Refs #6 - Ensure unsubscribing from services works, and deletes subsc…

…ription and data from external service

backend/core/api/views.py

@@ -84,6 +84,10 @@ def get_queryset(self):
     def get_serializer_class(self):
         return self.serializer_classes.get(self.action, self.serializer_class)
 
+    def perform_destroy(self, instance):
+        instance.delete_in_service()
+        instance.delete()
+
 
 @api_view(['POST'])
 @permission_classes([permissions.AllowAny])

backend/core/migrations/0025_service_unsubscribe_url.py

@@ -0,0 +1,18 @@
+# Generated by Django 2.2.8 on 2020-01-16 09:43
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('core', '0024_auto_20200116_0906'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='service',
+            name='unsubscribe_url',
+            field=models.URLField(default='', help_text='URL to which unsubscribe requests should be POSTed'),
+        ),
+    ]

backend/core/models.py

@@ -149,6 +149,7 @@ class Service(models.Model):
     img_service_url = models.CharField(max_length=255, null=True)
 
     subscribe_url = models.URLField(default='', help_text='URL to which new subscriptions should be POSTed')
+    unsubscribe_url = models.URLField(default='', help_text='URL to which unsubscribe requests should be POSTed')
     data_url = models.URLField(default='', help_text='URL to which sensor data should be POSTed')
     report_url = models.URLField(default='', help_text='URL to the main page presenting a subscription')
     preview_url = models.URLField(
@@ -196,13 +197,21 @@ def create_in_service(self):
         self.registered = timezone.now()
         self.save()
 
+    def delete_in_service(self):
+        """
+        Delete this subscription in the remote service.
+        """
+        data = {'uuid': str(self.uuid), 'auth_token': str(self.service.auth_token)}
+        response = self._post(self.service.unsubscribe_url, json=data)
+        response.raise_for_status()  # Raises exception if status code >=400
+
     def send_values(self, values):
         """
         Send the passed values to the external service.
         """
         data = SubscriptionDataSerializer(self, values=values).data
         response = self._post(self.service.data_url, json=data)
-        response.raise_for_status() # Raises exception if status code >=400
+        response.raise_for_status()  # Raises exception if status code >=400
 
     def submit_history(self):
         """

backend/core/tests/test_subscribe.py

@@ -33,6 +33,7 @@ def setUp(self):
             description='temperature', uri='http://urn.fi/URN:NBN:fi:au:ucum:r73')
         self.service = models.Service.objects.create(
             subscribe_url='https://service.com/api/subscriptions/',
+            unsubscribe_url='https://service.com/api/unsubscribe/',
             data_url='https://service.com/api/measurements/')
         self.service.requires.add(self.temperature)
 
@@ -146,3 +147,28 @@ def test_subscription_receives_data(self):
                 'timestamp': serializers.DateTimeField().to_representation(value.updated_at),
                 'value': str(value.value)}],
             'auth_token': str(self.service.auth_token)})
+
+    def test_unsubscribe(self):
+        # Given that there is a subscription for an external service
+        subscription = self.user.subscriptions.create(service=self.service)
+
+        # And given that the subscriber is signed in
+        self.client.force_login(self.user)
+
+        # When requesting to delete the subscription over the ReST API
+        url = reverse('subscription-detail', kwargs={'pk': subscription.id})
+        with self.mock_requests:
+            response = self.client.delete(url)
+
+        # Then a 204 response is returned
+        self.assertEqual(204, response.status_code)
+
+        # And the subscription is removed from the db
+        self.assertEqual(0, models.Subscription.objects.count())
+
+        # And the unsubscribe request is submitted to the external service
+        ([url], kwargs) = self.mock_requests.last_request
+        self.assertEqual(url, self.service.unsubscribe_url)
+        self.assert_dict_contains(kwargs['json'], {
+            'uuid': str(subscription.uuid),
+            'auth_token': str(self.service.auth_token)})