I have a problem with Login Register, do you help me?

FiveM Resource Development & Modding Discussion
1

Hello
I have a problem with creating a login and registration when a player enters the server I do not know how to create a check and under which event to connect to check if the player is in the database and if it is not to show him registration, or someone is able to me in somehow present or lead a good direction?

2

hard to help without reviewing any code

3 

function WczytajGracza(source, callback)
local identifier = GetPlayerIdentifiers(source)[1]
    MySQL.Async.fetchAll("SELECT * FROM `needrp_postacie` WHERE `p_hex` = @identifier",
  {
    ['@identifier'] = identifier
  },
  function(result)
    if result[1]['p_hex'] ~= nil then
      local data = {
		id  = result[1]['p_id'],
        identifier  = result[1]['p_hex'],
        firstname  = result[1]['p_firstname'],
        lastname  = result[1]['p_lastname'],
        dateofbirth  = result[1]['p_dateofbirth'],
        sex      = result[1]['p_sex'],
        height    = result[1]['p_height'],
		money	= result[1]['p_money'],
		bankmoney	= result[1]['p_bankmoney'],
		spawn	= result[1]['p_spawn']
      }

      callback(data)
    else
      local data = {
        identifier   = '',
        firstname   = '',
        lastname   = '',
        dateofbirth = '',
        sex     = '',
        height     = '',
		money	= '',
		bankmoney	= '',
		spawn	= ''
      }

      callback(data)
    end
  end)
end


AddEventHandler('playerConnecting', function(playerName, setKickReason)
  WczytajGracza(source, function(data)
    if data.p_hex ~= nil then
      print('Nie znaleziono ')
    else
      print('znaleziono gracza ' .. data.firstname .. ' ' .. data.lastname)
    end
  end)
  print('ss')
end)

Error running call reference function for resource mymode: citizen:/scripting/lua/scheduler.lua:403: mymode_server.lua:10: attempt to index a nil value (field ‘?’)
stack traceback:
mymode_server.lua:10: in upvalue ‘ref’
citizen:/scripting/lua/scheduler.lua:389: in function citizen:/scripting/lua/scheduler.lua:388
[C]: in function ‘xpcall’
citizen:/scripting/lua/scheduler.lua:388: in function citizen:/scripting/lua/scheduler.lua:387
stack traceback:
[C]: in function ‘error’
citizen:/scripting/lua/scheduler.lua:403: in function citizen:/scripting/lua/scheduler.lua:372
Error: Unhandled error: Error: BUFFER_SHORTAGE
Error: BUFFER_SHORTAGE
at n.e [as reserve] (citizen:/scripting/v8/msgpack.js:29:12766)
at h (citizen:/scripting/v8/msgpack.js:29:15761)
at n.r [as decode] (citizen:/scripting/v8/msgpack.js:29:13908)
at n.fetch (citizen:/scripting/v8/msgpack.js:29:6972)
at n.u [as read] (citizen:/scripting/v8/msgpack.js:29:12076)
at Object.n [as decode] (citizen:/scripting/v8/msgpack.js:29:7097)
at unpack (citizen:/scripting/v8/main.js:20:33)
at citizen:/scripting/v8/main.js:51:11
at setImmediate (mysql-async.js:4962:9)
at Object.callback (citizen:/scripting/v8/timer.js:56:6)

4

you are trying to index a empty table, that is what the error says

5

How can I do it differently or make it work?

6 
function WczytajGracza(source, callback)
	
  local pName = GetPlayerName(source)
  MySQL.Async.fetchAll("SELECT p_id FROM `needrp_postacie` WHERE `p_name` = @pName",
  {
    ['@pName'] = pName
  },
  function(result)
    if result[1]['p_name'] ~= nil then
      
	  local jest = true
      callback(jest)
    else
	  local jest = false
      callback(jest)
    end
  end)
end


AddEventHandler('playerConnecting', function(playerName, setKickReason)
  WczytajGracza(source, function(jest)
    if jest then
      print(' znaleziono ')
    else
      print('Nie znaleziono gracza ')
    end
  end)
  print('ss')
end)

and the same error…

7 
AddEventHandler('playerConnecting', function(playerName, setKickReason)
    local pName = GetPlayerName(source)
    print(pName)
    MySQL.Async.fetchAll("SELECT * FROM `needrp_postacie` WHERE `p_name` = @pName",
    {
        ['@pName'] = pName
    },
        function(result)
        print(#result)
        if result then
            print('Nie Znaleziono gracza')
        else
            print('Znaleziono gracza')
        end
    end)
end)

Ok no errors is good!

result return to me 1 if player exist or 0 if player no exist in base, but this code not working