98 lines
4.2 KiB
Python
98 lines
4.2 KiB
Python
# -*- coding: utf-8 -*-
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"""
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Contains code related to computing content gating course duration limits
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and course access based on these limits.
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"""
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from datetime import timedelta
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from django.apps import apps
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from django.utils import timezone
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from django.utils.translation import ugettext as _
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from util.date_utils import DEFAULT_SHORT_DATE_FORMAT, strftime_localized
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from lms.djangoapps.courseware.access_response import AccessError
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from lms.djangoapps.courseware.access_utils import ACCESS_GRANTED
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from openedx.core.djangoapps.catalog.utils import get_course_run_details
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from openedx.core.djangoapps.content.course_overviews.models import CourseOverview
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MIN_DURATION = timedelta(weeks=4)
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MAX_DURATION = timedelta(weeks=12)
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class AuditExpiredError(AccessError):
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"""
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Access denied because the user's audit timespan has expired
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"""
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def __init__(self, user, course, expiration_date):
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error_code = "audit_expired"
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developer_message = "User {} had access to {} until {}".format(user, course, expiration_date)
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expiration_date = strftime_localized(expiration_date, DEFAULT_SHORT_DATE_FORMAT)
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user_message = _("Access expired on {expiration_date}").format(expiration_date=expiration_date)
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try:
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course_name = CourseOverview.get_from_id(course.id).display_name_with_default
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additional_context_user_message = _("Access to {course_name} expired on {expiration_date}").format(
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course_name=course_name,
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expiration_date=expiration_date
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)
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except CourseOverview.DoesNotExist:
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additional_context_user_message = _("Access to the course you were looking"
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"for expired on {expiration_date}").format(
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expiration_date=expiration_date
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)
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super(AuditExpiredError, self).__init__(error_code, developer_message, user_message,
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additional_context_user_message)
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def get_user_course_expiration_date(user, course):
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"""
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Return expiration date for given user course pair.
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Return None if the course does not expire.
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Business Logic:
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- Course access duration is bounded by the min and max duration.
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- If course fields are missing, default course access duration to MIN_DURATION.
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"""
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access_duration = MIN_DURATION
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CourseEnrollment = apps.get_model('student.CourseEnrollment')
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enrollment = CourseEnrollment.get_enrollment(user, course.id)
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if enrollment is None or enrollment.mode != 'audit':
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return None
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try:
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# Content availability date is equivalent to max(enrollment date, course start date)
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# for most people. Using the schedule date will provide flexibility to deal with
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# more complex business rules in the future.
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content_availability_date = enrollment.schedule.start
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except CourseEnrollment.schedule.RelatedObjectDoesNotExist:
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content_availability_date = max(enrollment.created, course.start)
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if course.self_paced:
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# The user course expiration date for self paced courses is the
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# content availability date plus the weeks_to_complete field from course-discovery.
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discovery_course_details = get_course_run_details(course.id, ['weeks_to_complete'])
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expected_weeks = discovery_course_details['weeks_to_complete'] or int(MIN_DURATION.days / 7)
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access_duration = timedelta(weeks=expected_weeks)
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elif not course.self_paced and course.end and course.start:
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# The user course expiration date for instructor paced courses is the
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# content availability date plus the duration of the course (course end date minus course start date).
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access_duration = course.end - course.start
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# Course access duration is bounded by the min and max duration.
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access_duration = max(MIN_DURATION, min(MAX_DURATION, access_duration))
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return content_availability_date + access_duration
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def check_course_expired(user, course):
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"""
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Check if the course expired for the user.
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"""
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expiration_date = get_user_course_expiration_date(user, course)
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if expiration_date and timezone.now() > expiration_date:
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return AuditExpiredError(user, course, expiration_date)
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return ACCESS_GRANTED
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