-- mod_http_upload

--

-- Copyright (C) 2015 Kim Alvefur

--

-- This file is MIT/X11 licensed.

--

-- Implementation of HTTP Upload file transfer mechanism used by Conversations

--

-- imports

local st = require"util.stanza";

local lfs = require"lfs";

local uuid = require"util.uuid".generate;

local url = require "socket.url";

local dataform = require "util.dataforms".new;

local datamanager = require "util.datamanager";

local t_concat = table.concat;

local t_insert = table.insert;

local s_upper = string.upper;

local function join_path(...)

	return table.concat({ ... }, package.config:sub(1,1));

end

-- config

local file_size_limit = module:get_option_number(module.name .. "_file_size_limit", 1024 * 1024); -- 1 MB

--- sanity

local parser_body_limit = module:context("*"):get_option_number("http_max_content_size", 10*1024*1024);

if file_size_limit > parser_body_limit then

	module:log("warn", "%s_file_size_limit exceeds HTTP parser limit on body size, capping file size to %d B", module.name, parser_body_limit);

	file_size_limit = parser_body_limit;

end

-- depends

module:depends("http");

module:depends("disco");

-- identity and feature advertising

module:add_identity("store", "file", module:get_option_string("name", "HTTP File Upload"));

module:add_extension(dataform {

	{ name = "max-file-size", type = "text-single" },

}:form({ ["max-file-size"] = tostring(file_size_limit) }, "result"));

-- state

local pending_slots = module:shared("upload_slots");

local storage_path = module:get_option_string(module.name .. "_path", join_path(prosody.paths.data, module.name));

lfs.mkdir(storage_path);

	-- local clients only

	if origin.type ~= "c2s" then

		module:log("debug", "Request for upload slot from a %s", origin.type);

		origin.send(st.error_reply(stanza, "cancel", "not-authorized"));

		return true;

	end

	-- validate

	if not filename or filename:find("/") then

		module:log("debug", "Filename %q not allowed", filename or "");

		origin.send(st.error_reply(stanza, "modify", "bad-request", "Invalid filename"));

		return true;

	end

	if not filesize then

		module:log("debug", "Missing file size");

		origin.send(st.error_reply(stanza, "modify", "bad-request", "Missing or invalid file size"));

		return true;

	elseif filesize > file_size_limit then

		module:log("debug", "File too large (%d > %d)", filesize, file_size_limit);

		origin.send(st.error_reply(stanza, "modify", "not-acceptable", "File too large")

				:tag("max-file-size"):text(tostring(file_size_limit)));

		return true;

	end

	local reply = st.reply(stanza);

	local random;

	repeat random = uuid();

	until lfs.mkdir(join_path(storage_path, random)) or not lfs.attributes(join_path(storage_path, random, filename))

	datamanager.list_append(origin.username, origin.host, module.name, { filename = join_path(storage_path, random, filename), size = filesize, time = os.time() });

	local slot = random.."/"..filename;

	pending_slots[slot] = origin.full_jid;

	local base_url = module:http_url();

	local slot_url = url.parse(base_url);

	slot_url.path = url.parse_path(slot_url.path or "/");

	t_insert(slot_url.path, random);

	t_insert(slot_url.path, filename);

	slot_url.path.is_directory = false;

	slot_url.path = url.build_path(slot_url.path);

	slot_url = url.build(slot_url);

	reply:tag("get"):text(slot_url):up();

	reply:tag("put"):text(slot_url):up();

	origin.send(reply);

	origin.log("debug", "Given upload slot %q", slot);

	return true;

end);

-- http service

local function upload_data(event, path)

	local uploader = pending_slots[path];

	if not uploader then

		module:log("warn", "Attempt to upload to unknown slot %q", path);

		return; -- 404

	end

	local random, filename = path:match("^([^/]+)/([^/]+)$");

	if not random then

		module:log("warn", "Invalid file path %q", path);

		return 400;

	end

	if #event.request.body > file_size_limit then

		module:log("warn", "Uploaded file too large %d bytes", #event.request.body);

		return 400;

	end

	pending_slots[path] = nil;

	local full_filename = join_path(storage_path, random, filename);

	if lfs.attributes(full_filename) then

		module:log("warn", "File %s exists already, not replacing it", full_filename);

		return 409;

	end

	local fh, ferr = io.open(full_filename, "w");

	if not fh then

		module:log("error", "Could not open file %s for upload: %s", full_filename, ferr);

		return 500;

	end

	local ok, err = fh:write(event.request.body);

	if not ok then

		module:log("error", "Could not write to file %s for upload: %s", full_filename, err);

		os.remove(full_filename);

		return 500;

	end

	ok, err = fh:close();

	if not ok then

		module:log("error", "Could not write to file %s for upload: %s", full_filename, err);

		os.remove(full_filename);

		return 500;

	end

	module:log("info", "File uploaded by %s to slot %s", uploader, random);

	return 201;

end

-- FIXME Duplicated from net.http.server

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

local headerfix = setmetatable({}, {

	__index = function(t, k)

		local v = "\r\n"..k:gsub("_", "-"):gsub("%f[%w].", s_upper)..": ";

		t[k] = v;

		return v;

	end

});

local function send_response_sans_body(response, body)

	if response.finished then return; end

	response.finished = true;

	response.conn._http_open_response = nil;

	local status_line = "HTTP/"..response.request.httpversion.." "..(response.status or codes[response.status_code]);

	local headers = response.headers;

	body = body or response.body or "";

	headers.content_length = #body;

	local output = { status_line };

	for k,v in pairs(headers) do

		t_insert(output, headerfix[k]..v);

	end

	t_insert(output, "\r\n\r\n");

	-- Here we *don't* add the body to the output

	response.conn:write(t_concat(output));

	if response.on_destroy then

		response:on_destroy();

		response.on_destroy = nil;

	end

	if response.persistent then

		response:finish_cb();

	else

		response.conn:close();

	end

end

local serve_uploaded_files = module:depends("http_files").serve(storage_path);

local function serve_head(event, path)

	event.response.send = send_response_sans_body;

	return serve_uploaded_files(event, path);

end

local function serve_hello(event)

	event.response.headers.content_type = "text/html;charset=utf-8"

	return "<!DOCTYPE html>\n<h1>Hello from mod_"..module.name.."!</h1>\n";

end

module:provides("http", {

	route = {

		["GET"] = serve_hello;

		["GET /"] = serve_hello;

		["GET /*"] = serve_uploaded_files;

		["HEAD /*"] = serve_head;

		["PUT /*"] = upload_data;

	};

});

module:log("info", "URL: <%s>; Storage path: %s", module:http_url(), storage_path);