fail Lua HTTP server

gistfile1.lua

local socket=require("socket")
local sv=socket.bind("*",80)
sv:settimeout(0)
local cli={}

local function tpairs(tbl)
	local t={}
	for k,v in pairs(tbl) do
		table.insert(t,k)
	end
	local i=0
	return function()
		i=i+1
		return t[i],tbl[t[i]]
	end
end
local function formhttp(page)
	return "HTTP/1.1 200 Found\r\nContent-Type: text/html\r\nContent-Length: "..#page.."\r\n\r\n"..page.."\r\n"
end
local function req(cl)
	local cldat=cli[cl]
	local o="<h1>"..(cldat.post or "Hello, World!").."</h1>"
	o=o.."<form action=\"http://localhost/\" method=\"post\">"
	o=o.."<p><input type=\"text\" name=\"text\"></p><input type=\"submit\" value=\"Submit\"></form><br>"
	for k,v in pairs(cldat.header) do
		o=o.."<br>["..k.."]="..v
	end
	cl:send(formhttp(o))
	cl:close()
	cli[cl]=nil
end
while true do
	local cl=sv:accept()
	while cl do
		cl:settimeout(0)
		cli[cl]={header={},ip=cl:getpeername()}
		cl=sv:accept()
	end
	for cl,cldat in pairs(cli) do
		local s,e=cl:receive(0)
		if not s and e=="closed" then
			cl:close()
			cli[cl]=nil
		else
			local s,e=cl:receive(tonumber(cldat.post and cldat.header["Content-Length"]))
			if s then
				print(s)
				if cldat.post then
					cldat.post=s
					req(cl)
				elseif s=="" then
					if cldat.method=="POST" then
						cldat.post=""
					elseif cldat.method=="GET" then
						req(cl)
					else
						cl:close()
						cli[cl]=nil
					end
				else
					if not s:match(":") then
						cldat.method=s:match("^(%S+)")
					else
						cldat.header[s:match("^(.-):")]=s:match("^.-: (.+)")
					end
				end
			end
		end
	end
	local sel={sv}
	for k,v in pairs(cli) do
		table.insert(sel,k)
	end
	socket.select(sel,nil,10)
end