This is a MySQL Adapter for Codea + demo code. It lets your Codea app talk directly to a MySQL server.

Main.lua

--# Main
-- mysql adapter
--
-- TODO: write higher level API to mysql
-- app should cache inputs and push to mysql when server available
-- also queries should be wrapped in coroutines or something, to be async?


function setup()
    -- Config
    local config = {
        host = "192.168.0.209", -- localhost
        port = "3306",
        database = "codea-test",
        user = "guest",
        password = "guest"
    }
    
    
    -- Connect
    local function connect()
        local db, err = mysql:new()
        
        if not db then print(err) return end
        db:set_timeout(1000)
        
        local ok, err, errc, sqlstate = db:connect(config)
        if not ok then print(errc, err) return end
        
        print("successfully connected to mysql server at "..config.host..":"..config.port)
        
        return db
    end
    
    
    -- Disconnect
    local function disconnect(db)
        local ok, err = db:close()
        if ok then print("closed mysql server connection") end
    end
    
    
    -- Insert
    local function create_user(name)
        local db = connect()
        
        if not db then
            print("failed to connect to mysql server")
            return
        end
        
        local res, err, errc, sqlstate = db:query("INSERT INTO users (name) VALUES ('"..name.."')")
        
        if not err then
            print("added db record from custom query call...")
            pretty(res)
        end
        
        disconnect(db)
    end
    
    
    -- Fetch
    local function fetch_users()
        local db = connect()
        
        if not db then
            print("failed to connect to mysql server")
            return
        end
        
        local res, err, errc, sqlstate = db:query("select * from users")
        
        if not res then
            print("could not fetch data from mysql server")
            return
        end
        
        local numentries = 0
        dbquery = "database name: "..config.database.."\ntable name: users\n\n"
        
        for id, row in ipairs(res) do
            dbquery = dbquery.."row: "..id.."\n"
            for field, value in pairs(row) do
                dbquery = dbquery.."     "..field..": "..value.."\n"
            end
            dbquery = dbquery.."\n"
            numentries = id
        end
        
        print("successfully fetched "..numentries.." entries")
        
        disconnect(db)
    end
    
    
    -- UI
    parameter.text("NAME", "yourname")
    parameter.action("INSERT", function() create_user(NAME) end)
    parameter.action("FETCH", fetch_users)
end

function draw()
    background(35, 107, 214, 255)
    fill(0, 0, 0, 255)
    
    translate(WIDTH/2, HEIGHT/2)
    
    textMode(CENTER)
    text(dbquery or "-no data fetched-")
end

--# sha1
-- SHA-1 secure hash computation, and HMAC-SHA1 signature computation in pure Lua (tested on Lua 5.1)
-- Latest version always at:  http://regex.info/blog/lua/sha1
-- Algorithm: http://www.itl.nist.gov/fipspubs/fip180-1.htm
--
-- Copyright 2009 Jeffrey Friedl
-- jfriedl@yahoo.com
-- http://regex.info/blog/
--
-- This file creates four entries in the global namespace:
--
--   local hash_as_hex   = sha1(message)            -- returns a hex string
--   local hash_as_data  = sha1_binary(message)     -- returns raw bytes
--
--   local hmac_as_hex   = hmac_sha1(key, message)        -- hex string
--   local hmac_as_data  = hmac_sha1_binary(key, message) -- raw bytes


--
-- Return a W32 object for the number zero
--
local function ZERO()
   return {
      false, false, false, false,     false, false, false, false, 
      false, false, false, false,     false, false, false, false, 
      false, false, false, false,     false, false, false, false, 
      false, false, false, false,     false, false, false, false, 
   }
end

local hex_to_bits = {
   ["0"] = { false, false, false, false },
   ["1"] = { false, false, false, true  },
   ["2"] = { false, false, true,  false },
   ["3"] = { false, false, true,  true  },

   ["4"] = { false, true,  false, false },
   ["5"] = { false, true,  false, true  },
   ["6"] = { false, true,  true,  false },
   ["7"] = { false, true,  true,  true  },

   ["8"] = { true,  false, false, false },
   ["9"] = { true,  false, false, true  },
   ["A"] = { true,  false, true,  false },
   ["B"] = { true,  false, true,  true  },

   ["C"] = { true,  true,  false, false },
   ["D"] = { true,  true,  false, true  },
   ["E"] = { true,  true,  true,  false },
   ["F"] = { true,  true,  true,  true  },

   ["a"] = { true,  false, true,  false },
   ["b"] = { true,  false, true,  true  },
   ["c"] = { true,  true,  false, false },
   ["d"] = { true,  true,  false, true  },
   ["e"] = { true,  true,  true,  false },
   ["f"] = { true,  true,  true,  true  },
}

--
-- Given a string of 8 hex digits, return a W32 object representing that number
--
local function from_hex(hex)

   assert(type(hex) == 'string')
   assert(hex:match('^[0123456789abcdefABCDEF]+$'))
   assert(#hex == 8)

   local W32 = { }

   for letter in hex:gmatch('.') do
      local b = hex_to_bits[letter]
      assert(b)
      table.insert(W32, 1, b[1])
      table.insert(W32, 1, b[2])
      table.insert(W32, 1, b[3])
      table.insert(W32, 1, b[4])
   end

   return W32
end

local function COPY(old)
   local W32 = { }
   for k,v in pairs(old) do
      W32[k] = v
   end

   return W32
end

local function ADD(first, ...)

   local a = COPY(first)

   local C, b, sum

   for v = 1, select('#', ...) do
      b = select(v, ...)
      C = 0

      for i = 1, #a do
         sum = (a[i] and 1 or 0)
             + (b[i] and 1 or 0)
             + C

         if sum == 0 then
            a[i] = false
            C    = 0
         elseif sum == 1 then
            a[i] = true
            C    = 0
         elseif sum == 2 then
            a[i] = false
            C    = 1
         else
            a[i] = true
            C    = 1
         end
      end
      -- we drop any ending carry

   end

   return a
end

local function XOR(first, ...)

   local a = COPY(first)
   local b
   for v = 1, select('#', ...) do
      b = select(v, ...)
      for i = 1, #a do
         a[i] = a[i] ~= b[i]
      end
   end

   return a

end

local function AND(a, b)

   local c = ZERO()

   for i = 1, #a do
      -- only need to set true bits; other bits remain false
      if  a[i] and b[i] then
         c[i] = true
      end
   end

   return c
end

local function OR(a, b)

   local c = ZERO()

   for i = 1, #a do
      -- only need to set true bits; other bits remain false
      if  a[i] or b[i] then
         c[i] = true
      end
   end

   return c
end

local function OR3(a, b, c)

   local d = ZERO()

   for i = 1, #a do
      -- only need to set true bits; other bits remain false
      if a[i] or b[i] or c[i] then
         d[i] = true
      end
   end

   return d
end

local function NOT(a)

   local b = ZERO()

   for i = 1, #a do
      -- only need to set true bits; other bits remain false
      if not a[i] then
         b[i] = true
      end
   end

   return b
end

local function ROTATE(bits, a)

   local b = COPY(a)

   while bits > 0 do
      bits = bits - 1
      table.insert(b, 1, table.remove(b))
   end

   return b

end


local binary_to_hex = {
   ["0000"] = "0",
   ["0001"] = "1",
   ["0010"] = "2",
   ["0011"] = "3",
   ["0100"] = "4",
   ["0101"] = "5",
   ["0110"] = "6",
   ["0111"] = "7",
   ["1000"] = "8",
   ["1001"] = "9",
   ["1010"] = "a",
   ["1011"] = "b",
   ["1100"] = "c",
   ["1101"] = "d",
   ["1110"] = "e",
   ["1111"] = "f",
}

function asHEX(a)

   local hex = ""
   local i = 1
   while i < #a do
      local binary = (a[i + 3] and '1' or '0')
                     ..
                     (a[i + 2] and '1' or '0')
                     ..
                     (a[i + 1] and '1' or '0')
                     ..
                     (a[i + 0] and '1' or '0')

      hex = binary_to_hex[binary] .. hex

      i = i + 4
   end

   return hex

end

local x67452301 = from_hex("67452301")
local xEFCDAB89 = from_hex("EFCDAB89")
local x98BADCFE = from_hex("98BADCFE")
local x10325476 = from_hex("10325476")
local xC3D2E1F0 = from_hex("C3D2E1F0")

local x5A827999 = from_hex("5A827999")
local x6ED9EBA1 = from_hex("6ED9EBA1")
local x8F1BBCDC = from_hex("8F1BBCDC")
local xCA62C1D6 = from_hex("CA62C1D6")


function sha1(msg)

   assert(type(msg) == 'string')
   assert(#msg < 0x7FFFFFFF) -- have no idea what would happen if it were large

   local H0 = x67452301
   local H1 = xEFCDAB89
   local H2 = x98BADCFE
   local H3 = x10325476
   local H4 = xC3D2E1F0

   local msg_len_in_bits = #msg * 8

   local first_append = string.char(0x80) -- append a '1' bit plus seven '0' bits

   local non_zero_message_bytes = #msg +1 +8 -- the +1 is the appended bit 1, the +8 are for the final appended length
   local current_mod = non_zero_message_bytes % 64
   local second_append = ""
   if current_mod ~= 0 then
      second_append = string.rep(string.char(0), 64 - current_mod)
   end

   -- now to append the length as a 64-bit number.
   local B1, R1 = math.modf(msg_len_in_bits  / 0x01000000)
   local B2, R2 = math.modf( 0x01000000 * R1 / 0x00010000)
   local B3, R3 = math.modf( 0x00010000 * R2 / 0x00000100)
   local B4     =            0x00000100 * R3

   local L64 = string.char( 0) .. string.char( 0) .. string.char( 0) .. string.char( 0) -- high 32 bits
            .. string.char(B1) .. string.char(B2) .. string.char(B3) .. string.char(B4) --  low 32 bits



   msg = msg .. first_append .. second_append .. L64         

   assert(#msg % 64 == 0)

   --local fd = io.open("/tmp/msg", "wb")
   --fd:write(msg)
   --fd:close()

   local chunks = #msg / 64

   local W = { }
   local start, A, B, C, D, E, f, K, TEMP
   local chunk = 0

   while chunk < chunks do
      --
      -- break chunk up into W[0] through W[15]
      --
      start = chunk * 64 + 1
      chunk = chunk + 1

      for t = 0, 15 do
         W[t] = from_hex(string.format("%02x%02x%02x%02x", msg:byte(start, start + 3)))
         start = start + 4
      end

      --
      -- build W[16] through W[79]
      --
      for t = 16, 79 do
         -- For t = 16 to 79 let Wt = S1(Wt-3 XOR Wt-8 XOR Wt-14 XOR Wt-16). 
         W[t] = ROTATE(1, XOR(W[t-3], W[t-8], W[t-14], W[t-16]))
      end

      A = H0
      B = H1
      C = H2
      D = H3
      E = H4

      for t = 0, 79 do
         if t <= 19 then
            -- (B AND C) OR ((NOT B) AND D)
            f = OR(AND(B, C), AND(NOT(B), D))
            K = x5A827999
         elseif t <= 39 then
            -- B XOR C XOR D
            f = XOR(B, C, D)
            K = x6ED9EBA1
         elseif t <= 59 then
            -- (B AND C) OR (B AND D) OR (C AND D
            f = OR3(AND(B, C), AND(B, D), AND(C, D))
            K = x8F1BBCDC
         else
            -- B XOR C XOR D
            f = XOR(B, C, D)
            K = xCA62C1D6
         end

         -- TEMP = S5(A) + ft(B,C,D) + E + Wt + Kt; 
         TEMP = ADD(ROTATE(5, A), f, E, W[t], K)

         --E = D; 　　D = C; 　　　C = S30(B);　　 B = A; 　　A = TEMP;
         E = D
         D = C
         C = ROTATE(30, B)
         B = A
         A = TEMP

         --printf("t = %2d: %s  %s  %s  %s  %s", t, A:HEX(), B:HEX(), C:HEX(), D:HEX(), E:HEX())
      end

      -- Let H0 = H0 + A, H1 = H1 + B, H2 = H2 + C, H3 = H3 + D, H4 = H4 + E. 
      H0 = ADD(H0, A)
      H1 = ADD(H1, B)
      H2 = ADD(H2, C)
      H3 = ADD(H3, D)
      H4 = ADD(H4, E)
   end

   return asHEX(H0) .. asHEX(H1) .. asHEX(H2) .. asHEX(H3) .. asHEX(H4)
end

local function hex_to_binary(hex)
   return hex:gsub('..', function(hexval)
                            return string.char(tonumber(hexval, 16))
                         end)
end

function sha1_binary(msg)
   return hex_to_binary(sha1(msg))
end

local xor_with_0x5c = {
   [string.char(  0)] = string.char( 92),   [string.char(  1)] = string.char( 93),
   [string.char(  2)] = string.char( 94),   [string.char(  3)] = string.char( 95),
   [string.char(  4)] = string.char( 88),   [string.char(  5)] = string.char( 89),
   [string.char(  6)] = string.char( 90),   [string.char(  7)] = string.char( 91),
   [string.char(  8)] = string.char( 84),   [string.char(  9)] = string.char( 85),
   [string.char( 10)] = string.char( 86),   [string.char( 11)] = string.char( 87),
   [string.char( 12)] = string.char( 80),   [string.char( 13)] = string.char( 81),
   [string.char( 14)] = string.char( 82),   [string.char( 15)] = string.char( 83),
   [string.char( 16)] = string.char( 76),   [string.char( 17)] = string.char( 77),
   [string.char( 18)] = string.char( 78),   [string.char( 19)] = string.char( 79),
   [string.char( 20)] = string.char( 72),   [string.char( 21)] = string.char( 73),
   [string.char( 22)] = string.char( 74),   [string.char( 23)] = string.char( 75),
   [string.char( 24)] = string.char( 68),   [string.char( 25)] = string.char( 69),
   [string.char( 26)] = string.char( 70),   [string.char( 27)] = string.char( 71),
   [string.char( 28)] = string.char( 64),   [string.char( 29)] = string.char( 65),
   [string.char( 30)] = string.char( 66),   [string.char( 31)] = string.char( 67),
   [string.char( 32)] = string.char(124),   [string.char( 33)] = string.char(125),
   [string.char( 34)] = string.char(126),   [string.char( 35)] = string.char(127),
   [string.char( 36)] = string.char(120),   [string.char( 37)] = string.char(121),
   [string.char( 38)] = string.char(122),   [string.char( 39)] = string.char(123),
   [string.char( 40)] = string.char(116),   [string.char( 41)] = string.char(117),
   [string.char( 42)] = string.char(118),   [string.char( 43)] = string.char(119),
   [string.char( 44)] = string.char(112),   [string.char( 45)] = string.char(113),
   [string.char( 46)] = string.char(114),   [string.char( 47)] = string.char(115),
   [string.char( 48)] = string.char(108),   [string.char( 49)] = string.char(109),
   [string.char( 50)] = string.char(110),   [string.char( 51)] = string.char(111),
   [string.char( 52)] = string.char(104),   [string.char( 53)] = string.char(105),
   [string.char( 54)] = string.char(106),   [string.char( 55)] = string.char(107),
   [string.char( 56)] = string.char(100),   [string.char( 57)] = string.char(101),
   [string.char( 58)] = string.char(102),   [string.char( 59)] = string.char(103),
   [string.char( 60)] = string.char( 96),   [string.char( 61)] = string.char( 97),
   [string.char( 62)] = string.char( 98),   [string.char( 63)] = string.char( 99),
   [string.char( 64)] = string.char( 28),   [string.char( 65)] = string.char( 29),
   [string.char( 66)] = string.char( 30),   [string.char( 67)] = string.char( 31),
   [string.char( 68)] = string.char( 24),   [string.char( 69)] = string.char( 25),
   [string.char( 70)] = string.char( 26),   [string.char( 71)] = string.char( 27),
   [string.char( 72)] = string.char( 20),   [string.char( 73)] = string.char( 21),
   [string.char( 74)] = string.char( 22),   [string.char( 75)] = string.char( 23),
   [string.char( 76)] = string.char( 16),   [string.char( 77)] = string.char( 17),
   [string.char( 78)] = string.char( 18),   [string.char( 79)] = string.char( 19),
   [string.char( 80)] = string.char( 12),   [string.char( 81)] = string.char( 13),
   [string.char( 82)] = string.char( 14),   [string.char( 83)] = string.char( 15),
   [string.char( 84)] = string.char(  8),   [string.char( 85)] = string.char(  9),
   [string.char( 86)] = string.char( 10),   [string.char( 87)] = string.char( 11),
   [string.char( 88)] = string.char(  4),   [string.char( 89)] = string.char(  5),
   [string.char( 90)] = string.char(  6),   [string.char( 91)] = string.char(  7),
   [string.char( 92)] = string.char(  0),   [string.char( 93)] = string.char(  1),
   [string.char( 94)] = string.char(  2),   [string.char( 95)] = string.char(  3),
   [string.char( 96)] = string.char( 60),   [string.char( 97)] = string.char( 61),
   [string.char( 98)] = string.char( 62),   [string.char( 99)] = string.char( 63),
   [string.char(100)] = string.char( 56),   [string.char(101)] = string.char( 57),
   [string.char(102)] = string.char( 58),   [string.char(103)] = string.char( 59),
   [string.char(104)] = string.char( 52),   [string.char(105)] = string.char( 53),
   [string.char(106)] = string.char( 54),   [string.char(107)] = string.char( 55),
   [string.char(108)] = string.char( 48),   [string.char(109)] = string.char( 49),
   [string.char(110)] = string.char( 50),   [string.char(111)] = string.char( 51),
   [string.char(112)] = string.char( 44),   [string.char(113)] = string.char( 45),
   [string.char(114)] = string.char( 46),   [string.char(115)] = string.char( 47),
   [string.char(116)] = string.char( 40),   [string.char(117)] = string.char( 41),
   [string.char(118)] = string.char( 42),   [string.char(119)] = string.char( 43),
   [string.char(120)] = string.char( 36),   [string.char(121)] = string.char( 37),
   [string.char(122)] = string.char( 38),   [string.char(123)] = string.char( 39),
   [string.char(124)] = string.char( 32),   [string.char(125)] = string.char( 33),
   [string.char(126)] = string.char( 34),   [string.char(127)] = string.char( 35),
   [string.char(128)] = string.char(220),   [string.char(129)] = string.char(221),
   [string.char(130)] = string.char(222),   [string.char(131)] = string.char(223),
   [string.char(132)] = string.char(216),   [string.char(133)] = string.char(217),
   [string.char(134)] = string.char(218),   [string.char(135)] = string.char(219),
   [string.char(136)] = string.char(212),   [string.char(137)] = string.char(213),
   [string.char(138)] = string.char(214),   [string.char(139)] = string.char(215),
   [string.char(140)] = string.char(208),   [string.char(141)] = string.char(209),
   [string.char(142)] = string.char(210),   [string.char(143)] = string.char(211),
   [string.char(144)] = string.char(204),   [string.char(145)] = string.char(205),
   [string.char(146)] = string.char(206),   [string.char(147)] = string.char(207),
   [string.char(148)] = string.char(200),   [string.char(149)] = string.char(201),
   [string.char(150)] = string.char(202),   [string.char(151)] = string.char(203),
   [string.char(152)] = string.char(196),   [string.char(153)] = string.char(197),
   [string.char(154)] = string.char(198),   [string.char(155)] = string.char(199),
   [string.char(156)] = string.char(192),   [string.char(157)] = string.char(193),
   [string.char(158)] = string.char(194),   [string.char(159)] = string.char(195),
   [string.char(160)] = string.char(252),   [string.char(161)] = string.char(253),
   [string.char(162)] = string.char(254),   [string.char(163)] = string.char(255),
   [string.char(164)] = string.char(248),   [string.char(165)] = string.char(249),
   [string.char(166)] = string.char(250),   [string.char(167)] = string.char(251),
   [string.char(168)] = string.char(244),   [string.char(169)] = string.char(245),
   [string.char(170)] = string.char(246),   [string.char(171)] = string.char(247),
   [string.char(172)] = string.char(240),   [string.char(173)] = string.char(241),
   [string.char(174)] = string.char(242),   [string.char(175)] = string.char(243),
   [string.char(176)] = string.char(236),   [string.char(177)] = string.char(237),
   [string.char(178)] = string.char(238),   [string.char(179)] = string.char(239),
   [string.char(180)] = string.char(232),   [string.char(181)] = string.char(233),
   [string.char(182)] = string.char(234),   [string.char(183)] = string.char(235),
   [string.char(184)] = string.char(228),   [string.char(185)] = string.char(229),
   [string.char(186)] = string.char(230),   [string.char(187)] = string.char(231),
   [string.char(188)] = string.char(224),   [string.char(189)] = string.char(225),
   [string.char(190)] = string.char(226),   [string.char(191)] = string.char(227),
   [string.char(192)] = string.char(156),   [string.char(193)] = string.char(157),
   [string.char(194)] = string.char(158),   [string.char(195)] = string.char(159),
   [string.char(196)] = string.char(152),   [string.char(197)] = string.char(153),
   [string.char(198)] = string.char(154),   [string.char(199)] = string.char(155),
   [string.char(200)] = string.char(148),   [string.char(201)] = string.char(149),
   [string.char(202)] = string.char(150),   [string.char(203)] = string.char(151),
   [string.char(204)] = string.char(144),   [string.char(205)] = string.char(145),
   [string.char(206)] = string.char(146),   [string.char(207)] = string.char(147),
   [string.char(208)] = string.char(140),   [string.char(209)] = string.char(141),
   [string.char(210)] = string.char(142),   [string.char(211)] = string.char(143),
   [string.char(212)] = string.char(136),   [string.char(213)] = string.char(137),
   [string.char(214)] = string.char(138),   [string.char(215)] = string.char(139),
   [string.char(216)] = string.char(132),   [string.char(217)] = string.char(133),
   [string.char(218)] = string.char(134),   [string.char(219)] = string.char(135),
   [string.char(220)] = string.char(128),   [string.char(221)] = string.char(129),
   [string.char(222)] = string.char(130),   [string.char(223)] = string.char(131),
   [string.char(224)] = string.char(188),   [string.char(225)] = string.char(189),
   [string.char(226)] = string.char(190),   [string.char(227)] = string.char(191),
   [string.char(228)] = string.char(184),   [string.char(229)] = string.char(185),
   [string.char(230)] = string.char(186),   [string.char(231)] = string.char(187),
   [string.char(232)] = string.char(180),   [string.char(233)] = string.char(181),
   [string.char(234)] = string.char(182),   [string.char(235)] = string.char(183),
   [string.char(236)] = string.char(176),   [string.char(237)] = string.char(177),
   [string.char(238)] = string.char(178),   [string.char(239)] = string.char(179),
   [string.char(240)] = string.char(172),   [string.char(241)] = string.char(173),
   [string.char(242)] = string.char(174),   [string.char(243)] = string.char(175),
   [string.char(244)] = string.char(168),   [string.char(245)] = string.char(169),
   [string.char(246)] = string.char(170),   [string.char(247)] = string.char(171),
   [string.char(248)] = string.char(164),   [string.char(249)] = string.char(165),
   [string.char(250)] = string.char(166),   [string.char(251)] = string.char(167),
   [string.char(252)] = string.char(160),   [string.char(253)] = string.char(161),
   [string.char(254)] = string.char(162),   [string.char(255)] = string.char(163),
}

local xor_with_0x36 = {
   [string.char(  0)] = string.char( 54),   [string.char(  1)] = string.char( 55),
   [string.char(  2)] = string.char( 52),   [string.char(  3)] = string.char( 53),
   [string.char(  4)] = string.char( 50),   [string.char(  5)] = string.char( 51),
   [string.char(  6)] = string.char( 48),   [string.char(  7)] = string.char( 49),
   [string.char(  8)] = string.char( 62),   [string.char(  9)] = string.char( 63),
   [string.char( 10)] = string.char( 60),   [string.char( 11)] = string.char( 61),
   [string.char( 12)] = string.char( 58),   [string.char( 13)] = string.char( 59),
   [string.char( 14)] = string.char( 56),   [string.char( 15)] = string.char( 57),
   [string.char( 16)] = string.char( 38),   [string.char( 17)] = string.char( 39),
   [string.char( 18)] = string.char( 36),   [string.char( 19)] = string.char( 37),
   [string.char( 20)] = string.char( 34),   [string.char( 21)] = string.char( 35),
   [string.char( 22)] = string.char( 32),   [string.char( 23)] = string.char( 33),
   [string.char( 24)] = string.char( 46),   [string.char( 25)] = string.char( 47),
   [string.char( 26)] = string.char( 44),   [string.char( 27)] = string.char( 45),
   [string.char( 28)] = string.char( 42),   [string.char( 29)] = string.char( 43),
   [string.char( 30)] = string.char( 40),   [string.char( 31)] = string.char( 41),
   [string.char( 32)] = string.char( 22),   [string.char( 33)] = string.char( 23),
   [string.char( 34)] = string.char( 20),   [string.char( 35)] = string.char( 21),
   [string.char( 36)] = string.char( 18),   [string.char( 37)] = string.char( 19),
   [string.char( 38)] = string.char( 16),   [string.char( 39)] = string.char( 17),
   [string.char( 40)] = string.char( 30),   [string.char( 41)] = string.char( 31),
   [string.char( 42)] = string.char( 28),   [string.char( 43)] = string.char( 29),
   [string.char( 44)] = string.char( 26),   [string.char( 45)] = string.char( 27),
   [string.char( 46)] = string.char( 24),   [string.char( 47)] = string.char( 25),
   [string.char( 48)] = string.char(  6),   [string.char( 49)] = string.char(  7),
   [string.char( 50)] = string.char(  4),   [string.char( 51)] = string.char(  5),
   [string.char( 52)] = string.char(  2),   [string.char( 53)] = string.char(  3),
   [string.char( 54)] = string.char(  0),   [string.char( 55)] = string.char(  1),
   [string.char( 56)] = string.char( 14),   [string.char( 57)] = string.char( 15),
   [string.char( 58)] = string.char( 12),   [string.char( 59)] = string.char( 13),
   [string.char( 60)] = string.char( 10),   [string.char( 61)] = string.char( 11),
   [string.char( 62)] = string.char(  8),   [string.char( 63)] = string.char(  9),
   [string.char( 64)] = string.char(118),   [string.char( 65)] = string.char(119),
   [string.char( 66)] = string.char(116),   [string.char( 67)] = string.char(117),
   [string.char( 68)] = string.char(114),   [string.char( 69)] = string.char(115),
   [string.char( 70)] = string.char(112),   [string.char( 71)] = string.char(113),
   [string.char( 72)] = string.char(126),   [string.char( 73)] = string.char(127),
   [string.char( 74)] = string.char(124),   [string.char( 75)] = string.char(125),
   [string.char( 76)] = string.char(122),   [string.char( 77)] = string.char(123),
   [string.char( 78)] = string.char(120),   [string.char( 79)] = string.char(121),
   [string.char( 80)] = string.char(102),   [string.char( 81)] = string.char(103),
   [string.char( 82)] = string.char(100),   [string.char( 83)] = string.char(101),
   [string.char( 84)] = string.char( 98),   [string.char( 85)] = string.char( 99),
   [string.char( 86)] = string.char( 96),   [string.char( 87)] = string.char( 97),
   [string.char( 88)] = string.char(110),   [string.char( 89)] = string.char(111),
   [string.char( 90)] = string.char(108),   [string.char( 91)] = string.char(109),
   [string.char( 92)] = string.char(106),   [string.char( 93)] = string.char(107),
   [string.char( 94)] = string.char(104),   [string.char( 95)] = string.char(105),
   [string.char( 96)] = string.char( 86),   [string.char( 97)] = string.char( 87),
   [string.char( 98)] = string.char( 84),   [string.char( 99)] = string.char( 85),
   [string.char(100)] = string.char( 82),   [string.char(101)] = string.char( 83),
   [string.char(102)] = string.char( 80),   [string.char(103)] = string.char( 81),
   [string.char(104)] = string.char( 94),   [string.char(105)] = string.char( 95),
   [string.char(106)] = string.char( 92),   [string.char(107)] = string.char( 93),
   [string.char(108)] = string.char( 90),   [string.char(109)] = string.char( 91),
   [string.char(110)] = string.char( 88),   [string.char(111)] = string.char( 89),
   [string.char(112)] = string.char( 70),   [string.char(113)] = string.char( 71),
   [string.char(114)] = string.char( 68),   [string.char(115)] = string.char( 69),
   [string.char(116)] = string.char( 66),   [string.char(117)] = string.char( 67),
   [string.char(118)] = string.char( 64),   [string.char(119)] = string.char( 65),
   [string.char(120)] = string.char( 78),   [string.char(121)] = string.char( 79),
   [string.char(122)] = string.char( 76),   [string.char(123)] = string.char( 77),
   [string.char(124)] = string.char( 74),   [string.char(125)] = string.char( 75),
   [string.char(126)] = string.char( 72),   [string.char(127)] = string.char( 73),
   [string.char(128)] = string.char(182),   [string.char(129)] = string.char(183),
   [string.char(130)] = string.char(180),   [string.char(131)] = string.char(181),
   [string.char(132)] = string.char(178),   [string.char(133)] = string.char(179),
   [string.char(134)] = string.char(176),   [string.char(135)] = string.char(177),
   [string.char(136)] = string.char(190),   [string.char(137)] = string.char(191),
   [string.char(138)] = string.char(188),   [string.char(139)] = string.char(189),
   [string.char(140)] = string.char(186),   [string.char(141)] = string.char(187),
   [string.char(142)] = string.char(184),   [string.char(143)] = string.char(185),
   [string.char(144)] = string.char(166),   [string.char(145)] = string.char(167),
   [string.char(146)] = string.char(164),   [string.char(147)] = string.char(165),
   [string.char(148)] = string.char(162),   [string.char(149)] = string.char(163),
   [string.char(150)] = string.char(160),   [string.char(151)] = string.char(161),
   [string.char(152)] = string.char(174),   [string.char(153)] = string.char(175),
   [string.char(154)] = string.char(172),   [string.char(155)] = string.char(173),
   [string.char(156)] = string.char(170),   [string.char(157)] = string.char(171),
   [string.char(158)] = string.char(168),   [string.char(159)] = string.char(169),
   [string.char(160)] = string.char(150),   [string.char(161)] = string.char(151),
   [string.char(162)] = string.char(148),   [string.char(163)] = string.char(149),
   [string.char(164)] = string.char(146),   [string.char(165)] = string.char(147),
   [string.char(166)] = string.char(144),   [string.char(167)] = string.char(145),
   [string.char(168)] = string.char(158),   [string.char(169)] = string.char(159),
   [string.char(170)] = string.char(156),   [string.char(171)] = string.char(157),
   [string.char(172)] = string.char(154),   [string.char(173)] = string.char(155),
   [string.char(174)] = string.char(152),   [string.char(175)] = string.char(153),
   [string.char(176)] = string.char(134),   [string.char(177)] = string.char(135),
   [string.char(178)] = string.char(132),   [string.char(179)] = string.char(133),
   [string.char(180)] = string.char(130),   [string.char(181)] = string.char(131),
   [string.char(182)] = string.char(128),   [string.char(183)] = string.char(129),
   [string.char(184)] = string.char(142),   [string.char(185)] = string.char(143),
   [string.char(186)] = string.char(140),   [string.char(187)] = string.char(141),
   [string.char(188)] = string.char(138),   [string.char(189)] = string.char(139),
   [string.char(190)] = string.char(136),   [string.char(191)] = string.char(137),
   [string.char(192)] = string.char(246),   [string.char(193)] = string.char(247),
   [string.char(194)] = string.char(244),   [string.char(195)] = string.char(245),
   [string.char(196)] = string.char(242),   [string.char(197)] = string.char(243),
   [string.char(198)] = string.char(240),   [string.char(199)] = string.char(241),
   [string.char(200)] = string.char(254),   [string.char(201)] = string.char(255),
   [string.char(202)] = string.char(252),   [string.char(203)] = string.char(253),
   [string.char(204)] = string.char(250),   [string.char(205)] = string.char(251),
   [string.char(206)] = string.char(248),   [string.char(207)] = string.char(249),
   [string.char(208)] = string.char(230),   [string.char(209)] = string.char(231),
   [string.char(210)] = string.char(228),   [string.char(211)] = string.char(229),
   [string.char(212)] = string.char(226),   [string.char(213)] = string.char(227),
   [string.char(214)] = string.char(224),   [string.char(215)] = string.char(225),
   [string.char(216)] = string.char(238),   [string.char(217)] = string.char(239),
   [string.char(218)] = string.char(236),   [string.char(219)] = string.char(237),
   [string.char(220)] = string.char(234),   [string.char(221)] = string.char(235),
   [string.char(222)] = string.char(232),   [string.char(223)] = string.char(233),
   [string.char(224)] = string.char(214),   [string.char(225)] = string.char(215),
   [string.char(226)] = string.char(212),   [string.char(227)] = string.char(213),
   [string.char(228)] = string.char(210),   [string.char(229)] = string.char(211),
   [string.char(230)] = string.char(208),   [string.char(231)] = string.char(209),
   [string.char(232)] = string.char(222),   [string.char(233)] = string.char(223),
   [string.char(234)] = string.char(220),   [string.char(235)] = string.char(221),
   [string.char(236)] = string.char(218),   [string.char(237)] = string.char(219),
   [string.char(238)] = string.char(216),   [string.char(239)] = string.char(217),
   [string.char(240)] = string.char(198),   [string.char(241)] = string.char(199),
   [string.char(242)] = string.char(196),   [string.char(243)] = string.char(197),
   [string.char(244)] = string.char(194),   [string.char(245)] = string.char(195),
   [string.char(246)] = string.char(192),   [string.char(247)] = string.char(193),
   [string.char(248)] = string.char(206),   [string.char(249)] = string.char(207),
   [string.char(250)] = string.char(204),   [string.char(251)] = string.char(205),
   [string.char(252)] = string.char(202),   [string.char(253)] = string.char(203),
   [string.char(254)] = string.char(200),   [string.char(255)] = string.char(201),
}


local blocksize = 64 -- 512 bits

function hmac_sha1(key, text)
   assert(type(key)  == 'string', "key passed to hmac_sha1 should be a string")
   assert(type(text) == 'string', "text passed to hmac_sha1 should be a string")

   if #key > blocksize then
      key = sha1_binary(key)
   end

   local key_xord_with_0x36 = key:gsub('.', xor_with_0x36) .. string.rep(string.char(0x36), blocksize - #key)
   local key_xord_with_0x5c = key:gsub('.', xor_with_0x5c) .. string.rep(string.char(0x5c), blocksize - #key)

   return sha1(key_xord_with_0x5c .. sha1_binary(key_xord_with_0x36 .. text))
end

function hmac_sha1_binary(key, text)
   return hex_to_binary(hmac_sha1(key, text))
end
--# mysql
-- copyright (c) Yichun Zhang (agentzh)
-- original code available at https://github.com/openresty/lua-resty-mysql
--
-- this version was modified by jack0088@me.com specifically for use in Codea


local socket = require("socket")
local sub = string.sub
local tcp = socket.tcp
local strbyte = string.byte
local strchar = string.char
local strfind = string.find
local format = string.format
local strrep = string.rep
local null = false
local band = function(a, b) return a & b end
local bxor = function(a, b) return a ~ b end
local bor = function(a, b) return a | b end
local lshift = function(a, b) return a << b end
local rshift = function(a, b) return a >> b end
local sha1 = sha1_binary
local concat = table.concat
local unpack = unpack
local setmetatable = setmetatable
local error = error
local tonumber = tonumber
local new_tab = function (narr, nrec) return {} end


mysql = {
    _VERSION = '0.17-custom',
    _URL = "https://github.com/openresty/lua-resty-mysql",
    _DESCRIPTION = [[
        This Lua library is a MySQL client driver and takes advantage of luasocket 3.0 API.
        Note that this library was modified to work under Codea.
        Dependencies are: SHA1, Bit32 and LuaSocket! (Bit32 and LuaSocket 3.0 libraries are available in Codea by default)
    ]]
}
local mt = { __index = mysql }


-- constants

local COM_QUIT = 0x01
local COM_QUERY = 0x03
local CLIENT_SSL = 0x0800

local SERVER_MORE_RESULTS_EXISTS = 8

-- 16MB - 1, the default max allowed packet size used by libmysqlclient
local FULL_PACKET_SIZE = 16777215

-- mysql field value type converters
local converters = new_tab(0, 8)

for i = 0x01, 0x05 do
    -- tiny, short, long, float, double
    converters[i] = tonumber
end
-- converters[0x08] = tonumber  -- long long
converters[0x09] = tonumber  -- int24
converters[0x0d] = tonumber  -- year
converters[0xf6] = tonumber  -- newdecimal

local function _get_byte2(data, i)
    local a, b = strbyte(data, i, i + 1)
    return bor(a, lshift(b, 8)), i + 2
end

local function _get_byte3(data, i)
    local a, b, c = strbyte(data, i, i + 2)
    return bor(a, lshift(b, 8), lshift(c, 16)), i + 3
end

local function _get_byte4(data, i)
    local a, b, c, d = strbyte(data, i, i + 3)
    return bor(a, lshift(b, 8), lshift(c, 16), lshift(d, 24)), i + 4
end

local function _get_byte8(data, i)
    local a, b, c, d, e, f, g, h = strbyte(data, i, i + 7)

    -- XXX workaround for the lack of 64-bit support in bitop:
    local lo = bor(a, lshift(b, 8), lshift(c, 16), lshift(d, 24))
    local hi = bor(e, lshift(f, 8), lshift(g, 16), lshift(h, 24))
    return lo + hi * 4294967296, i + 8

    -- return bor(a, lshift(b, 8), lshift(c, 16), lshift(d, 24), lshift(e, 32), lshift(f, 40), lshift(g, 48), lshift(h, 56)), i + 8
end

local function _set_byte2(n)
    return strchar(band(n, 0xff), band(rshift(n, 8), 0xff))
end

local function _set_byte3(n)
    return strchar(band(n, 0xff),
                   band(rshift(n, 8), 0xff),
                   band(rshift(n, 16), 0xff))
end

local function _set_byte4(n)
    return strchar(band(n, 0xff),
                   band(rshift(n, 8), 0xff),
                   band(rshift(n, 16), 0xff),
                   band(rshift(n, 24), 0xff))
end

local function _from_cstring(data, i)
    local last = strfind(data, "\0", i, true)
    if not last then
        return nil, nil
    end

    return sub(data, i, last), last + 1
end

local function _to_cstring(data)
    return data .. "\0"
end

local function _to_binary_coded_string(data)
    return strchar(#data) .. data
end

local function _dump(data)
    local len = #data
    local bytes = new_tab(len, 0)
    for i = 1, len do
        bytes[i] = format("%x", strbyte(data, i))
    end
    return concat(bytes, " ")
end

local function _compute_token(password, scramble)
    if password == "" then
        return ""
    end

    local stage1 = sha1(password)
    local stage2 = sha1(stage1)
    local stage3 = sha1(scramble .. stage2)
    local n = #stage1
    local bytes = new_tab(n, 0)
    for i = 1, n do
         bytes[i] = strchar(bxor(strbyte(stage3, i), strbyte(stage1, i)))
    end

    return concat(bytes)
end

local function _send_packet(self, req, size)
    local sock = self.sock

    self.packet_no = self.packet_no + 1

    -- print("packet no: ", self.packet_no)

    local packet = _set_byte3(size) .. strchar(band(self.packet_no, 255)) .. req

    --print("sending packet: ", _dump(packet))

    -- print("sending packet... of size " .. #packet)

    return sock:send(packet)
end

local function _recv_packet(self)
    local sock = self.sock

    local data, err = sock:receive(4) -- packet header
    if not data then
        return nil, nil, "failed to receive packet header: " .. err
    end

    --print("packet header: ", _dump(data))

    local len, pos = _get_byte3(data, 1)

    --print("packet length: ", len)

    if len == 0 then
        return nil, nil, "empty packet"
    end

    if len > self._max_packet_size then
        return nil, nil, "packet size too big: " .. len
    end

    local num = strbyte(data, pos)

    --print("recv packet: packet no: ", num)

    self.packet_no = num

    data, err = sock:receive(len)

    --print("receive returned")

    if not data then
        return nil, nil, "failed to read packet content: " .. err
    end

    --print("packet content: ", _dump(data))
    --print("packet content (ascii): ", data)

    local field_count = strbyte(data, 1)

    local typ
    if field_count == 0x00 then
        typ = "OK"
    elseif field_count == 0xff then
        typ = "ERR"
    elseif field_count == 0xfe then
        typ = "EOF"
    elseif field_count <= 250 then
        typ = "DATA"
    end

    return data, typ
end

local function _from_length_coded_bin(data, pos)
    local first = strbyte(data, pos)

    --print("LCB: first: ", first)

    if not first then
        return nil, pos
    end

    if first >= 0 and first <= 250 then
        return first, pos + 1
    end

    if first == 251 then
        return null, pos + 1
    end

    if first == 252 then
        pos = pos + 1
        return _get_byte2(data, pos)
    end

    if first == 253 then
        pos = pos + 1
        return _get_byte3(data, pos)
    end

    if first == 254 then
        pos = pos + 1
        return _get_byte8(data, pos)
    end

    return nil, pos + 1
end

local function _from_length_coded_str(data, pos)
    local len
    len, pos = _from_length_coded_bin(data, pos)
    if not len or len == null then
        return null, pos
    end

    return sub(data, pos, pos + len - 1), pos + len
end

local function _parse_ok_packet(packet)
    local res = new_tab(0, 5)
    local pos

    res.affected_rows, pos = _from_length_coded_bin(packet, 2)

    --print("affected rows: ", res.affected_rows, ", pos:", pos)

    res.insert_id, pos = _from_length_coded_bin(packet, pos)

    --print("insert id: ", res.insert_id, ", pos:", pos)

    res.server_status, pos = _get_byte2(packet, pos)

    --print("server status: ", res.server_status, ", pos:", pos)

    res.warning_count, pos = _get_byte2(packet, pos)

    --print("warning count: ", res.warning_count, ", pos: ", pos)

    local message = sub(packet, pos)
    if message and message ~= "" then
        res.message = message
    end

    --print("message: ", res.message, ", pos:", pos)

    return res
end

local function _parse_eof_packet(packet)
    local pos = 2

    local warning_count, pos = _get_byte2(packet, pos)
    local status_flags = _get_byte2(packet, pos)

    return warning_count, status_flags
end

local function _parse_err_packet(packet)
    local errno, pos = _get_byte2(packet, 2)
    local marker = sub(packet, pos, pos)
    local sqlstate
    if marker == '#' then
        -- with sqlstate
        pos = pos + 1
        sqlstate = sub(packet, pos, pos + 5 - 1)
        pos = pos + 5
    end

    local message = sub(packet, pos)
    return errno, message, sqlstate
end

local function _parse_result_set_header_packet(packet)
    local field_count, pos = _from_length_coded_bin(packet, 1)

    local extra
    extra = _from_length_coded_bin(packet, pos)

    return field_count, extra
end

local function _parse_field_packet(data)
    local col = new_tab(0, 2)
    local catalog, db, table, orig_table, orig_name, charsetnr, length
    local pos
    catalog, pos = _from_length_coded_str(data, 1)

    --print("catalog: ", col.catalog, ", pos:", pos)

    db, pos = _from_length_coded_str(data, pos)
    table, pos = _from_length_coded_str(data, pos)
    orig_table, pos = _from_length_coded_str(data, pos)
    col.name, pos = _from_length_coded_str(data, pos)

    orig_name, pos = _from_length_coded_str(data, pos)

    pos = pos + 1 -- ignore the filler

    charsetnr, pos = _get_byte2(data, pos)

    length, pos = _get_byte4(data, pos)

    col.type = strbyte(data, pos)

    --[[
    pos = pos + 1
    col.flags, pos = _get_byte2(data, pos)
    col.decimals = strbyte(data, pos)
    pos = pos + 1
    local default = sub(data, pos + 2)
    if default and default ~= "" then
        col.default = default
    end
    --]]

    return col
end

local function _parse_row_data_packet(data, cols, compact)
    local pos = 1
    local ncols = #cols
    local row
    if compact then
        row = new_tab(ncols, 0)
    else
        row = new_tab(0, ncols)
    end
    for i = 1, ncols do
        local value
        value, pos = _from_length_coded_str(data, pos)
        local col = cols[i]
        local typ = col.type
        local name = col.name

        --print("row field value: ", value, ", type: ", typ)

        if value ~= null then
            local conv = converters[typ]
            if conv then
                value = conv(value)
            end
        end

        if compact then
            row[i] = value

        else
            row[name] = value
        end
    end

    return row
end

local function _recv_field_packet(self)
    local packet, typ, err = _recv_packet(self)
    if not packet then
        return nil, err
    end

    if typ == "ERR" then
        local errno, msg, sqlstate = _parse_err_packet(packet)
        return nil, msg, errno, sqlstate
    end

    if typ ~= 'DATA' then
        return nil, "bad field packet type: " .. typ
    end

    -- typ == 'DATA'

    return _parse_field_packet(packet)
end


-- Global accessors

function mysql.new(self)
    local sock, err = tcp()
    if not sock then
        return nil, err
    end
    return setmetatable({ sock = sock }, mt)
end


function mysql.set_timeout(self, timeout)
    local sock = self.sock
    if not sock then
        return nil, "not initialized"
    end

    return sock:settimeout(timeout)
end


function mysql.connect(self, opts)
    local sock = self.sock
    if not sock then
        return nil, "not initialized"
    end

    local max_packet_size = opts.max_packet_size
    if not max_packet_size then
        max_packet_size = 1024 * 1024 -- default 1 MB
    end
    self._max_packet_size = max_packet_size

    local ok, err

    self.compact = opts.compact_arrays

    local database = opts.database or ""
    local user = opts.user or "root"

    local pool = opts.pool

    local host = opts.host
    if host then
        local port = opts.port or 3306
        if not pool then
            pool = user .. ":" .. database .. ":" .. host .. ":" .. port
        end

        ok, err = sock:connect(host, port, { pool = pool })

    else
        local path = opts.path
        if not path then
            return nil, 'neither "host" nor "path" options are specified'
        end

        if not pool then
            pool = user .. ":" .. database .. ":" .. path
        end

        ok, err = sock:connect("unix:" .. path, { pool = pool })
    end

    if not ok then
        return nil, 'failed to connect: ' .. err
    end

    local packet, typ, err = _recv_packet(self)
    if not packet then
        return nil, err
    end

    if typ == "ERR" then
        local errno, msg, sqlstate = _parse_err_packet(packet)
        return nil, msg, errno, sqlstate
    end

    self.protocol_ver = strbyte(packet)

    --print("protocol version: ", self.protocol_ver)

    local server_ver, pos = _from_cstring(packet, 2)
    if not server_ver then
        return nil, "bad handshake initialization packet: bad server version"
    end

    --print("server version: ", server_ver)

    self._server_ver = server_ver

    local thread_id, pos = _get_byte4(packet, pos)

    --print("thread id: ", thread_id)

    local scramble = sub(packet, pos, pos + 8 - 1)
    if not scramble then
        return nil, "1st part of scramble not found"
    end

    pos = pos + 9 -- skip filler

    -- two lower bytes
    local capabilities  -- server capabilities
    capabilities, pos = _get_byte2(packet, pos)

    -- print(format("server capabilities: %#x", capabilities))

    self._server_lang = strbyte(packet, pos)
    pos = pos + 1

    --print("server lang: ", self._server_lang)

    self._server_status, pos = _get_byte2(packet, pos)

    --print("server status: ", self._server_status)

    local more_capabilities
    more_capabilities, pos = _get_byte2(packet, pos)

    capabilities = bor(capabilities, lshift(more_capabilities, 16))

    --print("server capabilities: ", capabilities)

    -- local len = strbyte(packet, pos)
    local len = 21 - 8 - 1

    --print("scramble len: ", len)

    pos = pos + 1 + 10

    local scramble_part2 = sub(packet, pos, pos + len - 1)
    if not scramble_part2 then
        return nil, "2nd part of scramble not found"
    end

    scramble = scramble .. scramble_part2
    --print("scramble: ", _dump(scramble))

    local client_flags = 0x3f7cf;

    local ssl_verify = opts.ssl_verify
    local use_ssl = opts.ssl or ssl_verify

    if use_ssl then
        if band(capabilities, CLIENT_SSL) == 0 then
            return nil, "ssl disabled on server"
        end

        -- send a SSL Request Packet
        local req = _set_byte4(bor(client_flags, CLIENT_SSL))
                    .. _set_byte4(self._max_packet_size)
                    .. "\0" -- TODO: add support for charset encoding
                    .. strrep("\0", 23)

        local packet_len = 4 + 4 + 1 + 23
        local bytes, err = _send_packet(self, req, packet_len)
        if not bytes then
            return nil, "failed to send client authentication packet: " .. err
        end

        local ok, err = sock:sslhandshake(false, nil, ssl_verify)
        if not ok then
            return nil, "failed to do ssl handshake: " .. (err or "")
        end
    end

    local password = opts.password or ""

    local token = _compute_token(password, scramble)

    --print("token: ", _dump(token))

    local req = _set_byte4(client_flags)
                .. _set_byte4(self._max_packet_size)
                .. "\0" -- TODO: add support for charset encoding
                .. strrep("\0", 23)
                .. _to_cstring(user)
                .. _to_binary_coded_string(token)
                .. _to_cstring(database)

    local packet_len = 4 + 4 + 1 + 23 + #user + 1
        + #token + 1 + #database + 1

    --print("packet content length: ", packet_len)
    --print("packet content: ", _dump(concat(req, "")))

    local bytes, err = _send_packet(self, req, packet_len)
    if not bytes then
        return nil, "failed to send client authentication packet: " .. err
    end

    --print("packet sent ", bytes, " bytes")

    local packet, typ, err = _recv_packet(self)
    if not packet then
        return nil, "failed to receive the result packet: " .. err
    end

    if typ == 'ERR' then
        local errno, msg, sqlstate = _parse_err_packet(packet)
        return nil, msg, errno, sqlstate
    end

    if typ == 'EOF' then
        return nil, "old pre-4.1 authentication protocol not supported"
    end

    if typ ~= 'OK' then
        return nil, "bad packet type: " .. typ
    end

    return 1
end


function mysql.close(self)
    local sock = self.sock
    if not sock then
        return nil, "not initialized"
    end

    local bytes, err = _send_packet(self, strchar(COM_QUIT), 1)
    if not bytes then
        return nil, err
    end

    return sock:close()
end


function mysql.server_ver(self)
    return self._server_ver
end


local function send_query(self, query)
    local sock = self.sock
    if not sock then
        return nil, "not initialized"
    end

    self.packet_no = -1

    local cmd_packet = strchar(COM_QUERY) .. query
    local packet_len = 1 + #query

    local bytes, err = _send_packet(self, cmd_packet, packet_len)
    if not bytes then
        return nil, err
    end

    --print("packet sent ", bytes, " bytes")

    return bytes
end
mysql.send_query = send_query


local function read_result(self, est_nrows)
    local sock = self.sock
    if not sock then
        return nil, "not initialized"
    end

    local packet, typ, err = _recv_packet(self)
    if not packet then
        return nil, err
    end

    if typ == "ERR" then
        local errno, msg, sqlstate = _parse_err_packet(packet)
        return nil, msg, errno, sqlstate
    end

    if typ == 'OK' then
        local res = _parse_ok_packet(packet)
        if res and band(res.server_status, SERVER_MORE_RESULTS_EXISTS) ~= 0 then
            return res, "again"
        end
        return res
    end

    if typ ~= 'DATA' then
        return nil, "packet type " .. typ .. " not supported"
    end

    -- typ == 'DATA'

    --print("read the result set header packet")

    local field_count, extra = _parse_result_set_header_packet(packet)

    --print("field count: ", field_count)

    local cols = new_tab(field_count, 0)
    for i = 1, field_count do
        local col, err, errno, sqlstate = _recv_field_packet(self)
        if not col then
            return nil, err, errno, sqlstate
        end

        cols[i] = col
    end

    local packet, typ, err = _recv_packet(self)
    if not packet then
        return nil, err
    end

    if typ ~= 'EOF' then
        return nil, "unexpected packet type " .. typ .. " while eof packet is "
            .. "expected"
    end

    -- typ == 'EOF'

    local compact = self.compact

    local rows = new_tab(est_nrows or 4, 0)
    local i = 0
    while true do
        --print("reading a row")

        packet, typ, err = _recv_packet(self)
        if not packet then
            return nil, err
        end

        if typ == 'EOF' then
            local warning_count, status_flags = _parse_eof_packet(packet)

            --print("status flags: ", status_flags)

            if band(status_flags, SERVER_MORE_RESULTS_EXISTS) ~= 0 then
                return rows, "again"
            end

            break
        end
h
        -- if typ ~= 'DATA' then
            -- return nil, 'bad row packet type: ' .. typ
        -- end

        -- typ == 'DATA'

        local row = _parse_row_data_packet(packet, cols, compact)
        i = i + 1
        rows[i] = row
    end

    return rows
end
mysql.read_result = read_result


function mysql.query(self, query, est_nrows)
    local bytes, err = send_query(self, query)
    if not bytes then
        return nil, "failed to send query: " .. err
    end

    return read_result(self, est_nrows)
end


function mysql.set_compact_arrays(self, value)
    self.compact = value
end
--# io
lfs = {}

local ENV = os.getenv("HOME")
local MIME = {
    [".text"] = "text/plain",
    [".txt"] = "text/plain",
    [".md"] = "text/markdown",
    [".markdown"] = "text/markdown",
    [".lua"] = "text/x-lua",
    [".luac"] = "application/x-lua-bytecode",
    [".pdf"] = "application/pdf",
    [".jpeg"] = "image/jpeg",
    [".jpg"] = "image/jpeg",
    [".gif"] = "image/gif",
    [".png"] = "image/png",
    [".tiff"] = "image/tiff",
    [".html"] = "text/html",
    [".htm"] = "text/html",
    [".css"] = "text/html",
    [".js"] = "application/javascript",
    [".json"] = "application/json",
}

local function breadcrumbs(path)
    return path:gsub(":", "/"):match("(.+)/(.+)(%.[^.]+)$")
end

function lfs.read(file)
    local DIR, FILE, EXT = breadcrumbs(file)
    local data = io.open(string.format("%s/%s/%s", ENV, DIR, FILE..EXT), "r")
    
    if data then
        local content = data:read("*all")
        data:close()
        return content, MIME[EXT]
    end
    
    return false
end

function lfs.write(file, content)
    local DIR, FILE, EXT = breadcrumbs(file)
    local data = io.open(string.format("%s/%s/%s", ENV, DIR, FILE..EXT), "w")
    
    if data then
        wFd:write(td)
        wFd:close()
        return true
    end
    
    return false
end

-- also an example how to read sequentially
function lfs.read_binary(file)
    local DIR, FILE, EXT = breadcrumbs(file)
    local data = io.open(string.format("%s/%s/%s", ENV, DIR, FILE..EXT), "rb")
    
    if data then
        local chunks = 512
        local content = ""
        
        while true do
            local bytes = data:read(chunks) -- Read only n bytes per iteration
            if not bytes then break end
            content = content..bytes
            break
        end
        
        data:close()
        
        return content, MIME[EXT]
    end
    
    return false
end

function lfs.write_binary(file, content)
    local DIR, FILE, EXT = breadcrumbs(file)
    local data = io.open(string.format("%s/%s/%s", ENV, DIR, FILE..EXT), "wb")
    
    if data then
        data:write(content) -- You could do it in parts, but oh.
        data:close()
        return true
    end
    
    return false
end