Merge pull request #159 from Andrew-Chen-Wang/update-duplicate-reg

Add UPDATE_ON_DUPLICATE_REG_ID

README.rst

@@ -57,6 +57,10 @@ Edit your settings.py file:
 		 # are deleted upon receiving error response from FCM
 		 # default: False
 		"DELETE_INACTIVE_DEVICES": True/False,
+		"UPDATE_ON_DUPLICATE_REG_ID": True/False,
+		 # Transform create of an existing Device (based on registration id) into
+		 # a update. See below section Update of device with duplicate registration ID
+		 # for more details.
 	}
 
 Native Django migrations are in use. ``manage.py migrate`` will install and migrate all models.
@@ -202,6 +206,18 @@ http://www.django-rest-framework.org/tutorial/6-viewsets-and-routers#binding-vie
 		# ...
 	)
 
+Update of device with duplicate registration ID
+-----------------------------------------------
+
+The DRF viewset enforce the uniqueness of the registration ID. In same use case it
+may cause an issue: If an already registered mobile device changes its user, then
+it will fail to register because the registration ID already exist.
+
+When option ``UPDATE_ON_DUPLICATE_REG_ID`` is set to True, then any creation of
+device with an already existing registration ID will be transformed into an update.
+
+The ``UPDATE_ON_DUPLICATE_REG_ID`` only works with DRF.
+
 Python 3 support
 ----------------
 ``fcm-django`` is fully compatible with Python 2.7 & 3.4 & 3.5 & 3.6 & 3.7

fcm_django/api/rest_framework.py

@@ -1,8 +1,10 @@
 from __future__ import absolute_import
-from rest_framework import permissions
+
+from rest_framework import permissions, status
 from rest_framework.serializers import ModelSerializer, ValidationError, \
     Serializer, CurrentUserDefault
 from rest_framework.mixins import CreateModelMixin
+from rest_framework.response import Response
 from rest_framework.viewsets import ModelViewSet, GenericViewSet
 from fcm_django.models import FCMDevice
 from django import VERSION as DJ_VERSION
@@ -106,6 +108,28 @@ def has_object_permission(self, request, view, obj):
 class DeviceViewSetMixin(object):
     lookup_field = "registration_id"
 
+    def create(self, request, *args, **kwargs):
+        serializer = None
+        is_update = False
+        if SETTINGS.get('UPDATE_ON_DUPLICATE_REG_ID') and 'registration_id' in request.data:
+            instance = self.queryset.model.objects.filter(
+                registration_id=request.data['registration_id']
+            ).first()
+            if instance:
+                serializer = self.get_serializer(instance, data=request.data)
+                is_update = True
+        if not serializer:
+            serializer = self.get_serializer(data=request.data)
+
+        serializer.is_valid(raise_exception=True)
+        if is_update:
+            self.perform_update(serializer)
+            return Response(serializer.data)
+        else:
+            self.perform_create(serializer)
+            headers = self.get_success_headers(serializer.data)
+            return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)
+
     def perform_create(self, serializer):
         if is_user_authenticated(self.request.user):
             if (SETTINGS["ONE_DEVICE_PER_USER"] and

fcm_django/settings.py

@@ -9,6 +9,7 @@
 FCM_DJANGO_SETTINGS.setdefault("FCM_SERVER_KEY", None)
 FCM_DJANGO_SETTINGS.setdefault("ONE_DEVICE_PER_USER", False)
 FCM_DJANGO_SETTINGS.setdefault("DELETE_INACTIVE_DEVICES", False)
+FCM_DJANGO_SETTINGS.setdefault("UPDATE_ON_DUPLICATE_REG_ID", False)
 
 # User model
 FCM_DJANGO_SETTINGS.setdefault("USER_MODEL", settings.AUTH_USER_MODEL)