def _init_field_data_for_block(self, block):
"""
Initialize the FieldData implementation for the specified XBlock
"""
if self.user is None:
# No user is specified, so we want to throw an error if anything attempts to read/write user-specific fields
student_data_store = None
elif self.user.is_anonymous:
# The user is anonymous. Future work will support saving their state
# in a cache or the django session but for now just use a highly
# ephemeral dict.
student_data_store = KvsFieldData(kvs=DictKeyValueStore())
elif self.system.student_data_mode == XBlockRuntimeSystem.STUDENT_DATA_EPHEMERAL:
# We're in an environment like Studio where we want to let the
# author test blocks out but not permanently save their state.
# This in-memory dict will typically only persist for one
# request-response cycle, so we need to soon replace it with a store
# that puts the state into a cache or the django session.
student_data_store = KvsFieldData(kvs=DictKeyValueStore())
else:
# Use database-backed field data (i.e. store user_state in StudentModule)
context_key = block.scope_ids.usage_id.context_key
if context_key not in self.django_field_data_caches:
field_data_cache = FieldDataCache(
[block],
course_id=context_key,
user=self.user,
asides=None,
read_only=False,
)
self.django_field_data_caches[context_key] = field_data_cache
else:
field_data_cache = self.django_field_data_caches[context_key]
field_data_cache.add_descriptors_to_cache([block])
student_data_store = KvsFieldData(
kvs=DjangoKeyValueStore(field_data_cache))
return SplitFieldData({
Scope.content: self.system.authored_data_store,
Scope.settings: self.system.authored_data_store,
Scope.parent: self.system.authored_data_store,
Scope.children: self.system.authored_data_store,
Scope.user_state_summary: student_data_store,
Scope.user_state: student_data_store,
Scope.user_info: student_data_store,
Scope.preferences: student_data_store,
})
