Merge pull request #12 from vittoriozamboni/limitfields

Added include_fields and exclude_fields kwargs to register method

src/auditlog/diff.py

@@ -1,11 +1,14 @@
 from django.db.models import Model
 
 
-def model_instance_diff(old, new):
+def model_instance_diff(old, new, **kwargs):
     """
     Calculate the differences between two model instances. One of the instances may be None (i.e., a newly
     created model or deleted model). This will cause all fields with a value to have changed (from None).
+
     """
+    from auditlog.registry import auditlog
+
     if not(old is None or isinstance(old, Model)):
         raise TypeError('The supplied old instance is not a valid model instance.')
     if not(new is None or isinstance(new, Model)):
@@ -15,13 +18,29 @@ def model_instance_diff(old, new):
 
     if old is not None and new is not None:
         fields = set(old._meta.fields + new._meta.fields)
+        model_fields = auditlog.get_model_fields(new._meta.model)
     elif old is not None:
         fields = set(old._meta.fields)
+        model_fields = auditlog.get_model_fields(old._meta.model)
     elif new is not None:
         fields = set(new._meta.fields)
+        model_fields = auditlog.get_model_fields(new._meta.model)
     else:
         fields = set()
 
+    # Check if fields must be filtered
+    if (model_fields['include_fields'] or model_fields['exclude_fields']) and fields:
+        filtered_fields = []
+        if model_fields['include_fields']:
+            filtered_fields = [field for field in fields
+                               if field.name in model_fields['include_fields']]
+        else:
+            filtered_fields = fields
+        if model_fields['exclude_fields']:
+            filtered_fields = [field for field in filtered_fields
+                               if field.name not in model_fields['exclude_fields']]
+        fields = filtered_fields
+
     for field in fields:
         old_value = unicode(getattr(old, field.name, None))
         new_value = unicode(getattr(new, field.name, None))

src/auditlog/models.py

@@ -38,7 +38,7 @@ class LogEntryManager(models.Manager):
 
             return self.create(**kwargs)
         return None
-        
+
     def get_for_object(self, instance):
         """
         Get log entries for the specified object.
@@ -152,7 +152,7 @@ class LogEntry(models.Model):
             substrings.append(substring)
 
         return separator.join(substrings)
-        
+
 
 class AuditlogHistoryField(generic.GenericRelation):
     """

src/auditlog/receivers.py

@@ -7,7 +7,7 @@ def log_create(sender, instance, created, **kwargs):
     """
     Signal receiver that creates a log entry when a model instance is first saved to the database.
 
-    Direct use is discouraged, connect your model through auditlog.registry.registry instead.
+    Direct use is discouraged, connect your model through auditlog.registry.register instead.
     """
     if created:
         changes = model_instance_diff(None, instance)
@@ -23,7 +23,7 @@ def log_update(sender, instance, **kwargs):
     """
     Signal receiver that creates a log entry when a model instance is changed and saved to the database.
 
-    Direct use is discouraged, connect your model through auditlog.registry.registry instead.
+    Direct use is discouraged, connect your model through auditlog.registry.register instead.
     """
     if instance.pk is not None:
         try:
@@ -48,7 +48,7 @@ def log_delete(sender, instance, **kwargs):
     """
     Signal receiver that creates a log entry when a model instance is deleted from the database.
 
-    Direct use is discouraged, connect your model through auditlog.registry.registry instead.
+    Direct use is discouraged, connect your model through auditlog.registry.register instead.
     """
     if instance.pk is not None:
         changes = model_instance_diff(instance, None)

src/auditlog/registry.py

@@ -1,6 +1,5 @@
 from django.db.models.signals import pre_save, post_save, post_delete
 from django.db.models import Model
-from auditlog.receivers import log_create, log_update, log_delete
 
 
 class AuditLogModelRegistry(object):
@@ -9,7 +8,8 @@ class AuditLogModelRegistry(object):
     """
 
     def __init__(self, create=True, update=True, delete=True, custom=None):
-        self._registry = []
+        from auditlog.receivers import log_create, log_update, log_delete
+        self._registry = {}
         self._signals = {}
 
         if create:
@@ -22,12 +22,19 @@ class AuditLogModelRegistry(object):
         if custom is not None:
             self._signals.update(custom)
 
-    def register(self, model):
+    def register(self, model, **kwargs):
         """
         Register a model with auditlog. Auditlog will then track mutations on this model's instances.
+
+        Kwargs:
+          - `include_fields`: list of field names to include in diff
+          - `exclude_fields`: list of field names to exclude in diff
         """
         if issubclass(model, Model):
-            self._registry.append(model)
+            self._registry[model] = {
+                'include_fields': kwargs.get('include_fields', []),
+                'exclude_fields': kwargs.get('exclude_fields', []),
+            }
             self._connect_signals(model)
         else:
             raise TypeError('Supplied model is not a valid model.')
@@ -43,7 +50,7 @@ class AuditLogModelRegistry(object):
         Unregister a model with auditlog. This will not affect the database.
         """
         try:
-            self._registry.pop(model)
+            del self._registry[model]
         except KeyError:
             pass
         else:
@@ -70,5 +77,10 @@ class AuditLogModelRegistry(object):
         """
         return (self.__class__, model, signal)
 
+    def get_model_fields(self, model):
+        return {
+            'include_fields': self._registry[model]['include_fields'],
+            'exclude_fields': self._registry[model]['exclude_fields'],
+        }
 
 auditlog = AuditLogModelRegistry()

src/testapp/models.py

@@ -60,6 +60,30 @@ class ManyRelatedModel(models.Model):
     history = AuditlogHistoryField()
 
 
+class SimpleIncludeModel(models.Model):
+    """
+    A simple model used for register's include_fields kwarg
+    """
+
+    label = models.CharField(max_length=100)
+    text = models.TextField(blank=True)
+
+    history = AuditlogHistoryField()
+
+
+class SimpleExcludeModel(models.Model):
+    """
+    A simple model used for register's exclude_fields kwarg
+    """
+
+    label = models.CharField(max_length=100)
+    text = models.TextField(blank=True)
+
+    history = AuditlogHistoryField()
+
+
 auditlog.register(SimpleModel)
 auditlog.register(AltPrimaryKeyModel)
 auditlog.register(ProxyModel)
+auditlog.register(SimpleIncludeModel, include_fields=['label', ])
+auditlog.register(SimpleExcludeModel, exclude_fields=['label', ])

src/testapp/tests.py

@@ -6,7 +6,8 @@ from django.http import HttpResponse
 from django.test import TestCase, RequestFactory
 from auditlog.middleware import AuditlogMiddleware
 from auditlog.models import LogEntry
-from testapp.models import SimpleModel, AltPrimaryKeyModel, ProxyModel
+from testapp.models import SimpleModel, AltPrimaryKeyModel, ProxyModel, \
+    SimpleIncludeModel, SimpleExcludeModel
 
 
 class SimpleModelTest(TestCase):
@@ -139,3 +140,41 @@ class MiddlewareTest(TestCase):
 
         # Validate result
         self.assertFalse(pre_save.has_listeners(LogEntry))
+
+
+class SimpeIncludeModelTest(TestCase):
+    """Log only changes in include_fields"""
+
+    def test_register_include_fields(self):
+        sim = SimpleIncludeModel(label='Include model', text='Looong text')
+        sim.save()
+        self.assertTrue(sim.history.count() == 1, msg="There is one log entry")
+
+        # Change label, record
+        sim.label = 'Changed label'
+        sim.save()
+        self.assertTrue(sim.history.count() == 2, msg="There are two log entries")
+
+        # Change text, ignore
+        sim.text = 'Short text'
+        sim.save()
+        self.assertTrue(sim.history.count() == 2, msg="There are two log entries")
+
+
+class SimpeExcludeModelTest(TestCase):
+    """Log only changes that are not in exclude_fields"""
+
+    def test_register_exclude_fields(self):
+        sem = SimpleIncludeModel(label='Exclude model', text='Looong text')
+        sem.save()
+        self.assertTrue(sem.history.count() == 1, msg="There is one log entry")
+
+        # Change label, ignore
+        sem.label = 'Changed label'
+        sem.save()
+        self.assertTrue(sem.history.count() == 2, msg="There are two log entries")
+
+        # Change text, record
+        sem.text = 'Short text'
+        sem.save()
+        self.assertTrue(sem.history.count() == 2, msg="There are two log entries")