WL-327: Add SiteConfiguration and SiteConfigurationHistory models to LMS

cms/envs/common.py

@@ -823,6 +823,9 @@
     # Theming
     'openedx.core.djangoapps.theming',
 
+    # Site configuration for theming and behavioral modification
+    'openedx.core.djangoapps.site_configuration',
+
     # comment common
     'django_comment_common',
 

lms/envs/common.py

@@ -1819,6 +1819,9 @@
     # Theming
     'openedx.core.djangoapps.theming',
 
+    # Site configuration for theming and behavioral modification
+    'openedx.core.djangoapps.site_configuration',
+
     # Our courseware
     'courseware',
     'student',

openedx/core/djangoapps/site_configuration/__init__.py

@@ -0,0 +1,26 @@
+"""
+This app is used for creating/updating site's configuration. This app encapsulate configuration related logic for sites
+and provides a way for sites to override default/system behavioural or presentation logic.
+
+Models:
+    SiteConfiguration (models.Model):
+        This model contains configuration for a site and can be used to override OpenEdx configurations.
+
+        Fields:
+            site (OneToOneField): one to one field relating each configuration to a single site
+            values (JSONField):  json field to store configurations for a site
+        Usage:
+            configuration of each site would be available as `configuration` attribute to django site.
+            If you want to access current site's configuration simply access it as `request.site.configuration`.
+
+    SiteConfigurationHistory (TimeStampedModel):
+        This model keeps a track of all the changes made to SiteConfiguration with time stamps.
+
+        Fields:
+            site (ForeignKey): foreign-key to django Site
+            values (JSONField): json field to store configurations for a site
+        Usage:
+            configuration history of each site would be available as `configuration_histories` attribute to django site.
+            If you want to access a list of current site's configuration history simply access it as
+            `request.site.configuration_histories.all()`.
+"""

openedx/core/djangoapps/site_configuration/migrations/0001_initial.py

@@ -0,0 +1,39 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import jsonfield.fields
+import django_extensions.db.fields
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('sites', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='SiteConfiguration',
+            fields=[
+                ('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
+                ('values', jsonfield.fields.JSONField(blank=True)),
+                ('site', models.OneToOneField(related_name='configuration', to='sites.Site')),
+            ],
+        ),
+        migrations.CreateModel(
+            name='SiteConfigurationHistory',
+            fields=[
+                ('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
+                ('created', django_extensions.db.fields.CreationDateTimeField(auto_now_add=True, verbose_name='created')),
+                ('modified', django_extensions.db.fields.ModificationDateTimeField(auto_now=True, verbose_name='modified')),
+                ('values', jsonfield.fields.JSONField(blank=True)),
+                ('site', models.ForeignKey(related_name='configuration_histories', to='sites.Site')),
+            ],
+            options={
+                'ordering': ('-modified', '-created'),
+                'abstract': False,
+                'get_latest_by': 'modified',
+            },
+        ),
+    ]

openedx/core/djangoapps/site_configuration/models.py

@@ -0,0 +1,77 @@
+"""
+Django models for site configurations.
+"""
+import collections
+
+from django.db import models
+from django.contrib.sites.models import Site
+from django.db.models.signals import post_save
+from django.dispatch import receiver
+
+from django_extensions.db.models import TimeStampedModel
+from jsonfield.fields import JSONField
+
+
+class SiteConfiguration(models.Model):
+    """
+    Model for storing site configuration. These configuration override OpenEdx configurations and settings.
+    e.g. You can override site name, logo image, favicon etc. using site configuration.
+
+    Fields:
+        site (OneToOneField): one to one field relating each configuration to a single site
+        values (JSONField):  json field to store configurations for a site
+    """
+    site = models.OneToOneField(Site, related_name='configuration')
+    values = JSONField(
+        null=False,
+        blank=True,
+        load_kwargs={'object_pairs_hook': collections.OrderedDict}
+    )
+
+    def __unicode__(self):
+        return u"<SiteConfiguration: {site} >".format(site=self.site)
+
+    def __repr__(self):
+        return self.__unicode__()
+
+
+class SiteConfigurationHistory(TimeStampedModel):
+    """
+    This is an archive table for SiteConfiguration, so that we can maintain a history of
+    changes. Note that the site field is not unique in this model, compared to SiteConfiguration.
+
+    Fields:
+        site (ForeignKey): foreign-key to django Site
+        values (JSONField): json field to store configurations for a site
+    """
+    site = models.ForeignKey(Site, related_name='configuration_histories')
+    values = JSONField(
+        null=False,
+        blank=True,
+        load_kwargs={'object_pairs_hook': collections.OrderedDict}
+    )
+
+    def __unicode__(self):
+        return u"<SiteConfigurationHistory: {site}, Last Modified: {modified} >".format(
+            modified=self.modified,
+            site=self.site,
+        )
+
+    def __repr__(self):
+        return self.__unicode__()
+
+
+@receiver(post_save, sender=SiteConfiguration)
+def update_site_configuration_history(sender, instance, **kwargs):  # pylint: disable=unused-argument
+    """
+    Add site configuration changes to site configuration history.
+
+    Args:
+        sender: sender of the signal i.e. SiteConfiguration model
+        instance: SiteConfiguration instance associated with the current signal
+        **kwargs: extra key word arguments
+    """
+    SiteConfigurationHistory.objects.create(
+        site=instance.site,
+        values=instance.values,
+    )

openedx/core/djangoapps/site_configuration/tests/factories.py

@@ -0,0 +1,16 @@
+"""
+Model factories for unit testing views or models.
+"""
+from factory.django import DjangoModelFactory
+
+from openedx.core.djangoapps.site_configuration.models import SiteConfiguration
+
+
+class SiteConfigurationFactory(DjangoModelFactory):
+    """
+    Factory class for SiteConfiguration model
+    """
+    class Meta(object):
+        model = SiteConfiguration
+
+    values = {}

openedx/core/djangoapps/site_configuration/tests/test_models.py

@@ -0,0 +1,93 @@
+"""
+Tests for site configuration's django models.
+"""
+
+from django.test import TestCase
+from django.db import IntegrityError, transaction
+from django.contrib.sites.models import Site
+
+from openedx.core.djangoapps.site_configuration.models import SiteConfigurationHistory
+from openedx.core.djangoapps.site_configuration.tests.factories import SiteConfigurationFactory
+
+
+class SiteConfigurationTests(TestCase):
+    """
+    Tests for SiteConfiguration and its signals/receivers.
+    """
+    domain = 'site_configuration_post_save_receiver_example.com'
+    name = 'site_configuration_post_save_receiver_example'
+
+    @classmethod
+    def setUpClass(cls):
+        super(SiteConfigurationTests, cls).setUpClass()
+        cls.site, _ = Site.objects.get_or_create(domain=cls.domain, name=cls.domain)
+
+    def test_site_configuration_post_save_receiver(self):
+        """
+        Test that and entry is added to SiteConfigurationHistory model each time a new
+        SiteConfiguration is added.
+        """
+        # add SiteConfiguration to database
+        site_configuration = SiteConfigurationFactory.create(
+            site=self.site,
+        )
+
+        # Verify an entry to SiteConfigurationHistory was added.
+        site_configuration_history = SiteConfigurationHistory.objects.filter(
+            site=site_configuration.site,
+        ).all()
+
+        # Make sure an entry (and only one entry) is saved for SiteConfiguration
+        self.assertEqual(len(site_configuration_history), 1)
+
+    def test_site_configuration_post_update_receiver(self):
+        """
+        Test that and entry is added to SiteConfigurationHistory each time a
+        SiteConfiguration is updated.
+        """
+        # add SiteConfiguration to database
+        site_configuration = SiteConfigurationFactory.create(
+            site=self.site,
+        )
+
+        site_configuration.values = {'test': 'test'}
+        site_configuration.save()
+
+        # Verify an entry to SiteConfigurationHistory was added.
+        site_configuration_history = SiteConfigurationHistory.objects.filter(
+            site=site_configuration.site,
+        ).all()
+
+        # Make sure two entries (one for save and one for update) are saved for SiteConfiguration
+        self.assertEqual(len(site_configuration_history), 2)
+
+    def test_no_entry_is_saved_for_errors(self):
+        """
+        Test that and entry is not added to SiteConfigurationHistory if there is an error while
+        saving SiteConfiguration.
+        """
+        # add SiteConfiguration to database
+        site_configuration = SiteConfigurationFactory.create(
+            site=self.site,
+        )
+
+        # Verify an entry to SiteConfigurationHistory was added.
+        site_configuration_history = SiteConfigurationHistory.objects.filter(
+            site=site_configuration.site,
+        ).all()
+
+        # Make sure entry is saved if there is no error
+        self.assertEqual(len(site_configuration_history), 1)
+
+        with transaction.atomic():
+            with self.assertRaises(IntegrityError):
+                # try to add a duplicate entry
+                site_configuration = SiteConfigurationFactory.create(
+                    site=self.site,
+                )
+        site_configuration_history = SiteConfigurationHistory.objects.filter(
+            site=site_configuration.site,
+        ).all()
+
+        # Make sure no entry is saved if there an error
+        self.assertEqual(len(site_configuration_history), 1)

openedx/core/djangoapps/theming/models.py

@@ -1,5 +1,5 @@
 """
-Comprehensive Theme related models.
+Django models supporting the Comprehensive Theming subsystem
 """
 from django.db import models
 from django.contrib.sites.models import Site