Files
edx-platform/common/lib/xmodule/xmodule/seq_module.py

748 lines
28 KiB
Python

"""
xModule implementation of a learning sequence
"""
# pylint: disable=abstract-method
import collections
import json
import logging
from datetime import datetime
from lxml import etree
from opaque_keys.edx.keys import UsageKey
from pkg_resources import resource_string
from pytz import UTC
from six import text_type
from web_fragments.fragment import Fragment
from xblock.completable import XBlockCompletionMode
from xblock.core import XBlock
from xblock.fields import Boolean, Integer, List, Scope, String
from .exceptions import NotFoundError
from .fields import Date
from .mako_module import MakoModuleDescriptor
from .progress import Progress
from .x_module import STUDENT_VIEW, PUBLIC_VIEW, XModule
from .xml_module import XmlDescriptor
log = logging.getLogger(__name__)
try:
import newrelic.agent
except ImportError:
newrelic = None # pylint: disable=invalid-name
# HACK: This shouldn't be hard-coded to two types
# OBSOLETE: This obsoletes 'type'
class_priority = ['video', 'problem']
# Make '_' a no-op so we can scrape strings. Using lambda instead of
# `django.utils.translation.ugettext_noop` because Django cannot be imported in this file
_ = lambda text: text
class SequenceFields(object):
has_children = True
completion_mode = XBlockCompletionMode.AGGREGATOR
# NOTE: Position is 1-indexed. This is silly, but there are now student
# positions saved on prod, so it's not easy to fix.
position = Integer(help="Last tab viewed in this sequence", scope=Scope.user_state)
due = Date(
display_name=_("Due Date"),
help=_("Enter the date by which problems are due."),
scope=Scope.settings,
)
hide_after_due = Boolean(
display_name=_("Hide sequence content After Due Date"),
help=_(
"If set, the sequence content is hidden for non-staff users after the due date has passed."
),
default=False,
scope=Scope.settings,
)
is_entrance_exam = Boolean(
display_name=_("Is Entrance Exam"),
help=_(
"Tag this course module as an Entrance Exam. "
"Note, you must enable Entrance Exams for this course setting to take effect."
),
default=False,
scope=Scope.settings,
)
class ProctoringFields(object):
"""
Fields that are specific to Proctored or Timed Exams
"""
is_time_limited = Boolean(
display_name=_("Is Time Limited"),
help=_(
"This setting indicates whether students have a limited time"
" to view or interact with this courseware component."
),
default=False,
scope=Scope.settings,
)
default_time_limit_minutes = Integer(
display_name=_("Time Limit in Minutes"),
help=_(
"The number of minutes available to students for viewing or interacting with this courseware component."
),
default=None,
scope=Scope.settings,
)
is_proctored_enabled = Boolean(
display_name=_("Is Proctoring Enabled"),
help=_(
"This setting indicates whether this exam is a proctored exam."
),
default=False,
scope=Scope.settings,
)
exam_review_rules = String(
display_name=_("Software Secure Review Rules"),
help=_(
"This setting indicates what rules the proctoring team should follow when viewing the videos."
),
default='',
scope=Scope.settings,
)
is_practice_exam = Boolean(
display_name=_("Is Practice Exam"),
help=_(
"This setting indicates whether this exam is for testing purposes only. Practice exams are not verified."
),
default=False,
scope=Scope.settings,
)
is_onboarding_exam = Boolean(
display_name=_("Is Onboarding Exam"),
help=_(
"This setting indicates whether this exam is an onboarding exam."
),
default=False,
scope=Scope.settings,
)
def _get_course(self):
"""
Return course by course id.
"""
return self.descriptor.runtime.modulestore.get_course(self.course_id) # pylint: disable=no-member
@property
def is_timed_exam(self):
"""
Alias the permutation of above fields that corresponds to un-proctored timed exams
to the more clearly-named is_timed_exam
"""
return not self.is_proctored_enabled and not self.is_practice_exam and self.is_time_limited
@property
def is_proctored_exam(self):
""" Alias the is_proctored_enabled field to the more legible is_proctored_exam """
return self.is_proctored_enabled
@property
def allow_proctoring_opt_out(self):
"""
Returns true if the learner should be given the option to choose between
taking a proctored exam, or opting out to take the exam without proctoring.
"""
return self._get_course().allow_proctoring_opt_out
@is_proctored_exam.setter
def is_proctored_exam(self, value):
""" Alias the is_proctored_enabled field to the more legible is_proctored_exam """
self.is_proctored_enabled = value
@XBlock.wants('proctoring')
@XBlock.wants('verification')
@XBlock.wants('gating')
@XBlock.wants('credit')
@XBlock.wants('completion')
@XBlock.needs('user')
@XBlock.needs('bookmarks')
@XBlock.needs('i18n')
class SequenceModule(SequenceFields, ProctoringFields, XModule):
"""
Layout module which lays out content in a temporal sequence
"""
js = {
'js': [resource_string(__name__, 'js/src/sequence/display.js')],
}
css = {
'scss': [resource_string(__name__, 'css/sequence/display.scss')],
}
js_module_name = "Sequence"
def __init__(self, *args, **kwargs):
super(SequenceModule, self).__init__(*args, **kwargs)
# If position is specified in system, then use that instead.
position = getattr(self.system, 'position', None)
if position is not None:
assert isinstance(position, int)
self.position = self.system.position
def get_progress(self):
''' Return the total progress, adding total done and total available.
(assumes that each submodule uses the same "units" for progress.)
'''
# TODO: Cache progress or children array?
children = self.get_children()
progresses = [child.get_progress() for child in children]
progress = reduce(Progress.add_counts, progresses, None)
return progress
def handle_ajax(self, dispatch, data): # TODO: bounds checking
''' get = request.POST instance '''
if dispatch == 'goto_position':
# set position to default value if either 'position' argument not
# found in request or it is a non-positive integer
position = data.get('position', u'1')
if position.isdigit() and int(position) > 0:
self.position = int(position)
else:
self.position = 1
return json.dumps({'success': True})
if dispatch == 'get_completion':
completion_service = self.runtime.service(self, 'completion')
usage_key = data.get('usage_key', None)
if not usage_key:
return None
item = self.get_child(UsageKey.from_string(usage_key))
if not item:
return None
complete = completion_service.vertical_is_complete(item)
return json.dumps({
'complete': complete
})
raise NotFoundError('Unexpected dispatch type')
@classmethod
def verify_current_content_visibility(cls, date, hide_after_date):
"""
Returns whether the content visibility policy passes
for the given date and hide_after_date values and
the current date-time.
"""
return (
not date or
not hide_after_date or
datetime.now(UTC) < date
)
def student_view(self, context):
_ = self.runtime.service(self, "i18n").ugettext
context = context or {}
self._capture_basic_metrics()
banner_text = None
prereq_met = True
prereq_meta_info = {}
if self._required_prereq():
if self.runtime.user_is_staff:
banner_text = _('This subsection is unlocked for learners when they meet the prerequisite requirements.')
else:
# check if prerequisite has been met
prereq_met, prereq_meta_info = self._compute_is_prereq_met(True)
if prereq_met:
special_html_view = self._hidden_content_student_view(context) or self._special_exam_student_view()
if special_html_view:
masquerading_as_specific_student = context.get('specific_masquerade', False)
banner_text, special_html = special_html_view
if special_html and not masquerading_as_specific_student:
return Fragment(special_html)
return self._student_or_public_view(context, prereq_met, prereq_meta_info, banner_text)
def public_view(self, context):
"""
Renders the preview view of the block in the LMS.
"""
prereq_met = True
prereq_meta_info = {}
if self._required_prereq():
prereq_met, prereq_meta_info = self._compute_is_prereq_met(True)
return self._student_or_public_view(context or {}, prereq_met, prereq_meta_info, None, PUBLIC_VIEW)
def _special_exam_student_view(self):
"""
Checks whether this sequential is a special exam. If so, returns
a banner_text or the fragment to display depending on whether
staff is masquerading.
"""
_ = self.runtime.service(self, "i18n").ugettext
if self.is_time_limited:
special_exam_html = self._time_limited_student_view()
if special_exam_html:
banner_text = _("This exam is hidden from the learner.")
return banner_text, special_exam_html
def _hidden_content_student_view(self, context):
"""
Checks whether the content of this sequential is hidden from the
runtime user. If so, returns a banner_text or the fragment to
display depending on whether staff is masquerading.
"""
_ = self.runtime.service(self, "i18n").ugettext
course = self._get_course()
if not self._can_user_view_content(course):
if course.self_paced:
banner_text = _("Because the course has ended, this assignment is hidden from the learner.")
else:
banner_text = _("Because the due date has passed, this assignment is hidden from the learner.")
hidden_content_html = self.system.render_template(
'hidden_content.html',
{
'self_paced': course.self_paced,
'progress_url': context.get('progress_url'),
}
)
return banner_text, hidden_content_html
def _can_user_view_content(self, course):
"""
Returns whether the runtime user can view the content
of this sequential.
"""
hidden_date = course.end if course.self_paced else self.due
return (
self.runtime.user_is_staff or
self.verify_current_content_visibility(hidden_date, self.hide_after_due)
)
def is_user_authenticated(self, context):
# NOTE (CCB): We default to true to maintain the behavior in place prior to allowing anonymous access access.
return context.get('user_authenticated', True)
def _student_or_public_view(self, context, prereq_met, prereq_meta_info, banner_text=None, view=STUDENT_VIEW):
"""
Returns the rendered student view of the content of this
sequential. If banner_text is given, it is added to the
content.
"""
_ = self.runtime.service(self, "i18n").ugettext
display_items = self.get_display_items()
self._update_position(context, len(display_items))
if prereq_met and not self._is_gate_fulfilled():
banner_text = _(
'This section is a prerequisite. You must complete this section in order to unlock additional content.'
)
fragment = Fragment()
items = self._render_student_view_for_items(context, display_items, fragment, view) if prereq_met else []
params = {
'items': items,
'element_id': self.location.html_id(),
'item_id': text_type(self.location),
'position': self.position,
'tag': self.location.block_type,
'ajax_url': self.system.ajax_url,
'next_url': context.get('next_url'),
'prev_url': context.get('prev_url'),
'banner_text': banner_text,
'save_position': view != PUBLIC_VIEW,
'show_completion': view != PUBLIC_VIEW,
'gated_content': self._get_gated_content_info(prereq_met, prereq_meta_info)
}
fragment.add_content(self.system.render_template("seq_module.html", params))
self._capture_full_seq_item_metrics(display_items)
self._capture_current_unit_metrics(display_items)
return fragment
def _get_gated_content_info(self, prereq_met, prereq_meta_info):
"""
Returns a dict of information about gated_content context
"""
gated_content = {}
gated_content['gated'] = not prereq_met
gated_content['prereq_url'] = prereq_meta_info['url'] if not prereq_met else None
gated_content['prereq_section_name'] = prereq_meta_info['display_name'] if not prereq_met else None
gated_content['gated_section_name'] = self.display_name
return gated_content
def _is_gate_fulfilled(self):
"""
Determines if this section is a prereq and has any unfulfilled milestones.
Returns:
True if section has no unfufilled milestones or is not a prerequisite.
False otherwise
"""
gating_service = self.runtime.service(self, 'gating')
if gating_service:
fulfilled = gating_service.is_gate_fulfilled(
self.course_id, self.location, self.runtime.user_id
)
return fulfilled
return True
def _required_prereq(self):
"""
Checks whether a prerequisite is required for this Section
Returns:
milestone if a prereq is required, None otherwise
"""
gating_service = self.runtime.service(self, 'gating')
if gating_service:
milestone = gating_service.required_prereq(
self.course_id, self.location, 'requires'
)
return milestone
return None
def _compute_is_prereq_met(self, recalc_on_unmet):
"""
Evaluate if the user has completed the prerequisite
Arguments:
recalc_on_unmet: Recalculate the subsection grade if prereq has not yet been met
Returns:
tuple: True|False,
prereq_meta_info = { 'url': prereq_url, 'display_name': prereq_name}
"""
gating_service = self.runtime.service(self, 'gating')
if gating_service:
return gating_service.compute_is_prereq_met(self.location, self.runtime.user_id, recalc_on_unmet)
return True, {}
def _update_position(self, context, number_of_display_items):
"""
Update the user's sequential position given the context and the
number_of_display_items
"""
position = context.get('position')
if position:
self.position = position
# If we're rendering this sequence, but no position is set yet,
# or exceeds the length of the displayable items,
# default the position to the first element
if context.get('requested_child') == 'first':
self.position = 1
elif context.get('requested_child') == 'last':
self.position = number_of_display_items or 1
elif self.position is None or self.position > number_of_display_items:
self.position = 1
def _render_student_view_for_items(self, context, display_items, fragment, view=STUDENT_VIEW):
"""
Updates the given fragment with rendered student views of the given
display_items. Returns a list of dict objects with information about
the given display_items.
"""
is_user_authenticated = self.is_user_authenticated(context)
bookmarks_service = self.runtime.service(self, 'bookmarks')
completion_service = self.runtime.service(self, 'completion')
context['username'] = self.runtime.service(self, 'user').get_current_user().opt_attrs.get(
'edx-platform.username')
display_names = [
self.get_parent().display_name_with_default,
self.display_name_with_default
]
contents = []
for item in display_items:
# NOTE (CCB): This seems like a hack, but I don't see a better method of determining the type/category.
item_type = item.get_icon_class()
usage_id = item.scope_ids.usage_id
if item_type == 'problem' and not is_user_authenticated:
log.info(
'Problem [%s] was not rendered because anonymous access is not allowed for graded content',
usage_id
)
continue
show_bookmark_button = False
is_bookmarked = False
if is_user_authenticated:
show_bookmark_button = True
is_bookmarked = bookmarks_service.is_bookmarked(usage_key=usage_id)
context['show_bookmark_button'] = show_bookmark_button
context['bookmarked'] = is_bookmarked
rendered_item = item.render(view, context)
fragment.add_fragment_resources(rendered_item)
iteminfo = {
'content': rendered_item.content,
'page_title': getattr(item, 'tooltip_title', ''),
'type': item_type,
'id': text_type(usage_id),
'bookmarked': is_bookmarked,
'path': " > ".join(display_names + [item.display_name_with_default]),
'graded': item.graded
}
if is_user_authenticated:
if item.location.block_type == 'vertical':
if completion_service:
iteminfo['complete'] = completion_service.vertical_is_complete(item)
contents.append(iteminfo)
return contents
def _locations_in_subtree(self, node):
"""
The usage keys for all descendants of an XBlock/XModule as a flat list.
Includes the location of the node passed in.
"""
stack = [node]
locations = []
while stack:
curr = stack.pop()
locations.append(curr.location)
if curr.has_children:
stack.extend(curr.get_children())
return locations
def _capture_basic_metrics(self):
"""
Capture basic information about this sequence in New Relic.
"""
if not newrelic:
return
newrelic.agent.add_custom_parameter('seq.block_id', unicode(self.location))
newrelic.agent.add_custom_parameter('seq.display_name', self.display_name or '')
newrelic.agent.add_custom_parameter('seq.position', self.position)
newrelic.agent.add_custom_parameter('seq.is_time_limited', self.is_time_limited)
def _capture_full_seq_item_metrics(self, display_items):
"""
Capture information about the number and types of XBlock content in
the sequence as a whole. We send this information to New Relic so that
we can do better performance analysis of courseware.
"""
if not newrelic:
return
# Basic count of the number of Units (a.k.a. VerticalBlocks) we have in
# this learning sequence
newrelic.agent.add_custom_parameter('seq.num_units', len(display_items))
# Count of all modules (leaf nodes) in this sequence (e.g. videos,
# problems, etc.) The units (verticals) themselves are not counted.
all_item_keys = self._locations_in_subtree(self)
newrelic.agent.add_custom_parameter('seq.num_items', len(all_item_keys))
# Count of all modules by block_type (e.g. "video": 2, "discussion": 4)
block_counts = collections.Counter(usage_key.block_type for usage_key in all_item_keys)
for block_type, count in block_counts.items():
newrelic.agent.add_custom_parameter('seq.block_counts.{}'.format(block_type), count)
def _capture_current_unit_metrics(self, display_items):
"""
Capture information about the current selected Unit within the Sequence.
"""
if not newrelic:
return
# Positions are stored with indexing starting at 1. If we get into a
# weird state where the saved position is out of bounds (e.g. the
# content was changed), avoid going into any details about this unit.
if 1 <= self.position <= len(display_items):
# Basic info about the Unit...
current = display_items[self.position - 1]
newrelic.agent.add_custom_parameter('seq.current.block_id', unicode(current.location))
newrelic.agent.add_custom_parameter('seq.current.display_name', current.display_name or '')
# Examining all items inside the Unit (or split_test, conditional, etc.)
child_locs = self._locations_in_subtree(current)
newrelic.agent.add_custom_parameter('seq.current.num_items', len(child_locs))
curr_block_counts = collections.Counter(usage_key.block_type for usage_key in child_locs)
for block_type, count in curr_block_counts.items():
newrelic.agent.add_custom_parameter('seq.current.block_counts.{}'.format(block_type), count)
def _time_limited_student_view(self):
"""
Delegated rendering of a student view when in a time
limited view. This ultimately calls down into edx_proctoring
pip installed djangoapp
"""
# None = no overridden view rendering
view_html = None
proctoring_service = self.runtime.service(self, 'proctoring')
credit_service = self.runtime.service(self, 'credit')
verification_service = self.runtime.service(self, 'verification')
# Is this sequence designated as a Timed Examination, which includes
# Proctored Exams
feature_enabled = (
proctoring_service and
credit_service and
self.is_time_limited
)
if feature_enabled:
user_id = self.runtime.user_id
user_role_in_course = 'staff' if self.runtime.user_is_staff else 'student'
course_id = self.runtime.course_id
content_id = self.location
context = {
'display_name': self.display_name,
'default_time_limit_mins': (
self.default_time_limit_minutes if
self.default_time_limit_minutes else 0
),
'is_practice_exam': self.is_practice_exam,
'allow_proctoring_opt_out': self.allow_proctoring_opt_out,
'due_date': self.due
}
# inject the user's credit requirements and fulfillments
if credit_service:
credit_state = credit_service.get_credit_state(user_id, course_id)
if credit_state:
context.update({
'credit_state': credit_state
})
# inject verification status
if verification_service:
verification_status = verification_service.get_status(user_id)
context.update({
'verification_status': verification_status['status'],
'reverify_url': verification_service.reverify_url(),
})
# See if the edx-proctoring subsystem wants to present
# a special view to the student rather
# than the actual sequence content
#
# This will return None if there is no
# overridden view to display given the
# current state of the user
view_html = proctoring_service.get_student_view(
user_id=user_id,
course_id=course_id,
content_id=content_id,
context=context,
user_role=user_role_in_course
)
return view_html
def get_icon_class(self):
child_classes = set(child.get_icon_class()
for child in self.get_children())
new_class = 'other'
for c in class_priority:
if c in child_classes:
new_class = c
return new_class
class SequenceDescriptor(SequenceFields, ProctoringFields, MakoModuleDescriptor, XmlDescriptor):
"""
A Sequence's Descriptor object
"""
mako_template = 'widgets/sequence-edit.html'
module_class = SequenceModule
resources_dir = None
show_in_read_only_mode = True
js = {
'js': [resource_string(__name__, 'js/src/sequence/edit.js')],
}
js_module_name = "SequenceDescriptor"
@classmethod
def definition_from_xml(cls, xml_object, system):
children = []
for child in xml_object:
try:
child_block = system.process_xml(etree.tostring(child, encoding='unicode'))
children.append(child_block.scope_ids.usage_id)
except Exception as e:
log.exception("Unable to load child when parsing Sequence. Continuing...")
if system.error_tracker is not None:
system.error_tracker(u"ERROR: {0}".format(e))
continue
return {}, children
def definition_to_xml(self, resource_fs):
xml_object = etree.Element('sequential')
for child in self.get_children():
self.runtime.add_block_as_child_node(child, xml_object)
return xml_object
@property
def non_editable_metadata_fields(self):
"""
`is_entrance_exam` should not be editable in the Studio settings editor.
"""
non_editable_fields = super(SequenceDescriptor, self).non_editable_metadata_fields
non_editable_fields.append(self.fields['is_entrance_exam'])
return non_editable_fields
def index_dictionary(self):
"""
Return dictionary prepared with module content and type for indexing.
"""
# return key/value fields in a Python dict object
# values may be numeric / string or dict
# default implementation is an empty dict
xblock_body = super(SequenceDescriptor, self).index_dictionary()
html_body = {
"display_name": self.display_name,
}
if "content" in xblock_body:
xblock_body["content"].update(html_body)
else:
xblock_body["content"] = html_body
xblock_body["content_type"] = "Sequence"
return xblock_body
class HighlightsFields(object):
"""Only Sections have summaries now, but we may expand that later."""
highlights = List(
help=_("A list summarizing what students should look forward to in this section."),
scope=Scope.settings
)
class SectionModule(HighlightsFields, SequenceModule):
"""Module for a Section/Chapter."""
class SectionDescriptor(HighlightsFields, SequenceDescriptor):
"""Descriptor for a Section/Chapter."""
module_class = SectionModule