Additional field for metadata

requirements.txt

@@ -1 +1,2 @@
 Django>=1.7
+django-jsonfield>=0.9.13

setup.py

@@ -11,6 +11,7 @@ setup(
     author_email='janjelle@jjkester.nl',
     description='Audit log app for Django',
     install_requires=[
-        'Django>=1.7'
+        'Django>=1.7',
+        'django-jsonfield>=0.9.13',
     ]
 )

src/auditlog/migrations/0003_logentry_detailed_object_repr.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+import jsonfield.fields
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('auditlog', '0002_auto_support_long_primary_keys'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='logentry',
+            name='additional_data',
+            field=jsonfield.fields.JSONField(null=True, blank=True),
+        ),
+    ]

src/auditlog/models.py

@@ -11,6 +11,8 @@ from django.utils.encoding import python_2_unicode_compatible, smart_text
 from django.utils.six import iteritems, integer_types
 from django.utils.translation import ugettext_lazy as _
 
+from jsonfield import JSONField
+
 
 class LogEntryManager(models.Manager):
     """
@@ -33,6 +35,10 @@ class LogEntryManager(models.Manager):
             if isinstance(pk, integer_types):
                 kwargs.setdefault('object_id', pk)
 
+            get_additional_data = getattr(instance, 'get_additional_data', None)
+            if callable(get_additional_data):
+                kwargs.setdefault('additional_data', get_additional_data())
+
             # Delete log entries with the same pk as a newly created model. This should only be necessary when an pk is
             # used twice.
             if kwargs.get('action', None) is LogEntry.Action.CREATE:
@@ -138,6 +144,7 @@ class LogEntry(models.Model):
     changes = models.TextField(blank=True, verbose_name=_("change message"))
     actor = models.ForeignKey(settings.AUTH_USER_MODEL, blank=True, null=True, on_delete=models.SET_NULL, related_name='+', verbose_name=_("actor"))
     timestamp = models.DateTimeField(auto_now_add=True, verbose_name=_("timestamp"))
+    additional_data = JSONField(blank=True, null=True, verbose_name=_("additional data"))
 
     objects = LogEntryManager()
 

src/auditlog_tests/models.py

@@ -82,11 +82,36 @@ class SimpleExcludeModel(models.Model):
     history = AuditlogHistoryField()
 
 
+class AdditionalDataIncludedModel(models.Model):
+    """
+    A model where get_additional_data is defined which allows for logging extra
+    information about the model in JSON
+    """
+
+    label = models.CharField(max_length=100)
+    text = models.TextField(blank=True)
+    related = models.ForeignKey(SimpleModel)
+
+    history = AuditlogHistoryField()
+
+    def get_additional_data(self):
+        """
+        Returns JSON that captures a snapshot of additional details of the
+        model instance. This method, if defined, is accessed by auditlog
+        manager and added to each logentry instance on creation.
+        """
+        object_details = {
+            'related_model_id': self.related.id,
+            'related_model_text': self.related.text
+        }
+        return object_details
+
 auditlog.register(SimpleModel)
 auditlog.register(AltPrimaryKeyModel)
 auditlog.register(ProxyModel)
 auditlog.register(RelatedModel)
 auditlog.register(ManyRelatedModel)
 auditlog.register(ManyRelatedModel.related.through)
-auditlog.register(SimpleIncludeModel, include_fields=['label', ])
-auditlog.register(SimpleExcludeModel, exclude_fields=['text', ])
+auditlog.register(SimpleIncludeModel, include_fields=['label'])
+auditlog.register(SimpleExcludeModel, exclude_fields=['text'])
+auditlog.register(AdditionalDataIncludedModel)

src/auditlog_tests/tests.py

@@ -7,7 +7,7 @@ from django.test import TestCase, RequestFactory
 from auditlog.middleware import AuditlogMiddleware
 from auditlog.models import LogEntry
 from auditlog_tests.models import SimpleModel, AltPrimaryKeyModel, ProxyModel, \
-    SimpleIncludeModel, SimpleExcludeModel, RelatedModel, ManyRelatedModel
+    SimpleIncludeModel, SimpleExcludeModel, RelatedModel, ManyRelatedModel, AdditionalDataIncludedModel
 
 
 class SimpleModelTest(TestCase):
@@ -192,3 +192,28 @@ class SimpeExcludeModelTest(TestCase):
         sem.text = 'Short text'
         sem.save()
         self.assertTrue(sem.history.count() == 2, msg="There are two log entries")
+
+
+class AdditionalDataModelTest(TestCase):
+    """Log additional data if get_additional_data is defined in the model"""
+
+    def test_model_without_additional_data(self):
+        obj_wo_additional_data = SimpleModel.objects.create(text='No additional '
+                                                                 'data')
+        obj_log_entry = obj_wo_additional_data.history.get()
+        self.assertIsNone(obj_log_entry.additional_data)
+
+    def test_model_with_additional_data(self):
+        related_model = SimpleModel.objects.create(text='Log my reference')
+        obj_with_additional_data = AdditionalDataIncludedModel(
+            label='Additional data to log entries', related=related_model)
+        obj_with_additional_data.save()
+        self.assertTrue(obj_with_additional_data.history.count() == 1,
+                        msg="There is 1 log entry")
+        log_entry = obj_with_additional_data.history.get()
+        self.assertIsNotNone(log_entry.additional_data)
+        extra_data = log_entry.additional_data
+        self.assertTrue(extra_data['related_model_text'] == related_model.text,
+                        msg="Related model's text is logged")
+        self.assertTrue(extra_data['related_model_id'] == related_model.id,
+                        msg="Related model's id is logged")