--- a/CHANGELOG	Sat Nov 10 10:16:38 2018 +0100
+++ b/CHANGELOG	Sat Nov 10 10:16:38 2018 +0100
@@ -5,6 +5,7 @@
     This is also the first "general audience" version.
     - XEP-0070 implementation (HTTP Auth via XMPP)
     - XEP-0184 implementation (Delivery Receipts)
+    - XEP-0199 implementation (XMPP Ping)
     - XEP-0231 implementation (Bits of Binary)
     - XEP-0264 implementation (Thumbnails)
     - XEP-0280 implementation (Mesage Carbons)

--- a/sat/core/sat_main.py	Sat Nov 10 10:16:38 2018 +0100
+++ b/sat/core/sat_main.py	Sat Nov 10 10:16:38 2018 +0100
@@ -606,7 +606,10 @@
     def getSessionInfos(self, profile_key):
         """compile interesting data on current profile session"""
         client = self.getClient(profile_key)
-        data = {"jid": client.jid.full(), "started": unicode(int(client.started))}
+        data = {
+            "jid": client.jid.full(),
+            "started": unicode(int(client.started))
+            }
         return defer.succeed(data)
 
     # local dirs

--- a/sat/plugins/plugin_misc_text_commands.py	Sat Nov 10 10:16:38 2018 +0100
+++ b/sat/plugins/plugin_misc_text_commands.py	Sat Nov 10 10:16:38 2018 +0100
@@ -57,7 +57,8 @@
     #       should be downloadable independently)
 
     HELP_SUGGESTION = _(
-        "Type '/help' to get a list of the available commands. If you didn't want to use a command, please start your message with '//' to escape the slash."
+        u"Type '/help' to get a list of the available commands. If you didn't want to "
+        u"use a command, please start your message with '//' to escape the slash."
     )
 
     def __init__(self, host):
@@ -75,7 +76,8 @@
         @param cmd: function or method callback for the command,
             its docstring will be used for self documentation in the following way:
             - first line is the command short documentation, shown with /help
-            - @command keyword can be used, see http://wiki.goffi.org/wiki/Coding_style/en for documentation
+            - @command keyword can be used,
+              see http://wiki.goffi.org/wiki/Coding_style/en for documentation
         @return (dict): dictionary with parsed data where key can be:
             - "doc_short_help" (default: ""): the untranslated short documentation
             - "type" (default "all"): the command type as specified in documentation
@@ -177,10 +179,12 @@
         """Add a callback which give information to the /whois command
 
         @param callback: a callback which will be called with the following arguments
-            - whois_msg: list of information strings to display, callback need to append its own strings to it
+            - whois_msg: list of information strings to display, callback need to append
+                         its own strings to it
             - target_jid: full jid from whom we want information
             - profile: %(doc_profile)s
-        @param priority: priority of the information to show (the highest priority will be displayed first)
+        @param priority: priority of the information to show (the highest priority will
+            be displayed first)
         """
         self._whois.append((priority, callback))
         self._whois.sort(key=lambda item: item[0], reverse=True)
@@ -195,11 +199,14 @@
     def _sendMessageCmdHook(self, mess_data, client):
         """ Check text commands in message, and react consequently
 
-        msg starting with / are potential command. If a command is found, it is executed, else and help message is sent
+        msg starting with / are potential command. If a command is found, it is executed,
+        else an help message is sent.
         msg starting with // are escaped: they are sent with a single /
-        commands can abord message sending (if they return anything evaluating to False), or continue it (if they return True), eventually after modifying the message
-        an "unparsed" key is added to message, containing part of the message not yet parsed
-        commands can be deferred or not
+        commands can abord message sending (if they return anything evaluating to False),
+        or continue it (if they return True), eventually after modifying the message
+        an "unparsed" key is added to message, containing part of the message not yet
+        parsed.
+        Commands can be deferred or not
         @param mess_data(dict): data comming from sendMessage trigger
         @param profile: %(doc_profile)s
         """

--- a/sat/plugins/plugin_xep_0045.py	Sat Nov 10 10:16:38 2018 +0100
+++ b/sat/plugins/plugin_xep_0045.py	Sat Nov 10 10:16:38 2018 +0100
@@ -472,8 +472,8 @@
         return muc_client
 
     def kick(self, client, nick, room_jid, options=None):
-        """
-        Kick a participant from the room
+        """Kick a participant from the room
+
         @param nick (str): nick of the user to kick
         @param room_jid_s (JID): jid of the room
         @param options (dict): attribute with extra info (reason, password) as in #XEP-0045

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/sat/plugins/plugin_xep_0199.py	Sat Nov 10 10:16:38 2018 +0100
@@ -0,0 +1,156 @@
+#!/usr/bin/env python2
+# -*- coding: utf-8 -*-
+
+# SAT plugin for Delayed Delivery (XEP-0199)
+# Copyright (C) 2009-2018 Jérôme Poisson (goffi@goffi.org)
+# Copyright (C) 2013-2016 Adrien Cossa (souliane@mailoo.org)
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# 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 _, D_
+from sat.core.log import getLogger
+
+log = getLogger(__name__)
+from sat.core.constants import Const as C
+from wokkel import disco, iwokkel
+from twisted.words.protocols.jabber import xmlstream, jid
+from zope.interface import implements
+import time
+
+
+PLUGIN_INFO = {
+    C.PI_NAME: u"XMPP PING",
+    C.PI_IMPORT_NAME: u"XEP-0199",
+    C.PI_TYPE: u"XEP",
+    C.PI_PROTOCOLS: [u"XEP-199"],
+    C.PI_MAIN: "XEP_0199",
+    C.PI_HANDLER: u"yes",
+    C.PI_DESCRIPTION: D_(u"""Implementation of XMPP Ping"""),
+}
+
+NS_PING = u"urn:xmpp:ping"
+PING_REQUEST = C.IQ_GET + '/ping[@xmlns="' + NS_PING + '"]'
+
+
+class XEP_0199(object):
+
+    def __init__(self, host):
+        log.info(_("XMPP Ping plugin initialization"))
+        self.host = host
+        host.bridge.addMethod(
+            "ping", ".plugin", in_sign='ss', out_sign='d', method=self._ping, async=True)
+        try:
+            self.text_cmds = self.host.plugins[C.TEXT_CMDS]
+        except KeyError:
+            log.info(_(u"Text commands not available"))
+        else:
+            self.text_cmds.registerTextCommands(self)
+
+    def getHandler(self, client):
+        return XEP_0199_handler(self)
+
+    def _pingRaiseIfFailure(self, pong):
+        """If ping didn't succeed, raise the failure, else return pong delay"""
+        if pong[0] != u"PONG":
+            raise pong[0]
+        return pong[1]
+
+    def _ping(self, jid_s, profile):
+        client = self.host.getClient(profile)
+        entity_jid = jid.JID(jid_s)
+        d = self.ping(client, entity_jid)
+        d.addCallback(self._pingRaiseIfFailure)
+        return d
+
+    def _pingCb(self, iq_result, send_time):
+        receive_time = time.time()
+        return (u"PONG", receive_time - send_time)
+
+    def _pingEb(self, failure_, send_time):
+        receive_time = time.time()
+        return (failure_.value, receive_time - send_time)
+
+    def ping(self, client, entity_jid):
+        """Ping an XMPP entity
+
+        @param entity_jid(jid.JID): entity to ping
+        @return (tuple[(unicode,failure), float]): pong data:
+            - either u"PONG" if it was successful, or failure
+            - delay between sending time and reception time
+        """
+        iq_elt = client.IQ("get")
+        iq_elt["to"] = entity_jid.full()
+        iq_elt.addElement((NS_PING, "ping"))
+        d = iq_elt.send()
+        send_time = time.time()
+        d.addCallback(self._pingCb, send_time)
+        d.addErrback(self._pingEb, send_time)
+        return d
+
+    def _cmd_ping_fb(self, pong, client, mess_data):
+        """Send feedback to client when pong data is received"""
+        txt_cmd = self.host.plugins[C.TEXT_CMDS]
+
+        if pong[0] == u"PONG":
+            txt_cmd.feedBack(client, u"PONG ({time} s)".format(time=pong[1]), mess_data)
+        else:
+            txt_cmd.feedBack(
+                client, _(u"ping error ({err_msg}). Response time: {time} s")
+                .format(err_msg=pong[0], time=pong[1]), mess_data)
+
+    def cmd_ping(self, client, mess_data):
+        """ping an entity
+
+        @command (all): [JID]
+            - JID: jid of the entity to ping
+        """
+        if mess_data["unparsed"].strip():
+            try:
+                entity_jid = jid.JID(mess_data["unparsed"].strip())
+            except RuntimeError:
+                txt_cmd = self.host.plugins[C.TEXT_CMDS]
+                txt_cmd.feedBack(client, _(u'Invalid jid: "{entity_jid}"').format(
+                    entity_jid=mess_data["unparsed"].strip()), mess_data)
+                return False
+        else:
+            entity_jid = mess_data["to"]
+        d = self.ping(client, entity_jid)
+        d.addCallback(self._cmd_ping_fb, client, mess_data)
+
+        return False
+
+    def onPingRequest(self, iq_elt, client):
+        log.info(_(u"XMPP PING received from {from_jid} [{profile}]").format(
+            from_jid=iq_elt["from"], profile=client.profile))
+        iq_elt.handled = True
+        iq_result_elt = xmlstream.toResponse(iq_elt, "result")
+        client.send(iq_result_elt)
+
+
+class XEP_0199_handler(xmlstream.XMPPHandler):
+    implements(iwokkel.IDisco)
+
+    def __init__(self, plugin_parent):
+        self.plugin_parent = plugin_parent
+
+    def connectionInitialized(self):
+        self.xmlstream.addObserver(
+            PING_REQUEST, self.plugin_parent.onPingRequest, client=self.parent
+        )
+
+    def getDiscoInfo(self, requestor, target, nodeIdentifier=""):
+        return [disco.DiscoFeature(NS_PING)]
+
+    def getDiscoItems(self, requestor, target, nodeIdentifier=""):
+        return []