Activate Versionning when using the REST API.

Squashing history by user added
Closes #11

backend/__init__.py

+default_app_config = 'backend.apps.BackendConfig'

backend/apps.py

@@ -3,3 +3,6 @@ from django.apps import AppConfig
 
 class BackendConfig(AppConfig):
     name = 'backend'
+
+    def ready(self):
+        import backend.signals  # noqa: F401

backend/models/module/versionnedModule.py

 from django.db import models
 from rest_framework import serializers
 from django.contrib.auth.models import User
+from backend.signals import new_revision_saved
+import reversion
 
 
 class VersionnedModule(models.Model):
@@ -23,5 +25,14 @@ class VersionnedModuleSerializer(serializers.ModelSerializer):
             return None
 
     def save(self, **kwargs):
-        self.validated_data['updated_by'] = self.context['request'].user
-        super(VersionnedModuleSerializer, self).save(**kwargs)
+        # Retrieve the user info from the request
+        user = self.context['request'].user
+
+        self.validated_data['updated_by'] = user
+        # Create a revision for the update or creation
+        with reversion.create_revision():
+            super(VersionnedModuleSerializer, self).save(**kwargs)
+            reversion.set_user(user)
+
+        # Signal save to perform concat of revisions
+        new_revision_saved.send(sender=self.__class__, obj=self.instance)

backend/signals.py

+from reversion.models import Version
+import django.dispatch
+
+new_revision_saved = django.dispatch.Signal(providing_args=["obj"])
+
+
+def squashRevisionByUser(sender, obj, **kwargs):
+    """
+    TODO add comment and unit test
+    """
+    versions = Version.objects\
+        .get_for_object(obj)\
+        .select_related('revision')\
+        .order_by('-revision__date_created')
+
+    last_edit = versions[0]
+    user_made_last_edit = last_edit.revision.user
+
+    if user_made_last_edit is not None:
+        for v in versions[1:]:
+            if v.revision.user == user_made_last_edit:
+                v.delete()
+            else:
+                break
+
+
+new_revision_saved.connect(
+    squashRevisionByUser,
+    dispatch_uid="receiver_concat_revisions"
+)