4f807dd702
* run modernizer on openedx/core/djangoapps/embargo/ * sorting imports * sort imports * docstring * try removing pylint disable
211 lines
6.9 KiB
Python
211 lines
6.9 KiB
Python
"""
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The Python API layer of the country access settings. Essentially the middle tier of the project, responsible for all
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business logic that is not directly tied to the data itself.
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This API is exposed via the middleware(emabargo/middileware.py) layer but may be used directly in-process.
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"""
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from __future__ import absolute_import
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import logging
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from django.conf import settings
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from django.core.cache import cache
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from ipware.ip import get_ip
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from rest_framework import status
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from rest_framework.response import Response
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import geoip2.database
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from student.auth import has_course_author_access
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from .models import CountryAccessRule, RestrictedCourse
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log = logging.getLogger(__name__)
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def redirect_if_blocked(course_key, access_point='enrollment', **kwargs):
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"""Redirect if the user does not have access to the course. In case of blocked if access_point
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is not enrollment and course has enabled is_disabled_access_check then user can view that course.
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Arguments:
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course_key (CourseKey): Location of the course the user is trying to access.
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Keyword Arguments:
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Same as `check_course_access` and `message_url_path`
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"""
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if settings.FEATURES.get('EMBARGO'):
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is_blocked = not check_course_access(course_key, **kwargs)
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if is_blocked:
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if access_point == "courseware":
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if not RestrictedCourse.is_disabled_access_check(course_key):
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return message_url_path(course_key, access_point)
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else:
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return message_url_path(course_key, access_point)
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def check_course_access(course_key, user=None, ip_address=None, url=None):
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"""
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Check is the user with this ip_address has access to the given course
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Arguments:
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course_key (CourseKey): Location of the course the user is trying to access.
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Keyword Arguments:
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user (User): The user making the request. Can be None, in which case
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the user's profile country will not be checked.
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ip_address (str): The IP address of the request.
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url (str): The URL the user is trying to access. Used in
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log messages.
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Returns:
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Boolean: True if the user has access to the course; False otherwise
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"""
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# No-op if the country access feature is not enabled
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if not settings.FEATURES.get('EMBARGO'):
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return True
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# First, check whether there are any restrictions on the course.
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# If not, then we do not need to do any further checks
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course_is_restricted = RestrictedCourse.is_restricted_course(course_key)
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if not course_is_restricted:
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return True
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# Always give global and course staff access, regardless of embargo settings.
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if user is not None and has_course_author_access(user, course_key):
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return True
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if ip_address is not None:
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# Retrieve the country code from the IP address
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# and check it against the allowed countries list for a course
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user_country_from_ip = _country_code_from_ip(ip_address)
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if not CountryAccessRule.check_country_access(course_key, user_country_from_ip):
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log.info(
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(
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u"Blocking user %s from accessing course %s at %s "
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u"because the user's IP address %s appears to be "
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u"located in %s."
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),
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getattr(user, 'id', '<Not Authenticated>'),
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course_key,
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url,
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ip_address,
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user_country_from_ip
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)
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return False
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if user is not None:
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# Retrieve the country code from the user's profile
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# and check it against the allowed countries list for a course.
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user_country_from_profile = _get_user_country_from_profile(user)
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if not CountryAccessRule.check_country_access(course_key, user_country_from_profile):
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log.info(
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(
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u"Blocking user %s from accessing course %s at %s "
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u"because the user's profile country is %s."
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),
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user.id, course_key, url, user_country_from_profile
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)
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return False
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return True
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def message_url_path(course_key, access_point):
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"""Determine the URL path for the message explaining why the user was blocked.
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This is configured per-course. See `RestrictedCourse` in the `embargo.models`
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module for more details.
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Arguments:
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course_key (CourseKey): The location of the course.
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access_point (str): How the user was trying to access the course.
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Can be either "enrollment" or "courseware".
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Returns:
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unicode: The URL path to a page explaining why the user was blocked.
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Raises:
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InvalidAccessPoint: Raised if access_point is not a supported value.
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"""
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return RestrictedCourse.message_url_path(course_key, access_point)
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def _get_user_country_from_profile(user):
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"""
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Check whether the user is embargoed based on the country code in the user's profile.
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Args:
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user (User): The user attempting to access courseware.
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Returns:
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user country from profile.
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"""
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cache_key = u'user.{user_id}.profile.country'.format(user_id=user.id)
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profile_country = cache.get(cache_key)
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if profile_country is None:
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profile = getattr(user, 'profile', None)
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if profile is not None and profile.country.code is not None:
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profile_country = profile.country.code.upper()
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else:
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profile_country = ""
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cache.set(cache_key, profile_country)
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return profile_country
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def _country_code_from_ip(ip_addr):
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"""
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Return the country code associated with an IP address.
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Handles both IPv4 and IPv6 addresses.
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Args:
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ip_addr (str): The IP address to look up.
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Returns:
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str: A 2-letter country code.
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"""
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reader = geoip2.database.Reader(settings.GEOIP_PATH)
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try:
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response = reader.country(ip_addr)
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# pylint: disable=no-member
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country_code = response.country.iso_code
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except geoip2.errors.AddressNotFoundError:
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country_code = ""
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reader.close()
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return country_code
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def get_embargo_response(request, course_id, user):
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"""
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Check whether any country access rules block the user from enrollment.
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Args:
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request (HttpRequest): The request object
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course_id (str): The requested course ID
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user (str): The current user object
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Returns:
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HttpResponse: Response of the embargo page if embargoed, None if not
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"""
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redirect_url = redirect_if_blocked(
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course_id, user=user, ip_address=get_ip(request), url=request.path)
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if redirect_url:
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return Response(
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status=status.HTTP_403_FORBIDDEN,
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data={
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"message": (
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u"Users from this location cannot access the course '{course_id}'."
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).format(course_id=course_id),
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"user_message_url": request.build_absolute_uri(redirect_url)
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}
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)
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