utils.py

#pylint: disable=E1103, E1101

import copy
import logging
import re

from django.conf import settings
from django.utils.translation import ugettext as _

from xmodule.contentstore.content import StaticContent
from xmodule.contentstore.django import contentstore
from xmodule.modulestore import Location
from xmodule.modulestore.django import modulestore
from xmodule.modulestore.exceptions import ItemNotFoundError
from django_comment_common.utils import unseed_permissions_roles
from xmodule.modulestore.store_utilities import delete_course
from xmodule.course_module import CourseDescriptor
from xmodule.modulestore.draft import DIRECT_ONLY_CATEGORIES
from student.roles import CourseInstructorRole, CourseStaffRole


log = logging.getLogger(__name__)

# In order to instantiate an open ended tab automatically, need to have this data
OPEN_ENDED_PANEL = {"name": _("Open Ended Panel"), "type": "open_ended"}
NOTES_PANEL = {"name": _("My Notes"), "type": "notes"}
EXTRA_TAB_PANELS = dict([(p['type'], p) for p in [OPEN_ENDED_PANEL, NOTES_PANEL]])


def delete_course_and_groups(course_id, commit=False):
    """
    This deletes the courseware associated with a course_id as well as cleaning update_item
    the various user table stuff (groups, permissions, etc.)
    """
    module_store = modulestore('direct')
    content_store = contentstore()

    org, course_num, _ = course_id.split("/")
    module_store.ignore_write_events_on_courses.append('{0}/{1}'.format(org, course_num))

    loc = CourseDescriptor.id_to_location(course_id)
    if delete_course(module_store, content_store, loc, commit):
        print 'removing forums permissions and roles...'
        unseed_permissions_roles(course_id)

        print 'removing User permissions from course....'
        # in the django layer, we need to remove all the user permissions groups associated with this course
        if commit:
            try:
                staff_role = CourseStaffRole(loc)
                staff_role.remove_users(*staff_role.users_with_role())
                instructor_role = CourseInstructorRole(loc)
                instructor_role.remove_users(*instructor_role.users_with_role())
            except Exception as err:
                log.error("Error in deleting course groups for {0}: {1}".format(loc, err))


def get_modulestore(category_or_location):
    """
    Returns the correct modulestore to use for modifying the specified location
    """
    if isinstance(category_or_location, Location):
        category_or_location = category_or_location.category

    if category_or_location in DIRECT_ONLY_CATEGORIES:
        return modulestore('direct')
    else:
        return modulestore()


def get_course_location_for_item(location):
    '''
    cdodge: for a given Xmodule, return the course that it belongs to
    NOTE: This makes a lot of assumptions about the format of the course location
    Also we have to assert that this module maps to only one course item - it'll throw an
    assert if not
    '''
    item_loc = Location(location)

    # check to see if item is already a course, if so we can skip this
    if item_loc.category != 'course':
        # @hack! We need to find the course location however, we don't
        # know the 'name' parameter in this context, so we have
        # to assume there's only one item in this query even though we are not specifying a name
        course_search_location = Location('i4x', item_loc.org, item_loc.course, 'course', None)
        courses = modulestore().get_items(course_search_location)

        # make sure we found exactly one match on this above course search
        found_cnt = len(courses)
        if found_cnt == 0:
            raise Exception('Could not find course at {0}'.format(course_search_location))

        if found_cnt > 1:
            raise Exception('Found more than one course at {0}. There should only be one!!! Dump = {1}'.format(course_search_location, courses))

        location = courses[0].location

    return location


def get_course_for_item(location):
    '''
    cdodge: for a given Xmodule, return the course that it belongs to
    NOTE: This makes a lot of assumptions about the format of the course location
    Also we have to assert that this module maps to only one course item - it'll throw an
    assert if not
    '''
    item_loc = Location(location)

    # @hack! We need to find the course location however, we don't
    # know the 'name' parameter in this context, so we have
    # to assume there's only one item in this query even though we are not specifying a name
    course_search_location = Location('i4x', item_loc.org, item_loc.course, 'course', None)
    courses = modulestore().get_items(course_search_location)

    # make sure we found exactly one match on this above course search
    found_cnt = len(courses)
    if found_cnt == 0:
        raise BaseException('Could not find course at {0}'.format(course_search_location))

    if found_cnt > 1:
        raise BaseException('Found more than one course at {0}. There should only be one!!! Dump = {1}'.format(course_search_location, courses))

    return courses[0]


def get_lms_link_for_item(location, preview=False, course_id=None):
    """
    Returns an LMS link to the course with a jump_to to the provided location.

    :param location: the location to jump to
    :param preview: True if the preview version of LMS should be returned. Default value is false.
    :param course_id: the course_id within which the location lives. If not specified, the course_id is obtained
           by calling Location(location).course_id; note that this only works for locations representing courses
           instead of elements within courses.
    """
    if course_id is None:
        course_id = Location(location).course_id

    if settings.LMS_BASE is not None:
        if preview:
            lms_base = settings.FEATURES.get('PREVIEW_LMS_BASE')
        else:
            lms_base = settings.LMS_BASE

        lms_link = "//{lms_base}/courses/{course_id}/jump_to/{location}".format(
            lms_base=lms_base,
            course_id=course_id,
            location=Location(location)
        )
    else:
        lms_link = None

    return lms_link


def get_lms_link_for_about_page(location):
    """
    Returns the url to the course about page from the location tuple.
    """
    if settings.FEATURES.get('ENABLE_MKTG_SITE', False):
        if not hasattr(settings, 'MKTG_URLS'):
            log.exception("ENABLE_MKTG_SITE is True, but MKTG_URLS is not defined.")
            about_base = None
        else:
            marketing_urls = settings.MKTG_URLS
            if marketing_urls.get('ROOT', None) is None:
                log.exception('There is no ROOT defined in MKTG_URLS')
                about_base = None
            else:
                # Root will be "https://www.edx.org". The complete URL will still not be exactly correct,
                # but redirects exist from www.edx.org to get to the Drupal course about page URL.
                about_base = marketing_urls.get('ROOT')
                # Strip off https:// (or http://) to be consistent with the formatting of LMS_BASE.
                about_base = re.sub(r"^https?://", "", about_base)
    elif settings.LMS_BASE is not None:
        about_base = settings.LMS_BASE
    else:
        about_base = None

    if about_base is not None:
        lms_link = "//{about_base_url}/courses/{course_id}/about".format(
            about_base_url=about_base,
            course_id=Location(location).course_id
        )
    else:
        lms_link = None

    return lms_link


def course_image_url(course):
    """Returns the image url for the course."""
    loc = course.location._replace(tag='c4x', category='asset', name=course.course_image)
    path = StaticContent.get_url_path_from_location(loc)
    return path


class UnitState(object):
    draft = 'draft'
    private = 'private'
    public = 'public'


def compute_unit_state(unit):
    """
    Returns whether this unit is 'draft', 'public', or 'private'.

    'draft' content is in the process of being edited, but still has a previous
        version visible in the LMS
    'public' content is locked and visible in the LMS
    'private' content is editabled and not visible in the LMS
    """

    if getattr(unit, 'is_draft', False):
        try:
            modulestore('direct').get_item(unit.location)
            return UnitState.draft
        except ItemNotFoundError:
            return UnitState.private
    else:
        return UnitState.public


def update_item(location, value):
    """
    If value is None, delete the db entry. Otherwise, update it using the correct modulestore.
    """
    if value is None:
        get_modulestore(location).delete_item(location)
    else:
        get_modulestore(location).update_item(location, value)


def add_extra_panel_tab(tab_type, course):
    """
    Used to add the panel tab to a course if it does not exist.
    @param tab_type: A string representing the tab type.
    @param course: A course object from the modulestore.
    @return: Boolean indicating whether or not a tab was added and a list of tabs for the course.
    """
    # Copy course tabs
    course_tabs = copy.copy(course.tabs)
    changed = False
    # Check to see if open ended panel is defined in the course

    tab_panel = EXTRA_TAB_PANELS.get(tab_type)
    if tab_panel not in course_tabs:
        # Add panel to the tabs if it is not defined
        course_tabs.append(tab_panel)
        changed = True
    return changed, course_tabs


def remove_extra_panel_tab(tab_type, course):
    """
    Used to remove the panel tab from a course if it exists.
    @param tab_type: A string representing the tab type.
    @param course: A course object from the modulestore.
    @return: Boolean indicating whether or not a tab was added and a list of tabs for the course.
    """
    # Copy course tabs
    course_tabs = copy.copy(course.tabs)
    changed = False
    # Check to see if open ended panel is defined in the course

    tab_panel = EXTRA_TAB_PANELS.get(tab_type)
    if tab_panel in course_tabs:
        # Add panel to the tabs if it is not defined
        course_tabs = [ct for ct in course_tabs if ct != tab_panel]
        changed = True
    return changed, course_tabs