view mod_pubsub_subscription/mod_pubsub_subscription.lua @ 4976:75b6e5df65f9

various: Improve error reporting if missing file server module on 0.12 If there is some error loading net.http.files then it would be swallowed by the pcall and then it would proceed to trying mod_http_files, which might cause unexpected behavior on 0.12 Ref #1765
author Kim Alvefur <zash@zash.se>
date Mon, 18 Jul 2022 22:47:54 +0200
parents 97fac0ba0469
children b40750891bee
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local st = require "util.stanza";
local uuid = require "util.uuid";
local mt = require "util.multitable";
local cache = require "util.cache";

local xmlns_pubsub = "http://jabber.org/protocol/pubsub";
local xmlns_pubsub_event = "http://jabber.org/protocol/pubsub#event";

-- TODO persist
-- TODO query known pubsub nodes to sync current subscriptions
-- TODO subscription ids per 'item' would be handy

local pending_subscription = cache.new(256); -- uuid → node
local pending_unsubscription = cache.new(256); -- uuid → node
local active_subscriptions = mt.new() -- service | node | uuid | { item }
function module.save()
	return { active_subscriptions = active_subscriptions.data }
end
function module.restore(data)
	if data and data.active_subscriptions then
		active_subscriptions.data = data.active_subscriptions
	end
end

local valid_events = {"subscribed"; "unsubscribed"; "error"; "item"; "retract"; "purge"; "delete"}

local function subscription_added(item_event)
	local item = item_event.item;
	assert(item.service, "pubsub subscription item MUST have a 'service' field.");
	assert(item.node, "pubsub subscription item MUST have a 'node' field.");

	local already_subscibed = false;
	for _ in active_subscriptions:iter(item.service, item.node, nil) do -- luacheck: ignore 512
		already_subscibed = true;
		break
	end

	item._id = uuid.generate();
	local iq_id = uuid.generate();
	pending_subscription:set(iq_id, item._id);
	active_subscriptions:set(item.service, item.node, item._id, item);

	if not already_subscibed then
		module:send(st.iq({ type = "set", id = iq_id, from = module.host, to = item.service })
			:tag("pubsub", { xmlns = xmlns_pubsub })
				:tag("subscribe", { jid = module.host, node = item.node }));
	end
end

for _, event_name in ipairs(valid_events) do
	module:hook("pubsub-event/host/"..event_name, function (event)
		for _, _, _, _, cb in active_subscriptions:iter(event.service, event.node, nil, "on_"..event_name) do
			pcall(cb, event);
		end
	end);
end

module:hook("iq/host", function (event)
	local stanza = event.stanza;
	local service = stanza.attr.from;

	if not stanza.attr.id then return end -- shouldn't be possible

	local subscribed_node = pending_subscription:get(stanza.attr.id);
	pending_subscription:set(stanza.attr.id, nil);
	local unsubscribed_node = pending_unsubscription:get(stanza.attr.id);
	pending_unsubscription:set(stanza.attr.id, nil);

	if stanza.attr.type == "result" then
		local pubsub_wrapper = stanza:get_child("pubsub", xmlns_pubsub);
		local subscription = pubsub_wrapper and pubsub_wrapper:get_child("subscription");
		if not subscription then return end
		local node = subscription.attr.node;

		local what;
		if subscription.attr.subscription == "subscribed" then
			what = "on_subscribed";
		elseif subscription.attr.subscription == "none" then
			what = "on_unsubscribed";
		end
		if not what then return end -- there are other states but we don't handle them
		for _, _, _, _, cb in active_subscriptions:iter(service, node, nil, what) do
			cb(event);
		end
		return true;

	elseif stanza.attr.type == "error" then
		local node = subscribed_node or unsubscribed_node;
		local error_type, error_condition, reason, pubsub_error = stanza:get_error();
		local err = { type = error_type, condition = error_condition, text = reason, extra = pubsub_error };
		if active_subscriptions:get(service) then
			for _, _, _, _, cb in active_subscriptions:iter(service, node, nil, "on_error") do
				cb(err);
			end
			return true;
		end
	end
end, 1);

local function subscription_removed(item_event)
	local item = item_event.item;
	active_subscriptions:set(item.service, item.node, item._id, nil);
	local node_subs = active_subscriptions:get(item.service, item.node);
	if node_subs and next(node_subs) then return end

	local iq_id = uuid.generate();
	pending_unsubscription:set(iq_id, item._id);

	module:send(st.iq({ type = "set", id = iq_id, from = module.host, to = item.service })
		:tag("pubsub", { xmlns = xmlns_pubsub })
			:tag("unsubscribe", { jid = module.host, node = item.node }))
end

module:handle_items("pubsub-subscription", subscription_added, subscription_removed, true);

module:hook("message/host", function(event)
	local origin, stanza = event.origin, event.stanza;
	local ret = nil;
	local service = stanza.attr.from;
	module:log("debug", "Got message/host: %s", stanza:top_tag());
	for event_container in stanza:childtags("event", xmlns_pubsub_event) do
		for pubsub_event in event_container:childtags() do
			module:log("debug", "Got pubsub event %s", pubsub_event:top_tag());
			local node = pubsub_event.attr.node;
			module:fire_event("pubsub-event/host/"..pubsub_event.name, {
					stanza = stanza;
					origin = origin;
					event = pubsub_event;
					service = service;
					node = node;
				});
			ret = true;
		end
	end
	return ret;
end);

module:hook("pubsub-event/host/items", function (event)
	for item in event.event:childtags() do
		module:log("debug", "Got pubsub item event %s", item:top_tag());
		event.item = item;
		event.payload = item.tags[1];
		module:fire_event("pubsub-event/host/"..item.name, event);
	end
end);