T50470: push websocket updates upon saving models

Author: knokko

README.md

@@ -15,7 +15,7 @@ Run with docker `docker compose run binder ./setup.py test` (but you may need to
 
 The tests are set up in such a way that there is no need to keep migration files. The setup procedure in `tests/__init__.py` handles the preparation of the database by directly calling some build-in Django commands.
 
-To only run a selection of the tests, use the `-s` flag like `./setup.py test -s tests.test_some_specific_test`.
+To only run a selection of the tests, use the `-s` flag like `docker compose run binder ./setup.py test -s tests.test_some_specific_test`.
 
 ## MySQL support
 

binder/models.py

@@ -9,7 +9,7 @@
 from decimal import Decimal
 
 from django import forms
-from django.db import models
+from django.db import models, transaction
 from django.db.models import Value
 from django.db.models.fields.files import FieldFile, FileField
 from django.contrib.postgres.fields import CITextField, ArrayField, DateTimeRangeField as DTRangeField
@@ -28,6 +28,7 @@
 from binder.json import jsonloads
 
 from binder.exceptions import BinderRequestError
+from binder.websocket import trigger
 
 from . import history
 
@@ -440,6 +441,32 @@ def clean_value(self, qualifier, v):
 			return jsonloads(bytes(v, 'utf-8'))
 
 
+class BinderQuerySet(models.QuerySet):
+	def update(self, *args, **kwargs):
+		result = super().update(*args, **kwargs)
+		self.model().push_default_websocket_update()
+		return result
+
+	def delete(self, *args, **kwargs):
+		result = super().delete(*args, **kwargs)
+		self.model().push_default_websocket_update()
+		return result
+
+
+class BinderManager(models.Manager):
+	def get_queryset(self):
+		return BinderQuerySet(self.model, using=self._db)
+
+	def bulk_create(self, *args, **kwargs):
+		result = super().bulk_create(*args, **kwargs)
+		self.model().push_default_websocket_update()
+		return result
+
+	def bulk_update(self, *args, **kwargs):
+		result = super().bulk_update(*args, **kwargs)
+		self.model().push_default_websocket_update()
+		return result
+
 
 class BinderModelBase(models.base.ModelBase):
 	def __new__(cls, name, bases, attrs):
@@ -458,6 +485,9 @@ def __new__(cls, name, bases, attrs):
 
 
 class BinderModel(models.Model, metaclass=BinderModelBase):
+	push_websocket_updates_upon_save = False
+	objects = BinderManager()
+
 	def binder_concrete_fields_as_dict(self, skip_deferred_fields=False):
 		fields = {}
 		deferred_fields = self.get_deferred_fields()
@@ -613,10 +643,21 @@ class Meta:
 		abstract = True
 		ordering = ['pk']
 
+	def push_default_websocket_update(self):
+		from binder.views import determine_model_resource_name
+		if self.push_websocket_updates_upon_save:
+			transaction.on_commit(lambda: trigger('', [{ 'auto-updates': determine_model_resource_name(self.__class__.__name__)}]))
+
 	def save(self, *args, **kwargs):
 		self.full_clean() # Never allow saving invalid models!
-		return super().save(*args, **kwargs)
-
+		result = super().save(*args, **kwargs)
+		self.push_default_websocket_update()
+		return result
+
+	def delete(self, *args, **kwargs):
+		result = super().delete(*args, **kwargs)
+		self.push_default_websocket_update()
+		return result
 
 	# This can be overridden in your model when there are special
 	# validation rules like partial indexes that may need to be

binder/permissions/views.py

@@ -190,6 +190,25 @@ def get_queryset(self, request):
 		return self.scope_view(request, queryset)
 
 
+	@classmethod
+	def get_rooms_for_user(cls, user):
+		from django.conf import settings
+
+		required_permission = cls.model._meta.app_label + '.view_' + cls.model.__name__.lower()
+		has_required_permission = False
+
+		for low_permission in list(user.get_all_permissions()) + ['default']:
+			for permission_tuple in settings.BINDER_PERMISSION.get(low_permission, []):
+				high_permission = permission_tuple[0]
+				if high_permission == required_permission:
+					has_required_permission = True
+					break
+
+		if has_required_permission:
+			return [{ 'auto-updates': cls._model_name() }]
+		else:
+			return []
+
 
 	def _require_model_perm(self, perm_type, request, pk=None):
 		"""

binder/views.py

@@ -342,6 +342,8 @@ def prefix_q_expression(value, prefix, antiprefix=None, model=None):
 			children.append((prefix + '__' + child[0], child[1]))
 	return Q(*children, _connector=value.connector, _negated=value.negated)
 
+def determine_model_resource_name(mn: str):
+	return ''.join((x + '_' if x.islower() and y.isupper() else x.lower() for x, y in zip(mn, mn[1:] + 'x')))
 
 class ModelView(View):
 	# Model this is a view for. Use None for views not tied to a particular model.
@@ -578,9 +580,7 @@ def get_field_filter(self, field_class, reset=False):
 	# Like model._meta.model_name, except it converts camelcase to underscores
 	@classmethod
 	def _model_name(cls):
-		mn = cls.model.__name__
-		return ''.join((x + '_' if x.islower() and y.isupper() else x.lower() for x, y in zip(mn, mn[1:] + 'x')))
-
+		return determine_model_resource_name(cls.model.__name__)
 
 
 	# Use this to instantiate other views you need. It returns a properly initialized view instance.

docs/websockets.md

@@ -4,8 +4,8 @@ Binder.websockets contains functions to connect with a [high-templar](https://gi
 
 ## Flow
 
-The client = a web/native/whatever frontend  
-The websocket server = a high-templar instance  
+The client = a web/native/whatever frontend
+The websocket server = a high-templar instance
 The binder app = a server created with django-binder
 
 - The client needs live updates of certain models.
@@ -24,7 +24,7 @@ The scoping of subscriptions is done through rooms. Roomnames are dictionaries.
 
 There is a chat application for a company. A manager can only view messages of a single location.
 
-The allowed_rooms of a manager of the eindhoven branch could look like 
+The allowed_rooms of a manager of the eindhoven branch could look like
 ```
 [{'location': 'Eindhoven'}]
 ```
@@ -43,9 +43,30 @@ Note: this doesn't mean a client can subscribe to room: `{'location': '*'}` and
 
 If you do really need a room with messages from all locations, just trigger twice: once in the location specific room and one in the location: * room.
 
+## Trigger on saves
+Since sending websocket updates upon saving models is something we often need, there is a 'shortcut' for this.
+If you set `push_websocket_updates_upon_save` to `True` in a model, it will automatically send websocket updates whenever it is saved or deleted.
+
+```python
+class Country(BinderModel):
+    push_websocket_updates_upon_save = True
+    name = models.CharField(unique=True, max_length=100)
+```
+For instance, whenever a `Country` is saved, it will trigger a websocket update to `auto-updates/country` with `data = country.id`.
+
+### Custom object managers
+Normally, websocket updates are also sent when an object is bulk created/updated/deleted. This is implemented by using a custom objects `Manager`.
+This is usually just an implementation detail, but it can be problematic when your model *also* has its own custom objects `Manager`.
+If you want to make bulk updating push websocket notifications, you need to ensure that your custom manager inherits from `binder.models.BinderManager`.
+
+### Forcing websocket updates
+If you want stores to re-fetch your objects, but you haven't saved them directly (e.g. when you changed related objects or annotation values),
+you can forcibly send a websocket update by calling the `push_default_websocket_update()` method on an instance of your model.
+
+
 ## Binder setup
 
-The high-templar instance is agnostic of the authentication/datamodel/permissions. The authentication is done by the proxy to /api/bootstrap. The datamodel / permission stuff is all done through rooms and the data that gets sent through it. 
+The high-templar instance is agnostic of the authentication/datamodel/permissions. The authentication is done by the proxy to /api/bootstrap. The datamodel / permission stuff is all done through rooms and the data that gets sent through it.
 
 `binder.websocket` provides 2 helpers for communicating with high-templar.
 
@@ -74,4 +95,3 @@ The RoomController checks every descendant of the ModelView and looks for a  `@c
 ### Trigger
 
 `binder.websocket` provides a `trigger` to the high_templar instance using a POST request. The url for this request is `getattr(settings, 'HIGH_TEMPLAR_URL', 'http://localhost:8002')`. It needs `data, rooms` as args, the data which will be sent in the publish and the rooms it will be publishes to.
-

tests/__init__.py

@@ -99,7 +99,11 @@
 		# Basic permissions which can be used to override stuff
 		'testapp.view_country': [
 
-		]
+		],
+		'testapp.manage_country': [
+			('testapp.view_country', 'all'),
+			('testapp.view_city', 'all'),
+		],
 	},
 	'GROUP_PERMISSIONS': {
 		'admin': [

tests/test_websocket.py

@@ -1,19 +1,23 @@
-from django.test import TestCase, Client
+from django.test import TestCase, TransactionTestCase, Client
 from django.contrib.auth.models import User
-from unittest import mock
+from unittest import mock, skipIf
 from binder.views import JsonResponse
 from binder.websocket import trigger
 from .testapp.urls import room_controller
-from .testapp.models import Animal, Costume
+from .testapp.models import Animal, Costume, Country
 import requests
 import json
+import os
 from django.test import override_settings
 
 
 class MockUser:
-	def __init__(self, costumes):
+	def __init__(self, costumes, permissions = []):
 		self.costumes = costumes
+		self.permissions = permissions
 
+	def get_all_permissions(self):
+		return self.permissions
 
 def mock_post_high_templar(*args, **kwargs):
 	return JsonResponse({'ok': True})
@@ -31,6 +35,9 @@ def setUp(self):
 
 	def test_room_controller_list_rooms_for_user(self):
 		allowed_rooms = [
+			{
+				'auto-updates': 'user'
+			},
 			{
 				'zoo': 'all',
 			},
@@ -70,6 +77,69 @@ def test_post_succeeds_when_trigger_fails(self):
 
 		self.assertIsNotNone(costume.pk)
 
+	def test_auto_update_rooms(self):
+		user = MockUser([], ['testapp.manage_country'])
+		rooms = room_controller.list_rooms_for_user(user)
+
+		found_it = False
+		for room in rooms:
+			if 'auto-updates' in room and room['auto-updates'] == 'city':
+				found_it = True
+		self.assertTrue(found_it)
+
+class AutoUpdateTest(TransactionTestCase):
+
+	@mock.patch('requests.post', side_effect=mock_post_high_templar)
+	@override_settings(HIGH_TEMPLAR_URL="http://localhost:8002")
+	def test_auto_update_trigger(self, mock):
+		country = Country.objects.create(name='YellowLand')
+		mock.assert_called_with('http://localhost:8002/trigger/', data=json.dumps({
+				'data': '',
+				'rooms': [{ 'auto-updates': 'country' }]
+			}))
+		mock.reset_mock()
+		country.delete()
+		mock.assert_called_with('http://localhost:8002/trigger/', data=json.dumps({
+				'data': '',
+				'rooms': [{ 'auto-updates': 'country' }]
+			}))
+
+	@mock.patch('requests.post', side_effect=mock_post_high_templar)
+	@override_settings(HIGH_TEMPLAR_URL="http://localhost:8002")
+	@skipIf(
+		os.environ.get('BINDER_TEST_MYSQL', '0') != '0',
+		"Only available with PostgreSQL"
+	)
+	def test_bulk_update_trigger(self, mock):
+		countries = Country.objects.bulk_create([Country(name='YellowLand')])
+		self.assertEqual(1, len(countries))
+		country = countries[0]
+
+		mock.assert_called_with('http://localhost:8002/trigger/', data=json.dumps({
+				'data': '',
+				'rooms': [{ 'auto-updates': 'country' }]
+			}))
+		mock.reset_mock()
+
+		Country.objects.bulk_update(countries, ['name'])
+		mock.assert_called_with('http://localhost:8002/trigger/', data=json.dumps({
+				'data': '',
+				'rooms': [{ 'auto-updates': 'country' }]
+			}))
+		mock.reset_mock()
+
+		Country.objects.all().update(name='YellowCountry')
+		mock.assert_called_with('http://localhost:8002/trigger/', data=json.dumps({
+				'data': '',
+				'rooms': [{ 'auto-updates': 'country' }]
+			}))
+		mock.reset_mock()
+
+		Country.objects.filter(id=country.pk).delete()
+		mock.assert_called_with('http://localhost:8002/trigger/', data=json.dumps({
+				'data': '',
+				'rooms': [{ 'auto-updates': 'country' }]
+			}))
 
 class TriggerConnectionCloseTest(TestCase):
 	@override_settings(
@@ -92,4 +162,3 @@ def test_trigger_calls_connection_close(self, mock_connection_class):
 		trigger(data, rooms)
 
 		mock_connection.close.assert_called_once()
-

tests/testapp/models/country.py

@@ -3,4 +3,5 @@
 
 
 class Country(BinderModel):
+    push_websocket_updates_upon_save = True
     name = models.CharField(unique=True, max_length=100)