--
-- This file is part of LEM, a Lua Event Machine.
-- Copyright 2011-2013 Emil Renner Berthing
-- Copyright 2013      Halfdan Mouritzen
--
-- LEM is free software: you can redistribute it and/or modify it
-- under the terms of the GNU Lesser General Public License as
-- published by the Free Software Foundation, either version 3 of
-- the License, or (at your option) any later version.
--
-- LEM is distributed in the hope that it will be useful, but
-- WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-- GNU Lesser General Public License for more details.
--
-- You should have received a copy of the GNU Lesser General Public
-- License along with LEM.  If not, see <http://www.gnu.org/licenses/>.
--

local setmetatable = setmetatable
local tostring = tostring
local tonumber = tonumber
local pairs = pairs
local type = type
local date = os.date
local format = string.format
local concat = table.concat
local remove = table.remove

local io       = require 'lem.io'
                 require 'lem.http'
local response = require 'lem.http.response'

local M = {}

function M.debug() end

local Request = {}
Request.__index = Request
M.Request = Request

function Request:body(maxsize)
	local len, body = self.headers['content-length'], ''
	if not len then return body end

	len = tonumber(len)
	if len <= 0 then return body end

	if maxsize and len > maxsize then
		return nil, 'oversized'
	end

	if self.headers['expect'] == '100-continue' then
		local ok, err = self.client:write('HTTP/1.1 100 Continue\r\n\r\n')
		if not ok then return nil, err end
	end

	local err
	body, err = self.client:read(len)
	if not body then return nil, err end

	return body
end

do
	local gsub, char, tonumber = string.gsub, string.char, tonumber

	local function tochar(str)
		return char(tonumber(str, 16))
	end

	function M.urldecode(str)
		return gsub(gsub(str, '+', ' '), '%%(%x%x)', tochar)
	end
end

local function check_match(entry, req, res, ok, ...)
	if not ok then return false end
	local handler = entry[req.method]
	if handler then
		handler(req, res, ok, ...)
	else
		response.method_not_allowed(req, res)
	end
	return true
end

local urldecode = M.urldecode
local newresponse = response.new

local function handleHTTP(self, client)
	repeat
		local req, err = client:read('HTTPRequest')
		if not req then self.debug('read', err) break end
		local method, uri, version = req.method, req.uri, req.version

		setmetatable(req, Request)
		req.client = client
		req.path = urldecode(uri:match('^([^?]*)'))

		local res = newresponse(req)

		if version ~= '1.0' and version ~= '1.1' then
			response.version_not_supported(req, res)
			version = '1.1'
		else
			local expect = req.headers['expect']
			if expect and expect ~= '100-continue' then
				response.expectation_failed(req, res)
			else
				self.handler(req, res)
			end
		end

		local headers = res.headers
		local file, close = res.file, false
		if type(file) == 'string' then
			file, err = io.open(file)
			if file then
				close = true
			else
				self.debug('open', err)
				res = newresponse(req)
				headers = res.headers
				response.not_found(req, res)
			end
		end

		if not res.status then
			if #res == 0 and file == nil then
				res.status = 204
			else
				res.status = 200
			end
		end

		if headers['Content-Length'] == nil and res.status ~= 204 then
			local len
			if file then
				len = file:size()
			else
				len = 0
				for i = 1, #res do
					len = len + #res[i]
				end
			end

			headers['Content-Length'] = len
		end

		if headers['Date'] == nil then
			headers['Date'] = date('!%a, %d %b %Y %H:%M:%S GMT')
		end

		if headers['Server'] == nil then
			headers['Server'] = 'Hathaway/0.1 LEM/0.3'
		end

		if req.headers['connection'] == 'close' and headers['Connection'] == nil then
			headers['Connection'] = 'close'
		end

		local rope = {}
		do
			local status = res.status
			if type(status) == 'number' then
				status = response.status_string[status]
			end

			rope[1] = format('HTTP/%s %s\r\n', version, status)
		end

		res:appendheader(rope, 1)

		client:cork()

		local ok, err = client:write(concat(rope))
		if not ok then self.debug('write', err) break end

		if method ~= 'HEAD' then
			if file then
				ok, err = client:sendfile(file, headers['Content-Length'])
				if close then file:close() end
			else
				local body = concat(res)
				if #body > 0 then
					ok, err = client:write(body)
				end
			end
			if not ok then self.debug('write', err) break end
		end

		client:uncork()

	until version == '1.0' or headers['Connection'] == 'close'

	client:close()
end

local Server = {}
Server.__index = Server
M.Server = Server

function Server:run()
	return self.socket:autospawn(function(...) return handleHTTP(self, ...) end)
end

function Server:close()
	return self.socket:close()
end

local type, setmetatable = type, setmetatable

function M.new(host, port, handler)
	local socket, err
	if type(host) == 'string' then
		socket, err = io.tcp.listen(host, port)
		if not socket then
			return nil, err
		end
	else
		socket = host
		handler = port
	end

	return setmetatable({
		socket = socket,
		handler = handler,
		debug = M.debug
	}, Server)
end

return M

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