MA-1189 - Discussion API: implemented GET comment children

lms/djangoapps/discussion_api/api.py

@@ -415,7 +415,7 @@ def get_comment_list(request, thread_id, endorsed, page, page_size, mark_as_read
         raise Http404
     num_pages = (resp_total + page_size - 1) / page_size if resp_total else 1
 
-    results = [CommentSerializer(response, context=context).data for response in responses]
+    results = [CommentSerializer(response, remove_fields=["children"], context=context).data for response in responses]
     return get_paginated_data(request, results, page, num_pages)
 
 
@@ -718,6 +718,50 @@ def get_thread(request, thread_id):
     return serializer.data
 
 
+def get_response_comments(request, comment_id, page, page_size):
+    """
+    Return the list of comments for the given thread response.
+
+    Arguments:
+
+        request: The django request object used for build_absolute_uri and
+          determining the requesting user.
+
+        comment_id: The id of the comment/response to get child comments for.
+
+        page: The page number (1-indexed) to retrieve
+
+        page_size: The number of comments to retrieve per page
+
+    Returns:
+
+        A paginated result containing a list of comments
+
+    """
+    try:
+        cc_comment = Comment(id=comment_id).retrieve()
+        cc_thread, context = _get_thread_and_context(request, cc_comment["thread_id"])
+        if cc_thread["thread_type"] == "question":
+            thread_responses = cc_thread["endorsed_responses"] + cc_thread["non_endorsed_responses"]
+        else:
+            thread_responses = cc_thread["children"]
+        response_comments = []
+        for response in thread_responses:
+            if response["id"] == comment_id:
+                response_comments = response["children"]
+                break
+
+        response_skip = page_size * (page - 1)
+        paged_response_comments = response_comments[response_skip:(response_skip + page_size)]
+        results = [CommentSerializer(comment, context=context).data for comment in paged_response_comments]
+
+        comments_count = len(response_comments)
+        num_pages = (comments_count + page_size - 1) / page_size if comments_count else 1
+        return get_paginated_data(request, results, page, num_pages)
+    except CommentClientRequestError:
+        raise Http404
+
+
 def delete_thread(request, thread_id):
     """
     Delete a thread.

lms/djangoapps/discussion_api/serializers.py

@@ -290,6 +290,15 @@ class CommentSerializer(_ContentSerializer):
 
     non_updatable_fields = NON_UPDATABLE_COMMENT_FIELDS
 
+    def __init__(self, *args, **kwargs):
+        remove_fields = kwargs.pop('remove_fields', None)
+        super(CommentSerializer, self).__init__(*args, **kwargs)
+
+        if remove_fields:
+            # for multiple fields in a list
+            for field_name in remove_fields:
+                self.fields.pop(field_name)
+
     def get_endorsed_by(self, obj):
         """
         Returns the username of the endorsing user, if the information is

lms/djangoapps/discussion_api/tests/test_api.py

@@ -1146,7 +1146,6 @@ class GetCommentListTest(CommentsServiceMockMixin, SharedModuleStoreTestCase):
                 "abuse_flagged": False,
                 "voted": False,
                 "vote_count": 4,
-                "children": [],
                 "editable_fields": ["abuse_flagged", "voted"],
             },
             {
@@ -1166,7 +1165,6 @@ class GetCommentListTest(CommentsServiceMockMixin, SharedModuleStoreTestCase):
                 "abuse_flagged": True,
                 "voted": False,
                 "vote_count": 7,
-                "children": [],
                 "editable_fields": ["abuse_flagged", "voted"],
             },
         ]

lms/djangoapps/discussion_api/tests/test_views.py

@@ -662,7 +662,6 @@ class CommentViewSetListTest(DiscussionAPIViewTestMixin, ModuleStoreTestCase):
             "endorsed": False,
             "abuse_flaggers": [],
             "votes": {"up_count": 4},
-            "children": [],
         }]
         expected_comments = [{
             "id": "test_comment",
@@ -681,7 +680,6 @@ class CommentViewSetListTest(DiscussionAPIViewTestMixin, ModuleStoreTestCase):
             "abuse_flagged": False,
             "voted": True,
             "vote_count": 4,
-            "children": [],
             "editable_fields": ["abuse_flagged", "voted"],
         }]
         self.register_get_thread_response({
@@ -1025,3 +1023,73 @@ class ThreadViewSetRetrieveTest(DiscussionAPIViewTestMixin, ModuleStoreTestCase)
         self.register_get_thread_error_response(self.thread_id, 404)
         response = self.client.get(self.url)
         self.assertEqual(response.status_code, 404)
+
+
+@httpretty.activate
+class CommentViewSetRetrieveTest(DiscussionAPIViewTestMixin, ModuleStoreTestCase):
+    """Tests for CommentViewSet Retrieve"""
+    def setUp(self):
+        super(CommentViewSetRetrieveTest, self).setUp()
+        self.url = reverse("comment-detail", kwargs={"comment_id": "test_comment"})
+        self.thread_id = "test_thread"
+        self.comment_id = "test_comment"
+
+    def make_comment_data(self, comment_id, parent_id=None, children=[]):  # pylint: disable=W0102
+        """
+        Returns comment dict object as returned by comments service
+        """
+        return make_minimal_cs_comment({
+            "id": comment_id,
+            "parent_id": parent_id,
+            "course_id": unicode(self.course.id),
+            "thread_id": self.thread_id,
+            "thread_type": "discussion",
+            "username": self.user.username,
+            "user_id": str(self.user.id),
+            "created_at": "2015-06-03T00:00:00Z",
+            "updated_at": "2015-06-03T00:00:00Z",
+            "body": "Original body",
+            "children": children,
+        })
+
+    def test_basic(self):
+        self.register_get_user_response(self.user)
+        cs_comment_child = self.make_comment_data("test_child_comment", self.comment_id, children=[])
+        cs_comment = self.make_comment_data(self.comment_id, None, [cs_comment_child])
+        cs_thread = make_minimal_cs_thread({
+            "id": self.thread_id,
+            "course_id": unicode(self.course.id),
+            "children": [cs_comment],
+        })
+        self.register_get_thread_response(cs_thread)
+        self.register_get_comment_response(cs_comment)
+
+        expected_response_data = {
+            "id": "test_child_comment",
+            "parent_id": self.comment_id,
+            "thread_id": self.thread_id,
+            "author": self.user.username,
+            "author_label": None,
+            "raw_body": "Original body",
+            "rendered_body": "<p>Original body</p>",
+            "created_at": "2015-06-03T00:00:00Z",
+            "updated_at": "2015-06-03T00:00:00Z",
+            "children": [],
+            "endorsed_at": None,
+            "endorsed": False,
+            "endorsed_by": None,
+            "endorsed_by_label": None,
+            "voted": False,
+            "vote_count": 0,
+            "abuse_flagged": False,
+            "editable_fields": ["abuse_flagged", "raw_body", "voted"]
+        }
+
+        response = self.client.get(self.url)
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(json.loads(response.content)['results'][0], expected_response_data)
+
+    def test_retrieve_nonexistent_comment(self):
+        self.register_get_comment_error_response(self.comment_id, 404)
+        response = self.client.get(self.url)
+        self.assertEqual(response.status_code, 404)

lms/djangoapps/discussion_api/views.py

@@ -18,6 +18,7 @@ from discussion_api.api import (
     delete_thread,
     delete_comment,
     get_comment_list,
+    get_response_comments,
     get_course,
     get_course_topics,
     get_thread,
@@ -25,7 +26,7 @@ from discussion_api.api import (
     update_comment,
     update_thread,
 )
-from discussion_api.forms import CommentListGetForm, ThreadListGetForm
+from discussion_api.forms import CommentListGetForm, ThreadListGetForm, _PaginationForm
 from openedx.core.lib.api.view_utils import DeveloperErrorViewMixin
 
 
@@ -299,6 +300,8 @@ class CommentViewSet(_ViewMixin, DeveloperErrorViewMixin, ViewSet):
 
         GET /api/discussion/v1/comments/?thread_id=0123456789abcdef01234567
 
+        GET /api/discussion/v1/comments/2123456789abcdef01234555
+
         POST /api/discussion/v1/comments/
         {
             "thread_id": "0123456789abcdef01234567",
@@ -310,7 +313,7 @@ class CommentViewSet(_ViewMixin, DeveloperErrorViewMixin, ViewSet):
 
         DELETE /api/discussion/v1/comments/comment_id
 
-    **GET Parameters**:
+    **GET Comment List Parameters**:
 
         * thread_id (required): The thread to retrieve comments for
 
@@ -325,6 +328,15 @@ class CommentViewSet(_ViewMixin, DeveloperErrorViewMixin, ViewSet):
         * mark_as_read: Will mark the thread of the comments as read. (default
             is False)
 
+    **GET Child Comment List Parameters**:
+
+        * comment_id (required): The comment to retrieve child comments for
+
+        * page: The (1-indexed) page to retrieve (default is 1)
+
+        * page_size: The number of items per page (default is 10, max is 100)
+
+
     **POST Parameters**:
 
         * thread_id (required): The thread to post the comment in
@@ -420,6 +432,22 @@ class CommentViewSet(_ViewMixin, DeveloperErrorViewMixin, ViewSet):
             )
         )
 
+    def retrieve(self, request, comment_id=None):
+        """
+        Implements the GET method for comments against response ID
+        """
+        form = _PaginationForm(request.GET)
+        if not form.is_valid():
+            raise ValidationError(form.errors)
+        return Response(
+            get_response_comments(
+                request,
+                comment_id,
+                form.cleaned_data["page"],
+                form.cleaned_data["page_size"]
+            )
+        )
+
     def create(self, request):
         """
         Implements the POST method for the list endpoint as described in the