socket.lua

-----------------------------------------------------------------------------
-- LuaSocket helper module
-- Author: Diego Nehab
-----------------------------------------------------------------------------

-----------------------------------------------------------------------------
-- Declare module and import dependencies
-----------------------------------------------------------------------------
local base = _G
local string = require("string")
local math = require("math")
local socket = require("socket.core")

local _M = socket

-----------------------------------------------------------------------------
-- Exported auxiliar functions
-----------------------------------------------------------------------------
function _M.connect4(address, port, laddress, lport)
	return socket.connect(address, port, laddress, lport, "inet")
end

function _M.connect6(address, port, laddress, lport)
	return socket.connect(address, port, laddress, lport, "inet6")
end

function _M.bind(host, port, backlog)
	if host == "*" then host = "0.0.0.0" end
	local addrinfo, err = socket.dns.getaddrinfo(host);
	if not addrinfo then return nil, err end
	local sock, res
	err = "no info on address"
	for i, alt in base.ipairs(addrinfo) do
		if alt.family == "inet" then
			sock, err = socket.tcp4()
		else
			sock, err = socket.tcp6()
		end
		if not sock then return nil, err end
		-- sock:setoption("reuseaddr", true)
		res, err = sock:bind(alt.addr, port)
		if not res then
			sock:close()
		else
			res, err = sock:listen(backlog)
			if not res then
				sock:close()
			else
				return sock
			end
		end
	end
	return nil, err
end

_M.try = _M.newtry()

function _M.choose(table)
	return function(name, opt1, opt2)
		if base.type(name) ~= "string" then
			name, opt1, opt2 = "default", name, opt1
		end
		local f = table[name or "nil"]
		if not f then
			base.error("unknown key (" .. base.tostring(name) .. ")", 3)
		else
			return f(opt1, opt2)
		end
	end
end

-----------------------------------------------------------------------------
-- Socket sources and sinks, conforming to LTN12
-----------------------------------------------------------------------------
-- create namespaces inside LuaSocket namespace
local sourcet, sinkt = {}, {}
_M.sourcet = sourcet
_M.sinkt = sinkt

_M.BLOCKSIZE = 2048

sinkt["close-when-done"] = function(sock)
	return base.setmetatable({
		getfd = function() return sock:getfd() end,
		dirty = function() return sock:dirty() end
	}, {
		__call = function(self, chunk, err)
			if not chunk then
				sock:close()
				return 1
			else
				return sock:send(chunk)
			end
		end
	})
end

sinkt["keep-open"] = function(sock)
	return base.setmetatable({
		getfd = function() return sock:getfd() end,
		dirty = function() return sock:dirty() end
	}, {
		__call = function(self, chunk, err)
			if chunk then
				return sock:send(chunk)
			else
				return 1
			end
		end
	})
end

sinkt["default"] = sinkt["keep-open"]

_M.sink = _M.choose(sinkt)

sourcet["by-length"] = function(sock, length)
	return base.setmetatable({
		getfd = function() return sock:getfd() end,
		dirty = function() return sock:dirty() end
	}, {
		__call = function()
			if length <= 0 then return nil end
			local size = math.min(socket.BLOCKSIZE, length)
			local chunk, err = sock:receive(size)
			if err then return nil, err end
			length = length - string.len(chunk)
			return chunk
		end
	})
end

sourcet["until-closed"] = function(sock)
	local done
	return base.setmetatable({
		getfd = function() return sock:getfd() end,
		dirty = function() return sock:dirty() end
	}, {
		__call = function()
			if done then return nil end
			local chunk, err, partial = sock:receive(socket.BLOCKSIZE)
			if not err then
				return chunk
			elseif err == "closed" then
				sock:close()
				done = 1
				return partial
			else
				return nil, err
			end
		end
	})
end


sourcet["default"] = sourcet["until-closed"]

_M.source = _M.choose(sourcet)

return _M