plugins/pubsub2room.lua

--[[ pubsub2room
relays pubsub broadcasts to rooms

example conf:
pubsub2room = {
	["pubsub.prosody.im#commits"] = {
		room = "prosody@conference.prosody.im";
		template = "${author.name} committed: ${title}";
	};
};
--]]

local verse = require "verse";
local st = require "util.stanza";
local json = require "util.json";

-- FIXME Should this really be here?
local extractor_mt = {
	__index = function (t, k)
		local n;
		if k:match("^data%.") then
			k = k:gsub("^data.", "");
			n = t.data;
		else
			n = t.stanza;
		end
		for x in k:gmatch("[^.]+") do
			local m, a = x:match("^([^@]*)@(.*)$");
			if m and a then
				m = n:get_child(m);
				return m and m.attr[a] or nil;
			end
			n = n:get_child(x);
			if not n then return end
		end
		return n[1];
	end
};

local json_extractor_mt = {
	__index = function (t, k)
		if not k:find"%." then
			return nil;
		end
		for x in k:gmatch("[^.]+") do
			t = rawget(t, x) or rawget(t, tonumber(x));
			if t == nil then return end
		end
		if type(t) == "table" then
			return json.encode(t);
		end
		return tostring(t);
	end
};

local function new_extractor(stanza, data)
	if not stanza then return nil end
	if stanza.attr.xmlns == "urn:xmpp:json:0" then
		local payload = json.decode(stanza:get_text());
		if type(payload) == "table" then
			return setmetatable(payload, json_extractor_mt);
		end
	end
	return setmetatable({ stanza = stanza, data = data }, extractor_mt);
end

local last_message_time = 0;

function riddim.plugins.pubsub2room(bot)
	local bare_jid = require "util.jid".bare;
	bot.stream:add_plugin("pubsub");

	local config = bot.config.pubsub2room;
	bot.stream:hook("pubsub/event", function(event)
		local conf = config[event.from .. "#" .. event.node];
		if not conf then return end
		local room = bot.rooms[conf.room];
		local data = st.stanza("data"):tag("id"):text(event.item.attr.id);
		local entry = event.item and new_extractor(event.item.tags[1], data)

		if not conf or not entry or not room then return end
		local message = conf.template:gsub("%${([^}]+)}", entry);

		-- Throttle to 1 message/second so we don't flood the room
		if os.time() - last_message_time > 0 then
			room:send_message(message);
			last_message_time = os.time();
		else
			last_message_time = last_message_time + 1;
			verse.add_task(last_message_time - os.time(), function ()
				room:send_message(message);
			end);
		end
	end);

	-- FIXME When to unsubscribe?
	bot:hook("started", function()
		local jid = bare_jid(bot.stream.jid);
		for hostnode in pairs(config) do
			local host, node = hostnode:match("^([^#]+)#(.*)");
			bot.stream.pubsub(host, node):subscribe(jid);
		end
	end);
end