Split extract_from_model and created extract_from_instance to allow f…

…or easier extending

djangomarkup/models.py

@@ -73,29 +73,35 @@ def delete_for_object(self, instance):
             object_id=pk,
         ).delete()
 
+    def extract_from_instance(self, instance, processor, fields, content_type=None):
+        if not content_type:
+            content_type = ContentType.objects.get_for_model(instance)
+
+        dirty = False
+        for f in fields:
+            st, created = self.get_or_create(
+                        content_type=content_type,
+                        object_id=instance.pk,
+                        field=f,
+                        defaults={
+                            'processor': processor,
+                            'content': getattr(instance, f),
+                        }
+                    )
+            if created:
+                setattr(instance, f, st.render())
+                dirty = True
+        if dirty:
+            instance.save(force_update=True)
+
     def extract_from_model(self, model, processor, fields):
         if not fields:
             return
 
         ct = ContentType.objects.get_for_model(model)
 
         for m in model._default_manager.all():
-            dirty = False
-            for f in fields:
-                st, created = self.get_or_create(
-                            content_type=ct,
-                            object_id=m.pk,
-                            field=f,
-                            defaults={
-                                'processor': processor,
-                                'content': getattr(m, f),
-                            }
-                        )
-                if created:
-                    setattr(m, f, st.render())
-                    dirty = True
-            if dirty:
-                m.save(force_update=True)
+            self.extract_from_instance(m, processor, fields, ct)
 
 
 class SourceText(models.Model):