def service(self, block, service_name):
"""Return a service, or None.
Services are objects implementing arbitrary other interfaces. They are
requested by agreed-upon names, see [XXX TODO] for a list of possible
services. The object returned depends on the service requested.
XBlocks must announce their intention to request services with the
`XBlock.needs` or `XBlock.wants` decorators. Use `needs` if you assume
that the service is available, or `wants` if your code is flexible and
can accept a None from this method.
Runtimes can override this method if they have different techniques for
finding and delivering services.
Arguments:
block (XBlock): this block's class will be examined for service
decorators.
service_name (str): the name of the service requested.
Returns:
An object implementing the requested service, or None.
"""
declaration = block.service_declaration(service_name)
if declaration is None:
raise NoSuchServiceError(
"Service {!r} was not requested.".format(service_name))
service = self._services.get(service_name)
if service is None and declaration == "need":
raise NoSuchServiceError(
"Service {!r} is not available.".format(service_name))
return service
def service(self, block, service_name):
"""
Return a service, or None.
Services are objects implementing arbitrary other interfaces.
"""
# TODO: Do these declarations actually help with anything? Maybe this check should
# be removed from here and from XBlock.runtime
declaration = block.service_declaration(service_name)
if declaration is None:
raise NoSuchServiceError("Service {!r} was not requested.".format(service_name))
# Most common service is field-data so check that first:
if service_name == "field-data":
if block.scope_ids not in self.block_field_datas:
try:
self.block_field_datas[block.scope_ids] = self._init_field_data_for_block(block)
except:
# Don't try again pointlessly every time another field is accessed
self.block_field_datas[block.scope_ids] = None
raise
return self.block_field_datas[block.scope_ids]
elif service_name == "completion":
context_key = block.scope_ids.usage_id.context_key
return CompletionService(user=self.user, context_key=context_key)
# Check if the XBlockRuntimeSystem wants to handle this:
service = self.system.get_service(block, service_name)
# Otherwise, fall back to the base implementation which loads services
# defined in the constructor:
if service is None:
service = super(XBlockRuntime, self).service(block, service_name)
return service
def service(self, _, service_name):
"""
Mocked version of `runtime.service(self, service_name)`
"""
if service_name == 'teams':
if self.has_teams_service:
return self.teams_service
elif service_name == 'teams_configuration':
if self.has_teams_configuration_service:
return self.teams_configuration_service
raise NoSuchServiceError()
def service(self, block, service_name):
"""
Return a service, or None.
Services are objects implementing arbitrary other interfaces.
"""
# TODO: Do these declarations actually help with anything? Maybe this check should
# be removed from here and from XBlock.runtime
declaration = block.service_declaration(service_name)
if declaration is None:
raise NoSuchServiceError(
f"Service {service_name!r} was not requested.")
# Most common service is field-data so check that first:
if service_name == "field-data":
if block.scope_ids not in self.block_field_datas:
try:
self.block_field_datas[
block.scope_ids] = self._init_field_data_for_block(
block)
except:
# Don't try again pointlessly every time another field is accessed
self.block_field_datas[block.scope_ids] = None
raise
return self.block_field_datas[block.scope_ids]
elif service_name == "completion":
context_key = block.scope_ids.usage_id.context_key
return CompletionService(user=self.user, context_key=context_key)
elif service_name == "user":
return DjangoXBlockUserService(
self.user,
# The value should be updated to whether the user is staff in the context when Blockstore runtime adds
# support for courses.
user_is_staff=self.user.is_staff,
anonymous_user_id=self.anonymous_student_id,
)
elif service_name == "mako":
return MakoService()
elif service_name == "i18n":
return ModuleI18nService(block=block)
elif service_name == 'sandbox':
context_key = block.scope_ids.usage_id.context_key
return SandboxService(contentstore=contentstore,
course_id=context_key)
elif service_name == 'cache':
return CacheService(cache)
# Check if the XBlockRuntimeSystem wants to handle this:
service = self.system.get_service(block, service_name)
# Otherwise, fall back to the base implementation which loads services
# defined in the constructor:
if service is None:
service = super().service(block, service_name)
return service
def service(self, block, service_name):
"""
Return a service, or None.
Services are objects implementing arbitrary other interfaces.
"""
# TODO: Do these declarations actually help with anything? Maybe this check should
# be removed from here and from XBlock.runtime
declaration = block.service_declaration(service_name)
if declaration is None:
raise NoSuchServiceError(
"Service {!r} was not requested.".format(service_name))
# Special case handling for some services:
service = self.system.get_service(block.scope_ids, service_name)
if service is None:
service = super(XBlockRuntime, self).service(block, service_name)
return service
