[FC-0099] feat: implement get_object method in scope data classes (#124)

Author: BryanttV

CHANGELOG.rst

@@ -16,6 +16,20 @@ Unreleased
 
 *
 
+0.10.0 - 2025-10-28
+*******************
+
+Added
+=====
+
+* New ``get_object()`` method in ScopeData to retrieve underlying domain objects
+* Implementation of ``get_object()`` for ContentLibraryData with canonical key validation
+
+Changed
+=======
+
+* Refactor ``ContentLibraryData.exists()`` to use ``get_object()`` internally
+
 0.9.1 - 2025-10-28
 ******************
 

openedx_authz/__init__.py

@@ -4,6 +4,6 @@
 
 import os
 
-__version__ = "0.9.1"
+__version__ = "0.10.0"
 
 ROOT_DIRECTORY = os.path.dirname(os.path.abspath(__file__))

openedx_authz/api/data.py

@@ -1,9 +1,11 @@
 """Data classes and enums for representing roles, permissions, and policies."""
 
+from __future__ import annotations
+
 import re
 from abc import abstractmethod
 from enum import Enum
-from typing import ClassVar, Literal, Type
+from typing import Any, ClassVar, Literal, Type
 
 from attrs import define
 from opaque_keys import InvalidKeyError
@@ -319,6 +321,20 @@ def validate_external_key(cls, _: str) -> bool:
         """
         return True
 
+    @abstractmethod
+    def get_object(self) -> Any | None:
+        """Retrieve the underlying domain object that this scope represents.
+
+        This method fetches the actual Open edX object (e.g., ContentLibrary, Organization)
+        associated with this scope's external_key. Subclasses should implement this to return
+        their specific object types.
+
+        Returns:
+            Any | None: The domain object associated with this scope, or None if the object
+                does not exist or cannot be retrieved.
+        """
+        raise NotImplementedError("Subclasses must implement get_object method.")
+
     @abstractmethod
     def exists(self) -> bool:
         """Check if the scope exists.
@@ -366,6 +382,15 @@ def library_id(self) -> str:
         """
         return self.external_key
 
+    @property
+    def library_key(self) -> LibraryLocatorV2:
+        """The LibraryLocatorV2 object for the content library.
+
+        Returns:
+            LibraryLocatorV2: The library locator object.
+        """
+        return LibraryLocatorV2.from_string(self.library_id)
+
     @classmethod
     def validate_external_key(cls, external_key: str) -> bool:
         """Validate the external_key format for ContentLibraryData.
@@ -382,18 +407,38 @@ def validate_external_key(cls, external_key: str) -> bool:
         except InvalidKeyError:
             return False
 
+    def get_object(self) -> ContentLibrary | None:
+        """Retrieve the ContentLibrary instance associated with this scope.
+
+        This method converts the library_id to a LibraryLocatorV2 key and queries the
+        database to fetch the corresponding ContentLibrary object.
+
+        Returns:
+            ContentLibrary | None: The ContentLibrary instance if found in the database,
+                or None if the library does not exist or has an invalid key format.
+
+        Examples:
+            >>> library_scope = ContentLibraryData(external_key='lib:DemoX:CSPROB')
+            >>> library_obj = library_scope.get_object() # ContentLibrary object
+        """
+        try:
+            library_obj = ContentLibrary.objects.get_by_key(self.library_key)
+            # Validate canonical key: get_by_key is case-insensitive, but we require exact match
+            # This ensures authorization uses canonical library IDs consistently
+            if library_obj.library_key != self.library_key:
+                raise ContentLibrary.DoesNotExist
+        except (InvalidKeyError, ContentLibrary.DoesNotExist):
+            return None
+
+        return library_obj
+
     def exists(self) -> bool:
         """Check if the content library exists.
 
         Returns:
             bool: True if the content library exists, False otherwise.
         """
-        try:
-            library_key = LibraryLocatorV2.from_string(self.library_id)
-            ContentLibrary.objects.get_by_key(library_key=library_key)
-            return True
-        except ContentLibrary.DoesNotExist:
-            return False
+        return self.get_object() is not None
 
     def __str__(self):
         """Human readable string representation of the content library."""

openedx_authz/tests/api/test_data.py

@@ -1,7 +1,10 @@
 """Test data for the authorization API."""
 
+from unittest.mock import Mock, patch
+
 from ddt import data, ddt, unpack
 from django.test import TestCase
+from opaque_keys.edx.locator import LibraryLocatorV2
 
 from openedx_authz.api.data import (
     ActionData,
@@ -507,3 +510,111 @@ def test_role_assignment_data_repr(self):
 
         expected_repr = "user^john_doe => [role^instructor, role^library_admin] @ lib^lib:DemoX:CSPROB"
         self.assertEqual(actual_repr, expected_repr)
+
+
+@ddt
+class TestContentLibraryData(TestCase):
+    """Test the ContentLibraryData class."""
+
+    @patch("openedx_authz.api.data.ContentLibrary")
+    def test_get_object_success(self, mock_content_library_model):
+        """Test get_object returns ContentLibrary when it exists with valid key.
+
+        Expected Result:
+            - Returns the ContentLibrary object when library exists
+            - Library key matches exactly (canonical validation passes)
+        """
+        library_id = "lib:DemoX:CSPROB"
+        library_scope = ContentLibraryData(external_key=library_id)
+        mock_library_obj = Mock()
+        mock_library_obj.library_key = library_scope.library_key
+        mock_content_library_model.objects.get_by_key.return_value = mock_library_obj
+
+        result = library_scope.get_object()
+
+        self.assertEqual(result, mock_library_obj)
+        mock_content_library_model.objects.get_by_key.assert_called_once_with(library_scope.library_key)
+
+    @patch("openedx_authz.api.data.ContentLibrary")
+    def test_get_object_does_not_exist(self, mock_content_library_model):
+        """Test get_object returns None when library does not exist.
+
+        Expected Result:
+            - Returns None when ContentLibrary.DoesNotExist is raised
+        """
+        library_id = "lib:DemoX:NonExistent"
+        library_scope = ContentLibraryData(external_key=library_id)
+        mock_content_library_model.DoesNotExist = Exception
+        mock_content_library_model.objects.get_by_key.side_effect = mock_content_library_model.DoesNotExist
+
+        result = library_scope.get_object()
+
+        self.assertIsNone(result)
+
+    @patch("openedx_authz.api.data.ContentLibrary")
+    def test_get_object_invalid_key_format(self, mock_content_library_model):
+        """Test get_object returns None when library_id has invalid format.
+
+        Expected Result:
+            - Returns None when InvalidKeyError is raised during key parsing
+        """
+        mock_content_library_model.DoesNotExist = Exception
+        library_scope = ContentLibraryData(external_key="invalid-library-format")
+
+        result = library_scope.get_object()
+
+        self.assertIsNone(result)
+        mock_content_library_model.objects.get_by_key.assert_not_called()
+
+    @patch("openedx_authz.api.data.ContentLibrary")
+    def test_get_object_non_canonical_key(self, mock_content_library_model):
+        """Test get_object returns None when library key is not canonical.
+
+        This test verifies the canonical key validation: get_by_key is case-insensitive,
+        but we require exact match to ensure authorization uses canonical library IDs.
+
+        Expected Result:
+            - Returns None when retrieved library's key doesn't match exactly
+            - Simulates case where user provides 'lib:demox:csprob' but canonical is 'lib:DemoX:CSPROB'
+        """
+        library_id = "lib:DemoX:CSPROB"
+        library_key = LibraryLocatorV2.from_string(library_id)
+        # Convert to lowercase to simulate case-insensitive comparison
+        library_scope = ContentLibraryData(external_key=library_id.lower())
+        mock_content_library_model.objects.get_by_key.return_value = Mock(library_key=library_key)
+        mock_content_library_model.DoesNotExist = Exception
+
+        result = library_scope.get_object()
+
+        self.assertIsNone(result)
+
+    @patch("openedx_authz.api.data.ContentLibrary")
+    def test_exists_returns_true_when_library_exists(self, mock_content_library_model):
+        """Test exists() returns True when get_object() returns a library.
+
+        Expected Result:
+            - exists() returns True when library object is found
+        """
+        library_id = "lib:DemoX:CSPROB"
+        library_scope = ContentLibraryData(external_key=library_id)
+        mock_content_library_model.objects.get_by_key.return_value = Mock(library_key=library_scope.library_key)
+
+        result = library_scope.exists()
+
+        self.assertTrue(result)
+
+    @patch("openedx_authz.api.data.ContentLibrary")
+    def test_exists_returns_false_when_library_does_not_exist(self, mock_content_library_model):
+        """Test exists() returns False when get_object() returns None.
+
+        Expected Result:
+            - exists() returns False when library is not found
+        """
+        library_id = "lib:DemoX:NonExistent"
+        library_scope = ContentLibraryData(external_key=library_id)
+        mock_content_library_model.DoesNotExist = Exception
+        mock_content_library_model.objects.get_by_key.side_effect = mock_content_library_model.DoesNotExist
+
+        result = library_scope.exists()
+
+        self.assertFalse(result)