Merge pull request #38 from edx/alangsto/add_content_cache

feat: cache unit content

CHANGELOG.rst

@@ -11,6 +11,10 @@ Change Log
 
 .. There should always be an "Unreleased" section for changes pending release.
 
+Unreleased
+**********
+* Add content cache
+
 1.5.0 - 2023-10-18
 ******************
 * Add management command to generate course prompts

learning_assistant/api.py

@@ -1,6 +1,10 @@
 """
 Library for the learning_assistant app.
 """
+from django.conf import settings
+from django.core.cache import cache
+from edx_django_utils.cache import get_cache_key
+
 from learning_assistant.constants import ACCEPTED_CATEGORY_TYPES, CATEGORY_TYPE_MAP
 from learning_assistant.models import CoursePrompt
 from learning_assistant.platform_imports import (
@@ -93,8 +97,18 @@ def get_block_content(request, user_id, course_id, unit_usage_key):
         length - the cummulative length of a block's children's content
         items - a list of dictionaries containing the content type and text for each child
     """
-    block = get_single_block(request, user_id, course_id, unit_usage_key)
-
-    length, items = _get_children_contents(block)
-
-    return length, items
+    cache_key = get_cache_key(
+        resource='learning_assistant',
+        user_id=user_id,
+        course_id=course_id,
+        unit_usage_key=unit_usage_key
+    )
+    cache_data = cache.get(cache_key)
+
+    if not isinstance(cache_data, dict):
+        block = get_single_block(request, user_id, course_id, unit_usage_key)
+        length, items = _get_children_contents(block)
+        cache_data = {'content_length': length, 'content_items': items}
+        cache.set(cache_key, cache_data, getattr(settings, 'LEARNING_ASSISTANT_CACHE_TIMEOUT', 360))
+
+    return cache_data['content_length'], cache_data['content_items']

learning_assistant/text_utils.py

@@ -34,7 +34,7 @@ def __init__(self):
 
     def handle_starttag(self, tag, _):
         """On each tag, check whether this is a tag we think is content."""
-        tags_to_filter = getattr(settings, 'HTML_TAGS_TO_REMOVE', None)
+        tags_to_filter = getattr(settings, 'LEARNING_ASSISTANT_HTML_TAGS_TO_REMOVE', None)
         self._is_content = not (tags_to_filter and tag in tags_to_filter)
 
     def handle_data(self, data):

test_settings.py

@@ -69,3 +69,9 @@ def root(*args):
 DISCOVERY_BACKEND_SERVICE_EDX_OAUTH2_PROVIDER_URL = 'http://edx.devstack.lms:18000/oauth2'
 DISCOVERY_BACKEND_SERVICE_EDX_OAUTH2_KEY = 'discovery-backend-service-key'
 DISCOVERY_BACKEND_SERVICE_EDX_OAUTH2_SECRET = 'discovery-backend-service-secret'
+
+CACHES = {
+    'default': {
+        'BACKEND': 'django.core.cache.backends.locmem.LocMemCache',
+    }
+}

tests/test_api.py

@@ -4,6 +4,7 @@
 from unittest.mock import MagicMock, patch
 
 import ddt
+from django.core.cache import cache
 from django.test import TestCase
 from opaque_keys.edx.keys import UsageKey
 
@@ -91,6 +92,8 @@ class GetBlockContentAPITests(TestCase):
     """
 
     def setUp(self):
+        cache.clear()
+
         self.children = [
             FakeChild('html', '01', '''
                         <p>
@@ -187,7 +190,17 @@ def test_get_block_content(self, mock_get_children_contents, mock_get_single_blo
 
         length, items = get_block_content(request, user_id, course_id, unit_usage_key)
 
+        mock_get_children_contents.assert_called_once()
         mock_get_children_contents.assert_called_with(self.block)
 
         self.assertEqual(length, len(block_content))
         self.assertEqual(items, content_items)
+
+        # call get_block_content again with same args to assert that cache is used
+        length, items = get_block_content(request, user_id, course_id, unit_usage_key)
+
+        # assert that the mock for _get_children_contents has not been called again,
+        # as subsequent calls should hit the cache
+        mock_get_children_contents.assert_called_once()
+        self.assertEqual(length, len(block_content))
+        self.assertEqual(items, content_items)