Merge branch '22-send-notifications-to-parents' into 'master'

Feature: parent subscriptions

Closes #22

See merge request djangoldp-packages/djangoldp-notification!28

README.md

@@ -31,6 +31,9 @@ An object allowing a User to be notified of any change on a resource or a contai
 | -------- | ---------- | ------- | ------------------------------------------------------------ |
 | `object` | `URLField` |         | ID of the resource or the container to watch                 |
 | `inbox`  | `URLField` |         | ID of the inbox to notify when the resource or the container change |
+| `field`  | `CharField` |         | (optional) if set, then object['field'] will be sent in the notification, not object |
+
+For convenience, when you create a subscription on an object, DjangoLDP-Notification will parse the object for any one-to-many nested field relations. It will then create nested-subscriptions, i.e. a subscription on the nested field which sends an update to the same inbox, passing the parent model. If this behaviour is undesired you can delete the `Subscription` instance
 
 # Middlewares
 

djangoldp_notification/migrations/0006_subscription_parent.py

@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.29 on 2020-06-02 10:35
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('djangoldp_notification', '0005_auto_20200505_1733'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='subscription',
+            name='parent',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='children', to='djangoldp_notification.Subscription'),
+        ),
+    ]

djangoldp_notification/migrations/0007_auto_20200604_1055.py

@@ -0,0 +1,24 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.29 on 2020-06-04 10:55
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('djangoldp_notification', '0006_subscription_parent'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='subscription',
+            name='parent',
+        ),
+        migrations.AddField(
+            model_name='subscription',
+            name='field',
+            field=models.CharField(blank=True, help_text='if set to a field name on the object model, the field will be passed instead of the object instance', max_length=255, null=True),
+        ),
+    ]

djangoldp_notification/models.py

@@ -7,7 +7,7 @@ from django.db import models
 from django.db.models.signals import post_save, post_delete
 from django.dispatch import receiver
 from django.template import loader
-from django.urls import NoReverseMatch
+from django.urls import NoReverseMatch, get_resolver
 from django.utils.translation import ugettext_lazy as _
 from djangoldp.fields import LDPUrlField
 from djangoldp.models import Model
@@ -53,6 +53,8 @@ class Notification(Model):
 class Subscription(Model):
     object = models.URLField()
     inbox = models.URLField()
+    field = models.CharField(max_length=255, blank=True, null=True,
+                             help_text='if set to a field name on the object model, the field will be passed instead of the object instance')
 
     def __str__(self):
         return '{}'.format(self.object)
@@ -62,30 +64,42 @@ class Subscription(Model):
         authenticated_perms = ["add", "view", "delete"]
         permission_classes = [SubscriptionsPermissions]
 
-    def save(self, *args, **kwargs):
-        # save subscriptions for nested fields
-        if self.pk is None and not self.is_backlink and self.object.startswith(settings.SITE_URL):
-            try:
-                # object is a WebID.. convert to local representation
-                local = Model.resolve(self.object.replace(settings.SITE_URL, ''))[0]
-                nested_fields = Model.get_meta(local, 'nested_fields', [])
 
-                for nested_field in nested_fields:
+@receiver(post_save, sender=Subscription, dispatch_uid="nested_subscriber_check")
-                    nested_url = str(self.object) + '1/' + nested_field + '/'
+def create_nested_subscribers(sender, instance, created, **kwargs):
+    # save subscriptions for one-to-many nested fields
+    if created and not instance.is_backlink and instance.object.startswith(settings.SITE_URL):
+        try:
+            # object is a WebID.. convert to local representation
+            local = Model.resolve(instance.object.replace(settings.SITE_URL, ''))[0]
+            nested_fields = Model.get_meta(local, 'nested_fields', [])
 
-                    # we have the nested_url, but we want the model contained within's container
+            for nested_field in nested_fields:
-                    nested_container = Model.resolve(nested_url)[0]
+                try:
+                    field = local._meta.get_field(nested_field)
+                    nested_container = field.related_model
                     nested_container_url = Model.absolute_url(nested_container)
 
-                    # check a Subscription on this pair doesn't exist already
+                    if field.one_to_many:
-                    existing_subscriptions = Subscription.objects.filter(object=nested_container_url, inbox=self.inbox)
+                        # get the nested view set
-                    # save a Subscription on this container
+                        nested_url = str(instance.object) + '1/' + nested_field + '/'
-                    if not existing_subscriptions.exists():
+                        view, args, kwargs = get_resolver().resolve(nested_url.replace(settings.SITE_URL, ''))
-                        Subscription.objects.create(object=nested_container_url, inbox=self.inbox, is_backlink=True)
+                        # get the reverse name for the field
-            except:
+                        field_name = view.initkwargs['nested_related_name']
-                pass
+
+                        if field_name is not None and field_name != '':
+                            # check that this nested-field subscription doesn't already exist
+                            existing_subscriptions = Subscription.objects.filter(object=nested_container_url, inbox=instance.inbox,
+                                                                                 field=field_name)
+                            # save a Subscription on this container
+                            if not existing_subscriptions.exists():
+                                Subscription.objects.create(object=nested_container_url, inbox=instance.inbox, is_backlink=True,
+                                                            field=field_name)
+                except:
+                    pass
+        except:
+            pass
 
-        super(Subscription, self).save(*args, **kwargs)
 
 
 # --- SUBSCRIPTION SYSTEM ---
@@ -94,6 +108,7 @@ class Subscription(Model):
 def send_notification(sender, instance, **kwargs):
     if sender != Notification:
         threads = []
+        recipients = []
         try:
             url_container = settings.BASE_URL + Model.container_id(instance)
             url_resource = settings.BASE_URL + Model.resource_id(instance)
@@ -102,11 +117,21 @@ def send_notification(sender, instance, **kwargs):
 
         # dispatch a notification for every Subscription on this resource
         for subscription in Subscription.objects.filter(models.Q(object=url_resource) | models.Q(object=url_container)):
-            if not instance.is_backlink:
+            if not instance.is_backlink and subscription.inbox not in recipients and \
+                    (not subscription.is_backlink or not kwargs.get("created")):
+                # I may have configured to send the subscription to a foreign key
+                if subscription.field is not None and len(subscription.field) > 1:
+                    instance = getattr(instance, subscription.field, instance)
+                    try:
+                        url_resource = settings.BASE_URL + Model.resource_id(instance)
+                    except NoReverseMatch:
+                        continue
+
                 process = Thread(target=send_request, args=[subscription.inbox, url_resource, instance,
                                                             kwargs.get("created", False)])
                 process.start()
                 threads.append(process)
+                recipients.append(subscription.inbox)
 
 
 def send_request(target, object_iri, instance, created):