--- a/src/server/session_iface.py	Sun Sep 24 16:50:39 2017 +0200
+++ b/src/server/session_iface.py	Fri Oct 27 18:31:42 2017 +0200
@@ -20,6 +20,8 @@
 from sat.tools.common import data_objects
 import shortuuid
 
+FLAGS_KEY = '_flags'
+
 class ISATSession(Interface):
     profile = Attribute("Sat profile")
     jid = Attribute("JID associated with the profile")
@@ -36,7 +38,80 @@
         self.uuid = unicode(shortuuid.uuid())
         self.identities = data_objects.Identities()
         self.csrf_token = unicode(shortuuid.uuid())
-        self.flags = set()
+        self.pages_data = {}  # used to keep data accross reloads (key is page instance)
+
+    def getPageData(self, page, key):
+        """get session data for a page
+
+        @param page(LiberviaPage): instance of the page
+        @param key(object): data key
+        return (None, object): value of the key
+            None if not found or page_data doesn't exist
+        """
+        return self.pages_data.get(page, {}).get(key)
+
+    def popPageData(self, page, key, default=None):
+        """like getPageData, but remove key once value is gotten
+
+        @param page(LiberviaPage): instance of the page
+        @param key(object): data key
+        @param default(object): value to return if key is not found
+        @return (object): found value or default
+        """
+        page_data = self.pages_data.get(page)
+        if page_data is None:
+            return default
+        value = page_data.pop(key, default)
+        if not page_data:
+            # no need to keep unused page_data
+            del self.pages_data[page]
+        return value
+
+    def setPageData(self, page, key, value):
+        """set data to persist on reload
+
+        @param page(LiberviaPage): instance of the page
+        @param key(object): data key
+        @param value(object): value to set
+        @return (object): set value
+        """
+        page_data = self.pages_data.setdefault(page, {})
+        page_data[key] = value
+        return value
+
+    def setPageFlag(self, page, flag):
+        """set a flag for this page
+
+        @param page(LiberviaPage): instance of the page
+        @param flag(unicode): flag to set
+        """
+        flags = self.getPageData(page, FLAGS_KEY)
+        if flags is None:
+            flags = self.setPageData(page, FLAGS_KEY, set())
+        flags.add(flag)
+
+    def popPageFlag(self, page, flag):
+        """return True if flag is set
+
+        flag is removed if it was set
+        @param page(LiberviaPage): instance of the page
+        @param flag(unicode): flag to set
+        @return (bool): True if flaag was set
+        """
+        page_data = self.pages_data.get(page, {})
+        flags = page_data.get(FLAGS_KEY)
+        if flags is None:
+            return False
+        if flag in flags:
+            flags.remove(flag)
+            # we remove data if they are not used anymore
+            if not flags:
+                del page_data[FLAGS_KEY]
+            if not page_data:
+                del self.pages_data[page]
+            return True
+        else:
+            return False
 
 
 class ISATGuestSession(Interface):