models: Add model for storing notifications

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

plinth/migrations/0005_storednotification.py

@@ -0,0 +1,61 @@
+#
+# This file is part of FreedomBox.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+#
+# Generated by Django 2.2.6 on 2020-01-29 03:17
+#
+"""
+Django migration for adding the notification model.
+"""
+
+from django.db import migrations, models
+
+from plinth.models import JSONField
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('plinth', '0004_userprofile'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='StoredNotification',
+            fields=[
+                ('id',
+                 models.CharField(max_length=128, primary_key=True,
+                                  serialize=False)),
+                ('app_id',
+                 models.CharField(default=None, max_length=128, null=True)),
+                ('severity', models.CharField(max_length=32)),
+                ('title', models.CharField(max_length=256)),
+                ('message', models.TextField(default=None, null=True)),
+                ('actions', JSONField(default=list)),
+                ('body_template',
+                 models.CharField(max_length=128, null=True, default=None)),
+                ('data', JSONField(default=dict)),
+                ('created_time', models.DateTimeField(auto_now_add=True)),
+                ('last_update_time', models.DateTimeField(auto_now=True)),
+                ('user',
+                 models.CharField(max_length=128, default=None, null=True)),
+                ('group',
+                 models.CharField(max_length=128, default=None, null=True)),
+                ('dismissed', models.BooleanField(default=False)),
+            ],
+        ),
+    ]

plinth/models.py

@@ -22,6 +22,7 @@ import json
 
 from django.conf import settings
 from django.contrib.auth.models import User
+from django.core.exceptions import ValidationError
 from django.db import models
 from django.dispatch import receiver
 
@@ -63,3 +64,41 @@ def _on_user_post_save(sender, instance, **kwargs):
         instance.userprofile.save()
     else:
         UserProfile.objects.update_or_create(user=instance)
+
+
+class JSONField(models.TextField):
+    """Store and retrieve JSON data into a TextField."""
+    def to_python(self, value):
+        """Deserialize a text string from form field to Python dict."""
+        if not value:
+            return self.default()
+
+        try:
+            return json.loads(value)
+        except json.decoder.JSONDecodeError:
+            raise ValidationError('Invalid JSON value')
+
+    def from_db_value(self, value, *args, **kwargs):
+        """Deserialize a value from DB to Python dict."""
+        return self.to_python(value)
+
+    def get_prep_value(self, value):
+        """Serialize the Python dict to text for form field."""
+        return json.dumps(value or self.default())
+
+
+class StoredNotification(models.Model):
+    """Model to store a user notification."""
+    id = models.CharField(primary_key=True, max_length=128)
+    app_id = models.CharField(max_length=128, null=True, default=None)
+    severity = models.CharField(max_length=32)
+    title = models.CharField(max_length=256)
+    message = models.TextField(null=True, default=None)
+    actions = JSONField(default=list)
+    body_template = models.CharField(max_length=128, null=True, default=None)
+    data = JSONField(default=dict)
+    created_time = models.DateTimeField(auto_now_add=True)
+    last_update_time = models.DateTimeField(auto_now=True)
+    user = models.CharField(max_length=128, null=True, default=None)
+    group = models.CharField(max_length=128, null=True, default=None)
+    dismissed = models.BooleanField(default=False)