-- Prosody IM

-- Copyright (C) 2008-2012 Matthew Wild

-- Copyright (C) 2008-2012 Waqas Hussain

--

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

module:set_global();

pcall(function ()

	module:depends("http_errors");

end);

local portmanager = require "core.portmanager";

local moduleapi = require "core.moduleapi";

local url_parse = require "socket.url".parse;

local url_build = require "socket.url".build;

local normalize_path = require "util.http".normalize_path;

local set = require "util.set";

local ip_util = require "util.ip";

local new_ip = ip_util.new_ip;

local match_ip = ip_util.match;

local parse_cidr = ip_util.parse_cidr;

local server = require "net.http.server";

server.set_default_host(module:get_option_string("http_default_host"));

server.set_option("body_size_limit", module:get_option_number("http_max_content_size"));

server.set_option("buffer_size_limit", module:get_option_number("http_max_buffer_size"));

-- CORS settings

local opt_methods = module:get_option_set("access_control_allow_methods", { "GET", "OPTIONS" });

local opt_headers = module:get_option_set("access_control_allow_headers", { "Content-Type" });

local opt_credentials = module:get_option_boolean("access_control_allow_credentials", false);

local opt_max_age = module:get_option_number("access_control_max_age", 2 * 60 * 60);

local function get_http_event(host, app_path, key)

	local method, path = key:match("^(%S+)%s+(.+)$");

	if not method then -- No path specified, default to "" (base path)

		method, path = key, "";

	end

	if method:sub(1,1) == "/" then

		return nil;

	end

	if app_path == "/" and path:sub(1,1) == "/" then

		app_path = "";

	end

	if host == "*" then

		return method:upper().." "..app_path..path;

	else

		return method:upper().." "..host..app_path..path;

	end

end

local function get_base_path(host_module, app_name, default_app_path)

	return (normalize_path(host_module:get_option("http_paths", {})[app_name] -- Host

		or module:get_option("http_paths", {})[app_name] -- Global

		or default_app_path)) -- Default

		:gsub("%$(%w+)", { host = host_module.host });

end

local function redir_handler(event)

	event.response.headers.location = event.request.path.."/";

	if event.request.url.query then

		event.response.headers.location = event.response.headers.location .. "?" .. event.request.url.query

	end

	return 301;

end

local ports_by_scheme = { http = 80, https = 443, };

-- Helper to deduce a module's external URL

function moduleapi.http_url(module, app_name, default_path)

	app_name = app_name or (module.name:gsub("^http_", ""));

	local external_url = url_parse(module:get_option_string("http_external_url")) or {};

	if external_url.scheme and external_url.port == nil then

		external_url.port = ports_by_scheme[external_url.scheme];

	end

	local services = portmanager.get_active_services();

	local http_services = services:get("https") or services:get("http") or {};

	for interface, ports in pairs(http_services) do -- luacheck: ignore 213/interface

		for port, service in pairs(ports) do -- luacheck: ignore 512

			local url = {

				scheme = (external_url.scheme or service[1].service.name);

				host = (external_url.host or module:get_option_string("http_host", module.host));

				port = tonumber(external_url.port) or port or 80;

				path = normalize_path(external_url.path or "/", true)..

					(get_base_path(module, app_name, default_path or "/"..app_name):sub(2));

			}

			if ports_by_scheme[url.scheme] == url.port then url.port = nil end

			return url_build(url);

		end

	end

	if prosody.process_type == "prosody" then

		module:log("warn", "No http ports enabled, can't generate an external URL");

	end

	return "http://disabled.invalid/";

end

local function apply_cors_headers(response, methods, headers, max_age, allow_credentials, origin)

	response.headers.access_control_allow_methods = tostring(methods);

	response.headers.access_control_allow_headers = tostring(headers);

	response.headers.access_control_max_age = tostring(max_age)

	response.headers.access_control_allow_origin = origin or "*";

	if allow_credentials then

		response.headers.access_control_allow_credentials = "true";

	end

end

function module.add_host(module)

	local host = module.host;

	if host ~= "*" then

		host = module:get_option_string("http_host", host);

	end

	local apps = {};

	module.environment.apps = apps;

	local function http_app_added(event)

		local app_name = event.item.name;

		local default_app_path = event.item.default_path or "/"..app_name;

		local app_path = get_base_path(module, app_name, default_app_path);

		if not app_name then

			-- TODO: Link to docs

			module:log("error", "HTTP app has no 'name', add one or use module:provides('http', app)");

			return;

		end

		apps[app_name] = apps[app_name] or {};

		local app_handlers = apps[app_name];

		local app_methods = opt_methods;

		local app_headers = opt_headers;

		local app_credentials = opt_credentials;

		local function cors_handler(event_data)

			local request, response = event_data.request, event_data.response;

			apply_cors_headers(response, app_methods, app_headers, opt_max_age, app_credentials, request.headers.origin);

		end

		local function options_handler(event_data)

			cors_handler(event_data);

			return "";

		end

		if event.item.cors then

			local cors = event.item.cors;

			if cors.credentials ~= nil then

				app_credentials = cors.credentials;

			end

			if cors.headers then

				for header, enable in pairs(cors.headers) do

					if enable and not app_headers:contains(header) then

						app_headers = app_headers + set.new { header };

					elseif not enable and app_headers:contains(header) then

						app_headers = app_headers - set.new { header };

					end

				end

			end

		end

		local streaming = event.item.streaming_uploads;

		if not event.item.route then

			-- TODO: Link to docs

			module:log("error", "HTTP app %q provides no 'route', add one to handle HTTP requests", app_name);

			return;

		end

		for key, handler in pairs(event.item.route) do

			local event_name = get_http_event(host, app_path, key);

			if event_name then

				local method = event_name:match("^%S+");

				if not app_methods:contains(method) then

					app_methods = app_methods + set.new{ method };

				end

				local options_event_name = event_name:gsub("^%S+", "OPTIONS");

				if type(handler) ~= "function" then

					local data = handler;

					handler = function () return data; end

				elseif event_name:sub(-2, -1) == "/*" then

					local base_path_len = #event_name:match("/.+$");

					local _handler = handler;

					handler = function (_event)

						local path = _event.request.path:sub(base_path_len);

						return _handler(_event, path);

					end;

					module:hook_object_event(server, event_name:sub(1, -3), redir_handler, -1);

				elseif event_name:sub(-1, -1) == "/" then

					module:hook_object_event(server, event_name:sub(1, -2), redir_handler, -1);

				end

				if not streaming then

					-- COMPAT Modules not compatible with streaming uploads behave as before.

					local _handler = handler;

					function handler(event) -- luacheck: ignore 432/event

						if event.request.body ~= false then

							return _handler(event);

						end

					end

				end

				if not app_handlers[event_name] then

					app_handlers[event_name] = {

						main = handler;

						cors = cors_handler;

						options = options_handler;

					};

					module:hook_object_event(server, event_name, handler);

					module:hook_object_event(server, event_name, cors_handler, 1);

					module:hook_object_event(server, options_event_name, options_handler, -1);

				else

					module:log("warn", "App %s added handler twice for '%s', ignoring", app_name, event_name);

				end

			else

				module:log("error", "Invalid route in %s, %q. See https://prosody.im/doc/developers/http#routes", app_name, key);

			end

		end

		local services = portmanager.get_active_services();

		if services:get("https") or services:get("http") then

			module:log("info", "Serving '%s' at %s", app_name, module:http_url(app_name, app_path));

		elseif prosody.process_type == "prosody" then

			module:log("warn", "Not listening on any ports, '%s' will be unreachable", app_name);

		end

	end

	local function http_app_removed(event)

		local app_handlers = apps[event.item.name];

		apps[event.item.name] = nil;

		for event_name, handlers in pairs(app_handlers) do

			module:unhook_object_event(server, event_name, handlers.main);

			module:unhook_object_event(server, event_name, handlers.cors);

			if event_name:sub(-2, -1) == "/*" then

				module:unhook_object_event(server, event_name:sub(1, -3), redir_handler, -1);

			elseif event_name:sub(-1, -1) == "/" then

				module:unhook_object_event(server, event_name:sub(1, -2), redir_handler, -1);

			end

			local options_event_name = event_name:gsub("^%S+", "OPTIONS");

			module:unhook_object_event(server, options_event_name, handlers.options);

		end

	end

	module:handle_items("http-provider", http_app_added, http_app_removed);

	if host ~= "*" then

		server.add_host(host);

		function module.unload()

			server.remove_host(host);

		end

	end

end

module.add_host(module); -- set up handling on global context too

local trusted_proxies = module:get_option_set("trusted_proxies", { "127.0.0.1", "::1" })._items;

local function is_trusted_proxy(ip)

	if trusted_proxies[ip] then

		return true;

	end

	local parsed_ip = new_ip(ip)

	for trusted_proxy in trusted_proxies do

		if match_ip(parsed_ip, parse_cidr(trusted_proxy)) then

			return true;

		end

	end

	return false

end

local function get_forwarded_connection_info(request) --> ip:string, secure:boolean

	local ip = request.ip;

	local secure = request.secure; -- set by net.http.server

	local forwarded_for = request.headers.x_forwarded_for;

	if forwarded_for then

		-- luacheck: ignore 631

		-- This logic looks weird at first, but it makes sense.

		-- The for loop will take the last non-trusted-proxy IP from `forwarded_for`.

		-- We append the original request IP to the header. Then, since the last IP wins, there are two cases:

		-- Case a) The original request IP is *not* in trusted proxies, in which case the X-Forwarded-For header will, effectively, be ineffective; the original request IP will win because it overrides any other IP in the header.

		-- Case b) The original request IP is in trusted proxies. In that case, the if branch in the for loop will skip the last IP, causing it to be ignored. The second-to-last IP will be taken instead.

		-- Case c) If the second-to-last IP is also a trusted proxy, it will also be ignored, iteratively, up to the last IP which isn’t in trusted proxies.

		-- Case d) If all IPs are in trusted proxies, something went obviously wrong and the logic never overwrites `ip`, leaving it at the original request IP.

		forwarded_for = forwarded_for..", "..ip;

		for forwarded_ip in forwarded_for:gmatch("[^%s,]+") do

			if not is_trusted_proxy(forwarded_ip) then

				ip = forwarded_ip;

			end

		end

	end

	secure = secure or request.headers.x_forwarded_proto == "https";

	return ip, secure;

end

module:wrap_object_event(server._events, false, function (handlers, event_name, event_data)

	local request = event_data.request;

	if request and is_trusted_proxy(request.ip) then

		-- Not included in eg http-error events

		request.ip, request.secure = get_forwarded_connection_info(request);

	end

	return handlers(event_name, event_data);

end);

module:provides("net", {

	name = "http";

	listener = server.listener;

	default_port = 5280;

	multiplex = {

		pattern = "^[A-Z]";

	};

});

module:provides("net", {

	name = "https";

	listener = server.listener;

	default_port = 5281;

	encryption = "ssl";

	multiplex = {

		protocol = "http/1.1";

		pattern = "^[A-Z]";

	};

});