.url_name == chapter)
         if chapter_descriptor is not None:

lms/templates/courseware/courseware.html

@@ -6,7 +6,7 @@
 <%block name="headextra">
   <%static:css group='course'/>
   <%include file="../discussion/_js_head_dependencies.html" />
-  % if course.show_chat:
+  % if show_chat:
     <link rel="stylesheet" href="${static.url('css/vendor/ui-lightness/jquery-ui-1.8.22.custom.css')}" />
     ## It'd be better to have this in a place like lms/css/vendor/candy,
     ## but the candy_res/ folder contains images and other junk, and it
@@ -115,7 +115,7 @@
   </script>
 % endif
 
-% if course.show_chat:
+% if show_chat:
   <script type="text/javascript" src="${static.url('js/vendor/candy_libs/libs.min.js')}"></script>
   <script type="text/javascript" src="${static.url('js/vendor/candy.min.js')}"></script>
 
@@ -189,7 +189,7 @@
   </div>
 </section>
 
-% if course.show_chat:
+% if show_chat:
   <div id="chat-wrapper">
     <div id="chat-toggle" class="closed">
       <span id="chat-open">Open Chat <em class="icon-chevron-up"></em></span>