--- a/dbapi.py	Thu Jul 02 12:59:16 2009 +0200
+++ b/dbapi.py	Thu Jul 02 13:00:20 2009 +0200
@@ -245,7 +245,7 @@
     @property
     def user(self):
         if self._user is None and self.cnx:
-            self.set_user(self.cnx.user(self))
+            self.set_user(self.cnx.user(self, {'lang': self.lang}))
         return self._user
 
     def set_user(self, user):
@@ -367,6 +367,10 @@
         """raise `BadSessionId` if the connection is no more valid"""
         self._repo.check_session(self.sessionid)
 
+    def set_session_props(self, **props):
+        """raise `BadSessionId` if the connection is no more valid"""
+        self._repo.set_session_props(self.sessionid, props)
+
     def get_shared_data(self, key, default=None, pop=False):
         """return value associated to `key` in shared data"""
         return self._repo.get_shared_data(self.sessionid, key, default, pop)
@@ -434,7 +438,8 @@
     def user(self, req=None, props=None):
         """return the User object associated to this connection"""
         # cnx validity is checked by the call to .user_info
-        eid, login, groups, properties = self._repo.user_info(self.sessionid, props)
+        eid, login, groups, properties = self._repo.user_info(self.sessionid,
+                                                              props)
         if req is None:
             req = self.request()
         rset = req.eid_rset(eid, 'CWUser')

--- a/server/repository.py	Thu Jul 02 12:59:16 2009 +0200
+++ b/server/repository.py	Thu Jul 02 13:00:20 2009 +0200
@@ -664,13 +664,22 @@
           custom properties)
         """
         session = self._get_session(sessionid, setpool=False)
-        if props:
-            # update session properties
-            for prop, value in props.items():
-                session.change_property(prop, value)
+        if props is not None:
+            self.set_session_props(sessionid, props)
         user = session.user
         return user.eid, user.login, user.groups, user.properties
 
+    def set_session_props(self, sessionid, props):
+        """this method should be used by client to:
+        * check session id validity
+        * update user information on each user's request (i.e. groups and
+          custom properties)
+        """
+        session = self._get_session(sessionid, setpool=False)
+        # update session properties
+        for prop, value in props.items():
+            session.change_property(prop, value)
+
     # public (inter-repository) interface #####################################
 
     def entities_modified_since(self, etypes, mtime):

--- a/web/request.py	Thu Jul 02 12:59:16 2009 +0200
+++ b/web/request.py	Thu Jul 02 13:00:20 2009 +0200
@@ -91,7 +91,7 @@
         or an anonymous connection is open
         """
         super(CubicWebRequestBase, self).set_connection(cnx, user)
-        # get request language:
+        # set request language
         vreg = self.vreg
         if self.user:
             try:
@@ -114,6 +114,7 @@
     def set_language(self, lang):
         self._ = self.__ = self.translations[lang]
         self.lang = lang
+        self.cnx.set_session_props(lang=lang)
         self.debug('request language: %s', lang)
 
     # input form parameters management ########################################
@@ -336,7 +337,6 @@
                 params[name] = value
         params['eid'] = eid
         if len(params) < minparams:
-            print eid, params
             raise RequestError(self._('missing parameters for entity %s') % eid)
         return params