feat(#43): send email notifications

- Add Follower model.
- Parent comment and main thread can now be subscribed.
- Follow and unfollow functionality is integrated in the UI and the API
- Email notification is sent to all thread followers when creating a
  comment in it.
- Tests clean up.
- Adjust translation tests.
- update docs for subscription

README.rst

@@ -53,6 +53,12 @@
 django-comments-dab
 ===================
 
+Thanks https://www.pythonanywhere.com/
+
+**Here is a** live_ **demo**
+
+.. _live: https://rmustafa.pythonanywhere.com/
+
 Full Documentation_
 
 .. _Documentation: https://django-comment-dab.readthedocs.io/
@@ -99,6 +105,8 @@ It allows you to integrate commenting functionality with any model you have e.g.
 
     8. Resolve or reject flag. This is used to revoke the flagged comment state (admins and moderators)
 
+    9. Follow and unfollow thread. (authenticated users)
+
 - All actions are done by Fetch API since V2.0.0
 
 - Bootstrap 4.1.1 is used in comment templates for responsive design.
@@ -281,6 +289,8 @@ The icons are picked from Feather_. Many thanks to them for the good work.
 .. _Feather: https://feathericons.com
 
 
+Email's HTML template is used from https://github.com/leemunroe/responsive-html-email-template
+
 Contributing
 ============
 

comment/__init__.py

@@ -4,24 +4,20 @@
 
 
 def _get_version():
-    _parent_project_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
-    with open(os.path.join(_parent_project_dir, 'VERSION')) as version_file:
-        version = version_file.read().strip()
-
-    if version.lower().startswith('v'):
-        version = version[1:]
+    parent_project_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+    with open(os.path.join(parent_project_dir, 'VERSION')) as version_file:
+        version = version_file.read().strip().strip('v')
 
     return version
 
 
 def check_release():
-    release = None
     try:
         release = _get_version()
-    except (FileNotFoundError, Exception):
-        pass
-    if release:
-        assert release == __version__, 'Current version does not match with manifest VERSION'
+    except FileNotFoundError:
+        return
+
+    assert release == __version__, 'Current version does not match with manifest VERSION'
 
 
 check_release()

comment/admin.py

@@ -1,6 +1,6 @@
 from django.contrib import admin
 
-from comment.models import Comment, Flag, FlagInstance, Reaction, ReactionInstance
+from comment.models import Comment, Flag, FlagInstance, Reaction, ReactionInstance, Follower
 
 
 class CommentModelAdmin(admin.ModelAdmin):
@@ -37,6 +37,13 @@ class FlagModelAdmin(admin.ModelAdmin):
     inlines = [InlineFlagInstance]
 
 
+class FollowerModelAdmin(admin.ModelAdmin):
+    list_display = ('email', 'username', 'content_type', 'content_object')
+    readonly_fields = list_display
+    search_fields = ('email',)
+
+
 admin.site.register(Comment, CommentModelAdmin)
 admin.site.register(Reaction, ReactionModelAdmin)
 admin.site.register(Flag, FlagModelAdmin)
+admin.site.register(Follower, FollowerModelAdmin)

comment/api/permissions.py

@@ -36,3 +36,18 @@ def has_permission(self, request, view):
 
     def has_object_permission(self, request, view, obj):
         return obj.is_flagged and (is_comment_admin(request.user) or is_comment_moderator(request.user))
+
+
+class SubscriptionEnabled(permissions.BasePermission):
+    """
+    This will check if the COMMENT_ALLOW_SUBSCRIPTION is enabled
+    """
+    def has_permission(self, request, view):
+        return getattr(settings, 'COMMENT_ALLOW_SUBSCRIPTION', False)
+
+
+class CanGetSubscribers(SubscriptionEnabled):
+    def has_permission(self, request, view):
+        if not super().has_permission(request, view):
+            return False
+        return is_comment_admin(request.user) or is_comment_moderator(request.user)

comment/api/serializers.py

@@ -7,8 +7,9 @@
 
 from comment.conf import settings
 from comment.models import Comment, Flag, Reaction
-from comment.utils import process_anonymous_commenting, get_user_for_request, get_profile_instance
+from comment.utils import get_user_for_request, get_profile_instance
 from comment.messages import EmailError
+from comment.service.email import DABEmailService
 
 
 def get_profile_model():
@@ -97,6 +98,7 @@ class Meta:
 
     def __init__(self, *args, **kwargs):
         user = kwargs['context']['request'].user
+        self.email_service = None
         if user.is_authenticated or not settings.COMMENT_ALLOW_ANONYMOUS:
             del self.fields['email']
 
@@ -122,11 +124,14 @@ def create(self, validated_data):
             parent=self.context['parent_comment'],
             email=email,
             posted=time_posted
-            )
+        )
+        self.email_service = DABEmailService(comment, request)
         if settings.COMMENT_ALLOW_ANONYMOUS and not user:
-            process_anonymous_commenting(request, comment, api=True)
+            self.email_service.send_confirmation_request(api=True)
         else:
             comment.save()
+            if settings.COMMENT_ALLOW_SUBSCRIPTION:
+                self.email_service.send_notification_to_followers()
         return comment
 
 

comment/api/urls.py

@@ -15,6 +15,8 @@
         name='comments-flag-state-change'
     ),
     re_path(r'^comments/confirm/(?P<key>[^/]+)/$', views.ConfirmComment.as_view(), name='confirm-comment'),
+    path('comments/toggle-subscription/', views.ToggleFollowAPI.as_view(), name='toggle-subscription'),
+    path('comments/subscribers/', views.SubscribersAPI.as_view(), name='subscribers'),
 ]
 
 urlpatterns = format_suffix_patterns(urlpatterns)

comment/api/views.py

@@ -4,19 +4,21 @@
 from rest_framework.response import Response
 from rest_framework.views import APIView
 
+from comment.conf import settings
 from comment.validators import ValidatorMixin, ContentTypeValidator
 from comment.api.serializers import CommentSerializer, CommentCreateSerializer
 from comment.api.permissions import (
-    IsOwnerOrReadOnly, FlagEnabledPermission, CanChangeFlaggedCommentState
-)
-from comment.models import Comment, Reaction, ReactionInstance, Flag, FlagInstance
+    IsOwnerOrReadOnly, FlagEnabledPermission, CanChangeFlaggedCommentState,
+    SubscriptionEnabled, CanGetSubscribers)
+from comment.models import Comment, Reaction, ReactionInstance, Flag, FlagInstance, Follower
 from comment.utils import get_comment_from_key, CommentFailReason
 from comment.messages import FlagError, EmailError
+from comment.views import BaseToggleFollowView
+from comment.service.email import DABEmailService
 
 
 class CommentCreate(ValidatorMixin, generics.CreateAPIView):
     serializer_class = CommentCreateSerializer
-    permission_classes = ()
     api = True
 
     def get_serializer_context(self):
@@ -131,15 +133,46 @@ def post(self, request, *args, **kwargs):
 
 
 class ConfirmComment(APIView):
-    @staticmethod
-    def get(request, *args, **kwargs):
+    email_service = None
+
+    def get(self, request, *args, **kwargs):
         key = kwargs.get('key', None)
-        comment = get_comment_from_key(key)
+        temp_comment = get_comment_from_key(key)
 
-        if comment.why_invalid == CommentFailReason.BAD:
+        if temp_comment.why_invalid == CommentFailReason.BAD:
             return Response({'detail': EmailError.BROKEN_VERIFICATION_LINK}, status=status.HTTP_400_BAD_REQUEST)
 
-        if comment.why_invalid == CommentFailReason.EXISTS:
+        if temp_comment.why_invalid == CommentFailReason.EXISTS:
             return Response({'detail': EmailError.USED_VERIFICATION_LINK}, status=status.HTTP_200_OK)
 
-        return Response(CommentSerializer(comment.obj).data, status=status.HTTP_201_CREATED)
+        comment = temp_comment.obj
+        comment.save()
+        comment.refresh_from_db()
+        if settings.COMMENT_ALLOW_SUBSCRIPTION:
+            self.email_service = DABEmailService(comment, request)
+            self.email_service.send_notification_to_followers()
+        return Response(CommentSerializer(comment).data, status=status.HTTP_201_CREATED)
+
+
+class ToggleFollowAPI(BaseToggleFollowView, APIView):
+    api = True
+    response_class = Response
+    permission_classes = (SubscriptionEnabled, permissions.IsAuthenticated)
+
+    def post(self, request, *args, **kwargs):
+        self.validate(request)
+        return super().post(request, *args, **kwargs)
+
+
+class SubscribersAPI(ContentTypeValidator, APIView):
+    api = True
+    permission_classes = (CanGetSubscribers,)
+
+    def get(self, request, *args, **kwargs):
+        self.validate(request)
+        return Response({
+            'app_name': self.model_obj._meta.app_label,
+            'model_name': self.model_obj.__class__.__name__,
+            'model_id': self.model_obj.id,
+            'followers': Follower.objects.get_emails_for_model_object(self.model_obj)
+        })

comment/conf/defaults.py

@@ -26,3 +26,5 @@
 COMMENT_USE_EMAIL_FIRST_PART_AS_USERNAME = False
 
 COMMENT_ALLOW_TRANSLATION = False
+
+COMMENT_ALLOW_SUBSCRIPTION = False