Exclude fields

AUTHORS.rst

@@ -15,6 +15,7 @@ Authors
 - Grzegorz Bialy
 - Hamish Downer
 - James Pulec
+- Joao Junior(@joaojunior)
 - Joao Pedro Francese
 - jofusa
 - John Whitlock

docs/advanced.rst

@@ -214,6 +214,32 @@ You can use the ``table_name`` parameter with both ``HistoricalRecords()`` or
 
     register(Question, table_name='polls_question_history')
 
+Choosing fields to not be stored
+--------------------------------
+
+It is possible to use the parameter ``excluded_fields`` to choose which fields
+will be stored on every create/update/delete.
+
+For example, if you have the model:
+
+.. code-block:: python
+
+    class PollWithExcludeFields(models.Model):
+        question = models.CharField(max_length=200)
+        pub_date = models.DateTimeField('date published')
+
+And you don't want to store the changes for the field ``pub_date``, it is necessary to update the model to:
+
+.. code-block:: python
+
+    class PollWithExcludeFields(models.Model):
+        question = models.CharField(max_length=200)
+        pub_date = models.DateTimeField('date published')
+
+        history = HistoricalRecords(excluded_fields=['pub_date'])
+
+By default, django-simple-history stores the changes for all fields in the model.
+
 Change Reason
 -------------
 

simple_history/models.py

@@ -36,11 +36,15 @@ class HistoricalRecords(object):
     thread = threading.local()
 
     def __init__(self, verbose_name=None, bases=(models.Model,),
-                 user_related_name='+', table_name=None, inherit=False):
+                 user_related_name='+', table_name=None, inherit=False,
+                 excluded_fields=None):
         self.user_set_verbose_name = verbose_name
         self.user_related_name = user_related_name
         self.table_name = table_name
         self.inherit = inherit
+        if excluded_fields is None:
+            excluded_fields = []
+        self.excluded_fields = excluded_fields
         try:
             if isinstance(bases, six.string_types):
                 raise TypeError
@@ -134,13 +138,20 @@ def create_history_model(self, model):
         return python_2_unicode_compatible(
             type(str(name), self.bases, attrs))
 
+    def fields_included(self, model):
+        fields = []
+        for field in model._meta.fields:
+            if field.name not in self.excluded_fields:
+                fields.append(field)
+        return fields
+
     def copy_fields(self, model):
         """
         Creates copies of the model's original fields, returning
         a dictionary mapping field name to copied field object.
         """
         fields = {}
-        for field in model._meta.fields:
+        for field in self.fields_included(model):
             field = copy.copy(field)
             try:
                 field.remote_field = copy.copy(field.remote_field)
@@ -212,7 +223,7 @@ def get_instance(self):
                 ('~', _('Changed')),
                 ('-', _('Deleted')),
             )),
-            'history_object': HistoricalObjectDescriptor(model),
+            'history_object': HistoricalObjectDescriptor(model, self.fields_included(model)),
             'instance': property(get_instance),
             'instance_type': model,
             'revert_url': revert_url,
@@ -252,7 +263,7 @@ def create_historical_record(self, instance, history_type):
         history_change_reason = getattr(instance, 'changeReason', None)
         manager = getattr(instance, self.manager_name)
         attrs = {}
-        for field in instance._meta.fields:
+        for field in self.fields_included(instance):
             attrs[field.attname] = getattr(instance, field.attname)
         manager.create(history_date=history_date, history_type=history_type,
                        history_user=history_user,
@@ -308,10 +319,11 @@ def convert_auto_field(field):
 
 
 class HistoricalObjectDescriptor(object):
-    def __init__(self, model):
+    def __init__(self, model, fields_included):
         self.model = model
+        self.fields_included = fields_included
 
     def __get__(self, instance, owner):
         values = (getattr(instance, f.attname)
-                  for f in self.model._meta.fields)
+                  for f in self.fields_included)
         return self.model(*values)

simple_history/tests/models.py

@@ -15,6 +15,13 @@ class Poll(models.Model):
     history = HistoricalRecords()
 
 
+class PollWithExcludeFields(models.Model):
+    question = models.CharField(max_length=200)
+    pub_date = models.DateTimeField('date published')
+
+    history = HistoricalRecords(excluded_fields=['pub_date'])
+
+
 class Temperature(models.Model):
     location = models.CharField(max_length=200)
     temperature = models.IntegerField()

simple_history/tests/tests/test_models.py

@@ -19,9 +19,10 @@
                       Country, Document, Employee, ExternalModel1,
                       ExternalModel3, FileModel, HistoricalChoice,
                       HistoricalCustomFKError, HistoricalPoll, HistoricalState,
-                      Library, MultiOneToOne, Person, Poll, PollInfo, Province,
-                      Restaurant, SelfFK, Series, SeriesWork, State,
-                      Temperature, UnicodeVerboseName, WaterLevel)
+                      Library, MultiOneToOne, Person, Poll, PollInfo,
+                      PollWithExcludeFields, Province, Restaurant, SelfFK,
+                      Series, SeriesWork, State, Temperature,
+                      UnicodeVerboseName, WaterLevel)
 
 try:
     from django.apps import apps
@@ -334,6 +335,14 @@ def test_foreignkey_primarykey(self):
         poll_info = PollInfo(poll=poll)
         poll_info.save()
 
+    def test_model_with_excluded_fields(self):
+        p = PollWithExcludeFields(question="what's up?", pub_date=today)
+        p.save()
+        history = PollWithExcludeFields.history.all()[0]
+        all_fields_names = [f.name for f in history._meta.fields]
+        self.assertIn('question', all_fields_names)
+        self.assertNotIn('pub_date', all_fields_names)
+
 
 class CreateHistoryModelTests(unittest.TestCase):