# HG changeset patch
# User Kim Alvefur <zash@zash.se>
# Date 1296441436 -3600
# Node ID 637dc0a040522afdf5d86b8b7ae5da2e7dcbb09d
# Parent  661f64627fedd0ef12e80771713abdcd47b39c9e
mod_pubsub_feed: Implement PubSubHubbub subscriber

diff -r 661f64627fed -r 637dc0a04052 mod_pubsub_feed/mod_pubsub_feed.lua
--- a/mod_pubsub_feed/mod_pubsub_feed.lua	Thu Jan 27 17:36:58 2011 +0100
+++ b/mod_pubsub_feed/mod_pubsub_feed.lua	Mon Jan 31 03:37:16 2011 +0100
@@ -1,5 +1,7 @@
 -- Fetches Atom feeds and publishes to PubSub nodes
 --
+-- Depends: http://code.matthewwild.co.uk/lua-feeds
+--
 -- Config:
 -- Component "pubsub.example.com" "pubsub"
 -- modules_enabled = {
@@ -9,37 +11,133 @@
 --   prosody_blog = "http://blog.prosody.im/feed/atom.xml";
 -- }
 -- feed_pull_interval = 20 -- minutes
+--
+-- Reference
+-- http://pubsubhubbub.googlecode.com/svn/trunk/pubsubhubbub-core-0.3.html
 
 local modules = hosts[module.host].modules;
 if not modules.pubsub then
+	--FIXME Should this throw an error() instead?
 	module:log("warn", "Pubsub needs to be loaded on this host");
 end
+
+
+local t_insert = table.insert;
 local add_task = require "util.timer".add_task;
 local date, time = os.date, os.time;
 local dt_parse, dt_datetime = require "util.datetime".parse, require "util.datetime".datetime;
 local http = require "net.http";
 local parse_feed = require "feeds".feed_from_string;
 local st = require "util.stanza";
+local httpserver = require "net.httpserver";
+local formencode = require "net.http".formencode;
+local dump = require "util.serialization".serialize;
+
+local urldecode = require "net.http".urldecode;
+local urlencode = require "net.http".urlencode;
+local urlparams = --require "net.http".getQueryParams or whatever MattJ names it, FIXME
+function(s)
+	if not s:match("=") then return urldecode(s); end
+	local r = {}
+	s:gsub("([^=&]*)=([^&]*)", function(k,v)
+		r[ urldecode(k) ] = urldecode(v);
+		return nil
+	end)
+	return r
+end;
 
 local config = module:get_option("feeds") or {
 	planet_jabber = "http://planet.jabber.org/atom.xml";
 	prosody_blog = "http://blog.prosody.im/feed/atom.xml";
 };
-local refresh_interval = (module:get_option("feed_pull_interval") or 15) * 60;
+local refresh_interval = module:get_option_number("feed_pull_interval", 15) * 60;
+local use_pubsubhubub = module:get_option_boolean("use_pubsubhubub", true); -- HTTP by default or not?
 local feed_list = { }
 for node, url in pairs(config) do
-	feed_list[node] = { url = url };
+	feed_list[node] = { url = url; node = node; last_update = 0 };
+end
+
+local response_codes = {
+	["202"] = "Accepted";
+	["400"] = "Bad Request";
+	["501"] = "Not Implemented";
+};
+
+local function http_response(code, headers, body)
+	return {
+		status = (type(code) == "number" and code .. " " .. response_codes[tostring(code)]) or code;
+		headers = headers or {};
+		body = body or "<h1>" .. response_codes[tostring(code)] .. "</h1>\n";
+	};
 end
 
-local function update(item, callback)
+local actor = module.host.."/"..module.name;
+
+function update_entry(item)
+	local node = item.node;
+	--module:log("debug", "parsing %d bytes of data in node %s", #item.data or 0, node)
+	local feed = parse_feed(item.data);
+	module:log("debug", "updating node %s", node);
+	for _, entry in ipairs(feed) do
+		entry.attr.xmlns = "http://www.w3.org/2005/Atom";
+
+		local e_published = entry:get_child("published");
+		e_published = e_published and e_published:get_text();
+		e_published = e_published and dt_parse(e_published);
+		local e_updated = entry:get_child("updated");
+		e_updated = e_updated and e_updated:get_text();
+		e_updated = e_updated and dt_parse(e_updated);
+
+		local timestamp = e_updated or e_published or nil;
+		--module:log("debug", "timestamp is %s, item.last_update is %s", tostring(timestamp), tostring(item.last_update));
+		if not timestamp or not item.last_update or timestamp > item.last_update then
+			local id = entry:get_child("id");
+			id = id and id:get_text() or item.url.."#"..dt_datetime(timestamp); -- Missing id, so make one up
+			local xitem = st.stanza("item", { id = id }):add_child(entry);
+			-- TODO Put data from /feed into item/source
+
+			module:log("debug", "publishing to %s, id %s", node, id);
+			local ok, err = modules.pubsub.service:publish(node, actor, id, xitem);
+			if not ok then
+				if err == "item-not-found" then -- try again
+					module:log("debug", "got item-not-found, creating %s and trying again", node);
+					local ok, err = modules.pubsub.service:create(node, actor);
+					if not ok then
+						module:log("error", "could not create node %s: %s", node, err);
+						return;
+					end
+					local ok, err = modules.pubsub.service:publish(node, actor, id, xitem);
+					if not ok then
+						module:log("error", "could not create or publish node %s: %s", node, err);
+						return
+					end
+				else
+					module:log("error", "publishing %s failed: %s", node, err);
+				end
+			end
+		end
+	end
+	
+	if use_pubsubhubub and not item.subscription then
+		module:log("debug", "check if %s has a hub", item.node);
+		local hub = feed.links and feed.links.hub;
+		if hub then
+			item.hub = hub;
+			module:log("debug", "%s has a hub: %s", item.node, item.hub);
+			subscribe(item);
+		end
+	end
+end
+
+function fetch(item, callback) -- HTTP Pull
 	local headers = { };
 	if item.data and item.last_update then
 		headers["If-Modified-Since"] = date("!%a, %d %b %Y %T %Z", item.last_update);
 	end
-	http.request(item.url, {headers = headers}, function(data, code, req) 
+	http.request(item.url, { headers = headers }, function(data, code, req) 
 		if code == 200 then
 			item.data = data;
-			callback(item)
+			if callback then callback(item) end
 			item.last_update = time();
 		end
 		if code == 304 then
@@ -48,57 +146,93 @@
 	end);
 end
 
-local actor = module.host.."/"..module.name;
-
-local function refresh_feeds()
+function refresh_feeds()
+	--module:log("debug", "Refreshing feeds");
 	for node, item in pairs(feed_list) do
-		update(item, function(item)
-			local feed = parse_feed(item.data);
-			module:log("debug", "node: %s", node);
-			for _, entry in ipairs(feed) do
-				entry.attr.xmlns = "http://www.w3.org/2005/Atom";
-
-				local e_published = entry:get_child("published");
-				e_published = e_published and e_published[1];
-				e_published = e_published and dt_parse(e_published);
-				local e_updated = entry:get_child("updated");
-				e_updated = e_updated and e_updated[1];
-				e_updated = e_updated and dt_parse(e_updated);
-
-				local timestamp = e_updated or e_published or nil;
-				module:log("debug", "timestamp is %s, item.last_update is %s", tostring(timestamp), tostring(item.last_update));
-				if not timestamp or not item.last_update or timestamp > item.last_update then
-					local id = entry:get_child("id");
-					id = id[1] or item.url.."#"..dt_datetime(timestamp); -- Missing id, so make one up
-					local item = st.stanza("item", { id = id }):add_child(entry);
-
-					module:log("debug", "publishing to %s, id %s", node, id);
-					local ok, err = modules.pubsub.service:publish(node, actor, id, item);
-					if not ok then
-						if err == "item-not-found" then -- try again
-							module:log("debug", "got item-not-found, creating %s and trying again", node);
-							local ok, err = modules.pubsub.service:create(node, actor);
-							if not ok then
-								module:log("error", "could not create node: %s", err);
-								return;
-							end
-							local ok, err = modules.pubsub.service:publish(node, actor, id, item);
-							if not ok then
-								module:log("error", "still could not create node: %s", err);
-								return
-							end
-						else
-							module:log("error", "publish failed: %s", err);
-						end
-					end
-				end
-			end
-		end);
+		--FIXME Don't fetch feeds which have a subscription
+		-- Otoho, what if the subscription expires or breaks?
+		if item.last_update + refresh_interval < time() then 
+			module:log("debug", "checking %s", item.node);
+			fetch(item, update_entry);
+		end
 	end
 	return refresh_interval;
 end
 
+function subscribe(feed, challenge)
+	local _body, body = {
+		["hub.callback"] = "http://"..module.host..":5280/callback?node=" .. urlencode(feed.node); --FIXME figure out your own hostname reliably?
+		["hub.mode"] = "subscribe"; --TODO unsubscribe
+		["hub.topic"] = feed.url;
+		["hub.verify"] = "async";
+		["hub.verify_token"] = challenge;
+		--["hub.lease_seconds"] = "";
+	}, { };
+	for name, value in pairs(_body) do
+		t_insert(body, { name = name, value = value });
+	end --FIXME Why do I have to do this?
+	body = formencode(body);
+
+	--module:log("debug", "subscription request, body: %s", body);
+
+	--FIXME The subscription states and related stuff
+	--feed.subscription = challenge and "asked" or "asking";
+	feed.subscription = "asking";
+	http.request(feed.hub, { body = body }, function(data, code, req) 
+		local code = tostring(code);
+		module:log("debug", "subscription to %s submitted, staus %s", feed.node, code);
+		if code == '202' then
+			if challenge then
+				module:log("debug", "subscribe to %s confirmed", feed.node);
+				feed.subscription = "active";
+			else
+				module:log("debug", "subscription to %s submitted", feed.node);
+				--feed.subscription = "incomplete"; 
+			end
+		end
+	end);
+end
+
+function handle_http_request(method, body, request)
+	--module:log("debug", "%s request to %s%s with body %s", method, request.url.path, request.url.query and "?" .. request.url.query or "", #body > 0 and body or "empty");
+	local query = request.url.query;
+	if query and type(query) == "string" then
+		query = urlparams(query);
+		--module:log("debug", "GET data: %s", dump(query));
+	end
+
+	-- TODO http://pubsubhubbub.googlecode.com/svn/trunk/pubsubhubbub-core-0.3.html#authednotify
+
+	if method == "GET" then
+		if query.node and feed_list[query.node] then
+			local feed = feed_list[query.node];
+			local challenge = query["hub.challenge"];
+			if challenge and feed.subscription == "asking" then
+				module:log("debug", "got a challenge for %s: %s", feed.node, challenge);
+				subscribe(feed, challenge);
+				return http_response(202);
+			end
+		end
+		return http_response(400);
+	elseif method == "POST" then
+		if #body > 0 and feed_list[query.node] then
+			module:log("debug", "got %d bytes PuSHed for %s", #body, query.node);
+			local feed = feed_list[query.node];
+			feed.data = body;
+			update_entry(feed);
+			feed.last_update = time();
+			return http_response(202);
+		end
+		return http_response(400);
+	end
+	return http_response(501);
+end
+
 function init()
+	module:log("debug", "initiating", module.name);
+	if use_pubsubhubub then
+		httpserver.new{ port = 5280, base = "callback", handler = handle_http_request }
+	end
 	add_task(0, refresh_feeds);
 end
 
@@ -107,4 +241,3 @@
 else
 	prosody.events.add_handler("server-started", init);
 end
-