general: only save session when there are changes (#22104)

wcs/qommon/sessions.py

@@ -14,6 +14,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, see <http://www.gnu.org/licenses/>.
 
+import copy
 import os
 import time
 
@@ -122,6 +123,25 @@ class Session(QommonSession, CaptchaSession, StorableObject):
             QuixoteSession.has_info(self)
     is_dirty = has_info
 
+    def migrate(self):
+        # abuse migrate (as it is called after a session is loaded) to keep
+        # track of original content, to avoid saving it when there's no change.
+        self.__orig_dict__ = copy.deepcopy(self.__dict__)
+
+    def __getstate__(self):
+        odict = copy.copy(self.__dict__)
+        if '__orig_dict__' in odict:
+            del odict['__orig_dict__']
+        return odict
+
+    def store(self, *args, **kwargs):
+        current_dict = copy.copy(self.__dict__)
+        orig_dict = current_dict.pop('__orig_dict__', {})
+        current_dict.pop('_access_time', None)
+        orig_dict.pop('_access_time', None)
+        if current_dict != orig_dict:
+            return super(Session, self).store(*args, **kwargs)
+
     def get_session_id(self):
         return self.id