Added story viewer backend handler (oppia#6237)

* First

* First

* Second

* Third

* Fourth

* Added new file

* Added test file and changes

* Added test file and running

* Fixed linting issues

* Fixed linting issues

* Fixed linting issues

* running tests success

* merge conflicts removed

* Fixed

* Fixed

* Changes_Done

* Changes_Done

core/controllers/acl_decorators.py

@@ -24,6 +24,7 @@
 from core.domain import rights_manager
 from core.domain import role_services
 from core.domain import skill_services
+from core.domain import story_services
 from core.domain import suggestion_services
 from core.domain import topic_services
 from core.domain import user_services
@@ -2352,6 +2353,47 @@ def test_can_access(self, topic_name, **kwargs):
     return test_can_access
 
 
+def can_access_story_viewer_page(handler):
+    """Decorator to check whether user can access story viewer page.
+
+    Args:
+        handler: function.  The function to be decorated.
+
+    Returns:
+        function. The newly decorated function that now checks
+            if the user can access the given story viewer page.
+    """
+
+    def test_can_access(self, story_id, **kwargs):
+        """Checks if the user can access story viewer page.
+
+        Args:
+            story_id: str. The unique id of the story.
+            **kwargs: *. Keyword arguments.
+
+        Returns:
+            *. The return value of the decorated function.
+
+        Raises:
+            PageNotFoundException: The given page cannot be found.
+        """
+        story = story_services.get_story_by_id(story_id, strict=False)
+
+        if story is None:
+            raise self.PageNotFoundException
+
+        story_rights = story_services.get_story_rights(
+            story_id, strict=False)
+
+        if story_rights.story_is_published:
+            return handler(self, story_id, **kwargs)
+        else:
+            raise self.PageNotFoundException
+    test_can_access.__wrapped__ = True
+
+    return test_can_access
+
+
 def get_decorator_for_accepting_suggestion(decorator):
     """Function that takes a decorator as an argument and then applies some
     common checks and then checks the permissions specified by the passed in

core/controllers/story_viewer.py

@@ -0,0 +1,54 @@
+# Copyright 2019 The Oppia Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS-IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Controllers for the story viewer page"""
+
+from constants import constants
+from core.controllers import acl_decorators
+from core.controllers import base
+from core.domain import story_services
+import feconf
+
+
+class StoryPageDataHandler(base.BaseHandler):
+    """Manages the data that needs to be displayed to a learner on the
+    story viewer page.
+    """
+    GET_HANDLER_ERROR_RETURN_TYPE = feconf.HANDLER_TYPE_JSON
+
+    @acl_decorators.can_access_story_viewer_page
+    def get(self, story_id):
+        """Handles GET requests."""
+        if not constants.ENABLE_NEW_STRUCTURE_PLAYERS:
+            raise self.PageNotFoundException
+
+        story = story_services.get_story_by_id(story_id)
+
+        completed_nodes = [completed_node.to_dict()
+                           for completed_node in
+                           story_services.get_completed_nodes_in_story(
+                               self.user_id, story_id)]
+
+        pending_nodes = [pending_node.to_dict()
+                         for pending_node in
+                         story_services.get_pending_nodes_in_story(
+                             self.user_id, story_id)]
+
+        self.values.update({
+            'story_title': story.title,
+            'story_description': story.description,
+            'completed_nodes': completed_nodes,
+            'pending_nodes': pending_nodes
+        })
+        self.render_json(self.values)

core/controllers/story_viewer_test.py

@@ -0,0 +1,108 @@
+# Copyright 2019 The Oppia Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS-IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Tests for the story viewer page"""
+
+from constants import constants
+from core.domain import rights_manager
+from core.domain import story_domain
+from core.domain import story_services
+from core.domain import user_services
+from core.tests import test_utils
+import feconf
+
+
+class BaseStoryViewerControllerTests(test_utils.GenericTestBase):
+
+    def _record_completion(self, user_id, STORY_ID, node_id):
+        """Records the completion of a node in the context of a story."""
+        story_services.record_completed_node_in_story_context(
+            user_id, STORY_ID, node_id)
+
+    def setUp(self):
+        """Completes the sign up process for the various users."""
+        super(BaseStoryViewerControllerTests, self).setUp()
+        self.VIEWER_EMAIL = '[email protected]'
+        self.VIEWER_USERNAME = 'viewer'
+        self.signup(self.ADMIN_EMAIL, self.ADMIN_USERNAME)
+        self.admin_id = self.get_user_id_from_email(self.ADMIN_EMAIL)
+        self.set_admins([self.ADMIN_USERNAME])
+        self.admin = user_services.UserActionsInfo(self.admin_id)
+        self.login(self.ADMIN_EMAIL)
+        self.STORY_ID_1 = 'story_id_1'
+        self.NODE_ID_1 = 'node_1'
+        self.NODE_ID_2 = 'node_2'
+        self.EXP_ID = 'exp_id'
+
+        self.save_new_valid_exploration(
+            self.EXP_ID, self.admin_id, title='Bridges in England',
+            category='Architecture', language_code='en')
+        rights_manager.publish_exploration(self.admin, self.EXP_ID)
+        story = story_domain.Story.create_default_story(
+            self.STORY_ID_1, 'Title')
+        story.description = ('Description')
+        self.node_1 = {
+            'id': self.NODE_ID_1,
+            'title': 'Title 1',
+            'destination_node_ids': ['node_2'],
+            'acquired_skill_ids': [],
+            'prerequisite_skill_ids': [],
+            'outline': '',
+            'outline_is_finalized': False,
+            'exploration_id': self.EXP_ID
+        }
+        self.node_2 = {
+            'id': self.NODE_ID_2,
+            'title': 'Title 2',
+            'destination_node_ids': [],
+            'acquired_skill_ids': [],
+            'prerequisite_skill_ids': [],
+            'outline': '',
+            'outline_is_finalized': False,
+            'exploration_id': self.EXP_ID
+        }
+        story.story_contents.nodes = [
+            story_domain.StoryNode.from_dict(self.node_1),
+            story_domain.StoryNode.from_dict(self.node_2)
+        ]
+        self.nodes = story.story_contents.nodes
+        story.story_contents.initial_node_id = 'node_1'
+        story.story_contents.next_node_id = 'node_3'
+        story_services.save_new_story(self.admin_id, story)
+        story_services.publish_story(self.STORY_ID_1, self.admin_id)
+        self.logout()
+        self.signup(self.VIEWER_EMAIL, self.VIEWER_USERNAME)
+        self.viewer_id = self.get_user_id_from_email(self.VIEWER_EMAIL)
+        self.login(self.VIEWER_EMAIL)
+        self._record_completion(self.viewer_id, self.STORY_ID_1, self.NODE_ID_1)
+
+
+class StoryPageDataHandlerTests(BaseStoryViewerControllerTests):
+    def test_get(self):
+        with self.swap(constants, 'ENABLE_NEW_STRUCTURE_PLAYERS', True):
+            json_response = self.get_json(
+                '%s/%s' % (feconf.STORY_DATA_HANDLER, 'story_id_1'))
+            expected_dict = {
+                'story_title': 'Title',
+                'story_description': 'Description',
+                'completed_nodes': [self.node_1],
+                'pending_nodes': [self.node_2]
+            }
+            self.assertDictContainsSubset(expected_dict, json_response)
+
+    def test_get_fails_when_new_structures_not_enabled(self):
+        with self.swap(constants, 'ENABLE_NEW_STRUCTURE_PLAYERS', False):
+            self.get_json(
+                '%s/%s' % (feconf.STORY_DATA_HANDLER, 'story_id_1'),
+                expected_status_int=404)

core/domain/story_services.py

@@ -605,6 +605,28 @@ def get_completed_nodes_in_story(user_id, story_id):
     return completed_nodes
 
 
+def get_pending_nodes_in_story(user_id, story_id):
+    """Returns the nodes that are pending in a story
+
+    Args:
+        user_id: str. The user id of the user.
+        story_id: str. The id of the story.
+
+    Returns:
+        list(StoryNode): The list of story nodes, pending
+        for the user.
+    """
+    story = get_story_by_id(story_id)
+    pending_nodes = []
+
+    completed_node_ids = get_completed_node_ids(user_id, story_id)
+    for node in story.story_contents.nodes:
+        if node.id not in completed_node_ids:
+            pending_nodes.append(node)
+
+    return pending_nodes
+
+
 def record_completed_node_in_story_context(user_id, story_id, node_id):
     """Records a node by a given user in a given story
     context as having been played.

core/domain/story_services_test.py

@@ -512,6 +512,15 @@ def test_get_completed_nodes_in_story(self):
             self.assertEqual(
                 completed_node.to_dict(), self.nodes[ind].to_dict())
 
+    def test_get_pending_nodes_in_story(self):
+        self._record_completion(self.owner_id, self.STORY_1_ID, self.NODE_ID_1)
+
+        for _, pending_node in enumerate(
+                story_services.get_pending_nodes_in_story(
+                    self.owner_id, self.STORY_1_ID)):
+            self.assertEqual(
+                pending_node.to_dict(), self.nodes[1].to_dict())
+
     def test_record_completed_node_in_story_context(self):
         # Ensure that node completed within the context of a story are
         # recorded correctly. This test actually validates both

feconf.py

@@ -681,6 +681,7 @@ def get_empty_ratings():
 SKILL_RIGHTS_URL_PREFIX = '/skill_editor_handler/rights'
 SKILL_PUBLISH_URL_PREFIX = '/skill_editor_handler/publish_skill'
 SPLASH_URL = '/splash'
+STORY_DATA_HANDLER = '/story_data_handler'
 STORY_EDITOR_URL_PREFIX = '/story_editor'
 STORY_EDITOR_DATA_URL_PREFIX = '/story_editor_handler/data'
 SUGGESTION_ACTION_URL_PREFIX = '/suggestionactionhandler'

main.py

@@ -43,6 +43,7 @@
 from core.controllers import resources
 from core.controllers import skill_editor
 from core.controllers import story_editor
+from core.controllers import story_viewer
 from core.controllers import subscriptions
 from core.controllers import suggestion
 from core.controllers import topic_editor
@@ -225,6 +226,9 @@ def ui_access_wrapper(self, *args, **kwargs):
     get_redirect_route(
         r'%s/<skill_id>' % feconf.NEW_QUESTION_URL,
         question_editor.QuestionCreationHandler),
+    get_redirect_route(
+        r'%s/<story_id>' % feconf.STORY_DATA_HANDLER,
+        story_viewer.StoryPageDataHandler),
     get_redirect_route(
         r'%s/<topic_id>' % feconf.TOPIC_EDITOR_STORY_URL,
         topic_editor.TopicEditorStoryHandler),