--- a/libervia/server/session_iface.py	Wed Mar 01 17:55:25 2023 +0100
+++ b/libervia/server/session_iface.py	Wed Mar 01 18:02:44 2023 +0100
@@ -15,14 +15,22 @@
 
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
-from zope.interface import Interface, Attribute
+from collections import OrderedDict, deque
+import os.path
+import time
+from typing import List, Dict, Optional
+
+import shortuuid
+from zope.interface import Attribute, Interface
 from zope.interface import implementer
-from libervia.server.constants import Const as C
+
+from sat.core.log import getLogger
+
 from libervia.server.classes import Notification
-from collections import OrderedDict
-import os.path
-import shortuuid
-import time
+from libervia.server.constants import Const as C
+
+
+log = getLogger(__name__)
 
 FLAGS_KEY = "_flags"
 NOTIFICATIONS_KEY = "_notifications"
@@ -37,10 +45,11 @@
 
 
 @implementer(ISATSession)
-class SATSession(object):
+class SATSession:
+    profiles_map: Dict[Optional[str], List["SATSession"]] = {}
 
     def __init__(self, session):
-        self.profile = None
+        self._profile = None
         self.jid = None
         self.started = time.time()
         # time when the backend session was started
@@ -48,10 +57,39 @@
         self.uuid = str(shortuuid.uuid())
         self.identities = {}
         self.csrf_token = str(shortuuid.uuid())
+        self.ws_token = str(shortuuid.uuid())
+        self.ws_socket = None
+        self.ws_buffer = deque(maxlen=200)
         self.locale = None  # i18n of the pages
         self.theme = None
         self.pages_data = {}  # used to keep data accross reloads (key is page instance)
         self.affiliations = OrderedDict()  # cache for node affiliations
+        self.profiles_map.setdefault(C.SERVICE_PROFILE, []).append(self)
+        log.debug(
+            f"session started for {C.SERVICE_PROFILE} "
+            f"({len(self.get_profile_sessions(C.SERVICE_PROFILE))} session(s) active)"
+        )
+
+    @property
+    def profile(self) -> Optional[str]:
+        return self._profile
+
+    @profile.setter
+    def profile(self, profile: Optional[str]) -> None:
+        old_profile = self._profile or C.SERVICE_PROFILE
+        new_profile = profile or C.SERVICE_PROFILE
+        try:
+            self.profiles_map[old_profile].remove(self)
+        except (ValueError, KeyError):
+            log.warning(f"session was not registered for profile {old_profile}")
+        else:
+            nb_session_old = len(self.get_profile_sessions(old_profile))
+            log.debug(f"{old_profile} has now {nb_session_old} session(s) active")
+
+        self._profile = profile
+        self.profiles_map.setdefault(new_profile, []).append(self)
+        nb_session_new = len(self.get_profile_sessions(new_profile))
+        log.debug(f"{new_profile} has now {nb_session_new} session(s) active")
 
     @property
     def cache_dir(self):
@@ -71,6 +109,36 @@
         else:
             return self.profile.startswith("guest@@")
 
+    @classmethod
+    def send(cls, profile: str, data_type: str, data: dict) -> None:
+        """Send a message to all session
+
+        If the session doesn't have an active websocket, the message is buffered until a
+        socket is available
+        """
+        for session in cls.profiles_map.get(profile, []):
+            if session.ws_socket is None or not session.ws_socket.init_ok:
+                session.ws_buffer.append({"data_type": data_type, "data": data})
+            else:
+                session.ws_socket.send(data_type, data)
+
+    def on_expire(self) -> None:
+        profile = self._profile or C.SERVICE_PROFILE
+        try:
+            self.profiles_map[profile].remove(self)
+        except (ValueError, KeyError):
+            log.warning(f"session was not registered for profile {profile}")
+        else:
+            nb_session = len(self.get_profile_sessions(profile))
+            log.debug(
+                f"Session for profile {profile} expired. {profile} has now {nb_session} "
+                f"session(s) active."
+            )
+
+    @classmethod
+    def get_profile_sessions(cls, profile: str) -> List["SATSession"]:
+        return cls.profiles_map.get(profile, [])
+
     def getPageData(self, page, key):
         """get session data for a page