gistfile1.txt

-- http://lua-users.org/lists/lua-l/2002-04/msg00180.html

require 'socket'

local header =
[[HTTP/1.1 200 OK
Date: Fri, 19 Apr 2002 20:37:57 GMT
Server: Apache/1.3.23 (Darwin) mod_ssl/2.8.7 OpenSSL/0.9.6b
Cache-Control: max-age=60
Expires: Fri, 19 Apr 2002 20:38:57 GMT
Last-Modified: Tue, 16 Apr 2002 02:00:34 GMT
ETag: "3c57e-1e47-3cbb85c2"
Accept-Ranges: bytes
Connection: close
]]


WebServer =
{
 _port = 8080,
 _header = header,
}

function WebServer:run()
  self._server = socket.bind("localhost", self._port)
  self._server:settimeout(.01)
  self._clients = {}
  self._sendClients = {}
  print("WebServer running on port "..self._port)
  self:mainLoop()
end

function WebServer:lookForNewClients()
  local client = self._server:accept()
  if client then
    client:settimeout(0.3)
    table.insert(self._clients, client)
  end
end

function split(str, pat)
  local t = {}  -- NOTE: use {n = 0} in Lua-5.0
  local fpat = "(.-)" .. pat
  local last_end = 1
  local s, e, cap = str:find(fpat, 1)
  while s do
    if s ~= 1 or cap ~= "" then
      table.insert(t,cap)
    end
    last_end = e+1
    s, e, cap = str:find(fpat, last_end)
  end
  if last_end <= #str then
    cap = str:sub(last_end)
    table.insert(t, cap)
  end
  return t
end

-- http://lua-users.org/lists/lua-l/2009-06/msg00572.html
function read(client, pattern, prefix)
  local data, emsg, partial = client:receive(pattern, prefix)
  if data then
    return data
  end
  if partial and #partial > 0 then
    return partial
  end
  return nil, emsg
end

cache = {}

function runfile(fname, req, resp)
  local newgt = {}        -- create new environment

  setmetatable(newgt, {__index = _G})
  local text = ""
  local oldprint = print
  local printfunc = function(...)
    for i, v in ipairs(arg) do
      resp.text = resp.text .. tostring(v)
    end
  end
  local redirfunc = function(uri)
    resp.text = "HTTP/1.1 302 Moved\r\nLocation: /" .. fname .. uri .. "\r\n\r\n"
  end
  local errtext = nil

  local errhandler = function(...)
    print("Error!")
    -- page:write("<pre>\n")
    -- e(debug.traceback())
    errtext = debug.traceback()
    print(errtext)
    -- page:write("</pre>\n")
  end
  -- print("runfile: about to switch environment...")

  newgt.request = req
  newgt.response = resp
  newgt.global_params = {}
  newgt.web_send = printfunc
  newgt.web_redirect = redirfunc

  setfenv(1, newgt)    -- set it

  -- print("Request:", request.url)

  request.url = string.sub(request.url, #fname + 1 + 1)
  
  local func, message
  if cache[fname] then
    func = cache[fname]
  else 
    func, message = loadfile(fname)
  end
  -- print("Loadfunc results:", func, message)
  if func then 
    setfenv(func, newgt) 
    -- TODO: proper caching
    -- cache[fname] = func
    local res, err = xpcall(func, errhandler)
    if not res then 
      print("result of pcall: ", err) 
    end
  else
    if message then
      print("Error in loadfile:", message)
    end
  end
  _G.print = oldprint
  _G.page = page
  setfenv(1, _G._G)
  if resp.text == "" then
    if errtext then
      resp.text = "HTTP/1.0 500 Error\r\n\r\n" .. errtext
    elseif page then
      resp.text = page:full_response()
    end
  end
  return resp
end

function WebServer:handleRequest(req)
  local text = ""
  local response = self._header.. "Content-length: " .. string.len(text) .. "\n\n" .. text
  return response
end

function WebServer:mainLoop()
  local clients = self._clients
  while 1 do
    self:lookForNewClients()

    local receivingClients, _, error = socket.select(clients, nil, .01)
    if error and error ~= "timeout" then
      print("error = "..tostring(error))
    end

    for i, client in ipairs(receivingClients) do
      local clientdata = {}
      repeat 
        local data, error = client:receive()
        if data then
          table.insert(clientdata, data)
          -- print("Data:", data)
        end
      until data == "" or not data
      local req = {}
      if clientdata[1] then
        local data = clientdata[1]
        -- print("Data: " .. data)
        req.firstline = split(data, "[ ]")
        req.method = req.firstline[1]
        req.full_url = req.firstline[2]
        -- print("Full URL", req.full_url)
        if req.full_url then
          req.url, req.query_string = string.match(req.full_url, "^([^?]+)[?]*(.*)$")
          req.query_string = req.query_string or ""
        else
          error = "no url in request"
        end
      end

      if error then
        print("error: "..tostring(error).." on client "..tostring(client))
        table.remove(clients, i)
      else
        bytesSent = client:send(WebServer:handleRequest(req))
        if bytesSent then
        --   print("bytesSent = ".. bytesSent.." bytes = ".. #response)
        end
        client:close()
        table.remove(clients, i)
      end
    end
  end
end

WebServer:run()