feat: new view & api calls to serve content library assets

This commit adds a new view to serve static assets for content
libraries, along with Content Library API calls to add, delete, and get
metadata about these assets. These assets come from Learning Core and
should ONLY BE ACCESSED FROM STUDIO. Users must have read access to the
library in order to see an asset in that library.

This also re-implments video transcript support for content libraries
and re-enables some previously disabled tests around it.

Author: ormsbee

cms/envs/test.py

@@ -333,3 +333,13 @@
     "SECRET": "***",
     "URL": "***",
 }
+
+############## openedx-learning (Learning Core) config ##############
+OPENEDX_LEARNING = {
+    'MEDIA': {
+        'BACKEND': 'django.core.files.storage.InMemoryStorage',
+        'OPTIONS': {
+            'location': MEDIA_ROOT + "_private"
+        }
+    }
+}

openedx/core/djangoapps/content_libraries/api.py

@@ -56,6 +56,7 @@
 import base64
 import hashlib
 import logging
+import mimetypes
 
 import attr
 import requests
@@ -68,6 +69,7 @@
 from django.db.models import Q, QuerySet
 from django.utils.translation import gettext as _
 from edx_rest_api_client.client import OAuthAPIClient
+from django.urls import reverse
 from lxml import etree
 from opaque_keys.edx.keys import BlockTypeKey, UsageKey, UsageKeyV2
 from opaque_keys.edx.locator import (
@@ -96,7 +98,11 @@
 from xblock.core import XBlock
 from xblock.exceptions import XBlockNotFoundError
 
-from openedx.core.djangoapps.xblock.api import get_component_from_usage_key, xblock_type_display_name
+from openedx.core.djangoapps.xblock.api import (
+    get_component_from_usage_key,
+    get_xblock_app_config,
+    xblock_type_display_name,
+)
 from openedx.core.lib.xblock_serializer.api import serialize_modulestore_block_for_learning_core
 from xmodule.modulestore.django import modulestore
 
@@ -1018,18 +1024,48 @@ def get_library_block_static_asset_files(usage_key) -> list[LibraryXBlockStaticF
 
     Returns a list of LibraryXBlockStaticFile objects, sorted by path.
 
-    TODO: This is not yet implemented for Learning Core backed libraries.
     TODO: Should this be in the general XBlock API rather than the libraries API?
     """
-    return []
+    component = get_component_from_usage_key(usage_key)
+    component_version = component.versioning.draft
+
+    # If there is no Draft version, then this was soft-deleted
+    if component_version is None:
+        return []
+
+    # cvc = the ComponentVersionContent through table
+    cvc_set = (
+        component_version
+        .componentversioncontent_set
+        .filter(content__has_file=True)
+        .order_by('key')
+        .select_related('content')
+    )
+
+    site_root_url = get_xblock_app_config().get_site_root_url()
+
+    return [
+        LibraryXBlockStaticFile(
+            path=cvc.key,
+            size=cvc.content.size,
+            url=site_root_url + reverse(
+                'content_libraries:library-assets',
+                kwargs={
+                    'component_version_uuid': component_version.uuid,
+                    'asset_path': cvc.key,
+                }
+            ),
+        )
+        for cvc in cvc_set
+    ]
 
 
-def add_library_block_static_asset_file(usage_key, file_name, file_content) -> LibraryXBlockStaticFile:
+def add_library_block_static_asset_file(usage_key, file_path, file_content, user=None) -> LibraryXBlockStaticFile:
     """
     Upload a static asset file into the library, to be associated with the
     specified XBlock. Will silently overwrite an existing file of the same name.
 
-    file_name should be a name like "doc.pdf". It may optionally contain slashes
+    file_path should be a name like "doc.pdf". It may optionally contain slashes
         like 'en/doc.pdf'
     file_content should be a binary string.
 
@@ -1041,10 +1077,67 @@ def add_library_block_static_asset_file(usage_key, file_name, file_content) -> L
         video_block = UsageKey.from_string("lb:VideoTeam:python-intro:video:1")
         add_library_block_static_asset_file(video_block, "subtitles-en.srt", subtitles.encode('utf-8'))
     """
-    raise NotImplementedError("Static assets not yet implemented for Learning Core")
+    # File path validations copied over from v1 library logic. This can't really
+    # hurt us inside our system because we never use these paths in an actual
+    # file system–they're just string keys that point to hash-named data files
+    # in a common library (learning package) level directory. But it might
+    # become a security issue during import/export serialization.
+    if file_path != file_path.strip().strip('/'):
+        raise InvalidNameError("file_path cannot start/end with / or whitespace.")
+    if '//' in file_path or '..' in file_path:
+        raise InvalidNameError("Invalid sequence (// or ..) in file_path.")
+
+    component = get_component_from_usage_key(usage_key)
+
+    media_type_str, _encoding = mimetypes.guess_type(file_path)
+    # We use "application/octet-stream" as a generic fallback media type, per
+    # RFC 2046: https://datatracker.ietf.org/doc/html/rfc2046
+    # TODO: This probably makes sense to push down to openedx-learning?
+    media_type_str = media_type_str or "application/octet-stream"
+
+    now = datetime.now(tz=timezone.utc)
+
+    with transaction.atomic():
+        media_type = authoring_api.get_or_create_media_type(media_type_str)
+        content = authoring_api.get_or_create_file_content(
+            component.publishable_entity.learning_package.id,
+            media_type.id,
+            data=file_content,
+            created=now,
+        )
+        component_version = authoring_api.create_next_component_version(
+            component.pk,
+            content_to_replace={file_path: content.id},
+            created=now,
+            created_by=user.id if user else None,
+        )
+        transaction.on_commit(
+            lambda: LIBRARY_BLOCK_UPDATED.send_event(
+                library_block=LibraryBlockData(
+                    library_key=usage_key.context_key,
+                    usage_key=usage_key,
+                )
+            )
+        )
 
+    # Now figure out the URL for the newly created asset...
+    site_root_url = get_xblock_app_config().get_site_root_url()
+    local_path = reverse(
+        'content_libraries:library-assets',
+        kwargs={
+            'component_version_uuid': component_version.uuid,
+            'asset_path': file_path,
+        }
+    )
+
+    return LibraryXBlockStaticFile(
+        path=file_path,
+        url=site_root_url + local_path,
+        size=content.size,
+    )
 
-def delete_library_block_static_asset_file(usage_key, file_name):
+
+def delete_library_block_static_asset_file(usage_key, file_path, user=None):
     """
     Delete a static asset file from the library.
 
@@ -1054,7 +1147,24 @@ def delete_library_block_static_asset_file(usage_key, file_name):
         video_block = UsageKey.from_string("lb:VideoTeam:python-intro:video:1")
         delete_library_block_static_asset_file(video_block, "subtitles-en.srt")
     """
-    raise NotImplementedError("Static assets not yet implemented for Learning Core")
+    component = get_component_from_usage_key(usage_key)
+    now = datetime.now(tz=timezone.utc)
+
+    with transaction.atomic():
+        component_version = authoring_api.create_next_component_version(
+            component.pk,
+            content_to_replace={file_path: None},
+            created=now,
+            created_by=user.id if user else None,
+        )
+        transaction.on_commit(
+            lambda: LIBRARY_BLOCK_UPDATED.send_event(
+                library_block=LibraryBlockData(
+                    library_key=usage_key.context_key,
+                    usage_key=usage_key,
+                )
+            )
+        )
 
 
 def get_allowed_block_types(library_key):  # pylint: disable=unused-argument

openedx/core/djangoapps/content_libraries/tests/test_content_libraries.py

@@ -661,13 +661,13 @@ def test_library_permissions(self):  # pylint: disable=too-many-statements
             self._get_library_block_olx(block3_key, expect_response=403)
             self._get_library_block_fields(block3_key, expect_response=403)
             self._get_library_block_assets(block3_key, expect_response=403)
-            self._get_library_block_asset(block3_key, file_name="whatever.png", expect_response=403)
+            self._get_library_block_asset(block3_key, file_name="static/whatever.png", expect_response=403)
             # Nor can they preview the block:
             self._render_block_view(block3_key, view_name="student_view", expect_response=403)
         # But if we grant allow_public_read, then they can:
         with self.as_user(admin):
             self._update_library(lib_id, allow_public_read=True)
-            # self._set_library_block_asset(block3_key, "whatever.png", b"data")
+            self._set_library_block_asset(block3_key, "static/whatever.png", b"data")
         with self.as_user(random_user):
             self._get_library_block_olx(block3_key)
             self._render_block_view(block3_key, view_name="student_view")
@@ -680,7 +680,7 @@ def test_library_permissions(self):  # pylint: disable=too-many-statements
             with self.as_user(user):
                 self._set_library_block_olx(block3_key, "<problem/>", expect_response=403)
                 self._set_library_block_fields(block3_key, {"data": "<problem />", "metadata": {}}, expect_response=403)
-                # self._set_library_block_asset(block3_key, "test.txt", b"data", expect_response=403)
+                self._set_library_block_asset(block3_key, "static/test.txt", b"data", expect_response=403)
                 self._delete_library_block(block3_key, expect_response=403)
                 self._commit_library_changes(lib_id, expect_response=403)
                 self._revert_library_changes(lib_id, expect_response=403)
@@ -690,9 +690,9 @@ def test_library_permissions(self):  # pylint: disable=too-many-statements
             olx = self._get_library_block_olx(block3_key)
             self._set_library_block_olx(block3_key, olx)
             self._set_library_block_fields(block3_key, {"data": olx, "metadata": {}})
-            # self._get_library_block_assets(block3_key)
-            # self._set_library_block_asset(block3_key, "test.txt", b"data")
-            # self._get_library_block_asset(block3_key, file_name="test.txt")
+            self._get_library_block_assets(block3_key)
+            self._set_library_block_asset(block3_key, "static/test.txt", b"data")
+            self._get_library_block_asset(block3_key, file_name="static/test.txt")
             self._delete_library_block(block3_key)
             self._commit_library_changes(lib_id)
             self._revert_library_changes(lib_id)  # This is a no-op after the commit, but should still have 200 response
@@ -915,7 +915,6 @@ def test_library_block_olx_update_event(self):
             event_receiver.call_args.kwargs
         )
 
-    @skip("We still need to re-implement static asset handling.")
     def test_library_block_add_asset_update_event(self):
         """
         Check that LIBRARY_BLOCK_CREATED event is sent when a static asset is
@@ -934,7 +933,7 @@ def test_library_block_add_asset_update_event(self):
 
         block = self._add_block_to_library(lib_id, "unit", "u1")
         block_id = block["id"]
-        self._set_library_block_asset(block_id, "test.txt", b"data")
+        self._set_library_block_asset(block_id, "static/test.txt", b"data")
 
         usage_key = LibraryUsageLocatorV2(
             lib_key=library_key,
@@ -955,7 +954,6 @@ def test_library_block_add_asset_update_event(self):
             event_receiver.call_args.kwargs
         )
 
-    @skip("We still need to re-implement static asset handling.")
     def test_library_block_del_asset_update_event(self):
         """
         Check that LIBRARY_BLOCK_CREATED event is sent when a static asset is
@@ -974,9 +972,9 @@ def test_library_block_del_asset_update_event(self):
 
         block = self._add_block_to_library(lib_id, "unit", "u1")
         block_id = block["id"]
-        self._set_library_block_asset(block_id, "test.txt", b"data")
+        self._set_library_block_asset(block_id, "static/test.txt", b"data")
 
-        self._delete_library_block_asset(block_id, 'text.txt')
+        self._delete_library_block_asset(block_id, 'static/text.txt')
 
         usage_key = LibraryUsageLocatorV2(
             lib_key=library_key,

openedx/core/djangoapps/content_libraries/tests/test_static_assets.py

@@ -1,11 +1,16 @@
 """
 Tests for static asset files in Learning-Core-based Content Libraries
 """
-from unittest import skip
+from uuid import UUID
 
+from opaque_keys.edx.keys import UsageKey
+
+from common.djangoapps.student.tests.factories import UserFactory
 from openedx.core.djangoapps.content_libraries.tests.base import (
     ContentLibrariesRestApiTest,
 )
+from openedx.core.djangoapps.xblock.api import get_component_from_usage_key
+from openedx.core.djangolib.testing.utils import skip_unless_cms
 
 # Binary data representing an SVG image file
 SVG_DATA = """<svg xmlns="http://www.w3.org/2000/svg" height="30" width="100">
@@ -23,15 +28,10 @@
 """
 
 
-@skip("Assets are being reimplemented in Learning Core. Disable until that's ready.")
+@skip_unless_cms
 class ContentLibrariesStaticAssetsTest(ContentLibrariesRestApiTest):
     """
     Tests for static asset files in Learning-Core-based Content Libraries
-
-    WARNING: every test should have a unique library slug, because even though
-    the django/mysql database gets reset for each test case, the lookup between
-    library slug and bundle UUID does not because it's assumed to be immutable
-    and cached forever.
     """
 
     def test_asset_filenames(self):
@@ -79,7 +79,7 @@ def test_video_transcripts(self):
             />
         """)
         # Upload the transcript file
-        self._set_library_block_asset(block_id, "3_yD_cEKoCk-en.srt", TRANSCRIPT_DATA)
+        self._set_library_block_asset(block_id, "static/3_yD_cEKoCk-en.srt", TRANSCRIPT_DATA)
 
         transcript_handler_url = self._get_block_handler_url(block_id, "transcript")
 
@@ -108,3 +108,79 @@ def check_download():
         self._commit_library_changes(library["id"])
         check_sjson()
         check_download()
+
+
+@skip_unless_cms
+class ContentLibrariesComponentVersionAssetTest(ContentLibrariesRestApiTest):
+    """
+    Tests for the view that actually delivers the Library asset in Studio.
+    """
+
+    def setUp(self):
+        super().setUp()
+
+        library = self._create_library(slug="asset-lib2", title="Static Assets Test Library")
+        block = self._add_block_to_library(library["id"], "html", "html1")
+        self._set_library_block_asset(block["id"], "static/test.svg", SVG_DATA)
+        usage_key = UsageKey.from_string(block["id"])
+        self.component = get_component_from_usage_key(usage_key)
+        self.draft_component_version = self.component.versioning.draft
+
+    def test_good_responses(self):
+        get_response = self.client.get(
+            f"/library_assets/{self.draft_component_version.uuid}/static/test.svg"
+        )
+        assert get_response.status_code == 200
+        content = b''.join(chunk for chunk in get_response.streaming_content)
+        assert content == SVG_DATA
+
+        good_head_response = self.client.head(
+            f"/library_assets/{self.draft_component_version.uuid}/static/test.svg"
+        )
+        assert good_head_response.headers == get_response.headers
+
+    def test_missing(self):
+        """Test asset requests that should 404."""
+        # Non-existent version...
+        wrong_version_uuid = UUID('11111111-1111-1111-1111-111111111111')
+        response = self.client.get(
+            f"/library_assets/{wrong_version_uuid}/static/test.svg"
+        )
+        assert response.status_code == 404
+
+        # Non-existent file...
+        response = self.client.get(
+            f"/library_assets/{self.draft_component_version.uuid}/static/missing.svg"
+        )
+        assert response.status_code == 404
+
+        # File-like ComponenVersionContent entry that isn't an actually
+        # downloadable file...
+        response = self.client.get(
+            f"/library_assets/{self.draft_component_version.uuid}/block.xml"
+        )
+        assert response.status_code == 404
+
+    def test_anonymous_user(self):
+        """Anonymous users shouldn't get access to library assets."""
+        self.client.logout()
+        response = self.client.get(
+            f"/library_assets/{self.draft_component_version.uuid}/static/test.svg"
+        )
+        assert response.status_code == 403
+
+    def test_unauthorized_user(self):
+        """User who is not a Content Library staff should not have access."""
+        self.client.logout()
+        student = UserFactory.create(
+            username="student",
+            email="student@example.com",
+            password="student-pass",
+            is_staff=False,
+            is_superuser=False,
+        )
+        self.client.login(username="student", password="student-pass")
+        get_response = self.client.get(
+            f"/library_assets/{self.draft_component_version.uuid}/static/test.svg"
+        )
+        assert get_response.status_code == 403