--- a/sat/plugins/plugin_xep_0047.py	Wed Jun 27 07:51:29 2018 +0200
+++ b/sat/plugins/plugin_xep_0047.py	Wed Jun 27 20:14:46 2018 +0200
@@ -19,6 +19,7 @@
 
 from sat.core.i18n import _
 from sat.core.log import getLogger
+
 log = getLogger(__name__)
 from sat.core.constants import Const as C
 from sat.core import exceptions
@@ -40,15 +41,15 @@
 except ImportError:
     from wokkel.subprotocols import XMPPHandler
 
-MESSAGE = '/message'
+MESSAGE = "/message"
 IQ_SET = '/iq[@type="set"]'
-NS_IBB = 'http://jabber.org/protocol/ibb'
+NS_IBB = "http://jabber.org/protocol/ibb"
 IBB_OPEN = IQ_SET + '/open[@xmlns="' + NS_IBB + '"]'
 IBB_CLOSE = IQ_SET + '/close[@xmlns="' + NS_IBB + '" and @sid="{}"]'
 IBB_IQ_DATA = IQ_SET + '/data[@xmlns="' + NS_IBB + '" and @sid="{}"]'
 IBB_MESSAGE_DATA = MESSAGE + '/data[@xmlns="' + NS_IBB + '" and @sid="{}"]'
 TIMEOUT = 120  # timeout for workflow
-DEFER_KEY = 'finished' # key of the deferred used to track session end
+DEFER_KEY = "finished"  # key of the deferred used to track session end
 
 PLUGIN_INFO = {
     C.PI_NAME: "In-Band Bytestream Plugin",
@@ -58,7 +59,7 @@
     C.PI_PROTOCOLS: ["XEP-0047"],
     C.PI_MAIN: "XEP_0047",
     C.PI_HANDLER: "yes",
-    C.PI_DESCRIPTION: _("""Implementation of In-Band Bytestreams""")
+    C.PI_DESCRIPTION: _("""Implementation of In-Band Bytestreams"""),
 }
 
 
@@ -82,8 +83,11 @@
         @param sid(unicode): session id of client.xep_0047_current_stream
         @param client: %(doc_client)s
         """
-        log.info(u"In-Band Bytestream: TimeOut reached for id {sid} [{profile}]"
-                 .format(sid=sid, profile=client.profile))
+        log.info(
+            u"In-Band Bytestream: TimeOut reached for id {sid} [{profile}]".format(
+                sid=sid, profile=client.profile
+            )
+        )
         self._killSession(sid, client, "TIMEOUT")
 
     def _killSession(self, sid, client, failure_reason=None):
@@ -101,14 +105,14 @@
             return
 
         try:
-            observer_cb = session['observer_cb']
+            observer_cb = session["observer_cb"]
         except KeyError:
             pass
         else:
             client.xmlstream.removeObserver(session["event_data"], observer_cb)
 
-        if session['timer'].active():
-            session['timer'].cancel()
+        if session["timer"].active():
+            session["timer"].cancel()
 
         del client.xep_0047_current_stream[sid]
 
@@ -136,15 +140,15 @@
         @return (dict): session data
         """
         if sid in client.xep_0047_current_stream:
-            raise exceptions.ConflictError(u'A session with this id already exists !')
-        session_data = client.xep_0047_current_stream[sid] = \
-            {'id': sid,
-             DEFER_KEY: defer.Deferred(),
-             'to': to_jid,
-             'stream_object': stream_object,
-             'seq': -1,
-             'timer': reactor.callLater(TIMEOUT, self._timeOut, sid, client),
-            }
+            raise exceptions.ConflictError(u"A session with this id already exists !")
+        session_data = client.xep_0047_current_stream[sid] = {
+            "id": sid,
+            DEFER_KEY: defer.Deferred(),
+            "to": to_jid,
+            "stream_object": stream_object,
+            "seq": -1,
+            "timer": reactor.callLater(TIMEOUT, self._timeOut, sid, client),
+        }
 
         return session_data
 
@@ -155,19 +159,21 @@
         """
         log.debug(_(u"IBB stream opening"))
         iq_elt.handled = True
-        open_elt = iq_elt.elements(NS_IBB, 'open').next()
-        block_size = open_elt.getAttribute('block-size')
-        sid = open_elt.getAttribute('sid')
-        stanza = open_elt.getAttribute('stanza', 'iq')
+        open_elt = iq_elt.elements(NS_IBB, "open").next()
+        block_size = open_elt.getAttribute("block-size")
+        sid = open_elt.getAttribute("sid")
+        stanza = open_elt.getAttribute("stanza", "iq")
         if not sid or not block_size or int(block_size) > 65535:
-            return self._sendError('not-acceptable', sid or None, iq_elt, client)
+            return self._sendError("not-acceptable", sid or None, iq_elt, client)
         if not sid in client.xep_0047_current_stream:
             log.warning(_(u"Ignoring unexpected IBB transfer: %s" % sid))
-            return self._sendError('not-acceptable', sid or None, iq_elt, client)
+            return self._sendError("not-acceptable", sid or None, iq_elt, client)
         session_data = client.xep_0047_current_stream[sid]
-        if session_data["to"] != jid.JID(iq_elt['from']):
-            log.warning(_("sended jid inconsistency (man in the middle attack attempt ?)"))
-            return self._sendError('not-acceptable', sid, iq_elt, client)
+        if session_data["to"] != jid.JID(iq_elt["from"]):
+            log.warning(
+                _("sended jid inconsistency (man in the middle attack attempt ?)")
+            )
+            return self._sendError("not-acceptable", sid, iq_elt, client)
 
         # at this stage, the session looks ok and will be accepted
 
@@ -175,7 +181,9 @@
         session_data["timer"].reset(TIMEOUT)
 
         # we save the xmlstream, events and observer data to allow observer removal
-        session_data["event_data"] = event_data = (IBB_MESSAGE_DATA if stanza == 'message' else IBB_IQ_DATA).format(sid)
+        session_data["event_data"] = event_data = (
+            IBB_MESSAGE_DATA if stanza == "message" else IBB_IQ_DATA
+        ).format(sid)
         session_data["observer_cb"] = observer_cb = self._onIBBData
         event_close = IBB_CLOSE.format(sid)
         # we now set the stream observer to look after data packet
@@ -184,7 +192,7 @@
         client.xmlstream.addObserver(event_data, observer_cb, client=client)
         client.xmlstream.addOnetimeObserver(event_close, self._onIBBClose, client=client)
         # finally, we send the accept stanza
-        iq_result_elt = xmlstream.toResponse(iq_elt, 'result')
+        iq_result_elt = xmlstream.toResponse(iq_elt, "result")
         client.send(iq_result_elt)
 
     def _onIBBClose(self, iq_elt, client):
@@ -194,11 +202,11 @@
         """
         iq_elt.handled = True
         log.debug(_("IBB stream closing"))
-        close_elt = iq_elt.elements(NS_IBB, 'close').next()
+        close_elt = iq_elt.elements(NS_IBB, "close").next()
         # XXX: this observer is only triggered on valid sid, so we don't need to check it
-        sid = close_elt['sid']
+        sid = close_elt["sid"]
 
-        iq_result_elt = xmlstream.toResponse(iq_elt, 'result')
+        iq_result_elt = xmlstream.toResponse(iq_elt, "result")
         client.send(iq_result_elt)
         self._killSession(sid, client)
 
@@ -209,29 +217,33 @@
         @param element(domish.Element): <iq> or <message> stanza
         """
         element.handled = True
-        data_elt = element.elements(NS_IBB, 'data').next()
-        sid = data_elt['sid']
+        data_elt = element.elements(NS_IBB, "data").next()
+        sid = data_elt["sid"]
 
         try:
             session_data = client.xep_0047_current_stream[sid]
         except KeyError:
             log.warning(_(u"Received data for an unknown session id"))
-            return self._sendError('item-not-found', None, element, client)
+            return self._sendError("item-not-found", None, element, client)
 
         from_jid = session_data["to"]
         stream_object = session_data["stream_object"]
 
-        if from_jid.full() != element['from']:
-            log.warning(_(u"sended jid inconsistency (man in the middle attack attempt ?)\ninitial={initial}\ngiven={given}").format(initial=from_jid, given=element['from']))
-            if element.name == 'iq':
-                self._sendError('not-acceptable', sid, element, client)
+        if from_jid.full() != element["from"]:
+            log.warning(
+                _(
+                    u"sended jid inconsistency (man in the middle attack attempt ?)\ninitial={initial}\ngiven={given}"
+                ).format(initial=from_jid, given=element["from"])
+            )
+            if element.name == "iq":
+                self._sendError("not-acceptable", sid, element, client)
             return
 
         session_data["seq"] = (session_data["seq"] + 1) % 65535
         if int(data_elt.getAttribute("seq", -1)) != session_data["seq"]:
             log.warning(_(u"Sequence error"))
-            if element.name == 'iq':
-                reason = 'not-acceptable'
+            if element.name == "iq":
+                reason = "not-acceptable"
                 self._sendError(reason, sid, element, client)
             self.terminateStream(session_data, client, reason)
             return
@@ -245,14 +257,14 @@
         except TypeError:
             # The base64 data is invalid
             log.warning(_(u"Invalid base64 data"))
-            if element.name == 'iq':
-                self._sendError('not-acceptable', sid, element, client)
+            if element.name == "iq":
+                self._sendError("not-acceptable", sid, element, client)
             self.terminateStream(session_data, client, reason)
             return
 
         # we can now ack success
-        if element.name == 'iq':
-            iq_result_elt = xmlstream.toResponse(element, 'result')
+        if element.name == "iq":
+            iq_result_elt = xmlstream.toResponse(element, "result")
             client.send(iq_result_elt)
 
     def _sendError(self, error_condition, sid, iq_elt, client):
@@ -264,7 +276,11 @@
         @param client: %(doc_client)s
         """
         iq_elt = error.StanzaError(error_condition).toResponse(iq_elt)
-        log.warning(u"Error while managing in-band bytestream session, cancelling: {}".format(error_condition))
+        log.warning(
+            u"Error while managing in-band bytestream session, cancelling: {}".format(
+                error_condition
+            )
+        )
         if sid is not None:
             self._killSession(sid, client, error_condition)
         client.send(iq_elt)
@@ -285,11 +301,11 @@
         session_data["block_size"] = block_size
 
         iq_elt = client.IQ()
-        iq_elt['to'] = to_jid.full()
-        open_elt = iq_elt.addElement((NS_IBB, 'open'))
-        open_elt['block-size'] = str(block_size)
-        open_elt['sid'] = sid
-        open_elt['stanza'] = 'iq' # TODO: manage <message> stanza ?
+        iq_elt["to"] = to_jid.full()
+        open_elt = iq_elt.addElement((NS_IBB, "open"))
+        open_elt["block-size"] = str(block_size)
+        open_elt["sid"] = sid
+        open_elt["stanza"] = "iq"  # TODO: manage <message> stanza ?
         args = [session_data, client]
         d = iq_elt.send()
         d.addCallbacks(self._IQDataStreamCb, self._IQDataStreamEb, args, None, args)
@@ -307,11 +323,11 @@
         buffer_ = session_data["stream_object"].read(session_data["block_size"])
         if buffer_:
             next_iq_elt = client.IQ()
-            next_iq_elt['to'] = session_data["to"].full()
-            data_elt = next_iq_elt.addElement((NS_IBB, 'data'))
-            seq = session_data['seq'] = (session_data['seq'] + 1) % 65535
-            data_elt['seq'] = unicode(seq)
-            data_elt['sid'] = session_data['id']
+            next_iq_elt["to"] = session_data["to"].full()
+            data_elt = next_iq_elt.addElement((NS_IBB, "data"))
+            seq = session_data["seq"] = (session_data["seq"] + 1) % 65535
+            data_elt["seq"] = unicode(seq)
+            data_elt["sid"] = session_data["id"]
             data_elt.addContent(base64.b64encode(buffer_))
             args = [session_data, client]
             d = next_iq_elt.send()
@@ -334,11 +350,11 @@
         @param failure_reason(unicode, None): reason of the failure, or None if steam was successful
         """
         iq_elt = client.IQ()
-        iq_elt['to'] = session_data["to"].full()
-        close_elt = iq_elt.addElement((NS_IBB, 'close'))
-        close_elt['sid'] = session_data['id']
+        iq_elt["to"] = session_data["to"].full()
+        close_elt = iq_elt.addElement((NS_IBB, "close"))
+        close_elt["sid"] = session_data["id"]
         iq_elt.send()
-        self._killSession(session_data['id'], client, failure_reason)
+        self._killSession(session_data["id"], client, failure_reason)
 
 
 class XEP_0047_handler(XMPPHandler):
@@ -348,10 +364,12 @@
         self.plugin_parent = parent
 
     def connectionInitialized(self):
-        self.xmlstream.addObserver(IBB_OPEN, self.plugin_parent._onIBBOpen, client=self.parent)
+        self.xmlstream.addObserver(
+            IBB_OPEN, self.plugin_parent._onIBBOpen, client=self.parent
+        )
 
-    def getDiscoInfo(self, requestor, target, nodeIdentifier=''):
+    def getDiscoInfo(self, requestor, target, nodeIdentifier=""):
         return [disco.DiscoFeature(NS_IBB)]
 
-    def getDiscoItems(self, requestor, target, nodeIdentifier=''):
+    def getDiscoItems(self, requestor, target, nodeIdentifier=""):
         return []