add a notification message model

part of #2282

InvenTree/common/admin.py

@@ -43,6 +43,16 @@ class NotificationEntryAdmin(admin.ModelAdmin):
     list_display = ('key', 'uid', 'updated', )
 
 
+class NotificationMessageAdmin(admin.ModelAdmin):
+
+    list_display = ('age_human', 'user', 'category', 'name', 'read', 'target_object', 'source_object', )
+
+    list_filter = ('category', 'read', 'user', )
+
+    search_fields = ('name', 'category', 'message', )
+
+
 admin.site.register(common.models.InvenTreeSetting, SettingsAdmin)
 admin.site.register(common.models.InvenTreeUserSetting, UserSettingsAdmin)
 admin.site.register(common.models.NotificationEntry, NotificationEntryAdmin)
+admin.site.register(common.models.NotificationMessage, NotificationMessageAdmin)

InvenTree/common/api.py

@@ -130,6 +130,57 @@ class UserSettingsDetail(generics.RetrieveUpdateAPIView):
     ]
 
 
+class NotificationList(generics.ListAPIView):
+    queryset = common.models.NotificationMessage.objects.all()
+    serializer_class = common.serializers.NotificationMessageSerializer
+
+    filter_backends = [
+        DjangoFilterBackend,
+        filters.SearchFilter,
+        filters.OrderingFilter,
+    ]
+
+    ordering_fields = [
+        #'age',  # TODO enable ordering by age
+        'category',
+        'name',
+    ]
+
+    search_fields = [
+        'name',
+        'message',
+    ]
+
+    def filter_queryset(self, queryset):
+        """
+        Only list notifications which apply to the current user
+        """
+
+        try:
+            user = self.request.user
+        except AttributeError:
+            return common.models.NotificationMessage.objects.none()
+
+        queryset = super().filter_queryset(queryset)
+        queryset = queryset.filter(user=user)
+        return queryset
+
+
+class NotificationDetail(generics.RetrieveDestroyAPIView):
+    """
+    Detail view for an individual notification object
+
+    - User can only view / delete their own notification objects
+    """
+
+    queryset = common.models.NotificationMessage.objects.all()
+    serializer_class = common.serializers.NotificationMessageSerializer
+
+    permission_classes = [
+        UserSettingsPermissions,
+    ]
+
+
 common_api_urls = [
 
     # User settings
@@ -148,6 +199,12 @@ common_api_urls = [
 
         # Global Settings List
         url(r'^.*$', GlobalSettingsList.as_view(), name='api-global-setting-list'),
-    ]))
+    ])),
+
+    # Notifications
+    url(r'^notifications/', include([
+        url(r'^(?P<pk>\d+)/', NotificationDetail.as_view(), name='api-notifications-detail'),
+        url(r'^.*$', NotificationList.as_view(), name='api-notifications-list'),
+    ])),
 
 ]

InvenTree/common/migrations/0013_notificationmessage.py

@@ -0,0 +1,33 @@
+# Generated by Django 3.2.5 on 2021-11-27 14:51
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('contenttypes', '0002_remove_content_type_name'),
+        ('common', '0012_notificationentry'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='NotificationMessage',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('target_object_id', models.PositiveIntegerField()),
+                ('source_object_id', models.PositiveIntegerField(blank=True, null=True)),
+                ('category', models.CharField(max_length=250)),
+                ('name', models.CharField(max_length=250)),
+                ('message', models.CharField(blank=True, max_length=250, null=True)),
+                ('creation', models.DateTimeField(auto_now=True)),
+                ('read', models.BooleanField(default=False)),
+                ('source_content_type', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='notification_source', to='contenttypes.contenttype')),
+                ('target_content_type', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='notification_target', to='contenttypes.contenttype')),
+                ('user', models.ForeignKey(blank=True, help_text='User', null=True, on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL, verbose_name='User')),
+            ],
+        ),
+    ]

InvenTree/common/models.py

@@ -13,8 +13,13 @@ from datetime import datetime, timedelta
 
 from django.db import models, transaction
 from django.contrib.auth.models import User, Group
+from django.contrib.contenttypes.fields import GenericForeignKey
+from django.contrib.contenttypes.models import ContentType
 from django.db.utils import IntegrityError, OperationalError
 from django.conf import settings
+from django.urls import reverse
+from django.utils.timezone import now
+from django.contrib.humanize.templatetags.humanize import naturaltime
 
 from djmoney.settings import CURRENCY_CHOICES
 from djmoney.contrib.exchange.models import convert_money
@@ -1419,3 +1424,89 @@ class NotificationEntry(models.Model):
         )
 
         entry.save()
+
+
+class NotificationMessage(models.Model):
+    """
+    A NotificationEntry records the last time a particular notifaction was sent out.
+
+    It is recorded to ensure that notifications are not sent out "too often" to users.
+
+    Attributes:
+    - key: A text entry describing the notification e.g. 'part.notify_low_stock'
+    - uid: An (optional) numerical ID for a particular instance
+    - date: The last time this notification was sent
+    """
+
+    # generic link to target
+    target_content_type = models.ForeignKey(
+        ContentType,
+        on_delete=models.CASCADE,
+        related_name='notification_target',
+    )
+
+    target_object_id = models.PositiveIntegerField()
+
+    target_object = GenericForeignKey('target_content_type', 'target_object_id')
+
+    # generic link to source
+    source_content_type = models.ForeignKey(
+        ContentType,
+        on_delete=models.SET_NULL,
+        related_name='notification_source',
+        null=True,
+        blank=True,
+    )
+
+    source_object_id = models.PositiveIntegerField(
+        null=True,
+        blank=True,
+    )
+
+    source_object = GenericForeignKey('source_content_type', 'source_object_id')
+
+    # user that receives the notification
+    user = models.ForeignKey(
+        User,
+        on_delete=models.CASCADE,
+        verbose_name=_('User'),
+        help_text=_('User'),
+    )
+
+    category = models.CharField(
+        max_length=250,
+        blank=False,
+    )
+
+    name = models.CharField(
+        max_length=250,
+        blank=False,
+    )
+
+    message = models.CharField(
+        max_length=250,
+        blank=True,
+        null=True,
+    )
+
+    creation = models.DateTimeField(
+        auto_now=True,
+        null=False,
+    )
+
+    read = models.BooleanField(
+        default=False,
+    )
+
+    @staticmethod
+    def get_api_url():
+        return reverse('api-notifications-list')
+
+    def age(self):
+        """age of the message in seconds"""
+        delta = now() - self.creation
+        return delta.seconds
+
+    def age_human(self):
+        """humanized age"""
+        return naturaltime(self.creation)

InvenTree/common/serializers.py

@@ -9,7 +9,7 @@ from InvenTree.serializers import InvenTreeModelSerializer
 
 from rest_framework import serializers
 
-from common.models import InvenTreeSetting, InvenTreeUserSetting
+from common.models import InvenTreeSetting, InvenTreeUserSetting, NotificationMessage
 
 
 class SettingsSerializer(InvenTreeModelSerializer):
@@ -95,3 +95,39 @@ class UserSettingsSerializer(SettingsSerializer):
             'type',
             'choices',
         ]
+
+
+class NotificationMessageSerializer(SettingsSerializer):
+    """
+    Serializer for the InvenTreeUserSetting model
+    """
+
+    #content_object = serializers.PrimaryKeyRelatedField(read_only=True)
+
+    user = serializers.PrimaryKeyRelatedField(read_only=True)
+
+    category = serializers.CharField(read_only=True)
+
+    name = serializers.CharField(read_only=True)
+
+    message = serializers.CharField(read_only=True)
+
+    creation = serializers.CharField(read_only=True)
+
+    age = serializers.IntegerField()
+
+    age_human = serializers.CharField()
+
+    class Meta:
+        model = NotificationMessage
+        fields = [
+            'pk',
+            #'content_object',
+            'user',
+            'category',
+            'name',
+            'message',
+            'creation',
+            'age',
+            'age_human',
+        ]