views: add a get_related_users function to get and cache user linked to the current session

docbow_project/docbow/views.py

@@ -533,6 +533,19 @@ class ExtraContextMixin(object):
         context.update(self.extra_ctx)
         return context
 
+def get_related_users(request):
+    '''Compute the list of users for which we can see the mailboxes, and cache
+       it in the session.
+
+    '''
+    if 'related_users' not in request.session:
+        users = [request.user]
+        delegations = user.delegations_by.select_related('by')
+        if delegations:
+            users.extend(delegation.by for delegation in delegations)
+        request.session['related_users'] = users
+    return request.session['realted_users']
+
 class MailboxQuerysetMixin(object):
     def get_queryset(self):
         qs = super(MailboxQuerysetMixin, self).get_queryset()