--- a/src/server/utils.py	Sun Mar 11 19:29:23 2018 +0100
+++ b/src/server/utils.py	Sun Mar 11 19:30:37 2018 +0100
@@ -16,9 +16,82 @@
 
 # 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 sat.core.i18n import _
+from twisted.internet import reactor
+from twisted.internet import defer
+from sat.core import exceptions
+from sat.core.log import getLogger
 import urllib
+log = getLogger(__name__)
 
 
 def quote(value, safe='@'):
     """shortcut to quote an unicode value for URL"""
     return urllib.quote(value.encode('utf-8'), safe=safe)
+
+
+class ProgressHandler(object):
+    """class to help the management of progressions"""
+    handlers = {}
+
+    def __init__(self, host, progress_id, profile):
+        self.host = host
+        self.progress_id = progress_id
+        self.profile = profile
+
+    @classmethod
+    def _signal(cls, name, progress_id, data, profile):
+        handlers = cls.handlers
+        if profile in handlers and progress_id in handlers[profile]:
+            handler_data = handlers[profile][progress_id]
+            timeout = handler_data[u'timeout']
+            if timeout.active():
+                timeout.cancel()
+            cb = handler_data[name]
+            if cb is not None:
+                cb(data)
+            if name == u'started':
+                pass
+            elif name == u'finished':
+                handler_data[u'deferred'].callback(data)
+                handler_data[u'instance'].unregister_handler()
+            elif name == u'error':
+                handler_data[u'deferred'].errback(Exception(data))
+                handler_data[u'instance'].unregister_handler()
+
+    def _timeout(self):
+        log.warning(_(u"No progress received, cancelling handler: {progress_id} [{profile}]").format(
+            progress_id = self.progress_id, profile = self.profile))
+
+    def unregister_handler(self):
+        """remove a previously registered handler"""
+        try:
+            del self.handlers[self.profile][self.progress_id]
+        except KeyError:
+            log.warning(_(u"Trying to remove unknown handler: {progress_id} [{profile}]").format(
+                progress_id = self.progress_id, profile = self.profile))
+        else:
+            if not self.handlers[self.profile]:
+                self.handlers[self.profile]
+
+    def register(self, started_cb=None, finished_cb=None, error_cb=None, timeout=30):
+        """register the signals to handle progression
+
+        @param started_cb(callable, None): method to call when progressStarted signal is received
+        @param finished_cb(callable, None): method to call when progressFinished signal is received
+        @param error_cb(callable, None): method to call when progressError signal is received
+        @param timeout(int): progress time out
+            if nothing happen in this progression during this delay,
+            an exception is raised
+        @return (D(dict[unicode,unicode])): a deferred called when progression is finished
+        """
+        handler_data = self.handlers.setdefault(self.profile, {}).setdefault(self.progress_id, {})
+        if handler_data:
+            raise exceptions.ConflictError(u"There is already one handler for this progression")
+        handler_data[u'instance'] = self
+        deferred = handler_data[u'deferred'] = defer.Deferred()
+        handler_data[u'started'] = started_cb
+        handler_data[u'finished'] = finished_cb
+        handler_data[u'error'] = error_cb
+        handler_data[u'timeout'] = reactor.callLater(timeout, self._timeout)
+        return deferred