Override field data within the XBlock runtime

Resolves an issue preventing students in self-paced courses from seeing all available discussion modules. ECOM-3733.

common/lib/xmodule/xmodule/modulestore/__init__.py

@@ -1160,7 +1160,7 @@ class ModuleStoreReadBase(BulkOperationsMixin, ModuleStoreRead):
         contentstore=None,
         doc_store_config=None,  # ignore if passed up
         metadata_inheritance_cache_subsystem=None, request_cache=None,
-        xblock_mixins=(), xblock_select=None, disabled_xblock_types=(),  # pylint: disable=bad-continuation
+        xblock_mixins=(), xblock_select=None, xblock_field_data_wrappers=(), disabled_xblock_types=(),  # pylint: disable=bad-continuation
         # temporary parms to enable backward compatibility. remove once all envs migrated
         db=None, collection=None, host=None, port=None, tz_aware=True, user=None, password=None,
         # allow lower level init args to pass harmlessly
@@ -1177,6 +1177,7 @@ class ModuleStoreReadBase(BulkOperationsMixin, ModuleStoreRead):
         self.request_cache = request_cache
         self.xblock_mixins = xblock_mixins
         self.xblock_select = xblock_select
+        self.xblock_field_data_wrappers = xblock_field_data_wrappers
         self.disabled_xblock_types = disabled_xblock_types
         self.contentstore = contentstore
 

common/lib/xmodule/xmodule/modulestore/django.py

@@ -120,11 +120,25 @@ def load_function(path):
     """
     Load a function by name.
 
-    path is a string of the form "path.to.module.function"
-    returns the imported python object `function` from `path.to.module`
+    Arguments:
+        path: String of the form 'path.to.module.function'. Strings of the form
+            'path.to.module:Class.function' are also valid.
+
+    Returns:
+        The imported object 'function'.
     """
-    module_path, _, name = path.rpartition('.')
-    return getattr(import_module(module_path), name)
+    if ':' in path:
+        module_path, _, method_path = path.rpartition(':')
+        module = import_module(module_path)
+
+        class_name, method_name = method_path.split('.')
+        _class = getattr(module, class_name)
+        function = getattr(_class, method_name)
+    else:
+        module_path, _, name = path.rpartition('.')
+        function = getattr(import_module(module_path), name)
+
+    return function
 
 
 def create_modulestore_instance(
@@ -179,12 +193,15 @@ def create_modulestore_instance(
     else:
         disabled_xblock_types = ()
 
+    xblock_field_data_wrappers = [load_function(path) for path in settings.XBLOCK_FIELD_DATA_WRAPPERS]
+
     return class_(
         contentstore=content_store,
         metadata_inheritance_cache_subsystem=metadata_inheritance_cache,
         request_cache=request_cache,
         xblock_mixins=getattr(settings, 'XBLOCK_MIXINS', ()),
         xblock_select=getattr(settings, 'XBLOCK_SELECT_FUNCTION', None),
+        xblock_field_data_wrappers=xblock_field_data_wrappers,
         disabled_xblock_types=disabled_xblock_types,
         doc_store_config=doc_store_config,
         i18n_service=i18n_service or ModuleI18nService(),

common/lib/xmodule/xmodule/modulestore/inheritance.py

@@ -218,6 +218,17 @@ class InheritanceMixin(XBlockMixin):
         default=False
     )
 
+    self_paced = Boolean(
+        display_name=_('Self Paced'),
+        help=_(
+            'Set this to "true" to mark this course as self-paced. Self-paced courses do not have '
+            'due dates for assignments, and students can progress through the course at any rate before '
+            'the course ends.'
+        ),
+        default=False,
+        scope=Scope.settings
+    )
+
 
 def compute_inherited_metadata(descriptor):
     """Given a descriptor, traverse all of its descendants and do metadata

common/lib/xmodule/xmodule/modulestore/mongo/base.py

@@ -12,27 +12,24 @@ structure:
 }
 """
 
-import pymongo
-import sys
-import logging
 import copy
+from datetime import datetime
+from importlib import import_module
+import logging
+import pymongo
 import re
+import sys
 from uuid import uuid4
 
 from bson.son import SON
-from datetime import datetime
+from contracts import contract, new_contract
 from fs.osfs import OSFS
 from mongodb_proxy import autoretry_read
+from opaque_keys.edx.keys import UsageKey, CourseKey, AssetKey
+from opaque_keys.edx.locations import Location, BlockUsageLocator, SlashSeparatedCourseKey
+from opaque_keys.edx.locator import CourseLocator, LibraryLocator
 from path import Path as path
 from pytz import UTC
-from contracts import contract, new_contract
-
-from importlib import import_module
-from opaque_keys.edx.keys import UsageKey, CourseKey, AssetKey
-from opaque_keys.edx.locations import Location, BlockUsageLocator
-from opaque_keys.edx.locations import SlashSeparatedCourseKey
-from opaque_keys.edx.locator import CourseLocator, LibraryLocator
-
 from xblock.core import XBlock
 from xblock.exceptions import InvalidScopeError
 from xblock.fields import Scope, ScopeIds, Reference, ReferenceList, ReferenceValueDict
@@ -54,6 +51,7 @@ from xmodule.modulestore.xml import CourseLocationManager
 from xmodule.modulestore.store_utilities import DETACHED_XBLOCK_TYPES
 from xmodule.services import SettingsService
 
+
 log = logging.getLogger(__name__)
 
 new_contract('CourseKey', CourseKey)
@@ -318,6 +316,9 @@ class CachingDescriptorSystem(MakoDescriptorSystem, EditInfoRuntimeMixin):
                         ).replace(tzinfo=UTC)
                     module._edit_info['published_by'] = raw_metadata.get('published_by')
 
+                for wrapper in self.modulestore.xblock_field_data_wrappers:
+                    module._field_data = wrapper(module, module._field_data)  # pylint: disable=protected-access
+
                 # decache any computed pending field settings
                 module.save()
                 return module

common/lib/xmodule/xmodule/modulestore/split_mongo/caching_descriptor_system.py

@@ -1,5 +1,6 @@
 import sys
 import logging
+
 from contracts import contract, new_contract
 from fs.osfs import OSFS
 from lazy import lazy
@@ -7,6 +8,7 @@ from xblock.runtime import KvsFieldData, KeyValueStore
 from xblock.fields import ScopeIds
 from xblock.core import XBlock
 from opaque_keys.edx.locator import BlockUsageLocator, LocalId, CourseLocator, LibraryLocator, DefinitionLocator
+
 from xmodule.library_tools import LibraryToolsService
 from xmodule.mako_module import MakoDescriptorSystem
 from xmodule.error_module import ErrorDescriptor
@@ -263,6 +265,10 @@ class CachingDescriptorSystem(MakoDescriptorSystem, EditInfoRuntimeMixin):
         module.update_version = edit_info.update_version
         module.source_version = edit_info.source_version
         module.definition_locator = DefinitionLocator(block_key.type, definition_id)
+
+        for wrapper in self.modulestore.xblock_field_data_wrappers:
+            module._field_data = wrapper(module, module._field_data)  # pylint: disable=protected-access
+
         # decache any pending field settings
         module.save()