Files
edx-platform/cms/djangoapps/contentstore/views/item.py
2014-07-09 21:10:12 -04:00

566 lines
23 KiB
Python

"""Views for items (modules)."""
from __future__ import absolute_import
import hashlib
import logging
from uuid import uuid4
from collections import OrderedDict
from functools import partial
from static_replace import replace_static_urls
from xmodule_modifiers import wrap_xblock
from django.core.exceptions import PermissionDenied
from django.contrib.auth.decorators import login_required
from django.http import HttpResponseBadRequest, HttpResponse, Http404
from django.utils.translation import ugettext as _
from django.views.decorators.http import require_http_methods
from xblock.fields import Scope
from xblock.fragment import Fragment
import xmodule
from xmodule.tabs import StaticTab, CourseTabList
from xmodule.modulestore import PublishState, ModuleStoreEnum
from xmodule.modulestore.django import modulestore
from xmodule.modulestore.draft import DIRECT_ONLY_CATEGORIES
from xmodule.modulestore.exceptions import ItemNotFoundError, InvalidLocationError, DuplicateItemError
from xmodule.modulestore.inheritance import own_metadata
from xmodule.x_module import PREVIEW_VIEWS, STUDIO_VIEW
from util.json_request import expect_json, JsonResponse
from .access import has_course_access
from .helpers import xblock_has_own_studio_page
from contentstore.utils import compute_publish_state
from contentstore.views.preview import get_preview_fragment
from edxmako.shortcuts import render_to_string
from models.settings.course_grading import CourseGradingModel
from cms.lib.xblock.runtime import handler_url, local_resource_url
from opaque_keys.edx.keys import UsageKey, CourseKey
__all__ = ['orphan_handler', 'xblock_handler', 'xblock_view_handler']
log = logging.getLogger(__name__)
CREATE_IF_NOT_FOUND = ['course_info']
# In order to allow descriptors to use a handler url, we need to
# monkey-patch the x_module library.
# TODO: Remove this code when Runtimes are no longer created by modulestores
xmodule.x_module.descriptor_global_handler_url = handler_url
xmodule.x_module.descriptor_global_local_resource_url = local_resource_url
def hash_resource(resource):
"""
Hash a :class:`xblock.fragment.FragmentResource`.
"""
md5 = hashlib.md5()
md5.update(repr(resource))
return md5.hexdigest()
# pylint: disable=unused-argument
@require_http_methods(("DELETE", "GET", "PUT", "POST"))
@login_required
@expect_json
def xblock_handler(request, usage_key_string):
"""
The restful handler for xblock requests.
DELETE
json: delete this xblock instance from the course.
GET
json: returns representation of the xblock (locator id, data, and metadata).
if ?fields=graderType, it returns the graderType for the unit instead of the above.
html: returns HTML for rendering the xblock (which includes both the "preview" view and the "editor" view)
PUT or POST
json: if xblock locator is specified, update the xblock instance. The json payload can contain
these fields, all optional:
:data: the new value for the data.
:children: the unicode representation of the UsageKeys of children for this xblock.
:metadata: new values for the metadata fields. Any whose values are None will be deleted not set
to None! Absent ones will be left alone.
:nullout: which metadata fields to set to None
:graderType: change how this unit is graded
:publish: can be one of three values, 'make_public, 'make_private', or 'create_draft'
The JSON representation on the updated xblock (minus children) is returned.
if usage_key_string is not specified, create a new xblock instance, either by duplicating
an existing xblock, or creating an entirely new one. The json playload can contain
these fields:
:parent_locator: parent for new xblock, required for both duplicate and create new instance
:duplicate_source_locator: if present, use this as the source for creating a duplicate copy
:category: type of xblock, required if duplicate_source_locator is not present.
:display_name: name for new xblock, optional
:boilerplate: template name for populating fields, optional and only used
if duplicate_source_locator is not present
The locator (unicode representation of a UsageKey) for the created xblock (minus children) is returned.
"""
if usage_key_string:
usage_key = UsageKey.from_string(usage_key_string)
if not has_course_access(request.user, usage_key.course_key):
raise PermissionDenied()
if request.method == 'GET':
accept_header = request.META.get('HTTP_ACCEPT', 'application/json')
if 'application/json' in accept_header:
fields = request.REQUEST.get('fields', '').split(',')
if 'graderType' in fields:
# right now can't combine output of this w/ output of _get_module_info, but worthy goal
return JsonResponse(CourseGradingModel.get_section_grader_type(usage_key))
# TODO: pass fields to _get_module_info and only return those
rsp = _get_module_info(usage_key, request.user)
return JsonResponse(rsp)
else:
return HttpResponse(status=406)
elif request.method == 'DELETE':
_delete_item(usage_key, request.user)
return JsonResponse()
else: # Since we have a usage_key, we are updating an existing xblock.
return _save_item(
request.user,
usage_key,
data=request.json.get('data'),
children=request.json.get('children'),
metadata=request.json.get('metadata'),
nullout=request.json.get('nullout'),
grader_type=request.json.get('graderType'),
publish=request.json.get('publish'),
)
elif request.method in ('PUT', 'POST'):
if 'duplicate_source_locator' in request.json:
parent_usage_key = UsageKey.from_string(request.json['parent_locator'])
duplicate_source_usage_key = UsageKey.from_string(request.json['duplicate_source_locator'])
dest_usage_key = _duplicate_item(
parent_usage_key,
duplicate_source_usage_key,
request.user,
request.json.get('display_name'),
)
return JsonResponse({"locator": unicode(dest_usage_key), "courseKey": unicode(dest_usage_key.course_key)})
else:
return _create_item(request)
else:
return HttpResponseBadRequest(
"Only instance creation is supported without a usage key.",
content_type="text/plain"
)
# pylint: disable=unused-argument
@require_http_methods(("GET"))
@login_required
@expect_json
def xblock_view_handler(request, usage_key_string, view_name):
"""
The restful handler for requests for rendered xblock views.
Returns a json object containing two keys:
html: The rendered html of the view
resources: A list of tuples where the first element is the resource hash, and
the second is the resource description
"""
usage_key = UsageKey.from_string(usage_key_string)
if not has_course_access(request.user, usage_key.course_key):
raise PermissionDenied()
accept_header = request.META.get('HTTP_ACCEPT', 'application/json')
if 'application/json' in accept_header:
store = modulestore()
xblock = store.get_item(usage_key)
is_read_only = _is_xblock_read_only(xblock)
container_views = ['container_preview', 'reorderable_container_child_preview']
unit_views = PREVIEW_VIEWS
# wrap the generated fragment in the xmodule_editor div so that the javascript
# can bind to it correctly
xblock.runtime.wrappers.append(partial(wrap_xblock, 'StudioRuntime', usage_id_serializer=unicode))
if view_name == STUDIO_VIEW:
try:
fragment = xblock.render(STUDIO_VIEW)
# catch exceptions indiscriminately, since after this point they escape the
# dungeon and surface as uneditable, unsaveable, and undeletable
# component-goblins.
except Exception as exc: # pylint: disable=w0703
log.debug("unable to render studio_view for %r", xblock, exc_info=True)
fragment = Fragment(render_to_string('html_error.html', {'message': str(exc)}))
store.update_item(xblock, request.user.id)
elif view_name in (unit_views + container_views):
is_container_view = (view_name in container_views)
# Determine the items to be shown as reorderable. Note that the view
# 'reorderable_container_child_preview' is only rendered for xblocks that
# are being shown in a reorderable container, so the xblock is automatically
# added to the list.
reorderable_items = set()
if view_name == 'reorderable_container_child_preview':
reorderable_items.add(xblock.location)
# Only show the new style HTML for the container view, i.e. for non-verticals
# Note: this special case logic can be removed once the unit page is replaced
# with the new container view.
context = {
'container_view': is_container_view,
'read_only': is_read_only,
'root_xblock': xblock if (view_name == 'container_preview') else None,
'reorderable_items': reorderable_items
}
fragment = get_preview_fragment(request, xblock, context)
# For old-style pages (such as unit and static pages), wrap the preview with
# the component div. Note that the container view recursively adds headers
# into the preview fragment, so we don't want to add another header here.
if not is_container_view:
# For non-leaf xblocks, show the special rendering which links to the new container page.
if xblock_has_own_studio_page(xblock):
template = 'container_xblock_component.html'
else:
template = 'component.html'
fragment.content = render_to_string(template, {
'xblock_context': context,
'xblock': xblock,
'locator': usage_key,
'preview': fragment.content,
'label': xblock.display_name or xblock.scope_ids.block_type,
})
else:
raise Http404
hashed_resources = OrderedDict()
for resource in fragment.resources:
hashed_resources[hash_resource(resource)] = resource
return JsonResponse({
'html': fragment.content,
'resources': hashed_resources.items()
})
else:
return HttpResponse(status=406)
def _is_xblock_read_only(xblock):
"""
Returns true if the specified xblock is read-only, meaning that it cannot be edited.
"""
# We allow direct editing of xblocks in DIRECT_ONLY_CATEGORIES (for example, static pages).
if xblock.category in DIRECT_ONLY_CATEGORIES:
return False
component_publish_state = compute_publish_state(xblock)
return component_publish_state == PublishState.public
def _save_item(user, usage_key, data=None, children=None, metadata=None, nullout=None,
grader_type=None, publish=None):
"""
Saves xblock w/ its fields. Has special processing for grader_type, publish, and nullout and Nones in metadata.
nullout means to truly set the field to None whereas nones in metadata mean to unset them (so they revert
to default).
"""
store = modulestore()
try:
existing_item = store.get_item(usage_key)
except ItemNotFoundError:
if usage_key.category in CREATE_IF_NOT_FOUND:
# New module at this location, for pages that are not pre-created.
# Used for course info handouts.
existing_item = store.create_and_save_xmodule(usage_key, user.id)
else:
raise
except InvalidLocationError:
log.error("Can't find item by location.")
return JsonResponse({"error": "Can't find item by location: " + unicode(usage_key)}, 404)
old_metadata = own_metadata(existing_item)
old_content = existing_item.get_explicitly_set_fields_by_scope(Scope.content)
if publish:
if publish == 'make_private':
try:
store.unpublish(existing_item.location, user.id),
except ItemNotFoundError:
pass
elif publish == 'create_draft':
try:
# This recursively clones the item subtree and marks the copies as draft
store.convert_to_draft(existing_item.location, user.id)
except DuplicateItemError:
pass
if data:
# TODO Allow any scope.content fields not just "data" (exactly like the get below this)
existing_item.data = data
else:
data = old_content['data'] if 'data' in old_content else None
if children is not None:
children_usage_keys = [
UsageKey.from_string(child)
for child
in children
]
existing_item.children = children_usage_keys
# also commit any metadata which might have been passed along
if nullout is not None or metadata is not None:
# the postback is not the complete metadata, as there's system metadata which is
# not presented to the end-user for editing. So let's use the original (existing_item) and
# 'apply' the submitted metadata, so we don't end up deleting system metadata.
if nullout is not None:
for metadata_key in nullout:
setattr(existing_item, metadata_key, None)
# update existing metadata with submitted metadata (which can be partial)
# IMPORTANT NOTE: if the client passed 'null' (None) for a piece of metadata that means 'remove it'. If
# the intent is to make it None, use the nullout field
if metadata is not None:
for metadata_key, value in metadata.items():
field = existing_item.fields[metadata_key]
if value is None:
field.delete_from(existing_item)
else:
try:
value = field.from_json(value)
except ValueError:
return JsonResponse({"error": "Invalid data"}, 400)
field.write_to(existing_item, value)
if callable(getattr(existing_item, "editor_saved", None)):
existing_item.editor_saved(user, old_metadata, old_content)
# commit to datastore
store.update_item(existing_item, user.id)
# for static tabs, their containing course also records their display name
if usage_key.category == 'static_tab':
course = store.get_course(usage_key.course_key)
# find the course's reference to this tab and update the name.
static_tab = CourseTabList.get_tab_by_slug(course.tabs, usage_key.name)
# only update if changed
if static_tab and static_tab['name'] != existing_item.display_name:
static_tab['name'] = existing_item.display_name
store.update_item(course, user.id)
result = {
'id': unicode(usage_key),
'data': data,
'metadata': own_metadata(existing_item)
}
if grader_type is not None:
result.update(CourseGradingModel.update_section_grader_type(existing_item, grader_type, user))
# Make public after updating the xblock, in case the caller asked
# for both an update and a publish.
if publish and publish == 'make_public':
modulestore().publish(existing_item.location, user.id)
# Note that children aren't being returned until we have a use case.
return JsonResponse(result)
@login_required
@expect_json
def _create_item(request):
"""View for create items."""
usage_key = UsageKey.from_string(request.json['parent_locator'])
category = request.json['category']
display_name = request.json.get('display_name')
if not has_course_access(request.user, usage_key.course_key):
raise PermissionDenied()
store = modulestore()
parent = store.get_item(usage_key)
dest_usage_key = usage_key.replace(category=category, name=uuid4().hex)
# get the metadata, display_name, and definition from the request
metadata = {}
data = None
template_id = request.json.get('boilerplate')
if template_id:
clz = parent.runtime.load_block_type(category)
if clz is not None:
template = clz.get_template(template_id)
if template is not None:
metadata = template.get('metadata', {})
data = template.get('data')
if display_name is not None:
metadata['display_name'] = display_name
created_block = store.create_and_save_xmodule(
dest_usage_key,
request.user.id,
definition_data=data,
metadata=metadata,
runtime=parent.runtime,
)
# VS[compat] cdodge: This is a hack because static_tabs also have references from the course module, so
# if we add one then we need to also add it to the policy information (i.e. metadata)
# we should remove this once we can break this reference from the course to static tabs
if category == 'static_tab':
course = store.get_course(dest_usage_key.course_key)
course.tabs.append(
StaticTab(
name=display_name,
url_slug=dest_usage_key.name,
)
)
store.update_item(course, request.user.id)
# TODO replace w/ nicer accessor
if not 'detached' in parent.runtime.load_block_type(category)._class_tags:
parent.children.append(created_block.location)
store.update_item(parent, request.user.id)
return JsonResponse({"locator": unicode(created_block.location), "courseKey": unicode(created_block.location.course_key)})
def _duplicate_item(parent_usage_key, duplicate_source_usage_key, user, display_name=None):
"""
Duplicate an existing xblock as a child of the supplied parent_usage_key.
"""
store = modulestore()
source_item = store.get_item(duplicate_source_usage_key)
# Change the blockID to be unique.
dest_usage_key = source_item.location.replace(name=uuid4().hex)
category = dest_usage_key.block_type
# Update the display name to indicate this is a duplicate (unless display name provided).
duplicate_metadata = own_metadata(source_item)
if display_name is not None:
duplicate_metadata['display_name'] = display_name
else:
if source_item.display_name is None:
duplicate_metadata['display_name'] = _("Duplicate of {0}").format(source_item.category)
else:
duplicate_metadata['display_name'] = _("Duplicate of '{0}'").format(source_item.display_name)
dest_module = store.create_and_save_xmodule(
dest_usage_key,
user.id,
definition_data=source_item.get_explicitly_set_fields_by_scope(Scope.content),
metadata=duplicate_metadata,
runtime=source_item.runtime,
)
# Children are not automatically copied over (and not all xblocks have a 'children' attribute).
# Because DAGs are not fully supported, we need to actually duplicate each child as well.
if source_item.has_children:
dest_module.children = []
for child in source_item.children:
dupe = _duplicate_item(dest_module.location, child, user=user)
dest_module.children.append(dupe)
store.update_item(dest_module, user.id)
if not 'detached' in source_item.runtime.load_block_type(category)._class_tags:
parent = store.get_item(parent_usage_key)
# If source was already a child of the parent, add duplicate immediately afterward.
# Otherwise, add child to end.
if source_item.location in parent.children:
source_index = parent.children.index(source_item.location)
parent.children.insert(source_index + 1, dest_module.location)
else:
parent.children.append(dest_module.location)
store.update_item(parent, user.id)
return dest_module.location
def _delete_item(usage_key, user):
"""
Deletes an existing xblock with the given usage_key.
If the xblock is a Static Tab, removes it from course.tabs as well.
"""
store = modulestore()
# VS[compat] cdodge: This is a hack because static_tabs also have references from the course module, so
# if we add one then we need to also add it to the policy information (i.e. metadata)
# we should remove this once we can break this reference from the course to static tabs
if usage_key.category == 'static_tab':
course = store.get_course(usage_key.course_key)
existing_tabs = course.tabs or []
course.tabs = [tab for tab in existing_tabs if tab.get('url_slug') != usage_key.name]
store.update_item(course, user.id)
store.delete_item(usage_key, user.id)
# pylint: disable=W0613
@login_required
@require_http_methods(("GET", "DELETE"))
def orphan_handler(request, course_key_string):
"""
View for handling orphan related requests. GET gets all of the current orphans.
DELETE removes all orphans (requires is_staff access)
An orphan is a block whose category is not in the DETACHED_CATEGORY list, is not the root, and is not reachable
from the root via children
"""
course_usage_key = CourseKey.from_string(course_key_string)
if request.method == 'GET':
if has_course_access(request.user, course_usage_key):
return JsonResponse(modulestore().get_orphans(course_usage_key))
else:
raise PermissionDenied()
if request.method == 'DELETE':
if request.user.is_staff:
store = modulestore()
items = store.get_orphans(course_usage_key)
for itemloc in items:
# get_orphans returns the deprecated string format w/o revision
usage_key = course_usage_key.make_usage_key_from_deprecated_string(itemloc)
# need to delete all versions
store.delete_item(usage_key, request.user.id, revision=ModuleStoreEnum.RevisionOption.all)
return JsonResponse({'deleted': items})
else:
raise PermissionDenied()
def _get_module_info(usage_key, user, rewrite_static_links=True):
"""
metadata, data, id representation of a leaf module fetcher.
:param usage_key: A UsageKey
"""
store = modulestore()
try:
module = store.get_item(usage_key)
except ItemNotFoundError:
if usage_key.category in CREATE_IF_NOT_FOUND:
# Create a new one for certain categories only. Used for course info handouts.
module = store.create_and_save_xmodule(usage_key, user.id)
else:
raise
data = getattr(module, 'data', '')
if rewrite_static_links:
data = replace_static_urls(
data,
None,
course_id=module.location.course_key
)
# Note that children aren't being returned until we have a use case.
return {
'id': unicode(module.location),
'data': data,
'metadata': own_metadata(module)
}