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-- Copyright (C) 2016-2020 Kim Alvefur
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--
module:depends"csi"
local jid = require "util.jid";
local st = require "util.stanza";
local dt = require "util.datetime";
local filters = require "util.filters";
local queue_size = module:get_option_number("csi_queue_size", 256);
local important_payloads = module:get_option_set("csi_important_payloads", { });
function is_important(stanza) --> boolean, reason: string
if stanza == " " then
return true, "whitespace keepalive";
elseif type(stanza) == "string" then
return true, "raw data";
elseif not st.is_stanza(stanza) then
-- This should probably never happen
return true, type(stanza);
end
if stanza.attr.xmlns ~= nil then
-- stream errors, stream management etc
return true, "nonza";
end
local st_name = stanza.name;
if not st_name then return false; end
local st_type = stanza.attr.type;
if st_name == "presence" then
if st_type == nil or st_type == "unavailable" or st_type == "error" then
return false, "presence update";
end
-- TODO Some MUC awareness, e.g. check for the 'this relates to you' status code
return true, "subscription request";
elseif st_name == "message" then
if st_type == "headline" then
-- Headline messages are ephemeral by definition
return false, "headline";
end
if st_type == "error" then
return true, "delivery failure";
end
if stanza:get_child("sent", "urn:xmpp:carbons:2") then
return true, "carbon";
end
local forwarded = stanza:find("{urn:xmpp:carbons:2}received/{urn:xmpp:forward:0}/{jabber:client}message");
if forwarded then
stanza = forwarded;
end
if stanza:get_child("body") then
return true, "body";
end
if stanza:get_child("subject") then
-- Last step of a MUC join
return true, "subject";
end
if stanza:get_child("encryption", "urn:xmpp:eme:0") then
-- Since we can't know what an encrypted message contains, we assume it's important
-- XXX Experimental XEP
return true, "encrypted";
end
if stanza:get_child("x", "jabber:x:conference") or stanza:find("{http://jabber.org/protocol/muc#user}x/invite") then
return true, "invite";
end
if stanza:get_child(nil, "urn:xmpp:jingle-message:0") then
-- XXX Experimental XEP
return true, "jingle call";
end
for important in important_payloads do
if stanza:find(important) then
return true;
end
end
return false;
elseif st_name == "iq" then
return true;
end
end
module:hook("csi-is-stanza-important", function (event)
local important, why = is_important(event.stanza);
event.reason = why;
return important;
end, -1);
local function should_flush(stanza, session, ctr) --> boolean, reason: string
if ctr >= queue_size then
return true, "queue size limit reached";
end
local event = { stanza = stanza, session = session };
local ret = module:fire_event("csi-is-stanza-important", event)
return ret, event.reason;
end
local function with_timestamp(stanza, from)
if st.is_stanza(stanza) and stanza.attr.xmlns == nil and stanza.name ~= "iq" then
stanza = st.clone(stanza);
stanza:add_direct_child(st.stanza("delay", {xmlns = "urn:xmpp:delay", from = from, stamp = dt.datetime()}));
end
return stanza;
end
local measure_buffer_hold = module:measure("buffer_hold", "times");
local flush_reasons = setmetatable({}, {
__index = function (t, reason)
local m = module:measure("flush_reason."..reason:gsub("%W", "_"), "rate");
t[reason] = m;
return m;
end;
});
local function manage_buffer(stanza, session)
local ctr = session.csi_counter or 0;
local flush, why = should_flush(stanza, session, ctr);
if flush then
if session.csi_measure_buffer_hold then
session.csi_measure_buffer_hold();
session.csi_measure_buffer_hold = nil;
end
flush_reasons[why or "important"]();
session.log("debug", "Flushing buffer (%s; queue size is %d)", why or "important", session.csi_counter);
session.conn:resume_writes();
session.state = "flushing";
else
session.log("debug", "Holding buffer (%s; queue size is %d)", why or "unimportant", session.csi_counter);
stanza = with_timestamp(stanza, jid.join(session.username, session.host))
end
session.csi_counter = ctr + 1;
return stanza;
end
local function flush_buffer(data, session)
session.log("debug", "Flushing buffer (%s; queue size is %d)", "client activity", session.csi_counter);
flush_reasons["client activity"]();
if session.csi_measure_buffer_hold then
session.csi_measure_buffer_hold();
session.csi_measure_buffer_hold = nil;
end
session.conn:resume_writes();
return data;
end
function enable_optimizations(session)
if session.conn and session.conn.pause_writes then
session.conn:pause_writes();
session.csi_measure_buffer_hold = measure_buffer_hold();
session.csi_counter = 0;
filters.add_filter(session, "stanzas/out", manage_buffer);
filters.add_filter(session, "bytes/in", flush_buffer);
else
session.log("warn", "Session connection does not support write pausing");
end
end
function disable_optimizations(session)
filters.remove_filter(session, "stanzas/out", manage_buffer);
filters.remove_filter(session, "bytes/in", flush_buffer);
session.csi_counter = nil;
if session.csi_measure_buffer_hold then
session.csi_measure_buffer_hold();
session.csi_measure_buffer_hold = nil;
end
if session.conn and session.conn.resume_writes then
session.conn:resume_writes();
end
end
module:hook("csi-client-inactive", function (event)
local session = event.origin;
enable_optimizations(session);
end);
module:hook("csi-client-active", function (event)
local session = event.origin;
disable_optimizations(session);
end);
module:hook("pre-resource-unbind", function (event)
local session = event.session;
disable_optimizations(session);
end, 1);
module:hook("c2s-ondrain", function (event)
local session = event.session;
if (session.state == "flushing" or session.state == "inactive") and session.conn and session.conn.pause_writes then
session.state = "inactive";
session.conn:pause_writes();
session.csi_measure_buffer_hold = measure_buffer_hold();
session.log("debug", "Buffer flushed, resuming inactive mode (queue size was %d)", session.csi_counter);
session.csi_counter = 0;
end
end);
function module.load()
for _, user_session in pairs(prosody.hosts[module.host].sessions) do
for _, session in pairs(user_session.sessions) do
if session.state == "inactive" then
enable_optimizations(session);
end
end
end
end
function module.unload()
for _, user_session in pairs(prosody.hosts[module.host].sessions) do
for _, session in pairs(user_session.sessions) do
if session.state == "inactive" then
disable_optimizations(session);
end
end
end
end
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