Remove {{BEFORE_END_HEAD_TAG_HOOK}} from Base.html (oppia#6835)

* remove before end head tag hook

* work on lint

* work on review changes and some refactoring

* work on failing test

* address review comments

* failing tests

* work on backend tests

* address review comments

core/controllers/admin_test.py

@@ -14,8 +14,8 @@
 
 """Tests for the admin page."""
 
-from core.controllers import base
 from core.domain import collection_services
+from core.domain import config_domain
 from core.domain import exp_domain
 from core.domain import exp_services
 from core.domain import search_services
@@ -58,51 +58,33 @@ def test_change_configuration_property(self):
         self.login(self.ADMIN_EMAIL, is_super_admin=True)
         response = self.get_html_response('/admin')
         csrf_token = self.get_csrf_token_from_response(response)
+        new_config_value = True
 
         response_dict = self.get_json('/adminhandler')
         response_config_properties = response_dict['config_properties']
         self.assertDictContainsSubset({
-            'value': '',
-        }, response_config_properties[base.BEFORE_END_HEAD_TAG_HOOK.name])
+            'value': False,
+        }, response_config_properties[
+            config_domain.IS_IMPROVEMENTS_TAB_ENABLED.name])
 
         payload = {
             'action': 'save_config_properties',
             'new_config_property_values': {
-                base.BEFORE_END_HEAD_TAG_HOOK.name: (
-                    self.UNICODE_TEST_STRING),
+                config_domain.IS_IMPROVEMENTS_TAB_ENABLED.name: (
+                    new_config_value),
             }
         }
         self.post_json('/adminhandler', payload, csrf_token=csrf_token)
 
         response_dict = self.get_json('/adminhandler')
         response_config_properties = response_dict['config_properties']
         self.assertDictContainsSubset({
-            'value': self.UNICODE_TEST_STRING,
-        }, response_config_properties[base.BEFORE_END_HEAD_TAG_HOOK.name])
+            'value': new_config_value,
+        }, response_config_properties[
+            config_domain.IS_IMPROVEMENTS_TAB_ENABLED.name])
 
         self.logout()
 
-    def test_change_about_page_config_property(self):
-        """Test that config property values are changed correctly."""
-        new_config_value = 'new_config_value'
-
-        response = self.get_html_response('/about')
-        self.assertNotIn(new_config_value, response.body)
-
-        self.login(self.ADMIN_EMAIL, is_super_admin=True)
-        response = self.get_html_response('/admin')
-        csrf_token = self.get_csrf_token_from_response(response)
-        self.post_json(
-            '/adminhandler', {
-                'action': 'save_config_properties',
-                'new_config_property_values': {
-                    base.BEFORE_END_HEAD_TAG_HOOK.name: new_config_value
-                }
-            }, csrf_token=csrf_token)
-
-        response = self.get_html_response('/about')
-        self.assertIn(new_config_value, response.body)
-
 
 class GenerateDummyExplorationsTest(test_utils.GenericTestBase):
     """Test the conditions for generation of dummy explorations."""

core/controllers/base.py

@@ -37,7 +37,6 @@
 import utils
 
 from google.appengine.api import users
-import jinja2
 import webapp2
 
 app_identity_services = models.Registry.import_app_identity_services()
@@ -50,14 +49,6 @@
     'oppia_csrf_secret', {'type': 'unicode'},
     'Text used to encrypt CSRF tokens.', DEFAULT_CSRF_SECRET)
 
-BEFORE_END_HEAD_TAG_HOOK = config_domain.ConfigProperty(
-    'before_end_head_tag_hook', {
-        'type': 'unicode',
-        'ui_config': {
-            'rows': 7,
-        },
-    },
-    'Code to insert just before the closing </head> tag in all pages.', '')
 
 
 def _clear_login_cookies(response_headers):
@@ -308,8 +299,6 @@ def render_template(self, filepath, iframe_restriction='DENY'):
         scheme, netloc, path, _, _ = urlparse.urlsplit(self.request.uri)
 
         values.update({
-            'BEFORE_END_HEAD_TAG_HOOK': jinja2.utils.Markup(
-                BEFORE_END_HEAD_TAG_HOOK.value),
             'DEV_MODE': constants.DEV_MODE,
             'DOMAIN_URL': '%s://%s' % (scheme, netloc),
             'ACTIVITY_STATUS_PRIVATE': (
@@ -586,3 +575,18 @@ def is_csrf_token_valid(cls, user_id, token):
             return False
         except Exception:
             return False
+
+
+class GoogleAnalyticsHandler(BaseHandler):
+    """Returns Google Analytics variables."""
+
+    GET_HANDLER_ERROR_RETURN_TYPE = feconf.HANDLER_TYPE_JSON
+
+    def get(self):
+        """Respond to a get request for the variables."""
+        google_analytics_data = {
+            'analytics_id': feconf.ANALYTICS_ID,
+            'site_name_for_analytics': feconf.SITE_NAME_FOR_ANALYTICS
+        }
+
+        self.render_json(google_analytics_data)

core/controllers/base_test.py

@@ -671,7 +671,8 @@ def test_every_method_has_decorator(self):
             # Following handler are present in base.py where acl_decorators
             # cannot be imported.
             if (handler.__name__ == 'LogoutPage' or
-                    handler.__name__ == 'Error404Handler'):
+                    handler.__name__ == 'Error404Handler' or
+                    handler.__name__ == 'GoogleAnalyticsHandler'):
                 continue
 
             if handler.get != base.BaseHandler.get:
@@ -888,3 +889,19 @@ def test_no_error_is_raised_on_opening_new_tab_after_signup(self):
         )
 
         self.get_html_response('/about')
+
+
+class GoogleAnalyticsHandlerTests(test_utils.GenericTestBase):
+
+    def test_analytics_handler_returns_required_values(self):
+
+        with self.swap(feconf, 'ANALYTICS_ID', 'test123'):
+            with self.swap(
+                feconf, 'SITE_NAME_FOR_ANALYTICS', 'Oppia foundation'):
+                response = self.get_json(feconf.GOOGLE_ANALYTICS_DATA_URL)
+                self.assertEqual(
+                    response, {
+                        'analytics_id': 'test123',
+                        'site_name_for_analytics': 'Oppia foundation'
+                    }
+                )

core/domain/config_domain.py

@@ -79,6 +79,7 @@ class ConfigProperty(object):
     - banned_usernames.
     - banner_alt_text.
     - before_end_body_tag_hook.
+    - before_end_head_tag_hook.
     - carousel_slides_config.
     - collection_editor_whitelist.
     - contact_email_address.

core/templates/dev/head/pages/base.html

@@ -91,7 +91,6 @@
       {% include 'pages/header_js_libs.html' %}
     {% endblock header_js %}
 
-    {{BEFORE_END_HEAD_TAG_HOOK}}
   </head>
 
   <body>

core/templates/dev/head/pages/header_js_libs.html

@@ -13,3 +13,24 @@
 <script src="/third_party/static/headroom-js-0.9.4/headroom.min.js"></script>
 <script src="/third_party/static/headroom-js-0.9.4/angular.headroom.min.js"></script>
 <script src="/third_party/static/angular-drag-and-drop-lists-2.1.0/angular-drag-and-drop-lists.min.js"></script>
+
+<script>
+  (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
+  (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
+  m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
+  })(window,document,'script','https://www.google-analytics.com/analytics.js','ga');
+
+  (function() {
+    fetch('/google_analytics').then(function(response) {
+      return response.text()
+    }).then(function(response) {
+      response = JSON.parse(response.substring(4));
+      ga('create', response.analytics_id, 'auto', {allowLinker: true});
+      ga('set', 'anonymizeIp', true);
+      ga('set', 'forceSSL', true);
+      ga('require', 'linker');
+      ga('linker:autoLink', [response.site_name_for_analytics]);
+      ga('send', 'pageview');
+    })
+  })();
+</script>

feconf.py

@@ -612,6 +612,7 @@ def get_empty_ratings():
 FEEDBACK_THREAD_VIEW_EVENT_URL = '/feedbackhandler/thread_view_event'
 FLAG_EXPLORATION_URL_PREFIX = '/flagexplorationhandler'
 FRACTIONS_LANDING_PAGE_URL = '/fractions'
+GOOGLE_ANALYTICS_DATA_URL = '/google_analytics'
 TOPIC_LANDING_PAGE_URL = '/learn/<subject>/<topic>'
 LEARNER_DASHBOARD_URL = '/learner_dashboard'
 LEARNER_DASHBOARD_DATA_URL = '/learnerdashboardhandler/data'
@@ -952,3 +953,7 @@ def get_empty_ratings():
 AVAILABLE_LANDING_PAGES = {
     'maths': ['fractions', 'ratios']
 }
+
+# Data required for Google Analytics.
+ANALYTICS_ID = ''
+SITE_NAME_FOR_ANALYTICS = ''

main.py

@@ -665,6 +665,10 @@ def ui_access_wrapper(self, *args, **kwargs):
     get_redirect_route(
         r'/resolveissuehandler/<exploration_id>', editor.ResolveIssueHandler),
 
+    get_redirect_route(
+        r'%s' % feconf.GOOGLE_ANALYTICS_DATA_URL,
+        base.GoogleAnalyticsHandler),
+
     # 404 error handler.
     get_redirect_route(r'/<:.*>', base.Error404Handler),
 ]