pagination page gives 404 in codeigniter3 framework

Question

I have written pagination code in Codeigniter3 framework, but when I want to go to the second, third and etc. page, it shows me 404 page. Where can be the problem? My routes file:

$route['courses/category/(:any)'] = 'courses/all_courses/$1';
$route['courses/(:any)'] = 'courses/single_course/$1';

My controller:

public function all_courses($categories_slug = NULL, $offset = 0) {

            //pagination
            $config['base_url'] = base_url() . 'courses/category/'.$categories_slug;
            $config['total_rows'] = $this->db->count_all('courses');
            $config['per_page'] = 2;
            $config['uri_segment'] = 4;

            $this->pagination->initialize($config);


            $data['title'] = 'Bütün Kurslar Burada';

            $data['courses'] = $this->courses_model->get_all_courses($categories_slug, $config['per_page'], $offset);


            $this->load->view('templates/header');
            $this->load->view('courses/courses', $data);
            $this->load->view('templates/footer');
        }

My model:

public function get_all_courses($categories_slug = FALSE, $limit = FALSE, $offset = FALSE) {
        if($limit) {
            $this->db->limit($limit, $offset);
        }
<-- and other codes here -->
}

And my view:

<div class="col-md-12 courses_page_btn2">
                <nav>
                    <ul class="pagination">
                        <li><a><?php echo $this->pagination->create_links(); ?> </a></li>
                    </ul>
                </nav>
            </div>

Answer 1

First, in your routes file, your route from courses/category/(:any) is set to route to courses/all_courses/$1, but your controller's all_courses method has a second parameter. So you need to do something about that. I'm guessing that since your pagination is using URI segment 4 that you'll need to adjust your route like this:

$route['courses/category/(:any)/(:num)'] = 'courses/all_courses/$1/$2';

The problem with that route is that if there is no (:num) then you'll get a 404. In most pagination schemes, you're going to want it to default to 1 (the first page). Consider this route instead:

$route['courses/category/(.+)'] = function ($x, $y = 1)
{
    return 'courses/all_courses/' . $x . '/' . $y;
};

This will route to your all_courses method, and provide both parameters, even if you leave out the second one.

This pagination works for me with that route:

public function all_courses( $x, $y )
{
    $this->load->helper('url');
    $this->load->library('pagination');

    $pconfig['base_url'] = base_url() . 'courses/category/'.$x;
    $pconfig['total_rows'] = 10;
    $pconfig['per_page'] = 2;
    $pconfig['uri_segment'] = 4;

    $this->pagination->initialize($pconfig);

    echo $this->pagination->create_links();
}