System error after it went up to server

Question

The system was developed in php using the codeigniter 3 framework.

Works great on localhost.

I went up to the server and started giving problems. I checked php installed and is in version 5.6

Mistakes that happen:

Message: Object of class Ci_db_mysqli_result could not be converted to int

Filename: models/Users.php

Line Number: 12

Message: Cannot Modify header information - headers already sent by (output Started at /home/user145/public_html/sistema/system/core/Exceptions.php:271)

Filename: helpers/url_helper.php

Line Number: 564

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

class Usuarios_model extends CI_Model {

public function login($username, $password) {
    $this->db->where("username", $username);
    $this->db->where("password", $password);

    $resultados = $this->db->get("usuarios");

    if ($resultados > 0) { ----------------------> LINHA 12
        return $resultados->row();
    }
    else {
        return false;
    }
}}

When I return to some page this error happens:

Severity: Warning

Message: unlink(/tmp/ci_session9c9ddb88511925d48aa2df5fd44857177296879f): Operation not permitted

Filename: drivers/Session_files_driver.php

Line Number: 384

Backtrace:

File: >/home/user145/public_html/sistema/application/controllers/Dashboard.php Line: 7 Function: __Construct

File: /home/user145/public_html/sistema/index.php Line: 315 Function: require_once

After going up the server, some pages are not being found when I try to access.

Answer 1

As the comments pointed out above, perhaps it lacks some experience in programming. On line 12 you are checking if the query returned any data. To do this it is not necessary to make $results > 0`, since in php everything is considered true except

1. 0 (zero in number)
2. "0" (zero string)
3. false
4. "" (empty string)
5. null
6. array() (empty array)

If you want to study a little more about it I suggest the documentation of the PHP

Therefore, to make this comparison just do

if ($resultados)

Review all your code to make sure it’s not happening elsewhere.