view mod_pubsub_hub/mod_pubsub_hub.lua @ 5256:44f7edd4f845

mod_http_oauth2: Reject non-local hosts in more code paths We're not issuing tokens for users on remote hosts, we can't even authenticate them since they're remote. Thus the host is always the local module.host so no need to pass around the host in most cases or use it for anything but enforcing the same host.
author Kim Alvefur <zash@zash.se>
date Thu, 16 Mar 2023 17:52:10 +0100
parents 4cec8b7aed6d
children
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-- Copyright (C) 2011 - 2012 Kim Alvefur
--
-- This file is MIT/X11 licensed.

local http = require "net.http";
local formdecode = http.formdecode;
local formencode = http.formencode;
local http_request = http.request;
local uuid = require "util.uuid".generate;
local hmac_sha1 = require "util.hmac".sha1;
local json_encode = require "util.json".encode;
local time = os.time;
local m_min, m_max = math.min, math.max;
local tostring = tostring;

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

local max_lease, min_lease, default_lease = 86400, 600, 3600;

module:depends"pubsub";

local valid_modes = { ["subscribe"] = true, ["unsubscribe"] = true, }

local function do_subscribe(subscription)
	-- FIXME handle other states
	if subscription.state == "subscribed" then
		local ok, err = hosts[module.host].modules.pubsub.service:add_subscription(subscription.topic, true, module.host);
		module:log(ok and "debug" or "error", "add_subscription() => %s, %s", tostring(ok), tostring(err));
	end
end

local function handle_request(event)
	local request, response = event.request, event.response;
	local method, body = request.method, request.body;

	local query = request.url.query or {};
	if query and type(query) == "string" then
		query = formdecode(query);
	end
	if body and request.headers.content_type == "application/x-www-form-urlencoded" then
		body = formdecode(body);
	end

	if method == "POST" then
		-- Subscription request
		if body["hub.callback"] and body["hub.mode"] and valid_modes[body["hub.mode"]]
			and body["hub.topic"] and body["hub.verify"] then

			-- http://pubsubhubbub.googlecode.com/svn/trunk/pubsubhubbub-core-0.3.html#anchor5
			local callback = body["hub.callback"];
			local mode = body["hub.mode"];
			local topic = body["hub.topic"];
			local lease_seconds = m_max(min_lease, m_min(tonumber(body["hub.lease_seconds"]) or default_lease, max_lease));
			local secret = body["hub.secret"];
			local verify_token = body["hub.verify_token"];

			module:log("debug", "topic is "..(type(topic)=="string" and "%q" or "%s"), tostring(topic));

			if not subs_by_topic[topic] then
				subs_by_topic[topic] = {};
			end
			local subscription = subs_by_topic[topic][callback];

			local verify_modes = {};
			for i=1,#body do
				if body[i].name == "hub.verify" then
					verify_modes[body[i].value] = true;
				end
			end

			subscription = subscription or {
				id = uuid(),
				callback = callback,
				topic = topic,
				state = "unsubscribed",
				secret = secret,
				want_state = mode,
			};
			subscription.lease_seconds = lease_seconds;
			subscription.expires = time() + lease_seconds;
			subs_by_topic[topic][callback] = subscription;
			local challenge = uuid();

			local callback_url = callback .. (callback:match("%?") and "&" or "?") .. formencode{
				["hub.mode"] = mode,
				["hub.topic"] = topic,
				["hub.challenge"] = challenge,
				["hub.lease_seconds"] = tostring(lease_seconds),
				["hub.verify_token"] = verify_token, -- COMPAT draft version 0.3
			}
			module:log("debug", "Sending async verification request to %s for %s", tostring(callback_url), tostring(subscription));
			http_request(callback_url, nil, function(body, code)
				if body == challenge and code > 199 and code < 300 then
					if not subscription.want_state then
						module:log("warn", "Verification of already verified request, probably");
						return;
					end
					subscription.state = subscription.want_state .. "d";
					subscription.want_state = nil;
					module:log("debug", "calling do_subscribe()");
					do_subscribe(subscription);
					subs_by_topic[topic][callback] = subscription;
				else
					module:log("warn", "status %d and body was %q", tostring(code), tostring(body));
					subs_by_topic[topic][callback] = subscription;
				end
			end)
			return 202;
		else
			response.status = 400;
			response.headers.content_type = "text/html";
			return "<h1>Bad Request</h1>\n<a href='http://pubsubhubbub.googlecode.com/svn/trunk/pubsubhubbub-core-0.3.html#anchor5'>Missing required parameter(s)</a>\n"
		end
	end
end

local function periodic(now)
	local next_check = now + max_lease;
	local purge = false;
	for topic, callbacks in pairs(subs_by_topic) do
		for callback, subscription in pairs(callbacks) do
			if subscription.mode == "subscribed" then
				if subscription.expires < now then
					-- Subscription has expired, drop it.
					purge = true;
				else
					next_check = m_min(next_check, subscription.expires);
				end
			end
		end
		if purge then
			local new_callbacks = {};
			for callback, subscription in pairs(callbacks) do
				if (subscription.state == "subscribed" and subscription.expires < now)
					and subscription.want_state ~= "remove" then
					new_callbacks[callback] = subscription;
				end
			end
			subs_by_topic[topic] = new_callbacks;
			purge = false;
		end
	end
	return m_max((now - next_check) - min_lease, min_lease);
end

local xmlns_atom = "http://www.w3.org/2005/Atom";
local st = require "util.stanza";

local function on_notify(subscription, content)
	if content.attr and content.attr.xmlns == xmlns_atom then
		-- COMPAT This is required by the PubSubHubbub spec.
		content = st.stanza("feed", {xmlns=xmlns_atom}):add_child(content);
	end
	local body = tostring(content);
	local headers = {
		["Content-Type"] = "application/atom+xml",
	};
	if subscription.secret then
		headers["X-Hub-Signature"] = "sha1="..hmac_sha1(subscription.secret, body, true);
	end
	http_request(subscription.callback, { method = "POST", body = body, headers = headers }, function(body, code)
		if code >= 200 and code <= 299 then
			module:log("debug", "Delivered");
		else
			module:log("warn", "Got status code %d on delivery to %s", tonumber(code) or -1, tostring(subscription.callback));
			-- TODO Retry
			-- ... but the spec says that you should not retry, wtf?
		end
	end);
end

module:hook("message/host", function(event)
	local stanza = event.stanza;
	if stanza.attr.from ~= module.host then return end;

	for pubsub_event in stanza:childtags("event", xmlns_pubsub_event) do
		local items = pubsub_event:get_child("items");
		local node = items.attr.node;
		if items and node and subs_by_topic[node] then
			for item in items:childtags("item") do
				local content = item.tags[1];
				for callback, subscription in pairs(subs_by_topic[node]) do
					on_notify(subscription, content)
				end
			end
		end
	end
	return true;
end, 10);

module:depends"http";
module:provides("http", {
	default_path = "/hub";
	route = {
		POST = handle_request;
		GET = function()
			return json_encode(subs_by_topic);
		end;
		["GET /topic/*"] = function(event, path)
			return json_encode(subs_by_topic[path])
		end;
	};
});

module:add_timer(1, periodic);