Merge pull request #8209 from edx/mobile/xblock-support

Course Blocks + Navigation API (feature flagged) for Mobile

common/djangoapps/util/module_utils.py

@@ -3,7 +3,7 @@ Utility library containing operations used/shared by multiple courseware modules
 """
 
 
-def yield_dynamic_descriptor_descendents(descriptor, module_creator):  # pylint: disable=invalid-name
+def yield_dynamic_descriptor_descendants(descriptor, user_id, module_creator):  # pylint: disable=invalid-name
     """
     This returns all of the descendants of a descriptor. If the descriptor
     has dynamic children, the module will be created using module_creator
@@ -13,16 +13,20 @@ def yield_dynamic_descriptor_descendents(descriptor, module_creator):  # pylint:
 
     while len(stack) > 0:
         next_descriptor = stack.pop()
-        stack.extend(get_dynamic_descriptor_children(next_descriptor, module_creator))
+        stack.extend(get_dynamic_descriptor_children(next_descriptor, user_id, module_creator))
         yield next_descriptor
 
 
-def get_dynamic_descriptor_children(descriptor, module_creator, usage_key_filter=None):
+def get_dynamic_descriptor_children(descriptor, user_id, module_creator=None, usage_key_filter=None):
     """
     Returns the children of the given descriptor, while supporting descriptors with dynamic children.
     """
     module_children = []
     if descriptor.has_dynamic_children():
+        # do not rebind the module if it's already bound to a user.
+        if descriptor.scope_ids.user_id and user_id == descriptor.scope_ids.user_id:
+            module = descriptor
+        else:
             module = module_creator(descriptor)
         if module is not None:
             module_children = module.get_child_descriptors()

common/lib/capa/capa/capa_problem.py

@@ -527,6 +527,13 @@ class LoncapaProblem(object):
             log.warning("Could not find matching input for id: %s", input_id)
             return {}
 
+    @property
+    def has_responsive_ui(self):
+        """
+        Returns whether this capa problem has support for responsive UI.
+        """
+        return all(responder.has_responsive_ui for responder in self.responders.values())
+
     # ======= Private Methods Below ========
 
     def _process_includes(self):

common/lib/capa/capa/responsetypes.py

@@ -138,6 +138,11 @@ class LoncapaResponse(object):
     allowed_inputfields = []
     required_attributes = []
 
+    # Overridable field that specifies whether this capa response type has support for
+    # responsive UI, for rendering on devices of different sizes and shapes.
+    # By default, we set this to False, allowing subclasses to override as appropriate.
+    has_responsive_ui = False
+
     def __init__(self, xml, inputfields, context, system):
         """
         Init is passed the following arguments:
@@ -692,6 +697,7 @@ class ChoiceResponse(LoncapaResponse):
     max_inputfields = 1
     allowed_inputfields = ['checkboxgroup', 'radiogroup']
     correct_choices = None
+    has_responsive_ui = True
 
     def setup_response(self):
 
@@ -763,6 +769,7 @@ class MultipleChoiceResponse(LoncapaResponse):
     max_inputfields = 1
     allowed_inputfields = ['choicegroup']
     correct_choices = None
+    has_responsive_ui = True
 
     def setup_response(self):
         # call secondary setup for MultipleChoice questions, to set name
@@ -1084,6 +1091,7 @@ class OptionResponse(LoncapaResponse):
     hint_tag = 'optionhint'
     allowed_inputfields = ['optioninput']
     answer_fields = None
+    has_responsive_ui = True
 
     def setup_response(self):
         self.answer_fields = self.inputfields
@@ -1136,6 +1144,7 @@ class NumericalResponse(LoncapaResponse):
     allowed_inputfields = ['textline', 'formulaequationinput']
     required_attributes = ['answer']
     max_inputfields = 1
+    has_responsive_ui = True
 
     def __init__(self, *args, **kwargs):
         self.correct_answer = ''
@@ -1338,6 +1347,7 @@ class StringResponse(LoncapaResponse):
     required_attributes = ['answer']
     max_inputfields = 1
     correct_answer = []
+    has_responsive_ui = True
 
     def setup_response_backward(self):
         self.correct_answer = [

common/lib/xmodule/xmodule/capa_module.py

@@ -187,6 +187,13 @@ class CapaDescriptor(CapaFields, RawDescriptor):
         registered_tags = responsetypes.registry.registered_tags()
         return set([node.tag for node in tree.iter() if node.tag in registered_tags])
 
+    @property
+    def has_responsive_ui(self):
+        """
+        Returns whether this module has support for responsive UI.
+        """
+        return self.lcp.has_responsive_ui
+
     def index_dictionary(self):
         """
         Return dictionary prepared with module content and type for indexing.

common/lib/xmodule/xmodule/html_module.py

@@ -95,6 +95,7 @@ class HtmlDescriptor(HtmlFields, XmlDescriptor, EditingDescriptor):  # pylint: d
     module_class = HtmlModule
     filename_extension = "xml"
     template_dir_name = "html"
+    has_responsive_ui = True
 
     js = {'coffee': [resource_string(__name__, 'js/src/html/edit.coffee')]}
     js_module_name = "HTMLEditingDescriptor"

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

@@ -7,13 +7,11 @@ import logging
 import re
 import json
 import datetime
-from uuid import uuid4
 
 from pytz import UTC
-from collections import namedtuple, defaultdict
+from collections import defaultdict
 import collections
 from contextlib import contextmanager
-import functools
 import threading
 from operator import itemgetter
 from sortedcontainers import SortedListWithKey
@@ -27,8 +25,6 @@ from xmodule.errortracker import make_error_tracker
 from xmodule.assetstore import AssetMetadata
 from opaque_keys.edx.keys import CourseKey, UsageKey, AssetKey
 from opaque_keys.edx.locations import Location  # For import backwards compatibility
-from opaque_keys import InvalidKeyError
-from opaque_keys.edx.locations import SlashSeparatedCourseKey
 from xblock.runtime import Mixologist
 from xblock.core import XBlock
 
@@ -1195,41 +1191,6 @@ class ModuleStoreReadBase(BulkOperationsMixin, ModuleStoreRead):
             raise ValueError(u"Cannot set default store to type {}".format(store_type))
         yield
 
-    @staticmethod
-    def memoize_request_cache(func):
-        """
-        Memoize a function call results on the request_cache if there's one. Creates the cache key by
-        joining the unicode of all the args with &; so, if your arg may use the default &, it may
-        have false hits
-        """
-        @functools.wraps(func)
-        def wrapper(self, *args, **kwargs):
-            """
-            Wraps a method to memoize results.
-            """
-            if self.request_cache:
-                cache_key = '&'.join([hashvalue(arg) for arg in args])
-                if cache_key in self.request_cache.data.setdefault(func.__name__, {}):
-                    return self.request_cache.data[func.__name__][cache_key]
-
-                result = func(self, *args, **kwargs)
-
-                self.request_cache.data[func.__name__][cache_key] = result
-                return result
-            else:
-                return func(self, *args, **kwargs)
-        return wrapper
-
-
-def hashvalue(arg):
-    """
-    If arg is an xblock, use its location. otherwise just turn it into a string
-    """
-    if isinstance(arg, XBlock):
-        return unicode(arg.location)
-    else:
-        return unicode(arg)
-
 
 # pylint: disable=abstract-method
 class ModuleStoreWriteBase(ModuleStoreReadBase, ModuleStoreWrite):

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

@@ -915,6 +915,9 @@ class MongoModuleStore(ModuleStoreDraftAndPublished, ModuleStoreWriteBase, Mongo
                 services["user"] = self.user_service
             services["settings"] = SettingsService()
 
+            if self.request_cache:
+                services["request_cache"] = self.request_cache
+
             system = CachingDescriptorSystem(
                 modulestore=self,
                 course_key=course_key,

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

@@ -10,6 +10,7 @@ import pymongo
 import logging
 
 from opaque_keys.edx.locations import Location
+from openedx.core.lib.cache_utils import memoize_in_request_cache
 from xmodule.exceptions import InvalidVersionError
 from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.exceptions import (
@@ -634,7 +635,7 @@ class DraftModuleStore(MongoModuleStore):
             bulk_record.dirty = True
             self.collection.remove({'_id': {'$in': to_be_deleted}}, safe=self.collection.safe)
 
-    @MongoModuleStore.memoize_request_cache
+    @memoize_in_request_cache('request_cache')
     def has_changes(self, xblock):
         """
         Check if the subtree rooted at xblock has any drafts and thus may possibly have changes

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

@@ -671,6 +671,9 @@ class SplitMongoModuleStore(SplitBulkWriteMixin, ModuleStoreWriteBase):
         if user_service is not None:
             self.services["user"] = user_service
 
+        if self.request_cache is not None:
+            self.services["request_cache"] = self.request_cache
+
         self.signal_handler = signal_handler
 
     def close_connections(self):

common/lib/xmodule/xmodule/video_module/video_handlers.py

@@ -250,9 +250,10 @@ class VideoStudentViewHandlers(object):
                 response.content_type = Transcript.mime_types['sjson']
 
         elif dispatch == 'download':
+            lang = request.GET.get('lang', None)
             try:
                 transcript_content, transcript_filename, transcript_mime_type = self.get_transcript(
-                    transcripts, transcript_format=self.transcript_download_format
+                    transcripts, transcript_format=self.transcript_download_format, lang=lang
                 )
             except (NotFoundError, ValueError, KeyError, UnicodeDecodeError):
                 log.debug("Video@download exception")

common/lib/xmodule/xmodule/video_module/video_module.py

@@ -20,12 +20,12 @@ import logging
 import random
 from collections import OrderedDict
 from operator import itemgetter
-
 from lxml import etree
 from pkg_resources import resource_string
 
 from django.conf import settings
 
+from openedx.core.lib.cache_utils import memoize_in_request_cache
 from xblock.core import XBlock
 from xblock.fields import ScopeIds
 from xblock.runtime import KvsFieldData
@@ -329,6 +329,7 @@ class VideoModule(VideoFields, VideoTranscriptsMixin, VideoStudentViewHandlers,
         return self.system.render_template('video.html', context)
 
 
+@XBlock.wants("request_cache")
 @XBlock.wants("settings")
 class VideoDescriptor(VideoFields, VideoTranscriptsMixin, VideoStudioViewHandlers,
                       TabsEditingDescriptor, EmptyDataRawDescriptor):
@@ -722,7 +723,7 @@ class VideoDescriptor(VideoFields, VideoTranscriptsMixin, VideoStudioViewHandler
         if self.sub:
             _update_transcript_for_index()
 
-        # check to see if there are transcripts in other languages besides default transcript
+        # Check to see if there are transcripts in other languages besides default transcript
         if self.transcripts:
             for language in self.transcripts.keys():
                 _update_transcript_for_index(language)
@@ -734,3 +735,79 @@ class VideoDescriptor(VideoFields, VideoTranscriptsMixin, VideoStudioViewHandler
         xblock_body["content_type"] = "Video"
 
         return xblock_body
+
+    @property
+    def request_cache(self):
+        """
+        Returns the request_cache from the runtime.
+        """
+        return self.runtime.service(self, "request_cache")
+
+    @memoize_in_request_cache('request_cache')
+    def get_cached_val_data_for_course(self, video_profile_names, course_id):
+        """
+        Returns the VAL data for the requested video profiles for the given course.
+        """
+        return edxval_api.get_video_info_for_course_and_profiles(unicode(course_id), video_profile_names)
+
+    def student_view_json(self, context):
+        """
+        Returns a JSON representation of the student_view of this XModule.
+        The contract of the JSON content is between the caller and the particular XModule.
+        """
+        # If the "only_on_web" field is set on this video, do not return the rest of the video's data
+        # in this json view, since this video is to be accessed only through its web view."
+        if self.only_on_web:
+            return {"only_on_web": True}
+
+        encoded_videos = {}
+        val_video_data = {}
+
+        # Check in VAL data first if edx_video_id exists
+        if self.edx_video_id:
+            video_profile_names = context.get("profiles", [])
+
+            # get and cache bulk VAL data for course
+            val_course_data = self.get_cached_val_data_for_course(video_profile_names, self.location.course_key)
+            val_video_data = val_course_data.get(self.edx_video_id, {})
+
+            # Get the encoded videos if data from VAL is found
+            if val_video_data:
+                encoded_videos = val_video_data.get('profiles', {})
+
+            # If information for this edx_video_id is not found in the bulk course data, make a
+            # separate request for this individual edx_video_id, unless cache misses are disabled.
+            # This is useful/required for videos that don't have a course designated, such as the introductory video
+            # that is shared across many courses.  However, this results in a separate database request so watch
+            # out for any performance hit if many such videos exist in a course.  Set the 'allow_cache_miss' parameter
+            # to False to disable this fall back.
+            elif context.get("allow_cache_miss", "True").lower() == "true":
+                try:
+                    val_video_data = edxval_api.get_video_info(self.edx_video_id)
+                    # Unfortunately, the VAL API is inconsistent in how it returns the encodings, so remap here.
+                    for enc_vid in val_video_data.pop('encoded_videos'):
+                        encoded_videos[enc_vid['profile']] = {key: enc_vid[key] for key in ["url", "file_size"]}
+                except edxval_api.ValVideoNotFoundError:
+                    pass
+
+        # Fall back to other video URLs in the video module if not found in VAL
+        if not encoded_videos:
+            video_url = self.html5_sources[0] if self.html5_sources else self.source
+            if video_url:
+                encoded_videos["fallback"] = {
+                    "url": video_url,
+                    "file_size": 0,  # File size is unknown for fallback URLs
+                }
+
+        transcripts_info = self.get_transcripts_info()
+        transcripts = {
+            lang: self.runtime.handler_url(self, 'transcript', 'download', query="lang=" + lang, thirdparty=True)
+            for lang in self.available_translations(transcripts_info, verify_assets=False)
+        }
+
+        return {
+            "only_on_web": self.only_on_web,
+            "duration": val_video_data.get('duration', None),
+            "transcripts": transcripts,
+            "encoded_videos": encoded_videos,
+        }

lms/djangoapps/course_structure_api/v0/urls.py

@@ -14,5 +14,33 @@ urlpatterns = patterns(
     url(r'^courses/$', views.CourseList.as_view(), name='list'),
     url(r'^courses/{}/$'.format(COURSE_ID_PATTERN), views.CourseDetail.as_view(), name='detail'),
     url(r'^course_structures/{}/$'.format(COURSE_ID_PATTERN), views.CourseStructure.as_view(), name='structure'),
-    url(r'^grading_policies/{}/$'.format(COURSE_ID_PATTERN), views.CourseGradingPolicy.as_view(), name='grading_policy')
+    url(
+        r'^grading_policies/{}/$'.format(COURSE_ID_PATTERN),
+        views.CourseGradingPolicy.as_view(),
+        name='grading_policy'
+    ),
 )
+
+if settings.FEATURES.get('ENABLE_COURSE_BLOCKS_NAVIGATION_API'):
+    # TODO (MA-789) This endpoint still needs to be approved by the arch council.
+    # TODO (MA-704) This endpoint still needs to be made performant.
+    urlpatterns += (
+        url(
+            r'^courses/{}/blocks/$'.format(COURSE_ID_PATTERN),
+            views.CourseBlocksAndNavigation.as_view(),
+            {'return_blocks': True, 'return_nav': False},
+            name='blocks'
+        ),
+        url(
+            r'^courses/{}/navigation/$'.format(COURSE_ID_PATTERN),
+            views.CourseBlocksAndNavigation.as_view(),
+            {'return_blocks': False, 'return_nav': True},
+            name='navigation'
+        ),
+        url(
+            r'^courses/{}/blocks\+navigation/$'.format(COURSE_ID_PATTERN),
+            views.CourseBlocksAndNavigation.as_view(),
+            {'return_blocks': True, 'return_nav': True},
+            name='blocks+navigation'
+        ),
+    )

lms/djangoapps/courseware/entrance_exams.py

@@ -9,7 +9,7 @@ from courseware.models import StudentModule
 from opaque_keys.edx.keys import UsageKey
 from student.models import EntranceExamConfiguration
 from util.milestones_helpers import get_required_content
-from util.module_utils import yield_dynamic_descriptor_descendents
+from util.module_utils import yield_dynamic_descriptor_descendants
 from xmodule.modulestore.django import modulestore
 
 
@@ -147,8 +147,9 @@ def get_entrance_exam_score(request, course):
             course.id
         )
 
-    exam_module_generators = yield_dynamic_descriptor_descendents(
+    exam_module_generators = yield_dynamic_descriptor_descendants(
         exam_descriptor,
+        request.user.id,
         inner_get_module
     )
     exam_modules = [module for module in exam_module_generators]

lms/djangoapps/courseware/grades.py

@@ -15,7 +15,7 @@ import dogstats_wrapper as dog_stats_api
 from courseware import courses
 from courseware.model_data import FieldDataCache
 from student.models import anonymous_id_for_user
-from util.module_utils import yield_dynamic_descriptor_descendents
+from util.module_utils import yield_dynamic_descriptor_descendants
 from xmodule import graders
 from xmodule.graders import Score
 from xmodule.modulestore.django import modulestore
@@ -209,7 +209,9 @@ def _grade(student, request, course, keep_raw_scores):
                         field_data_cache = FieldDataCache([descriptor], course.id, student)
                     return get_module_for_descriptor(student, request, descriptor, field_data_cache, course.id)
 
-                for module_descriptor in yield_dynamic_descriptor_descendents(section_descriptor, create_module):
+                for module_descriptor in yield_dynamic_descriptor_descendants(
+                        section_descriptor, student.id, create_module
+                ):
 
                     (correct, total) = get_score(
                         course.id, student, module_descriptor, create_module, scores_cache=submissions_scores
@@ -364,7 +366,9 @@ def _progress_summary(student, request, course):
 
                 module_creator = section_module.xmodule_runtime.get_module
 
-                for module_descriptor in yield_dynamic_descriptor_descendents(section_module, module_creator):
+                for module_descriptor in yield_dynamic_descriptor_descendants(
+                        section_module, student.id, module_creator
+                ):
                     course_id = course.id
                     (correct, total) = get_score(
                         course_id, student, module_descriptor, module_creator, scores_cache=submissions_scores

lms/djangoapps/courseware/tests/test_video_mongo.py

 # -*- coding: utf-8 -*-
 """Video xmodule tests in mongo."""
+import ddt
+import itertools
 import json
 from collections import OrderedDict
 
@@ -13,7 +15,7 @@ from django.test.utils import override_settings
 
 from xmodule.video_module import VideoDescriptor, bumper_utils, video_utils
 from xmodule.x_module import STUDENT_VIEW
-from xmodule.tests.test_video import VideoDescriptorTestBase
+from xmodule.tests.test_video import VideoDescriptorTestBase, instantiate_descriptor
 from xmodule.tests.test_import import DummySystem
 
 from edxval.api import (
@@ -861,6 +863,119 @@ class TestVideoDescriptorInitialization(BaseTestXmodule):
         self.assertFalse(self.item_descriptor.download_video)
 
 
+@ddt.ddt
+class TestVideoDescriptorStudentViewJson(TestCase):
+    """
+    Tests for the student_view_json method on VideoDescriptor.
+    """
+    TEST_DURATION = 111.0
+    TEST_PROFILE = "mobile"
+    TEST_SOURCE_URL = "http://www.example.com/source.mp4"
+    TEST_LANGUAGE = "ge"
+    TEST_ENCODED_VIDEO = {
+        'profile': TEST_PROFILE,
+        'bitrate': 333,
+        'url': 'http://example.com/video',
+        'file_size': 222,
+    }
+    TEST_EDX_VIDEO_ID = 'test_edx_video_id'
+
+    def setUp(self):
+        super(TestVideoDescriptorStudentViewJson, self).setUp()
+        sample_xml = (
+            "<video display_name='Test Video'> " +
+            "<source src='" + self.TEST_SOURCE_URL + "'/> " +
+            "<transcript language='" + self.TEST_LANGUAGE + "' src='german_translation.srt' /> " +
+            "</video>"
+        )
+        self.transcript_url = "transcript_url"
+        self.video = instantiate_descriptor(data=sample_xml)
+        self.video.runtime.handler_url = Mock(return_value=self.transcript_url)
+
+    def setup_val_video(self, associate_course_in_val=False):
+        """
+        Creates a video entry in VAL.
+        Arguments:
+            associate_course - If True, associates the test course with the video in VAL.
+        """
+        create_profile('mobile')
+        create_video({
+            'edx_video_id': self.TEST_EDX_VIDEO_ID,
+            'client_video_id': 'test_client_video_id',
+            'duration': self.TEST_DURATION,
+            'status': 'dummy',
+            'encoded_videos': [self.TEST_ENCODED_VIDEO],
+            'courses': [self.video.location.course_key] if associate_course_in_val else [],
+        })
+        self.val_video = get_video_info(self.TEST_EDX_VIDEO_ID)  # pylint: disable=attribute-defined-outside-init
+
+    def get_result(self, allow_cache_miss=True):
+        """
+        Returns the result from calling the video's student_view_json method.
+        Arguments:
+            allow_cache_miss is passed in the context to the student_view_json method.
+        """
+        context = {
+            "profiles": [self.TEST_PROFILE],
+            "allow_cache_miss": "True" if allow_cache_miss else "False"
+        }
+        return self.video.student_view_json(context)
+
+    def verify_result_with_fallback_url(self, result):
+        """
+        Verifies the result is as expected when returning "fallback" video data (not from VAL).
+        """
+        self.assertDictEqual(
+            result,
+            {
+                "only_on_web": False,
+                "duration": None,
+                "transcripts": {self.TEST_LANGUAGE: self.transcript_url},
+                "encoded_videos": {"fallback": {"url": self.TEST_SOURCE_URL, "file_size": 0}},
+            }
+        )
+
+    def verify_result_with_val_profile(self, result):
+        """
+        Verifies the result is as expected when returning video data from VAL.
+        """
+        self.assertDictContainsSubset(
+            result.pop("encoded_videos")[self.TEST_PROFILE],
+            self.TEST_ENCODED_VIDEO,
+        )
+        self.assertDictEqual(
+            result,
+            {
+                "only_on_web": False,
+                "duration": self.TEST_DURATION,
+                "transcripts": {self.TEST_LANGUAGE: self.transcript_url},
+            }
+        )
+
+    def test_only_on_web(self):
+        self.video.only_on_web = True
+        result = self.get_result()
+        self.assertDictEqual(result, {"only_on_web": True})
+
+    def test_no_edx_video_id(self):
+        result = self.get_result()
+        self.verify_result_with_fallback_url(result)
+
+    @ddt.data(
+        *itertools.product([True, False], [True, False], [True, False])
+    )
+    @ddt.unpack
+    def test_with_edx_video_id(self, allow_cache_miss, video_exists_in_val, associate_course_in_val):
+        self.video.edx_video_id = self.TEST_EDX_VIDEO_ID
+        if video_exists_in_val:
+            self.setup_val_video(associate_course_in_val)
+        result = self.get_result(allow_cache_miss)
+        if video_exists_in_val and (associate_course_in_val or allow_cache_miss):
+            self.verify_result_with_val_profile(result)
+        else:
+            self.verify_result_with_fallback_url(result)
+
+
 @attr('shard_1')
 class VideoDescriptorTest(TestCase, VideoDescriptorTestBase):
     """

lms/djangoapps/mobile_api/video_outlines/serializers.py

@@ -86,6 +86,7 @@ class BlockOutline(object):
             if curr_block.has_children:
                 children = get_dynamic_descriptor_children(
                     curr_block,
+                    self.request.user.id,
                     create_module,
                     usage_key_filter=parent_or_requested_block_type
                 )

lms/envs/common.py

@@ -321,7 +321,10 @@ FEATURES = {
     # ENABLE_OAUTH2_PROVIDER to True
     'ENABLE_MOBILE_REST_API': False,
     'ENABLE_MOBILE_SOCIAL_FACEBOOK_FEATURES': False,
+
+    # Enable APIs required for xBlocks on Mobile, and supported in general
     'ENABLE_RENDER_XBLOCK_API': False,
+    'ENABLE_COURSE_BLOCKS_NAVIGATION_API': False,
 
     # Enable the combined login/registration form
     'ENABLE_COMBINED_LOGIN_REGISTRATION': False,

lms/envs/test.py

@@ -268,6 +268,8 @@ FEATURES['ENABLE_OAUTH2_PROVIDER'] = True
 FEATURES['ENABLE_MOBILE_REST_API'] = True
 FEATURES['ENABLE_MOBILE_SOCIAL_FACEBOOK_FEATURES'] = True
 FEATURES['ENABLE_VIDEO_ABSTRACTION_LAYER_API'] = True
+FEATURES['ENABLE_COURSE_BLOCKS_NAVIGATION_API'] = True
+FEATURES['ENABLE_RENDER_XBLOCK_API'] = True
 
 ###################### Payment ##############################3
 # Enable fake payment processing page

openedx/core/lib/cache_utils.py

+"""
+Utilities related to caching.
+"""
+
+import functools
+from xblock.core import XBlock
+
+
+def memoize_in_request_cache(request_cache_attr_name=None):
+    """
+    Memoize a method call's results in the request_cache if there's one. Creates the cache key by
+    joining the unicode of all the args with &; so, if your arg may use the default &, it may
+    have false hits.
+
+    Arguments:
+        request_cache_attr_name - The name of the field or property in this method's containing
+         class that stores the request_cache.
+    """
+    def _decorator(func):
+        """Outer method decorator."""
+        @functools.wraps(func)
+        def _wrapper(self, *args, **kwargs):
+            """
+            Wraps a method to memoize results.
+            """
+            request_cache = getattr(self, request_cache_attr_name, None)
+            if request_cache:
+                cache_key = '&'.join([hashvalue(arg) for arg in args])
+                if cache_key in request_cache.data.setdefault(func.__name__, {}):
+                    return request_cache.data[func.__name__][cache_key]
+
+                result = func(self, *args, **kwargs)
+
+                request_cache.data[func.__name__][cache_key] = result
+                return result
+            else:
+                return func(self, *args, **kwargs)
+        return _wrapper
+    return _decorator
+
+
+def hashvalue(arg):
+    """
+    If arg is an xblock, use its location. otherwise just turn it into a string
+    """
+    if isinstance(arg, XBlock):
+        return unicode(arg.location)
+    else:
+        return unicode(arg)

openedx/core/lib/tests/test_cache_utils.py

+"""
+Tests for cache_utils.py
+"""
+import ddt
+from mock import MagicMock
+from unittest import TestCase
+
+from openedx.core.lib.cache_utils import memoize_in_request_cache
+
+
+@ddt.ddt
+class TestMemoizeInRequestCache(TestCase):
+    """
+    Test the memoize_in_request_cache helper function.
+    """
+    class TestCache(object):
+        """
+        A test cache that provides a data dict for caching values, analogous to the request_cache.
+        """
+        def __init__(self):
+            self.data = {}
+
+    def setUp(self):
+        super(TestMemoizeInRequestCache, self).setUp()
+        self.request_cache = self.TestCache()
+
+    @memoize_in_request_cache('request_cache')
+    def func_to_memoize(self, param):
+        """
+        A test function whose results are to be memoized in the request_cache.
+        """
+        return self.func_to_count(param)
+
+    @memoize_in_request_cache('request_cache')
+    def multi_param_func_to_memoize(self, param1, param2):
+        """
+        A test function with multiple parameters whose results are to be memoized in the request_cache.
+        """
+        return self.func_to_count(param1, param2)
+
+    def test_memoize_in_request_cache(self):
+        """
+        Tests the memoize_in_request_cache decorator for both single-param and multiple-param functions.
+        """
+        funcs_to_test = (
+            (self.func_to_memoize, ['foo'], ['bar']),
+            (self.multi_param_func_to_memoize, ['foo', 'foo2'], ['foo', 'foo3']),
+        )
+
+        for func_to_memoize, arg_list1, arg_list2 in funcs_to_test:
+            self.func_to_count = MagicMock()  # pylint: disable=attribute-defined-outside-init
+            self.assertFalse(self.func_to_count.called)
+
+            func_to_memoize(*arg_list1)
+            self.func_to_count.assert_called_once_with(*arg_list1)
+
+            func_to_memoize(*arg_list1)
+            self.func_to_count.assert_called_once_with(*arg_list1)
+
+            for _ in range(10):
+                func_to_memoize(*arg_list1)
+                func_to_memoize(*arg_list2)
+
+            self.assertEquals(self.func_to_count.call_count, 2)