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edx-platform/lms/djangoapps/course_blocks/transformers/visibility.py
Feanil Patel 9cf2f9f298 Run 2to3 -f future . -w
This will remove imports from __future__ that are no longer needed.

https://docs.python.org/3.5/library/2to3.html#2to3fixer-future
2019-12-30 10:35:30 -05:00

74 lines
2.3 KiB
Python

"""
Visibility Transformer implementation.
"""
from openedx.core.djangoapps.content.block_structure.transformer import (
BlockStructureTransformer,
FilteringTransformerMixin
)
from .utils import collect_merged_boolean_field
class VisibilityTransformer(FilteringTransformerMixin, BlockStructureTransformer):
"""
A transformer that enforces the visible_to_staff_only field on
blocks by removing blocks from the block structure for which the
user does not have access. The visible_to_staff_only field on a
block is percolated down to its descendants, so that all blocks
enforce the visibility settings from their ancestors.
For a block with multiple parents, access is denied only if
visibility is denied for all its parents.
Staff users are exempted from visibility rules.
"""
WRITE_VERSION = 1
READ_VERSION = 1
MERGED_VISIBLE_TO_STAFF_ONLY = 'merged_visible_to_staff_only'
@classmethod
def name(cls):
"""
Unique identifier for the transformer's class;
same identifier used in setup.py.
"""
return "visibility"
@classmethod
def _get_visible_to_staff_only(cls, block_structure, block_key):
"""
Returns whether the block with the given block_key in the
given block_structure should be visible to staff only per
computed value from ancestry chain.
"""
return block_structure.get_transformer_block_field(
block_key, cls, cls.MERGED_VISIBLE_TO_STAFF_ONLY, False
)
@classmethod
def collect(cls, block_structure):
"""
Collects any information that's necessary to execute this
transformer's transform method.
"""
collect_merged_boolean_field(
block_structure,
transformer=cls,
xblock_field_name='visible_to_staff_only',
merged_field_name=cls.MERGED_VISIBLE_TO_STAFF_ONLY,
)
def transform_block_filters(self, usage_info, block_structure):
# Users with staff access bypass the Visibility check.
if usage_info.has_staff_access:
return [block_structure.create_universal_filter()]
return [
block_structure.create_removal_filter(
lambda block_key: self._get_visible_to_staff_only(block_structure, block_key),
)
]