""" LibraryContent: The XBlock used to include blocks from a library in a course. """ import json import logging import random from copy import copy from gettext import ngettext from rest_framework import status import bleach from django.conf import settings from django.utils.functional import classproperty from lazy import lazy from lxml import etree from lxml.etree import XMLSyntaxError from opaque_keys.edx.locator import LibraryLocator from pkg_resources import resource_string from web_fragments.fragment import Fragment from webob import Response from xblock.completable import XBlockCompletionMode from xblock.core import XBlock from xblock.fields import Integer, List, Scope, String, Boolean from capa.responsetypes import registry from xmodule.mako_module import MakoTemplateBlockBase from xmodule.studio_editable import StudioEditableBlock from xmodule.util.xmodule_django import add_webpack_to_fragment from xmodule.validation import StudioValidation, StudioValidationMessage from xmodule.xml_module import XmlMixin from xmodule.x_module import ( HTMLSnippet, ResourceTemplates, shim_xmodule_js, STUDENT_VIEW, XModuleMixin, XModuleToXBlockMixin, ) # 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 logger = logging.getLogger(__name__) ANY_CAPA_TYPE_VALUE = 'any' def _get_human_name(problem_class): """ Get the human-friendly name for a problem type. """ return getattr(problem_class, 'human_name', problem_class.__name__) def _get_capa_types(): """ Gets capa types tags and labels """ capa_types = {tag: _get_human_name(registry.get_class_for_tag(tag)) for tag in registry.registered_tags()} return [{'value': ANY_CAPA_TYPE_VALUE, 'display_name': _('Any Type')}] + sorted([ {'value': capa_type, 'display_name': caption} for capa_type, caption in capa_types.items() ], key=lambda item: item.get('display_name')) @XBlock.wants('library_tools') # Only needed in studio @XBlock.wants('studio_user_permissions') # Only available in studio @XBlock.wants('user') @XBlock.needs('mako') class LibraryContentBlock( MakoTemplateBlockBase, XmlMixin, XModuleToXBlockMixin, HTMLSnippet, ResourceTemplates, XModuleMixin, StudioEditableBlock, ): """ An XBlock whose children are chosen dynamically from a content library. Can be used to create randomized assessments among other things. Note: technically, all matching blocks from the content library are added as children of this block, but only a subset of those children are shown to any particular student. """ # pylint: disable=abstract-method has_children = True has_author_view = True resources_dir = 'assets/library_content' preview_view_js = { 'js': [], 'xmodule_js': resource_string(__name__, 'js/src/xmodule.js'), } preview_view_css = { 'scss': [], } mako_template = 'widgets/metadata-edit.html' studio_js_module_name = "VerticalDescriptor" studio_view_js = { 'js': [ resource_string(__name__, 'js/src/vertical/edit.js'), ], 'xmodule_js': resource_string(__name__, 'js/src/xmodule.js'), } studio_view_css = { 'scss': [], } show_in_read_only_mode = True # noinspection PyMethodParameters @classproperty def completion_mode(cls): # pylint: disable=no-self-argument """ Allow overriding the completion mode with a feature flag. This is a property, so it can be dynamically overridden in tests, as it is not evaluated at runtime. """ if settings.FEATURES.get('MARK_LIBRARY_CONTENT_BLOCK_COMPLETE_ON_VIEW', False): return XBlockCompletionMode.COMPLETABLE return XBlockCompletionMode.AGGREGATOR display_name = String( display_name=_("Display Name"), help=_("The display name for this component."), default="Randomized Content Block", scope=Scope.settings, ) source_library_id = String( display_name=_("Library"), help=_("Select the library from which you want to draw content."), scope=Scope.settings, values_provider=lambda instance: instance.source_library_values(), ) source_library_version = String( # This is a hidden field that stores the version of source_library when we last pulled content from it display_name=_("Library Version"), scope=Scope.settings, ) mode = String( display_name=_("Mode"), help=_("Determines how content is drawn from the library"), default="random", values=[ {"display_name": _("Choose n at random"), "value": "random"} # Future addition: Choose a new random set of n every time the student refreshes the block, for self tests # Future addition: manually selected blocks ], scope=Scope.settings, ) max_count = Integer( display_name=_("Count"), help=_("Enter the number of components to display to each student."), default=1, scope=Scope.settings, ) capa_type = String( display_name=_("Problem Type"), help=_('Choose a problem type to fetch from the library. If "Any Type" is selected no filtering is applied.'), default=ANY_CAPA_TYPE_VALUE, values=_get_capa_types(), scope=Scope.settings, ) selected = List( # This is a list of (block_type, block_id) tuples used to record # which random/first set of matching blocks was selected per user default=[], scope=Scope.user_state, ) # This cannot be called `show_reset_button`, because children blocks inherit this as a default value. allow_resetting_children = Boolean( display_name=_("Show Reset Button"), help=_("Determines whether a 'Reset Problems' button is shown, so users may reset their answers and reshuffle " "selected items."), scope=Scope.settings, default=False ) @property def source_library_key(self): """ Convenience method to get the library ID as a LibraryLocator and not just a string """ return LibraryLocator.from_string(self.source_library_id) @classmethod def make_selection(cls, selected, children, max_count, mode): """ Dynamically selects block_ids indicating which of the possible children are displayed to the current user. Arguments: selected - list of (block_type, block_id) tuples assigned to this student children - children of this block max_count - number of components to display to each student mode - how content is drawn from the library Returns: A dict containing the following keys: 'selected' (set) of (block_type, block_id) tuples assigned to this student 'invalid' (set) of dropped (block_type, block_id) tuples that are no longer valid 'overlimit' (set) of dropped (block_type, block_id) tuples that were previously selected 'added' (set) of newly added (block_type, block_id) tuples """ rand = random.Random() selected_keys = {tuple(k) for k in selected} # set of (block_type, block_id) tuples assigned to this student # Determine which of our children we will show: valid_block_keys = {(c.block_type, c.block_id) for c in children} # Remove any selected blocks that are no longer valid: invalid_block_keys = (selected_keys - valid_block_keys) if invalid_block_keys: selected_keys -= invalid_block_keys # If max_count has been decreased, we may have to drop some previously selected blocks: overlimit_block_keys = set() if len(selected_keys) > max_count: num_to_remove = len(selected_keys) - max_count overlimit_block_keys = set(rand.sample(selected_keys, num_to_remove)) selected_keys -= overlimit_block_keys # Do we have enough blocks now? num_to_add = max_count - len(selected_keys) added_block_keys = None if num_to_add > 0: # We need to select [more] blocks to display to this user: pool = valid_block_keys - selected_keys if mode == "random": num_to_add = min(len(pool), num_to_add) added_block_keys = set(rand.sample(pool, num_to_add)) # We now have the correct n random children to show for this user. else: raise NotImplementedError("Unsupported mode.") selected_keys |= added_block_keys if any((invalid_block_keys, overlimit_block_keys, added_block_keys)): selected = list(selected_keys) random.shuffle(selected) return { 'selected': selected, 'invalid': invalid_block_keys, 'overlimit': overlimit_block_keys, 'added': added_block_keys, } def _publish_event(self, event_name, result, **kwargs): """ Helper method to publish an event for analytics purposes """ event_data = { "location": str(self.location), "result": result, "previous_count": getattr(self, "_last_event_result_count", len(self.selected)), "max_count": self.max_count, } event_data.update(kwargs) self.runtime.publish(self, f"edx.librarycontentblock.content.{event_name}", event_data) self._last_event_result_count = len(result) # pylint: disable=attribute-defined-outside-init @classmethod def publish_selected_children_events(cls, block_keys, format_block_keys, publish_event): """ Helper method for publishing events when children blocks are selected/updated for a user. This helper is also used by the ContentLibraryTransformer. Arguments: block_keys - A dict describing which events to publish (add or remove), see `make_selection` above for format details. format_block_keys - A function to convert block keys to the format expected by publish_event. Must have the signature: [(block_type, block_id)] -> T Where T is a collection of block keys as accepted by `publish_event`. publish_event - Function that handles the actual publishing. Must have the signature: <'removed'|'assigned'> -> result:T -> removed:T -> reason:str -> None Where T is a collection of block_keys as returned by `format_block_keys`. """ if block_keys['invalid']: # reason "invalid" means deleted from library or a different library is now being used. publish_event( "removed", result=format_block_keys(block_keys['selected']), removed=format_block_keys(block_keys['invalid']), reason="invalid" ) if block_keys['overlimit']: publish_event( "removed", result=format_block_keys(block_keys['selected']), removed=format_block_keys(block_keys['overlimit']), reason="overlimit" ) if block_keys['added']: publish_event( "assigned", result=format_block_keys(block_keys['selected']), added=format_block_keys(block_keys['added']) ) def selected_children(self): """ Returns a [] of block_ids indicating which of the possible children have been selected to display to the current user. This reads and updates the "selected" field, which has user_state scope. Note: the return value (self.selected) contains block_ids. To get actual BlockUsageLocators, it is necessary to use self.children, because the block_ids alone do not specify the block type. """ block_keys = self.make_selection(self.selected, self.children, self.max_count, "random") # pylint: disable=no-member # Publish events for analytics purposes: lib_tools = self.runtime.service(self, 'library_tools') format_block_keys = lambda keys: lib_tools.create_block_analytics_summary(self.location.course_key, keys) self.publish_selected_children_events( block_keys, format_block_keys, self._publish_event, ) if any(block_keys[changed] for changed in ('invalid', 'overlimit', 'added')): # Save our selections to the user state, to ensure consistency: selected = block_keys['selected'] self.selected = selected # TODO: this doesn't save from the LMS "Progress" page. return self.selected @XBlock.handler def reset_selected_children(self, _, __): """ Resets the XBlock's state for a user. This resets the state of all `selected` children and then clears the `selected` field so that the new blocks are randomly chosen for this user. """ if not self.allow_resetting_children: return Response('"Resetting selected children" is not allowed for this XBlock', status=status.HTTP_400_BAD_REQUEST) for block_type, block_id in self.selected_children(): block = self.runtime.get_block(self.location.course_key.make_usage_key(block_type, block_id)) if hasattr(block, 'reset_problem'): block.reset_problem(None) block.save() self.selected = [] return Response(json.dumps(self.student_view({}).content)) def _get_selected_child_blocks(self): """ Generator returning XBlock instances of the children selected for the current user. """ for block_type, block_id in self.selected_children(): yield self.runtime.get_block(self.location.course_key.make_usage_key(block_type, block_id)) def student_view(self, context): # lint-amnesty, pylint: disable=missing-function-docstring fragment = Fragment() contents = [] child_context = {} if not context else copy(context) for child in self._get_selected_child_blocks(): if child is None: # TODO: Fix the underlying issue in TNL-7424 # This shouldn't be happening, but does for an as-of-now # unknown reason. Until we address the underlying issue, # let's at least log the error explicitly, ignore the # exception, and prevent the page from resulting in a # 500-response. logger.error('Skipping display for child block that is None') continue for displayable in child.displayable_items(): rendered_child = displayable.render(STUDENT_VIEW, child_context) fragment.add_fragment_resources(rendered_child) contents.append({ 'id': str(displayable.location), 'content': rendered_child.content, }) fragment.add_content(self.runtime.service(self, 'mako').render_template('vert_module.html', { 'items': contents, 'xblock_context': context, 'show_bookmark_button': False, 'watched_completable_blocks': set(), 'completion_delay_ms': None, 'reset_button': self.allow_resetting_children, })) fragment.add_javascript_url(self.runtime.local_resource_url(self, 'public/js/library_content_reset.js')) fragment.initialize_js('LibraryContentReset') return fragment def author_view(self, context): """ Renders the Studio views. Normal studio view: If block is properly configured, displays library status summary Studio container view: displays a preview of all possible children. """ fragment = Fragment() root_xblock = context.get('root_xblock') is_root = root_xblock and root_xblock.location == self.location if is_root: # User has clicked the "View" link. Show a preview of all possible children: if self.children: # pylint: disable=no-member fragment.add_content(self.runtime.service(self, 'mako').render_template( "library-block-author-preview-header.html", { 'max_count': self.max_count, 'display_name': self.display_name or self.url_name, })) context['can_edit_visibility'] = False context['can_move'] = False self.render_children(context, fragment, can_reorder=False, can_add=False) # else: When shown on a unit page, don't show any sort of preview - # just the status of this block in the validation area. # The following JS is used to make the "Update now" button work on the unit page and the container view: fragment.add_javascript_url(self.runtime.local_resource_url(self, 'public/js/library_content_edit.js')) fragment.initialize_js('LibraryContentAuthorView') return fragment def studio_view(self, _context): """ Return the studio view. """ fragment = Fragment( self.runtime.service(self, 'mako').render_template(self.mako_template, self.get_context()) ) add_webpack_to_fragment(fragment, 'LibraryContentBlockStudio') shim_xmodule_js(fragment, self.studio_js_module_name) return fragment def get_child_descriptors(self): """ Return only the subset of our children relevant to the current student. """ return list(self._get_selected_child_blocks()) @property def non_editable_metadata_fields(self): non_editable_fields = super().non_editable_metadata_fields # The only supported mode is currently 'random'. # Add the mode field to non_editable_metadata_fields so that it doesn't # render in the edit form. non_editable_fields.extend([ LibraryContentBlock.mode, LibraryContentBlock.source_library_version, ]) return non_editable_fields @lazy def tools(self): """ Grab the library tools service or raise an error. """ return self.runtime.service(self, 'library_tools') def get_user_id(self): """ Get the ID of the current user. """ user_service = self.runtime.service(self, 'user') if user_service: # May be None when creating bok choy test fixtures user_id = user_service.get_current_user().opt_attrs.get('edx-platform.user_id', None) else: user_id = None return user_id @XBlock.handler def refresh_children(self, request=None, suffix=None): # lint-amnesty, pylint: disable=unused-argument """ Refresh children: This method is to be used when any of the libraries that this block references have been updated. It will re-fetch all matching blocks from the libraries, and copy them as children of this block. The children will be given new block_ids, but the definition ID used should be the exact same definition ID used in the library. This method will update this block's 'source_library_id' field to store the version number of the libraries used, so we easily determine if this block is up to date or not. """ user_perms = self.runtime.service(self, 'studio_user_permissions') if not self.tools: return Response("Library Tools unavailable in current runtime.", status=400) self.tools.update_children(self, user_perms) return Response() # Copy over any overridden settings the course author may have applied to the blocks. def _copy_overrides(self, store, user_id, source, dest): """ Copy any overrides the user has made on blocks in this library. """ for field in source.fields.values(): if field.scope == Scope.settings and field.is_set_on(source): setattr(dest, field.name, field.read_from(source)) if source.has_children: source_children = [self.runtime.get_block(source_key) for source_key in source.children] dest_children = [self.runtime.get_block(dest_key) for dest_key in dest.children] for source_child, dest_child in zip(source_children, dest_children): self._copy_overrides(store, user_id, source_child, dest_child) store.update_item(dest, user_id) def studio_post_duplicate(self, store, source_block): """ Used by the studio after basic duplication of a source block. We handle the children ourselves, because we have to properly reference the library upstream and set the overrides. Otherwise we'll end up losing data on the next refresh. """ # The first task will be to refresh our copy of the library to generate the children. # We must do this at the currently set version of the library block. Otherwise we may not have # exactly the same children-- someone may be duplicating an out of date block, after all. user_id = self.get_user_id() user_perms = self.runtime.service(self, 'studio_user_permissions') if not self.tools: raise RuntimeError("Library tools unavailable, duplication will not be sane!") self.tools.update_children(self, user_perms, version=self.source_library_version) self._copy_overrides(store, user_id, source_block, self) # Children have been handled. return True def _validate_library_version(self, validation, lib_tools, version, library_key): """ Validates library version """ latest_version = lib_tools.get_library_version(library_key) if latest_version is not None: if version is None or version != str(latest_version): validation.set_summary( StudioValidationMessage( StudioValidationMessage.WARNING, _('This component is out of date. The library has new content.'), # TODO: change this to action_runtime_event='...' once the unit page supports that feature. # See https://openedx.atlassian.net/browse/TNL-993 action_class='library-update-btn', # Translators: {refresh_icon} placeholder is substituted to "↻" (without double quotes) action_label=_("{refresh_icon} Update now.").format(refresh_icon="↻") ) ) return False else: validation.set_summary( StudioValidationMessage( StudioValidationMessage.ERROR, _('Library is invalid, corrupt, or has been deleted.'), action_class='edit-button', action_label=_("Edit Library List.") ) ) return False return True def _set_validation_error_if_empty(self, validation, summary): """ Helper method to only set validation summary if it's empty """ if validation.empty: validation.set_summary(summary) def validate(self): """ Validates the state of this Library Content Module Instance. This is the override of the general XBlock method, and it will also ask its superclass to validate. """ validation = super().validate() if not isinstance(validation, StudioValidation): validation = StudioValidation.copy(validation) library_tools = self.runtime.service(self, "library_tools") if not (library_tools and library_tools.can_use_library_content(self)): validation.set_summary( StudioValidationMessage( StudioValidationMessage.ERROR, _( "This course does not support content libraries. " "Contact your system administrator for more information." ) ) ) return validation if not self.source_library_id: validation.set_summary( StudioValidationMessage( StudioValidationMessage.NOT_CONFIGURED, _("A library has not yet been selected."), action_class='edit-button', action_label=_("Select a Library.") ) ) return validation lib_tools = self.runtime.service(self, 'library_tools') self._validate_library_version(validation, lib_tools, self.source_library_version, self.source_library_key) # Note: we assume refresh_children() has been called # since the last time fields like source_library_id or capa_types were changed. matching_children_count = len(self.children) # pylint: disable=no-member if matching_children_count == 0: self._set_validation_error_if_empty( validation, StudioValidationMessage( StudioValidationMessage.WARNING, _('There are no matching problem types in the specified libraries.'), action_class='edit-button', action_label=_("Select another problem type.") ) ) if matching_children_count < self.max_count: self._set_validation_error_if_empty( validation, StudioValidationMessage( StudioValidationMessage.WARNING, ( ngettext( 'The specified library is configured to fetch {count} problem, ', 'The specified library is configured to fetch {count} problems, ', self.max_count ) + ngettext( 'but there is only {actual} matching problem.', 'but there are only {actual} matching problems.', matching_children_count ) ).format(count=self.max_count, actual=matching_children_count), action_class='edit-button', action_label=_("Edit the library configuration.") ) ) return validation def source_library_values(self): """ Return a list of possible values for self.source_library_id """ lib_tools = self.runtime.service(self, 'library_tools') user_perms = self.runtime.service(self, 'studio_user_permissions') all_libraries = [ (key, bleach.clean(name)) for key, name in lib_tools.list_available_libraries() if user_perms.can_read(key) or self.source_library_id == str(key) ] all_libraries.sort(key=lambda entry: entry[1]) # Sort by name if self.source_library_id and self.source_library_key not in [entry[0] for entry in all_libraries]: all_libraries.append((self.source_library_id, _("Invalid Library"))) all_libraries = [("", _("No Library Selected"))] + all_libraries values = [{"display_name": name, "value": str(key)} for key, name in all_libraries] return values def editor_saved(self, user, old_metadata, old_content): # lint-amnesty, pylint: disable=unused-argument """ If source_library_id or capa_type has been edited, refresh_children automatically. """ old_source_library_id = old_metadata.get('source_library_id', []) if (old_source_library_id != self.source_library_id or old_metadata.get('capa_type', ANY_CAPA_TYPE_VALUE) != self.capa_type): try: self.refresh_children() except ValueError: pass # The validation area will display an error message, no need to do anything now. def has_dynamic_children(self): """ Inform the runtime that our children vary per-user. See get_child_descriptors() above """ return True def get_content_titles(self): """ Returns list of friendly titles for our selected children only; without thi, all possible children's titles would be seen in the sequence bar in the LMS. This overwrites the get_content_titles method included in x_module by default. """ titles = [] for child in self.get_child_descriptors(): titles.extend(child.get_content_titles()) return titles @classmethod def definition_from_xml(cls, xml_object, system): children = [] for child in xml_object.getchildren(): try: children.append(system.process_xml(etree.tostring(child)).scope_ids.usage_id) except (XMLSyntaxError, AttributeError): msg = ( "Unable to load child when parsing Library Content Block. " "This can happen when a comment is manually added to the course export." ) logger.error(msg) if system.error_tracker is not None: system.error_tracker(msg) definition = { attr_name: json.loads(attr_value) for attr_name, attr_value in xml_object.attrib.items() } return definition, children def definition_to_xml(self, resource_fs): """ Exports Library Content Module to XML """ xml_object = etree.Element('library_content') for child in self.get_children(): self.runtime.add_block_as_child_node(child, xml_object) # Set node attributes based on our fields. for field_name, field in self.fields.items(): # pylint: disable=no-member if field_name in ('children', 'parent', 'content'): continue if field.is_set_on(self): xml_object.set(field_name, str(field.read_from(self))) return xml_object class LibrarySummary: """ A library summary object which contains the fields required for library listing on studio. """ def __init__(self, library_locator, display_name): """ Initialize LibrarySummary Arguments: library_locator (LibraryLocator): LibraryLocator object of the library. display_name (unicode): display name of the library. """ self.display_name = display_name if display_name else _("Empty") self.id = library_locator # pylint: disable=invalid-name self.location = library_locator.make_usage_key('library', 'library') @property def display_org_with_default(self): """ Org display names are not implemented. This just provides API compatibility with CourseBlock. Always returns the raw 'org' field from the key. """ return self.location.library_key.org @property def display_number_with_default(self): """ Display numbers are not implemented. This just provides API compatibility with CourseBlock. Always returns the raw 'library' field from the key. """ return self.location.library_key.library