refactor: Update get block OLX view to support versions [FC-0062] (op…

…enedx#35932)

* Deprecate `get_block_draft_olx`
* Deprecate get olx view in content libraries
* Create `get_block_olx` in xblock API with support of versions
* Create get olx view in xblock

openedx/core/djangoapps/content_libraries/views.py

@@ -715,6 +715,9 @@ class LibraryBlockOlxView(APIView):
     @convert_exceptions
     def get(self, request, usage_key_str):
         """
+        DEPRECATED. Use get_block_olx_view() in xblock REST-API.
+        Can be removed post-Teak.
+
         Get the block's OLX
         """
         key = LibraryUsageLocatorV2.from_string(usage_key_str)

openedx/core/djangoapps/xblock/api.py

@@ -33,7 +33,12 @@
     LearningCoreXBlockRuntime,
 )
 from .data import CheckPerm, LatestVersion
-from .utils import get_secure_token_for_xblock_handler, get_xblock_id_for_anonymous_user
+from .rest_api.url_converters import VersionConverter
+from .utils import (
+    get_secure_token_for_xblock_handler,
+    get_xblock_id_for_anonymous_user,
+    get_auto_latest_version,
+)
 
 from .runtime.learning_core_runtime import LearningCoreXBlockRuntime
 
@@ -208,13 +213,26 @@ def get_component_from_usage_key(usage_key: UsageKeyV2) -> Component:
     )
 
 
-def get_block_draft_olx(usage_key: UsageKeyV2) -> str:
+def get_block_olx(
+    usage_key: UsageKeyV2,
+    *,
+    version: int | LatestVersion = LatestVersion.AUTO
+) -> str:
     """
-    Get the OLX source of the draft version of the given Learning-Core-backed XBlock.
+    Get the OLX source of the of the given Learning-Core-backed XBlock and a version.
     """
-    # Inefficient but simple approach. Optimize later if needed.
     component = get_component_from_usage_key(usage_key)
-    component_version = component.versioning.draft
+    version = get_auto_latest_version(version)
+
+    if version == LatestVersion.DRAFT:
+        component_version = component.versioning.draft
+    elif version == LatestVersion.PUBLISHED:
+        component_version = component.versioning.published
+    else:
+        assert isinstance(version, int)
+        component_version = component.versioning.version_num(version)
+    if component_version is None:
+        raise NoSuchUsage(usage_key)
 
     # TODO: we should probably make a method on ComponentVersion that returns
     # a content based on the name. Accessing by componentversioncontent__key is
@@ -224,6 +242,11 @@ def get_block_draft_olx(usage_key: UsageKeyV2) -> str:
     return content.text
 
 
+def get_block_draft_olx(usage_key: UsageKeyV2) -> str:
+    """ DEPRECATED. Use get_block_olx(). Can be removed post-Teak. """
+    return get_block_olx(usage_key, version=LatestVersion.DRAFT)
+
+
 def render_block_view(block, view_name, user):  # pylint: disable=unused-argument
     """
     Get the HTML, JS, and CSS needed to render the given XBlock view.

openedx/core/djangoapps/xblock/rest_api/serializers.py

@@ -0,0 +1,11 @@
+"""
+Serializers for the xblock REST API
+"""
+from rest_framework import serializers
+
+
+class XBlockOlxSerializer(serializers.Serializer):
+    """
+    Serializer for representing an XBlock's OLX
+    """
+    olx = serializers.CharField()

openedx/core/djangoapps/xblock/rest_api/urls.py

@@ -19,6 +19,8 @@
     path('', views.block_metadata),
     # get/post full json fields of an XBlock:
     path('fields/', views.BlockFieldsView.as_view()),
+    # Get the OLX source code of the specified block
+    path('olx/', views.get_block_olx_view),
     # render one of this XBlock's views (e.g. student_view)
     path('view/<str:view_name>/', views.render_block_view),
     # get the URL needed to call this XBlock's handlers

openedx/core/djangoapps/xblock/rest_api/views.py

@@ -33,9 +33,11 @@
     get_handler_url as _get_handler_url,
     load_block,
     render_block_view as _render_block_view,
+    get_block_olx,
 )
 from ..utils import validate_secure_token_for_xblock_handler
 from .url_converters import VersionConverter
+from .serializers import XBlockOlxSerializer
 
 User = get_user_model()
 
@@ -213,6 +215,23 @@ def xblock_handler(
     return response
 
 
+@api_view(['GET'])
+@view_auth_classes(is_authenticated=False)
+def get_block_olx_view(
+    request,
+    usage_key: UsageKeyV2,
+    version: LatestVersion | int = LatestVersion.AUTO,
+):
+    """
+    Get the OLX (XML serialization) of the specified XBlock
+    """
+    context_impl = get_learning_context_impl(usage_key)
+    if not context_impl.can_view_block_for_editing(request.user, usage_key):
+        raise PermissionDenied(f"You don't have permission to access the OLX of component '{usage_key}'.")
+    olx = get_block_olx(usage_key, version=version)
+    return Response(XBlockOlxSerializer({"olx": olx}).data)
+
+
 def cors_allow_xblock_handler(sender, request, **kwargs):  # lint-amnesty, pylint: disable=unused-argument
     """
     Sandboxed XBlocks need to be able to call XBlock handlers via POST,

openedx/core/djangoapps/xblock/runtime/learning_core_runtime.py

@@ -24,6 +24,7 @@
 from openedx.core.lib.xblock_serializer.api import serialize_modulestore_block_for_learning_core
 from openedx.core.lib.xblock_serializer.data import StaticFile
 from ..data import AuthoredDataMode, LatestVersion
+from ..utils import get_auto_latest_version
 from ..learning_context.manager import get_learning_context_impl
 from .runtime import XBlockRuntime
 
@@ -178,11 +179,7 @@ def get_block(self, usage_key, for_parent=None, *, version: int | LatestVersion
         # just get it the easy way.
         component = self._get_component_from_usage_key(usage_key)
 
-        if version == LatestVersion.AUTO:
-            if self.authored_data_mode == AuthoredDataMode.DEFAULT_DRAFT:
-                version = LatestVersion.DRAFT
-            else:
-                version = LatestVersion.PUBLISHED
+        version = get_auto_latest_version(version)
         if self.authored_data_mode == AuthoredDataMode.STRICTLY_PUBLISHED and version != LatestVersion.PUBLISHED:
             raise ValidationError("This runtime only allows accessing the published version of components")
         if version == LatestVersion.DRAFT:

openedx/core/djangoapps/xblock/utils.py

@@ -11,6 +11,10 @@
 import crum
 from django.conf import settings
 
+from openedx.core.djangoapps.xblock.apps import get_xblock_app_config
+
+from .data import AuthoredDataMode, LatestVersion
+
 
 def get_secure_token_for_xblock_handler(user_id, block_key_str, time_idx=0):
     """
@@ -167,3 +171,18 @@ def get_xblock_id_for_anonymous_user(user):
         return current_request.session["xblock_id_for_anonymous_user"]
     else:
         raise RuntimeError("Cannot get a user ID for an anonymous user outside of an HTTP request context.")
+
+
+def get_auto_latest_version(version: int | LatestVersion) -> int | LatestVersion:
+    """
+    Gets the actual LatestVersion if is `LatestVersion.AUTO`;
+    otherwise, returns the same value.
+    """
+    if version == LatestVersion.AUTO:
+        authored_data_mode = get_xblock_app_config().get_runtime_params()["authored_data_mode"]
+        version = (
+            LatestVersion.DRAFT
+            if authored_data_mode == AuthoredDataMode.DEFAULT_DRAFT
+            else LatestVersion.PUBLISHED
+        )
+    return version