Exception thrown when instructor list results contain records without a profile

[bermudezjd]

The sort_and_format_instructor_display method assumes that instructor result records will contain a profile key that is either null or a list. However, the rest api returns None records instead of nulls, so using default values with a get doesn't fall back to the default. This results in a 'NoneType' object has no attribute 'get' exception that looks like this (from Splunk logs):

Server Error: /course_info/lti_launch Traceback (most recent call last): File "/var/opt/virtualenvs/canvas_course_info/local/lib/python2.7/site-packages/django/core/handlers/exception.py", line 39, in inner response = get_response(request) File "/var/opt/virtualenvs/canvas_course_info/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 249, in _legacy_get_response response = self._get_response(request) File "/var/opt/virtualenvs/canvas_course_info/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 187, in _get_response response = self.process_exception_by_middleware(e, request) File "/var/opt/virtualenvs/canvas_course_info/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 185, in _get_response response = wrapped_callback(request, *callback_args, **callback_kwargs) File "/var/opt/virtualenvs/canvas_course_info/local/lib/python2.7/site-packages/django/contrib/auth/decorators.py", line 23, in _wrapped_view return view_func(request, *args, **kwargs) File "/var/opt/virtualenvs/canvas_course_info/local/lib/python2.7/site-packages/django/views/decorators/http.py", line 40, in inner return func(request, *args, **kwargs) File "/var/opt/virtualenvs/canvas_course_info/local/lib/python2.7/site-packages/django/views/decorators/csrf.py", line 58, in wrapped_view return view_func(*args, **kwargs) File "/opt/tlt/canvas_course_info/course_info/views.py", line 82, in lti_launch return editor(request) File "/opt/tlt/canvas_course_info/course_info/views.py", line 196, in editor course_instance_id=course_instance_id) File "/opt/tlt/canvas_course_info/course_info/views.py", line 142, in _course_context instructor_display = sort_and_format_instructor_display(course_instructor_list) File "/opt/tlt/canvas_course_info/course_info/views.py", line 211, in sort_and_format_instructor_display course_instructor_list.sort(key=lambda x: (x.get('role', {}).get('role_id'), File "/opt/tlt/canvas_course_info/course_info/views.py", line 213, in <lambda> x.get('profile', {}).get('name_last'))) AttributeError: 'NoneType' object has no attribute 'get'

Further checks may be needed in the code to handle cases where instructors don't have profiles, including adding checks to the get_display_name method.

[Chris-Thornton-Harvard]

The gets for first and last names don't have defaults. Providing an empty string as a default for each should stop the error.
Line 233 in course_info/views.py should be:
return person.get('profile', {}).get('name_first', '')+' '+person.get('profile', {}).get('name_last', '')