view mod_ogp/mod_ogp.lua @ 5186:fa3059e653fa

mod_http_oauth2: Implement the Implicit flow Everyone says this is insecure and bad, but it's also the only thing that makes sense for e.g. pure JavaScript clients, but hey implement this even more complicated thing instead!
author Kim Alvefur <zash@zash.se>
date Thu, 02 Mar 2023 22:06:50 +0100
parents 09f0911c735d
children
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local mod_muc = module:depends("muc")
local http = require "net.http"
local st = require "util.stanza"
local url_pattern = [[https?://%S+]]
local domain_pattern = '^%w+://([^/]+)'
local xmlns_fasten = "urn:xmpp:fasten:0"
local xmlns_xhtml = "http://www.w3.org/1999/xhtml"
local allowlist = module:get_option_set("ogp_domain_allowlist", module:get_option_set("ogp_domain_whitelist", {}))
local denylist = module:get_option_set("ogp_domain_denylist", {})


local function is_allowed(domain)
	if allowlist:empty() then
		return true
	end
	if allowlist:contains(domain) then
		return true
	end
	return false
end

local function is_denied(domain)
	if denylist:empty() then
		return false
	end
	if denylist:contains(domain) then
		return true
	end
	return false
end


local function fetch_ogp_data(room, url, origin_id)
	if not url then
		return;
	end

	local domain = url:match(domain_pattern);
	if is_denied(domain) or not is_allowed(domain) then
		return;
	end

	http.request(
		url,
		nil,
		function(response_body, response_code, _)
			if response_code ~= 200 then
				module:log("debug", "Call to %s returned code %s and body %s", url, response_code, response_body)
				return
			end

			local to = room.jid
			local from = room and room.jid or module.host
			local fastening = st.message({to = to, from = from, type = 'groupchat'}):tag("apply-to", {xmlns = xmlns_fasten, id = origin_id})
			local found_metadata = false
			local message_body = ""

			local meta_pattern = [[<meta (.-)/?>]]
			for match in response_body:gmatch(meta_pattern) do
				local property = match:match([[property=%s*["']?(og:.-)["']?%s]])
				if not property then
					property = match:match([[property=["']?(og:.-)["']$]])
				end

				local content = match:match([[content=%s*["'](.-)["']%s]])
				if not content then
					content = match:match([[content=["']?(.-)["']$]])
				end
				if not content then
					content = match:match([[content=(.-) property]])
				end
				if not content then
					content = match:match([[content=(.-)$]])
				end

				if property and content then
					module:log("debug", property .. "\t" .. content)
					fastening:tag(
						"meta",
						{
							xmlns = xmlns_xhtml,
							property = property,
							content = content
						}
					):up()
					found_metadata = true
					message_body = message_body .. property .. "\t" .. content .. "\n"
				end
			end

			if found_metadata then
				mod_muc.get_room_from_jid(room.jid):broadcast_message(fastening)
			end
			module:log("debug", tostring(fastening))
		end
	)
end

local function ogp_handler(event)
	local room, stanza = event.room, st.clone(event.stanza)
	local body = stanza:get_child_text("body")

	if not body then return; end

	local origin_id = stanza:find("{urn:xmpp:sid:0}origin-id@id")
	if not origin_id then return; end

	for url in body:gmatch(url_pattern) do
		fetch_ogp_data(room, url, origin_id);
	end
end

module:hook("muc-occupant-groupchat", ogp_handler)


module:hook("muc-message-is-historic", function (event)
	local fastening = event.stanza:get_child('apply-to', xmlns_fasten)
	if fastening and fastening:get_child('meta', xmlns_xhtml) then
		return true
	end
end);