def get_block(self, usage_id, for_parent=None):
"""
Create an XBlock instance in this runtime.
The `usage_id` is used to find the XBlock class and data.
"""
def_id = self.id_reader.get_definition_id(usage_id)
if def_id is None:
raise ValueError(
"Definition not found for usage {}".format(usage_id))
if not isinstance(def_id, BundleDefinitionLocator):
raise TypeError(
"This runtime can only load blocks stored in Blockstore bundles."
)
try:
block_type = self.id_reader.get_block_type(def_id)
except NoSuchDefinition:
raise NoSuchUsage(repr(usage_id))
keys = ScopeIds(self.user_id, block_type, def_id, usage_id)
if self.system.authored_data_store.has_cached_definition(def_id):
return self.construct_xblock(block_type,
keys,
for_parent=for_parent)
else:
# We need to load this block's field data from its OLX file in blockstore:
xml_node = xml_for_definition(def_id)
if xml_node.get("url_name", None):
log.warning(
"XBlock at %s should not specify an old-style url_name attribute.",
def_id.olx_path)
block_class = self.mixologist.mix(self.load_block_type(block_type))
if hasattr(block_class, 'parse_xml_new_runtime'):
# This is a (former) XModule with messy XML parsing code; let its parse_xml() method continue to work
# as it currently does in the old runtime, but let this parse_xml_new_runtime() method parse the XML in
# a simpler way that's free of tech debt, if defined.
# In particular, XmlParserMixin doesn't play well with this new runtime, so this is mostly about
# bypassing that mixin's code.
# When a former XModule no longer needs to support the old runtime, its parse_xml_new_runtime method
# should be removed and its parse_xml() method should be simplified to just call the super().parse_xml()
# plus some minor additional lines of code as needed.
block = block_class.parse_xml_new_runtime(xml_node,
runtime=self,
keys=keys)
else:
block = block_class.parse_xml(xml_node,
runtime=self,
keys=keys,
id_generator=None)
# Update field data with parsed values. We can't call .save() because it will call save_block(), below.
block.force_save_fields(block._get_fields_to_save()) # pylint: disable=protected-access
self.system.authored_data_store.cache_fields(block)
# There is no way to set the parent via parse_xml, so do what
# HierarchyMixin would do:
if for_parent is not None:
block._parent_block = for_parent # pylint: disable=protected-access
block._parent_block_id = for_parent.scope_ids.usage_id # pylint: disable=protected-access
return block
def get_usage_id_from_aside(self, aside_id):
"""
Extract the usage_id from the aside_id.
Arguments:
aside_id: An XBlockAside usage_id
"""
try:
return self._aside_usages[aside_id][0]
except KeyError:
raise NoSuchUsage(usage_id)
def get_aside_type_from_usage(self, usage_id):
"""
Parse the type of the aside from an XBlockAside usage_id.
Arguments:
usage_id: An XBlockAside usage_id.
"""
try:
return self._aside_usages[usage_id][1]
except KeyError:
raise NoSuchUsage(usage_id)
def get_block(self, usage_id, for_parent=None):
"""
Create an XBlock instance in this runtime.
The `usage_id` is used to find the XBlock class and data.
"""
def_id = self.id_reader.get_definition_id(usage_id)
try:
block_type = self.id_reader.get_block_type(def_id)
except NoSuchDefinition:
raise NoSuchUsage(repr(usage_id))
keys = ScopeIds(self.user_id, block_type, def_id, usage_id)
block = self.construct_xblock(block_type, keys, for_parent=for_parent)
return block
def get_definition_id(self, usage_id):
"""Get a definition_id by its usage id."""
try:
return self._usages[usage_id]
except KeyError:
raise NoSuchUsage(repr(usage_id))
