cgilua.lua

cgi for lua, you can build your personal web site by lua

-- @param path String with the path.
-- @param protocol String with the name of the protocol (default = "http").
-- @return String in URL format.
----------------------------------------------------------------------------
function mkabsoluteurl (path, protocol)
	protocol = protocol or "http"
	if path:sub(1,1) ~= '/' then
		path = '/'..path
	end
	return format("%s://%s:%s%s",
		protocol,
		servervariable"SERVER_NAME",
		servervariable"SERVER_PORT",
		path)
end

----------------------------------------------------------------------------
-- Extract the "directory" and "file" parts of a path
-- @param path String with a path.
-- @return String with the directory part.
-- @return String with the file part.
----------------------------------------------------------------------------
function splitpath (path)
	local _,_,dir,file = strfind(path,"^(.-)([^:/\\]*)$")
	return dir,file
end

--
-- Define variables and build the cgilua.POST, cgilua.GET and the global `cgi' table.
-- @param args Table where to store the parameters (the actual `cgi' table).
--
local function getparams ()
	-- Define variables.
	script_path = script_path or servervariable"PATH_TRANSLATED"
    if not script_path then
        script_path = servervariable"DOCUMENT_ROOT" ..
            servervariable"SCRIPT_NAME"
    end
    script_pdir, script_file = splitpath (script_path)
	local vpath = servervariable"PATH_INFO"
	script_vpath = vpath
	if vpath and vpath ~= "" then
		script_vdir = splitpath (vpath)
		urlpath = servervariable"SCRIPT_NAME"
	else
		script_vdir = splitpath (servervariable"SCRIPT_NAME")
		urlpath = ""
	end
	-- Fill in the POST table.
	POST = {}
	if servervariable"REQUEST_METHOD" == "POST" then
		post.parsedata {
			read = SAPI.Request.getpostdata,
			discardinput = ap and ap.discard_request_body,
			content_type = servervariable"CONTENT_TYPE",
			content_length = servervariable"CONTENT_LENGTH",
			maxinput = maxinput,
			maxfilesize = maxfilesize,
			args = POST,
		}
	end
	-- Fill in the QUERY table.
	QUERY = {}
	urlcode.parsequery (servervariable"QUERY_STRING", QUERY)
	-- Links POST and QUERY data to the CGI table for backward compatibility
	local mt = {}
	mt.__index = function(t,v) return POST[v] or QUERY[v] end
	setmetatable(CGI, mt)
end

--
-- Stores all script handlers and the file extensions used to identify
-- them.
local script_handlers = {}

--
-- Default handler.
-- Sends the contents of the file to the output without processing it.
-- @param filename String with the name of the file.
--
local function default_handler (filename)
	htmlheader ()
	local fh = assert (_open (filename))
	local prog = fh:read("*a")
	fh:close()
	put (prog)
end

----------------------------------------------------------------------------
-- Add a script handler.
-- @param file_extension String with the lower-case extension of the script.
-- @param func Function to handle this kind of scripts.
----------------------------------------------------------------------------
function addscripthandler (file_extension, func)
	assert (type(file_extension) == "string", "File extension must be a string")
	if strfind (file_extension, '%.', 1) then
		file_extension = strsub (file_extension, 2)
	end
	file_extension = strlower(file_extension)
	assert (type(func) == "function", "Handler must be a function")

	script_handlers[file_extension] = func
end

---------------------------------------------------------------------------
-- Obtains the handler corresponding to the given script path.
-- @param path String with a script path.
-- @return Function that handles it or nil.
----------------------------------------------------------------------------
function getscripthandler (path)
	local i,f, ext = strfind (path, "%.([^.]+)$")
	return script_handlers[strlower(ext or '')]
end

---------------------------------------------------------------------------
-- Execute the given path with the corresponding handler.
-- @param path String with a script path.
-- @return The returned values from the script.
---------------------------------------------------------------------------
function handle (path)
	local h = assert (getscripthandler (path), "There is no handler defined to process this kind of file ("..path..")")
	return h (path)
end

---------------------------------------------------------------------------
-- Sets "errorhandler" function
-- This function is called by Lua when an error occurs.
-- It receives the error message generated by Lua and it is resposible
-- for the final message which should be returned.
-- @param Function.
---------------------------------------------------------------------------
function seterrorhandler (f)
	local tf = type(f)
	if tf == "function" then
		errorhandler = f
	else
		error (format ("Invalid type: expected `function', got `%s'", tf))
	end
end

---------------------------------------------------------------------------
-- Defines the "erroroutput" function
-- This function is called to generate the error output.
-- @param Function.
---------------------------------------------------------------------------
function seterroroutput (f)
	local tf = type(f)
	if tf == "function" then
		erroroutput = f
	else
		error (format ("Invalid type: expected `function', got `%s'", tf))
	end
end

--
-- Executes a function with an error handler.
-- @param f Function to be called.
--
local function _xpcall (f)
	local ok, result = xpcall (f, errorhandler)
	if ok then
		return result
	else
		erroroutput (result)
	end
end

--
-- Stores all close functions in order they are set.
local close_functions = {
}

---------------------------------------------------------------------------
-- Adds a function to be executed after the script.
-- @param f Function to be registered.
---------------------------------------------------------------------------
function addclosefunction (f)
	local tf = type(f)
	if tf == "function" then
		tinsert (close_functions, f)
	else
		error (format ("Invalid type: expected `function', got `%s'", tf))
	end
end

--
-- Close function.
--
local function close()
	for i = #close_functions, 1, -1 do
		close_functions[i]()
	end
end

--
-- Stores all open functions in order they are set.
local open_functions = {
}

---------------------------------------------------------------------------
-- Adds a function to be executed before the script.
-- @param f Function to be registered.
---------------------------------------------------------------------------
function addopenfunction (f)
	local tf = type(f)
	if tf == "function" then
		tinsert (open_functions, f)
	else
		error (format ("Invalid type: expected `function', got `%s'", tf))
	end
end

--
-- Open function.
-- Call all defined open-functions in the order they were created.
--
local function open()
	for i = #open_functions, 1, -1 do
		open_functions[i]()
	end
end

--
-- Resets CGILua's state.
--
local function reset ()
	script_path = false
	maxfilesize = default_maxfilesize
	maxinput = default_maxinput
	-- Error Handling
	errorhandler = default_errorhandler
	erroroutput = default_erroroutput
	-- Handlers
	script_handlers = {}
	open_function = {}
	close_functions = {}
end

---------------------------------------------------------------------------
-- Request processing.
---------------------------------------------------------------------------
function main ()
	-- Default values
	addscripthandler ("lua", doscript)
	addscripthandler ("lp", handlelp)
	CGI = {}
	-- Configuring CGILua (trying to load cgilua/config.lua)
	_xpcall (function () _G.require"cgilua.config" end)

	-- Cleaning environment
	removeglobals {
		"os.execute",
		"loadlib",
		"package",
		"debug",
	}
	-- Build fake package
	_G.package = { seeall = seeall, }
	_xpcall (getparams)
	-- Changing curent directory to the script's "physical" dir
	local curr_dir = lfs.currentdir ()
	_xpcall (function () lfs.chdir (script_pdir) end)
	-- Opening function
	_xpcall (open)
	-- Executing script
	local result = _xpcall (function () return handle (script_file) end)

	-- Closing function
	_xpcall (close)
	-- Cleanup
	reset ()
	-- Changing to original directory
	_xpcall (function () lfs.chdir (curr_dir) end)
	if result then -- script executed ok!
		return result
	end
end