Added primitive Back button to EventCreate.

dav_events/forms/generic.py

@@ -17,6 +17,11 @@ class ChainedForm(forms.Form):
         self._request = kwargs.pop('request', None)
         self._load_session_data()
 
+        if 'initial' not in kwargs:
+            kwargs['initial'] = self._session_data
+        else:
+            kwargs['initial'].update(self._session_data)
+
         super(ChainedForm, self).__init__(*args, **kwargs)
 
         self._proceed_session_data(self._session_data)
@@ -34,6 +39,9 @@ class ChainedForm(forms.Form):
             for k in session_data:
                 self._session_data[k] = self._deserialize_value(session_data[k])
 
+    def _proceed_session_data(self, session_data):
+        pass
+
     def _save_session_data(self):
         if self._request is not None and hasattr(self._request, 'session'):
             session_var_name = '{}_chained_form_session_data'.format(self._request.resolver_match.url_name)
@@ -42,9 +50,6 @@ class ChainedForm(forms.Form):
                 session_data[k] = self._serialize_value(self._session_data[k])
             self._request.session[session_var_name] = session_data
 
-    def _proceed_session_data(self, session_data):
-        pass
-
     def _get_model(self):
         if not hasattr(self, '_model'):
             raise ImproperlyConfigured('{cls} is missing a Model.'
@@ -99,7 +104,7 @@ class ChainedForm(forms.Form):
 
     def save(self):
         object_kwargs = dict()
-        data = self._session_data
+        data = self._session_data.copy()
         if 'deadline' in data:
             buf = data['deadline']
             if isinstance(buf, basestring):
@@ -114,3 +119,10 @@ class ChainedForm(forms.Form):
                 object_kwargs[field] = data[field]
 
         return self._get_object(object_kwargs)
+
+    def flush_session_data(self):
+        if self._request is not None and hasattr(self._request, 'session'):
+            session_var_name = '{}_chained_form_session_data'.format(self._request.resolver_match.url_name)
+            if session_var_name in self._request.session:
+                del self._request.session[session_var_name]
+            self._session_data = dict()