Merge pull request #49 from MITx/specific-error-handling

Specific error handling

djangoapps/courseware/views.py

 import logging
 import urllib
+import json
 
 from django.conf import settings
 from django.core.context_processors import csrf
@@ -16,6 +17,8 @@ from lxml import etree
 from module_render import render_module, make_track_function, I4xSystem
 from models import StudentModule
 from student.models import UserProfile
+from util.errors import record_exception
+from util.views import accepts
 from multicourse import multicourse_settings
 
 import courseware.content_parser as content_parser
@@ -110,12 +113,16 @@ def render_section(request, section):
     if 'coursename' in request.session: coursename = request.session['coursename']
     else: coursename = None
 
-#    try: 
-    dom = content_parser.section_file(user, section, coursename)
-    #except:
-     #   raise Http404
+    try:
+        dom = content_parser.section_file(user, section, coursename)
+    except:
+        record_exception(log, "Unable to parse courseware xml")
+        return render_to_response('courseware-error.html', {})
 
-    accordion=render_accordion(request, '', '', '')
+    context = {
+        'csrf': csrf(request)['csrf_token'],
+        'accordion': render_accordion(request, '', '', '')
+    }
 
     module_ids = dom.xpath("//@id")
     
@@ -125,15 +132,20 @@ def render_section(request, section):
     else:
         module_object_preload = []
     
-    module=render_module(user, request, dom, module_object_preload)
-
-    if 'init_js' not in module:
-        module['init_js']=''
-
-    context={'init':module['init_js'],
-             'accordion':accordion,
-             'content':module['content'],
-             'csrf':csrf(request)['csrf_token']}
+    try:
+        module = render_module(user, request, dom, module_object_preload)
+    except:
+        record_exception(log, "Unable to load module")
+        context.update({
+            'init': '',
+            'content': render_to_string("module-error.html", {}),
+        })
+        return render_to_response('courseware.html', context)
+
+    context.update({
+        'init':module.get('init_js', ''),
+        'content':module['content'],
+    })
 
     result = render_to_response('courseware.html', context)
     return result
@@ -167,22 +179,22 @@ def index(request, course=None, chapter="Using the System", section="Hints"):
     if not multicourse_settings.is_valid_course(course):
         return redirect('/')
 
-    #import logging
-    #log = logging.getLogger("mitx")
-    #log.info(  "DEBUG: "+str(user) )
-
     request.session['coursename'] = course		# keep track of current course being viewed in django's request.session
 
-    dom = content_parser.course_file(user,course)	# also pass course to it, for course-specific XML path
+    try:
+        dom = content_parser.course_file(user,course)	# also pass course to it, for course-specific XML path
+    except:
+        record_exception(log, "Unable to parse courseware xml")
+        return render_to_response('courseware-error.html', {})
+
     dom_module = dom.xpath("//course[@name=$course]/chapter[@name=$chapter]//section[@name=$section]/*[1]", 
                            course=course, chapter=chapter, section=section)
+
     if len(dom_module) == 0:
         module = None
     else:
         module = dom_module[0]
 
-    accordion=render_accordion(request, course, chapter, section)
-
     module_ids = dom.xpath("//course[@name=$course]/chapter[@name=$chapter]//section[@name=$section]//@id", 
                            course=course, chapter=chapter, section=section)
 
@@ -191,18 +203,27 @@ def index(request, course=None, chapter="Using the System", section="Hints"):
                                                                   module_id__in=module_ids))
     else:
         module_object_preload = []
-    
-
-    module=render_module(user, request, module, module_object_preload)
 
-    if 'init_js' not in module:
-        module['init_js']=''
-
-    context={'init':module['init_js'],
-             'accordion':accordion,
-             'content':module['content'],
-             'COURSE_TITLE':multicourse_settings.get_course_title(course),
-             'csrf':csrf(request)['csrf_token']}
+    context = {
+        'csrf': csrf(request)['csrf_token'],
+        'accordion': render_accordion(request, course, chapter, section),
+        'COURSE_TITLE':multicourse_settings.get_course_title(course),
+    }
+
+    try:
+        module = render_module(user, request, module, module_object_preload)
+    except:
+        record_exception(log, "Unable to load module")
+        context.update({
+            'init': '',
+            'content': render_to_string("module-error.html", {}),
+        })
+        return render_to_response('courseware.html', context)
+
+    context.update({
+        'init': module.get('init_js', ''),
+        'content': module['content'],
+    })
 
     result = render_to_response('courseware.html', context)
     return result
@@ -234,7 +255,15 @@ def modx_dispatch(request, module=None, dispatch=None, id=None):
     else: coursename = None
 
     # Grab the XML corresponding to the request from course.xml
-    xml = content_parser.module_xml(request.user, module, 'id', id, coursename)
+    try:
+        xml = content_parser.module_xml(request.user, module, 'id', id, coursename)
+    except:
+        record_exception(log, "Unable to load module during ajax call")
+        if accepts(request, 'text/html'):
+            return render_to_response("module-error.html", {})
+        else:
+            response = HttpResponse(json.dumps({'success': "We're sorry, this module is temporarily unavailable. Our staff is working to fix it as soon as possible"}))
+        return response
 
     # Create the module
     system = I4xSystem(track_function = make_track_function(request), 
@@ -242,10 +271,20 @@ def modx_dispatch(request, module=None, dispatch=None, id=None):
                        ajax_url = ajax_url,
                        filestore = None
                        )
-    instance=courseware.modules.get_module_class(module)(system, 
-                                                         xml, 
-                                                         id, 
-                                                         state=oldstate)
+
+    try:
+        instance=courseware.modules.get_module_class(module)(system, 
+                                                             xml, 
+                                                             id, 
+                                                             state=oldstate)
+    except:
+        record_exception(log, "Unable to load module instance during ajax call")
+        if accepts(request, 'text/html'):
+            return render_to_response("module-error.html", {})
+        else:
+            response = HttpResponse(json.dumps({'success': "We're sorry, this module is temporarily unavailable. Our staff is working to fix it as soon as possible"}))
+        return response
+
     # Let the module handle the AJAX
     ajax_return=instance.handle_ajax(dispatch, request.POST)
     # Save the state back to the database

envs/common.py

@@ -79,6 +79,7 @@ TEMPLATE_DIRS = (
 
 TEMPLATE_CONTEXT_PROCESSORS = (
     'django.core.context_processors.request',
+    'django.core.context_processors.static',
     'askbot.context.application_settings',
     'django.contrib.messages.context_processors.messages',
     #'django.core.context_processors.i18n',
@@ -105,6 +106,20 @@ DEV_CONTENT = True
 TRACK_MAX_EVENT = 10000 
 DEBUG_TRACK_LOG = False
 
+MITX_ROOT_URL = ''
+
+COURSE_NAME = "6.002_Spring_2012"
+COURSE_NUMBER = "6.002x"
+COURSE_TITLE = "Circuits and Electronics"
+
+ROOT_URLCONF = 'urls'
+
+### Dark code. Should be enabled in local settings for devel. 
+
+ENABLE_MULTICOURSE = False     # set to False to disable multicourse display (see lib.util.views.mitxhome)
+
+###
+
 ############################### DJANGO BUILT-INS ###############################
 # Change DEBUG/TEMPLATE_DEBUG in your environment settings files, not here
 DEBUG = False
@@ -159,14 +174,22 @@ MESSAGE_STORAGE = 'django.contrib.messages.storage.session.SessionStorage'
 AWS_QUERYSTRING_EXPIRE = 10 * 365 * 24 * 60 * 60 # 10 years
 
 ################################### ASKBOT #####################################
+LIVESETTINGS_OPTIONS['MITX_ROOT_URL'] = MITX_ROOT_URL
+skin_settings = LIVESETTINGS_OPTIONS[1]['SETTINGS']['GENERAL_SKIN_SETTINGS']
+skin_settings['SITE_FAVICON'] = unicode(MITX_ROOT_URL) + skin_settings['SITE_FAVICON']
+skin_settings['SITE_LOGO_URL'] = unicode(MITX_ROOT_URL) +  skin_settings['SITE_LOGO_URL']
+skin_settings['LOCAL_LOGIN_ICON'] = unicode(MITX_ROOT_URL) + skin_settings['LOCAL_LOGIN_ICON']
+LIVESETTINGS_OPTIONS[1]['SETTINGS']['LOGIN_PROVIDERS']['WORDPRESS_SITE_ICON'] = unicode(MITX_ROOT_URL) + LIVESETTINGS_OPTIONS[1]['SETTINGS']['LOGIN_PROVIDERS']['WORDPRESS_SITE_ICON']
+LIVESETTINGS_OPTIONS[1]['SETTINGS']['LICENSE_SETTINGS']['LICENSE_LOGO_URL'] = unicode(MITX_ROOT_URL) + LIVESETTINGS_OPTIONS[1]['SETTINGS']['LICENSE_SETTINGS']['LICENSE_LOGO_URL']
+
 ASKBOT_EXTRA_SKINS_DIR = ASKBOT_ROOT / "askbot" / "skins"
 ASKBOT_ALLOWED_UPLOAD_FILE_TYPES = ('.jpg', '.jpeg', '.gif', '.bmp', '.png', '.tiff')
 ASKBOT_MAX_UPLOAD_FILE_SIZE = 1024 * 1024 # result in bytes
 
 CACHE_MIDDLEWARE_ANONYMOUS_ONLY = True
 ASKBOT_URL = 'discussion/'
-LOGIN_REDIRECT_URL = '/'
-LOGIN_URL = '/'
+LOGIN_REDIRECT_URL = MITX_ROOT_URL + '/'
+LOGIN_URL = MITX_ROOT_URL + '/'
 
 ALLOW_UNICODE_SLUGS = False
 ASKBOT_USE_STACKEXCHANGE_URLS = False # mimic url scheme of stackexchange
@@ -181,6 +204,9 @@ djcelery.setup_loader()
 SIMPLE_WIKI_REQUIRE_LOGIN_EDIT = True
 SIMPLE_WIKI_REQUIRE_LOGIN_VIEW = False
 
+################################# Jasmine ###################################
+JASMINE_TEST_DIRECTORY = PROJECT_ROOT + '/templates/coffee'
+
 ################################# Middleware ###################################
 # List of finder classes that know how to find static files in
 # various locations.
@@ -199,6 +225,7 @@ TEMPLATE_LOADERS = (
 
 MIDDLEWARE_CLASSES = (
     'util.middleware.ExceptionLoggingMiddleware',
+    'util.middleware.AcceptMiddleware',
     'django.middleware.cache.UpdateCacheMiddleware',
     'django.middleware.common.CommonMiddleware',
     'django.contrib.sessions.middleware.SessionMiddleware',
@@ -245,6 +272,9 @@ INSTALLED_APPS = (
     'track',
     'util',
 
+    # For testing
+    'django_jasmine',
+
     # For Askbot 
     'django.contrib.sitemaps',
     'django.contrib.admin',

envs/dev.py

@@ -10,8 +10,8 @@ sessions. Assumes structure:
 from envs.common import *
 from envs.logsettings import get_logger_config
 
-DEBUG = True
-TEMPLATE_DEBUG = True
+DEBUG = False
+TEMPLATE_DEBUG = False
 
 LOGGING = get_logger_config(ENV_ROOT / "log", 
                             logging_env="dev",

lib/util/errors.py

+import newrelic.agent
+import sys
+
+def record_exception(logger, msg, params={}, ignore_errors=[]):
+    logger.exception(msg)
+    newrelic.agent.record_exception(*sys.exc_info())
+

lib/util/middleware.py

@@ -13,3 +13,4 @@ class ExceptionLoggingMiddleware(object):
         def process_exception(self, request, exception):
             log.exception(exception)
             return HttpResponseServerError("Server Error - Please try again later.")
+

lib/util/views.py

@@ -66,3 +66,29 @@ def mitxhome(request):
     if settings.ENABLE_MULTICOURSE:
         return render_to_response("mitxhome.html", {})
     return info(request)
+
+# From http://djangosnippets.org/snippets/1042/
+def parse_accept_header(accept):
+    """Parse the Accept header *accept*, returning a list with pairs of
+    (media_type, q_value), ordered by q values.
+    """
+    result = []
+    for media_range in accept.split(","):
+        parts = media_range.split(";")
+        media_type = parts.pop(0)
+        media_params = []
+        q = 1.0
+        for part in parts:
+            (key, value) = part.lstrip().split("=", 1)
+            if key == "q":
+                q = float(value)
+            else:
+                media_params.append((key, value))
+        result.append((media_type, tuple(media_params), q))
+    result.sort(lambda x, y: -cmp(x[2], y[2]))
+    return result
+
+def accepts(request, media_type):
+    """Return whether this request has an Accept header that matches type"""
+    accept = parse_accept_header(request.META.get("HTTP_ACCEPT", ""))
+    return media_type in [t for (t, p, q) in accept]

requirements.txt

@@ -18,3 +18,4 @@ fs
 django-jasmine
 beautifulsoup
 requests
+newrelic

settings.py

@@ -133,6 +133,7 @@ TEMPLATE_LOADERS = (
 
 MIDDLEWARE_CLASSES = (
     'util.middleware.ExceptionLoggingMiddleware',
+    'util.middleware.AcceptMiddleware',
     'django.middleware.cache.UpdateCacheMiddleware',
     'django.middleware.common.CommonMiddleware',
     'django.contrib.sessions.middleware.SessionMiddleware',

templates/courseware-error.html

+<%inherit file="main.html" />
+<%block name="bodyclass">courseware</%block>
+<%block name="title"><title>Courseware – MITx 6.002x</title></%block>
+
+<%include file="navigation.html" args="active_page='courseware'" />
+
+<section class="main-content">
+  <section class="outside-app">
+    <h1>There has been an error on the <em>MITx</em> servers</h1>
+    <p>We're sorry, this module is temporarily unavailable. Our staff is working to fix it as soon as possible. Please email us at <a href="mailto:technical@mitx.mit.edu">technical@mitx.mit.edu</a> to report any problems or downtime.</p>
+  </section>
+</section>

templates/module-error.html

+<section class="outside-app">
+  <h1>There has been an error on the <em>MITx</em> servers</h1>
+  <p>We're sorry, this module is temporarily unavailable. Our staff is working to fix it as soon as possible. Please email us at <a href="mailto:technical@mitx.mit.edu">technical@mitx.mit.edu</a> to report any problems or downtime.</p>
+</section>