File

mod_devices/mod_devices.lua @ 4282:281a864e7472

mod_pubsub_feeds: Don't skip publishing items after an existing one I encountered a feed which was backwards, such that older entries were considered first and then it would skip newer entries. This may however run into trouble if the feed contains more items than what's persisted in pubsub.
author Kim Alvefur <zash@zash.se>
date Mon, 30 Nov 2020 15:17:29 +0100
parent 3397:4cf65afd90f4
line wrap: on
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local it = require "util.iterators";
local new_id = require "util.id".medium;

local max_user_devices = module:get_option_number("max_user_devices", 5);

local device_store = module:open_store("devices");
local device_map_store = module:open_store("devices", "map");

--- Helper functions

local function _compare_device_timestamps(a, b)
	return (a.last_activity_at or 0) < (b.last_activity_at or 0);
end
local function sorted_devices(devices)
	return it.sorted_pairs(devices, _compare_device_timestamps);
end

local function new_device(username, alt_ids)
	local current_time = os.time();
	local device = {
		id = "dv-"..new_id();
		created_at = current_time;
		last_activity = "created";
		last_activity_at = current_time;
		alt_ids = alt_ids or {};
	};

	local devices = device_store:get(username);
	if not devices then
		devices = {};
	end
	devices[device.id] = device;
	local devices_ordered = {};
	for id in sorted_devices(devices) do
		table.insert(devices_ordered, id);
	end
	if #devices_ordered > max_user_devices then
		-- Iterate through oldest devices that are above limit, backwards
		for i = #devices_ordered, max_user_devices+1, -1 do
			local id = table.remove(devices_ordered, i);
			devices[id] = nil;
			module:log("debug", "Removing old device for %s: %s", username, id);
		end
	end
	device_store:set(username, devices);
	return device;
end

local function get_device_with_alt_id(username, alt_id_type, alt_id)
	local devices = device_store:get(username);
	if not devices then
		return nil;
	end

	for _, device in pairs(devices) do
		if device.alt_ids[alt_id_type] == alt_id then
			return device;
		end
	end
end

local function set_device_alt_id(username, device_id, alt_id_type, alt_id)
	local devices = device_store:get(username);
	if not devices or not devices[device_id] then
		return nil, "no such device";
	end
	devices[device_id].alt_ids[alt_id_type] = alt_id;
end

local function record_device_state(username, device_id, activity, time)
	local device = device_map_store:get(username, device_id);
	device.last_activity = activity;
	device.last_activity_at = time or os.time();
	device_map_store:set(username, device_id, device);
end

local function find_device(username, info)
	for _, alt_id_type in ipairs({ "resumption_token", "resource" }) do
		local alt_id = info[alt_id_type];
		if alt_id then
			local device = get_device_with_alt_id(username, alt_id_type, alt_id);
			if device then
				return device, alt_id_type;
			end
		end
	end
end

--- Information gathering

module:hook("pre-resource-bind", function (event)
	event.session.device_requested_resource = event.resource;
end, 1000);


local function store_resumption_token(session, stanza)
	session.device_requested_resume = stanza.attr.previd;
end
module:hook_stanza("urn:xmpp:sm:2", "resume", store_resumption_token, 5);
module:hook_stanza("urn:xmpp:sm:3", "resume", store_resumption_token, 5);

--- Identify device after resource bind

module:hook("resource-bind", function (event)
	local info = {
		resource = event.session.device_requested_resource;
		resumption_token = event.session.device_requested_resume;
	};
	local device, source = find_device(event.session.username, info);
	if device then
		event.session.log("debug", "Associated with device %s (from %s)", device.id, source);
		event.session.device_id = device.id;
	else
		device = new_device(event.session.username, info);
		event.session.log("debug", "Creating new device %s for session", device.id);
		event.session.device_id = device.id;
	end
	record_device_state(event.session.username, device.id, "login");
end, 1000);

module:hook("resource-unbind", function (event)
	if event.session.device_id then
		record_device_state(event.session.username, event.session.device_id, "logout");
	end
end);