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-rw-r--r--plugins/mod_carbons.lua111
1 files changed, 111 insertions, 0 deletions
diff --git a/plugins/mod_carbons.lua b/plugins/mod_carbons.lua
new file mode 100644
index 00000000..51242809
--- /dev/null
+++ b/plugins/mod_carbons.lua
@@ -0,0 +1,111 @@
+-- XEP-0280: Message Carbons implementation for Prosody
+-- Copyright (C) 2011 Kim Alvefur
+--
+-- This file is MIT/X11 licensed.
+
+local st = require "util.stanza";
+local jid_bare = require "util.jid".bare;
+local xmlns_carbons = "urn:xmpp:carbons:2";
+local xmlns_forward = "urn:xmpp:forward:0";
+local full_sessions, bare_sessions = full_sessions, bare_sessions;
+
+local function toggle_carbons(event)
+ local origin, stanza = event.origin, event.stanza;
+ local state = stanza.tags[1].name;
+ module:log("debug", "%s %sd carbons", origin.full_jid, state);
+ origin.want_carbons = state == "enable" and stanza.tags[1].attr.xmlns;
+ return origin.send(st.reply(stanza));
+end
+module:hook("iq-set/self/"..xmlns_carbons..":disable", toggle_carbons);
+module:hook("iq-set/self/"..xmlns_carbons..":enable", toggle_carbons);
+
+local function message_handler(event, c2s)
+ local origin, stanza = event.origin, event.stanza;
+ local orig_type = stanza.attr.type;
+ local orig_from = stanza.attr.from;
+ local orig_to = stanza.attr.to;
+
+ if not (orig_type == nil
+ or orig_type == "normal"
+ or orig_type == "chat") then
+ return -- No carbons for messages of type error or headline
+ end
+
+ -- Stanza sent by a local client
+ local bare_jid = jid_bare(orig_from);
+ local target_session = origin;
+ local top_priority = false;
+ local user_sessions = bare_sessions[bare_jid];
+
+ -- Stanza about to be delivered to a local client
+ if not c2s then
+ bare_jid = jid_bare(orig_to);
+ target_session = full_sessions[orig_to];
+ user_sessions = bare_sessions[bare_jid];
+ if not target_session and user_sessions then
+ -- The top resources will already receive this message per normal routing rules,
+ -- so we are going to skip them in order to avoid sending duplicated messages.
+ local top_resources = user_sessions.top_resources;
+ top_priority = top_resources and top_resources[1].priority
+ end
+ end
+
+ if not user_sessions then
+ module:log("debug", "Skip carbons for offline user");
+ return -- No use in sending carbons to an offline user
+ end
+
+ if stanza:get_child("private", xmlns_carbons) then
+ if not c2s then
+ stanza:maptags(function(tag)
+ if not ( tag.attr.xmlns == xmlns_carbons and tag.name == "private" ) then
+ return tag;
+ end
+ end);
+ end
+ module:log("debug", "Message tagged private, ignoring");
+ return
+ elseif stanza:get_child("no-copy", "urn:xmpp:hints") then
+ module:log("debug", "Message has no-copy hint, ignoring");
+ return
+ elseif stanza:get_child("x", "http://jabber.org/protocol/muc#user") then
+ module:log("debug", "MUC PM, ignoring");
+ return
+ end
+
+ -- Create the carbon copy and wrap it as per the Stanza Forwarding XEP
+ local copy = st.clone(stanza);
+ copy.attr.xmlns = "jabber:client";
+ local carbon = st.message{ from = bare_jid, type = orig_type, }
+ :tag(c2s and "sent" or "received", { xmlns = xmlns_carbons })
+ :tag("forwarded", { xmlns = xmlns_forward })
+ :add_child(copy):reset();
+
+ user_sessions = user_sessions and user_sessions.sessions;
+ for _, session in pairs(user_sessions) do
+ -- Carbons are sent to resources that have enabled it
+ if session.want_carbons
+ -- but not the resource that sent the message, or the one that it's directed to
+ and session ~= target_session
+ -- and isn't among the top resources that would receive the message per standard routing rules
+ and (c2s or session.priority ~= top_priority) then
+ carbon.attr.to = session.full_jid;
+ module:log("debug", "Sending carbon to %s", session.full_jid);
+ session.send(carbon);
+ end
+ end
+end
+
+local function c2s_message_handler(event)
+ return message_handler(event, true)
+end
+
+-- Stanzas sent by local clients
+module:hook("pre-message/host", c2s_message_handler, 1);
+module:hook("pre-message/bare", c2s_message_handler, 1);
+module:hook("pre-message/full", c2s_message_handler, 1);
+-- Stanzas to local clients
+module:hook("message/bare", message_handler, 1);
+module:hook("message/full", message_handler, 1);
+
+module:add_feature(xmlns_carbons);