Files
edx-platform/lms/djangoapps/course_structure_api/v0/views.py
2015-02-17 13:23:34 -05:00

233 lines
7.3 KiB
Python

""" API implementation for course-oriented interactions. """
import logging
from operator import attrgetter
from django.conf import settings
from django.http import Http404
from rest_framework.authentication import OAuth2Authentication, SessionAuthentication
from rest_framework.exceptions import PermissionDenied, AuthenticationFailed
from rest_framework.generics import RetrieveAPIView, ListAPIView
from rest_framework.response import Response
from xmodule.modulestore.django import modulestore
from opaque_keys.edx.keys import CourseKey
from courseware.access import has_access
from openedx.core.djangoapps.content.course_structures import models
from openedx.core.lib.api.permissions import IsAuthenticatedOrDebug
from openedx.core.lib.api.serializers import PaginationSerializer
from courseware import courses
from course_structure_api.v0 import serializers
from student.roles import CourseInstructorRole, CourseStaffRole
log = logging.getLogger(__name__)
class CourseViewMixin(object):
"""
Mixin for views dealing with course content. Also handles authorization and authentication.
"""
lookup_field = 'course_id'
authentication_classes = (OAuth2Authentication, SessionAuthentication,)
permission_classes = (IsAuthenticatedOrDebug,)
def get_course_or_404(self):
"""
Retrieves the specified course, or raises an Http404 error if it does not exist.
Also checks to ensure the user has permissions to view the course
"""
try:
course_id = self.kwargs.get('course_id')
course_key = CourseKey.from_string(course_id)
course = courses.get_course(course_key)
self.check_course_permissions(self.request.user, course)
return course
except ValueError:
raise Http404
def user_can_access_course(self, user, course):
"""
Determines if the user is staff or an instructor for the course.
Always returns True if DEBUG mode is enabled.
"""
return (settings.DEBUG
or has_access(user, CourseStaffRole.ROLE, course)
or has_access(user, CourseInstructorRole.ROLE, course))
def check_course_permissions(self, user, course):
"""
Checks if the request user can access the course.
Raises PermissionDenied if the user does not have course access.
"""
if not self.user_can_access_course(user, course):
raise PermissionDenied
def perform_authentication(self, request):
"""
Ensures that the user is authenticated (e.g. not an AnonymousUser), unless DEBUG mode is enabled.
"""
super(CourseViewMixin, self).perform_authentication(request)
if request.user.is_anonymous() and not settings.DEBUG:
raise AuthenticationFailed
class CourseList(CourseViewMixin, ListAPIView):
"""
**Use Case**
CourseList returns paginated list of courses in the edX Platform. The list can be filtered by course_id.
**Example Request**
GET /api/course_structure/v0/courses/
GET /api/course_structure/v0/courses/?course_id={course_id1},{course_id2}
**Response Values**
* id: The unique identifier for the course.
* name: The name of the course.
* category: The type of content. In this case, the value is always "course".
* org: The organization specified for the course.
* course: The course number.
* org: The run for the course.
* uri: The URI to use to get details of the course.
* image_url: The URI for the course's main image.
* start: Course start date
* end: Course end date
"""
paginate_by = 10
paginate_by_param = 'page_size'
pagination_serializer_class = PaginationSerializer
serializer_class = serializers.CourseSerializer
def get_queryset(self):
course_ids = self.request.QUERY_PARAMS.get('course_id', None)
course_descriptors = []
if course_ids:
course_ids = course_ids.split(',')
for course_id in course_ids:
course_key = CourseKey.from_string(course_id)
course_descriptor = courses.get_course(course_key)
course_descriptors.append(course_descriptor)
else:
course_descriptors = modulestore().get_courses()
results = [course for course in course_descriptors if self.user_can_access_course(self.request.user, course)]
# Sort the results in a predictable manner.
results.sort(key=attrgetter('id'))
return results
class CourseDetail(CourseViewMixin, RetrieveAPIView):
"""
**Use Case**
CourseDetail returns details for a course.
**Example requests**:
GET /api/course_structure/v0/courses/{course_id}/
**Response Values**
* category: The type of content.
* name: The name of the course.
* uri: The URI to use to get details of the course.
* course: The course number.
* due: The due date. For courses, the value is always null.
* org: The organization specified for the course.
* id: The unique identifier for the course.
"""
serializer_class = serializers.CourseSerializer
def get_object(self, queryset=None):
return self.get_course_or_404()
class CourseStructure(CourseViewMixin, RetrieveAPIView):
"""
**Use Case**
Retrieves course structure.
**Example requests**:
GET /api/course_structure/v0/course_structures/{course_id}/
**Response Values**
* root: ID of the root node of the structure
* blocks: Dictionary mapping IDs to block nodes.
"""
serializer_class = serializers.CourseStructureSerializer
course = None
def retrieve(self, request, *args, **kwargs):
try:
return super(CourseStructure, self).retrieve(request, *args, **kwargs)
except models.CourseStructure.DoesNotExist:
# If we don't have data stored, generate it and return a 503.
models.update_course_structure.delay(self.course.id)
return Response(status=503, headers={'Retry-After': '120'})
def get_object(self, queryset=None):
# Make sure the course exists and the user has permissions to view it.
self.course = self.get_course_or_404()
course_structure = models.CourseStructure.objects.get(course_id=self.course.id)
return course_structure.structure
class CourseGradingPolicy(CourseViewMixin, ListAPIView):
"""
**Use Case**
Retrieves course grading policy.
**Example requests**:
GET /api/course_structure/v0/grading_policies/{course_id}/
**Response Values**
* assignment_type: The type of the assignment (e.g. Exam, Homework). Note: These values are course-dependent.
Do not make any assumptions based on assignment type.
* count: Number of assignments of the type.
* dropped: Number of assignments of the type that are dropped.
* weight: Effect of the assignment type on grading.
"""
serializer_class = serializers.GradingPolicySerializer
allow_empty = False
def get_queryset(self):
course = self.get_course_or_404()
# Return the raw data. The serializer will handle the field mappings.
return course.raw_grader