From c0263dfb30f2a59c096a0ae70664a219d3a756c4 Mon Sep 17 00:00:00 2001
From: Kim Alvefur <zash@zash.se>
Date: Thu, 30 May 2019 15:16:56 +0200
Subject: mod_pep: Handle presence based subscription outside of util.pubsub
 (fixes #1372)

Subscriptions were updated for each incoming presence stanza from
contacts. Each subscription change triggered a configuration save, which
would filter out the presence based subscriptions and usually end up
replacing the existing data with identical data. With many subscribed
nodes this adds up to a fair bit of IO bound work that is avoided by
keeping them separate.
---
 plugins/mod_pep.lua | 54 +++++++++++++++++------------------------------------
 1 file changed, 17 insertions(+), 37 deletions(-)

(limited to 'plugins')

diff --git a/plugins/mod_pep.lua b/plugins/mod_pep.lua
index 7a4aac2b..f60f84c9 100644
--- a/plugins/mod_pep.lua
+++ b/plugins/mod_pep.lua
@@ -90,21 +90,6 @@ local function nodestore(username)
 		return data, err;
 	end
 	function store:set(node, data)
-		if data then
-			-- Save the data without subscriptions
-			local subscribers = {};
-			for jid, sub in pairs(data.subscribers) do
-				if type(sub) ~= "table" or not sub.presence then
-					subscribers[jid] = sub;
-				end
-			end
-			data = {
-				name = data.name;
-				config = data.config;
-				affiliations = data.affiliations;
-				subscribers = subscribers;
-			};
-		end
 		return node_config:set(username, node, data);
 	end
 	function store:users()
@@ -151,7 +136,23 @@ local function get_broadcaster(username)
 			end
 			message:add_child(item);
 		end
+
+		local broadcast_to = {};
 		for jid in pairs(jids) do
+			broadcast_to[jid] = true;
+		end
+
+		local service_recipients = recipients[username];
+		if service_recipients then
+			local service = services[username];
+			for recipient, nodes in pairs(service_recipients) do
+				if nodes:contains(node) and service:may(node, recipient, "subscribe") then
+					broadcast_to[recipient] = true;
+				end
+			end
+		end
+
+		for jid in pairs(broadcast_to) do
 			module:log("debug", "Sending notification to %s from %s: %s", jid, user_bare, tostring(item));
 			message.attr.to = jid;
 			module:send(message);
@@ -160,20 +161,6 @@ local function get_broadcaster(username)
 	return simple_broadcast;
 end
 
-local function on_node_creation(event)
-	local service = event.service;
-	local node = event.node;
-	local username = service.config.pep_username;
-
-	local service_recipients = recipients[username];
-	if not service_recipients then return; end
-
-	for recipient, nodes in pairs(service_recipients) do
-		if nodes:contains(node) then
-			service:add_subscription(node, recipient, recipient, { presence = true });
-		end
-	end
-end
 
 function get_pep_service(username)
 	module:log("debug", "get_pep_service(%q)", username);
@@ -233,10 +220,6 @@ function get_pep_service(username)
 	return service;
 end
 
-module:hook("item-added/pep-service", function (event)
-	local service = event.item.service;
-	module:hook_object_event(service.events, "node-created", on_node_creation);
-end);
 
 function handle_pubsub_iq(event)
 	local origin, stanza = event.origin, event.stanza;
@@ -303,12 +286,9 @@ local function update_subscriptions(recipient, service_name, nodes)
 	end
 
 	local service = get_pep_service(service_name);
-	for node in current - nodes do
-		service:remove_subscription(node, recipient, recipient);
-	end
 
 	for node in nodes - current do
-		if service:add_subscription(node, recipient, recipient, { presence = true }) then
+		if service:may(node, recipient, "subscribe") then
 			resend_last_item(recipient, node, service);
 		end
 	end
-- 
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