plugins/rtbl_guard.lua

local jid_bare = require "prosody.util.jid".bare;

local jid_prep = require "prosody.util.jid".prep;

local sha256 = require "prosody.util.hashes".sha256;

local function get_ban_reason(blocklist, entry)

	local msg = { ("Banned by %s"):format(blocklist.name or "RTBL"), nil, nil };

	local reason = entry.reason:match("^urn:xmpp:reporting:(%w+)$");

	if reason then

		msg[2] = "for "..reason;

	end

	if entry.text then

		msg[#msg+1] = "("..entry.text..")";

	end

	return table.concat(msg, " ");

end

function riddim.plugins.rtbl_guard(bot)

	bot.stream:add_plugin("pubsub");

	local config = bot.config.rtbl_guard;

	if not config then return; end

	-- {

	--   [rtbl_name] = {

	--     entries = {

	--       [jid/hash] = {

	--         reason = <string>

	--         text = <string>

	--       }

	--     }

	--   }

	local blocklists = {};

	local function check_blocklists(jid, only_blocklist, only_entry_id)

		jid = jid_bare(jid_prep(jid));

		local hash = sha256(jid, true);

		if only_blocklist and only_entry_id then

			if only_entry_id ~= jid and only_entry_id ~= hash then

				bot.stream:debug("No match for single entry %q == (%q | %q)", only_entry_id, jid, hash)

				return;

			end

			return only_blocklist.entries[only_entry_id], only_blocklist;

		end

		for rtbl_id, blocklist in pairs(only_blocklist and {only_blocklist} or blocklists) do

			bot.stream:debug("Checking %s for (%q | %q)", rtbl_id, jid, hash);

			for k in pairs(blocklist.entries) do

				bot.stream:debug("[%q]", k);

			end

			local entry = blocklist.entries[hash] or blocklist.entries[jid];

			if entry then

				return entry, blocklist;

			end

		end

	end

	local function guard_room(room)

		local function process_occupant(occupant, only_blocklist, only_entry_id)

			if not occupant.real_jid then

				bot.stream:debug("Unable to determine real JID for %s - skipping RTBL checks", occupant.nick);

				return;

			end

			local matched_entry, matched_blocklist = check_blocklists(occupant.real_jid, only_blocklist, only_entry_id);

			if not matched_entry then

				bot.stream:debug("%s is not on any RTBLs", occupant.nick);

				return;

			end

			room:ban(occupant.nick, get_ban_reason(matched_blocklist, matched_entry));

		end

		-- Check future occupants when they join

		room:hook("occupant-joined", process_occupant);

		local function process_all_occupants(blocklist, entry_id)

			bot.stream:debug("Checking all occupants of %s against RTBL (%s)", room.jid, entry_id or "all entries");

			for _, occupant in pairs(room.occupants) do

				process_occupant(occupant, blocklist, entry_id);

			end

		end

		-- Check existing occupants against all existing entries

		process_all_occupants();

		-- Check existing occupants when new entries are added

		room:hook("rtbl-entry-added", function (event)

			process_all_occupants(event.blocklist, event.entry_id);

		end);

		room:hook("rtbl-updated", function (event)

			process_all_occupants(event.blocklist);

		end);

	end

	local function handle_entry(blocklist, item)

		local report = item:get_child("report", "urn:xmpp:reporting:1");

		if not report then return; end

		blocklist.entries[item.attr.id] = {

			reason = report.attr.reason;

			text = report:get_child_text("text");

		};

		return blocklist.entries[item.attr.id];

	end

	local function clear_entry(blocklist, retract)

		local cleared_entry = blocklist.entries[retract.attr.id];

		if not cleared_entry then

			return;

		end

		blocklist.entries[retract.attr.id] = nil;

		return cleared_entry;

	end

	bot.stream:hook("pubsub/event", function (event)

		local blocklist_id = event.from.."::"..event.node;

		local blocklist = blocklists[blocklist_id];

		if not blocklist then return; end

		local entry = handle_entry(blocklist, event.item);

		for _, room in pairs(bot.rooms) do

			room:event("rtbl-entry-added", {

				blocklist = blocklist;

				entry = entry;

				entry_id = event.item.attr.id;

			});

		end

	end);

	-- COMPAT: current verse does not emit an event for retraction

	bot.stream:hook("message", function (message)

		local m_from = message.attr.from;

		for pubsub_event in message:childtags("event", "http://jabber.org/protocol/pubsub#event") do

			local items = pubsub_event:get_child("items");

			if items then

				local node = items.attr.node;

				local blocklist_id = m_from.."::"..node;

				local blocklist = blocklists[blocklist_id];

				if not blocklist then return; end

				for retract in items:childtags("retract") do

					local entry = clear_entry(blocklist, retract);

					if entry then

						for _, room in pairs(bot.rooms) do

							room:event("rtbl-entry-removed", {

								blocklist = blocklist;

								entry = entry;

							});

						end

					end

				end

			end

		end

	end);

	bot:hook("started", function ()

		for _, rtbl_config in ipairs(config) do

			local host, node = rtbl_config.host, rtbl_config.node;

			if host and node then

				bot.stream.pubsub(host, node):subscribe(nil, nil, function (response)

					if response.attr.type ~= "result" then

						bot.stream:warn("Failed to subscribe to RTBL %s::%s", host, node);

						return;

					end

					bot.stream:info("Subscribed to RTBL %s::%s", host, node);

					local blocklist = { name = rtbl_config.name, entries = {} };

					bot.stream.pubsub(host, node):items(true, function (items_response)

						if items_response.attr.type ~= "result" then

							bot.stream:warn("Failed to synchronize with RTBL: %s", tostring(items_response));

							return;

						end

						local items = items_response.tags[1].tags[1];

						bot.stream:debug("RTBL sync: %s", items);

						for item in items:childtags("item") do

							bot.stream:debug("RTBL item: %s", item);

							handle_entry(blocklist, item);

						end

						for _, room in pairs(bot.rooms) do

							room:event("rtbl-updated", {

								blocklist = blocklist;

							});

						end

					end);

					local blocklist_id = host.."::"..node;

					blocklists[blocklist_id] = blocklist;

				end);

			end

		end

		for _, room in pairs(bot.rooms) do

			guard_room(room);

		end

		bot:hook("groupchat/joined", guard_room);

	end);

end