plugins/mod_carbons.lua

   1 -- XEP-0280: Message Carbons implementation for Prosody
   2 -- Copyright (C) 2011-2016 Kim Alvefur
   3 --
   4 -- This file is MIT/X11 licensed.
   5
   6 local st = require "util.stanza";
   7 local jid_bare = require "util.jid".bare;
   8 local xmlns_carbons = "urn:xmpp:carbons:2";
   9 local xmlns_forward = "urn:xmpp:forward:0";
  10 local full_sessions, bare_sessions = prosody.full_sessions, prosody.bare_sessions;
  11
  12 local function toggle_carbons(event)
  13         local origin, stanza = event.origin, event.stanza;
  14         local state = stanza.tags[1].name;
  15         module:log("debug", "%s %sd carbons", origin.full_jid, state);
  16         origin.want_carbons = state == "enable" and stanza.tags[1].attr.xmlns;
  17         origin.send(st.reply(stanza));
  18         return true;
  19 end
  20 module:hook("iq-set/self/"..xmlns_carbons..":disable", toggle_carbons);
  21 module:hook("iq-set/self/"..xmlns_carbons..":enable", toggle_carbons);
  22
  23 local function message_handler(event, c2s)
  24         local origin, stanza = event.origin, event.stanza;
  25         local orig_type = stanza.attr.type or "normal";
  26         local orig_from = stanza.attr.from;
  27         local bare_from = jid_bare(orig_from);
  28         local orig_to = stanza.attr.to;
  29         local bare_to = jid_bare(orig_to);
  30
  31         if not(orig_type == "chat" or (orig_type == "normal" and stanza:get_child("body"))) then
  32                 return -- Only chat type messages
  33         end
  34
  35         -- Stanza sent by a local client
  36         local bare_jid = bare_from; -- JID of the local user
  37         local target_session = origin;
  38         local top_priority = false;
  39         local user_sessions = bare_sessions[bare_from];
  40
  41         -- Stanza about to be delivered to a local client
  42         if not c2s then
  43                 bare_jid = bare_to;
  44                 target_session = full_sessions[orig_to];
  45                 user_sessions = bare_sessions[bare_jid];
  46                 if not target_session and user_sessions then
  47                         -- The top resources will already receive this message per normal routing rules,
  48                         -- so we are going to skip them in order to avoid sending duplicated messages.
  49                         local top_resources = user_sessions.top_resources;
  50                         top_priority = top_resources and top_resources[1].priority
  51                 end
  52         end
  53
  54         if not user_sessions then
  55                 module:log("debug", "Skip carbons for offline user");
  56                 return -- No use in sending carbons to an offline user
  57         end
  58
  59         if stanza:get_child("private", xmlns_carbons) then
  60                 if not c2s then
  61                         stanza:maptags(function(tag)
  62                                 if not ( tag.attr.xmlns == xmlns_carbons and tag.name == "private" ) then
  63                                         return tag;
  64                                 end
  65                         end);
  66                 end
  67                 module:log("debug", "Message tagged private, ignoring");
  68                 return
  69         elseif stanza:get_child("no-copy", "urn:xmpp:hints") then
  70                 module:log("debug", "Message has no-copy hint, ignoring");
  71                 return
  72         elseif not c2s and bare_jid == orig_from and stanza:get_child("x", "http://jabber.org/protocol/muc#user") then
  73                 module:log("debug", "MUC PM, ignoring");
  74                 return
  75         end
  76
  77         -- Create the carbon copy and wrap it as per the Stanza Forwarding XEP
  78         local copy = st.clone(stanza);
  79         if c2s and not orig_to then
  80                 stanza.attr.to = bare_from;
  81         end
  82         copy.attr.xmlns = "jabber:client";
  83         local carbon = st.message{ from = bare_jid, type = orig_type, }
  84                 :tag(c2s and "sent" or "received", { xmlns = xmlns_carbons })
  85                         :tag("forwarded", { xmlns = xmlns_forward })
  86                                 :add_child(copy):reset();
  87
  88         user_sessions = user_sessions and user_sessions.sessions;
  89         for _, session in pairs(user_sessions) do
  90                 -- Carbons are sent to resources that have enabled it
  91                 if session.want_carbons
  92                 -- but not the resource that sent the message, or the one that it's directed to
  93                 and session ~= target_session
  94                 -- and isn't among the top resources that would receive the message per standard routing rules
  95                 and (c2s or session.priority ~= top_priority) then
  96                         carbon.attr.to = session.full_jid;
  97                         module:log("debug", "Sending carbon to %s", session.full_jid);
  98                         session.send(carbon);
  99                 end
 100         end
 101 end
 102
 103 local function c2s_message_handler(event)
 104         return message_handler(event, true)
 105 end
 106
 107 -- Stanzas sent by local clients
 108 module:hook("pre-message/host", c2s_message_handler, -0.5);
 109 module:hook("pre-message/bare", c2s_message_handler, -0.5);
 110 module:hook("pre-message/full", c2s_message_handler, -0.5);
 111 -- Stanzas to local clients
 112 module:hook("message/bare", message_handler, -0.5);
 113 module:hook("message/full", message_handler, -0.5);
 114
 115 module:add_feature(xmlns_carbons);