DataTable with Ajax is not working well after use

问题:

I have an user table using DataTables, that will contain more than 200 rows. It's look so fine when I'm using DataTables for default the "pageLength": 10, and this is the table example.

  Username     |   Type    |    Request   |
user01               1         request01
user02               1         request02
user03               2         request03
user04               1         request04
user05               1         request05
user06               1         request06
user07               1         request07
user08               1         request08
user09               1         request09
user10               1         request10

Showing 1 to 10 of 200 entries FirstPrevious123...20NextLast

So, for reducing the loading time, I decide to use "processing": true and "serverSide": true. Then I got some issue with this "serverSide" : true, It's print 200 rows of data in table.

Showing 0 to 0 of 0 entries (filtered from NaN total entries). Then the pagination is still print and after I click the page 2, it's doing nothing.

I wan't the DataTables is getting the 10 data for the first, after pagination 2 is clicked, it will get 10 more and so on.

I'm using CodeIgniter, here is my code :

On my Views + Js :

<select name="task" id="task">
   <option value="1">Task 1</option>
   <option value="2">Task 2</option>
</select>
<table id="user-request" class="table">
<thead>
   <tr>
      <th>Username</th>
      <th>Type</th>
      <th>Request</th>
   </tr>
</thead>
</table>
<script>
... on task change ...
... var task = $("#task").val(); ...
   $('#user-request').DataTable({
        'processing': true,
        'serverSide': true,
        'ajax': {
            'type': 'POST',
            'url': base_url+'user/get_user_request',
            'data': {"task":task,"csrf_token":$("input[name=csrf_token]").val()}
        }
    })
</script>

Note : Task is a different group, example like Class 1 or Class 2, Orchard University or Harvard University

On my Controller :

$task = $this->input->post('task', TRUE);
$user_request = $this->model->all_user_request(task);
foreach ($user_request as $ur)
{
    $arr = array();
    $arr[] = $ur->username;
    $arr[] = $ur->type;
    $arr[] = $ur->request;
    $data[] = $arr;
}
$output = array(
    "data" => $data
);
if (COUNT($output) > 0)
{
    echo json_encode($output);
}

On my Model :

public function all_user_request($task_id) {
   $query = "SELECT * FROM user_request WHERE task_id = ?";
   return $this->db->query($query, $task_id)->result();
}

Note : In model is actually using 2 INNER JOIN, I'm just simplifying the select only for asking here. (turning into denormalization table only in here).

I was trying to add draw, recordsTotal, recordsFiltered to $output in my controller just using numeric data. Example

$output = array(
    "draw" => 5,
    "recordsTotal" => 5,
    "recordsFiltered" => 5,
    "data" => $data
);
if (COUNT($output) > 0)
{
    echo json_encode($output);
}

I was searching for the answer but, and I think the problem is here but I still have no idea where I must get the draw - recordsTotal - recordsFiltered data. I see on another answer from others, they use "draw" => $_POST['draw'], then I tried it, and it's do nothing.

So I'm trying that using numeric data, but the result is still same. I need some help with this. It's still print 200 rows of data in table.

Showing 0 to 0 of 0 entries (filtered from NaN total entries). Then the pagination is still print and after I click the page 2, it's doing nothing.

回答1:

Datatables send everything you need - if you take a look in your console under network you'll see, that they use the ajax-get method to send those requests to the server

The GET Parameter are as follows

draw
columns
start
length
search

You can find the entire list here

which means - you've to adapt your model properly...

something like that should work

public function all_user_request($task_id) 
{
    $intStart = intval($this->input->get("start"));
    $intLength = intval($this->input->get("length"));
    $strSearch = (strlen($this->input->get("search")["value"]) >= 2) ?   $this->input->get("search",true)["value"]    :   false;
    $order = $this->input->get("order",true);


    $this->setQuery($task_id,$strSearch);

    $query = $this->db->get();
    $this->recordsTotal = $query->num_rows();

    $this->setQuery($task_id, $strSearch);

    if ($intStart >= 0 && $intLength > 0)
    {
        $this->db->limit($intLength,$intStart);
    }

    $strOrderField = 'username';
    $strDirection = "ASC";
    if (is_array($order))
    {
        switch($order[0]['column'])
        {
            case 1:
                $strOrderField = 'type';
                break;
            case 2:
                $strOrderField = 'request';
                break;

        }
        if (!empty($order[0]['dir']))    $strDirection = $order[0]['dir'];
    }
    $this->db->order_by($strOrderField,$strDirection);


    $query = $this->db->get();

    $arrData = $query->result();

    return $arrData;

}

public function getRecordsTotal()
{
    return $this->recordsTotal;
}

private function setQuery($task_id, $strSearch="")
{
    $this->db
        ->select('*')
        ->from('user_request')
        ->where('task_id', $task_id);

    if (!empty($strSearch))
    {
        $this->db->like('task_id', $strSearch);
    }

}

and your controller

//controller
$task = $this->input->post('task', TRUE);
$user_request = $this->model->all_user_request($task);

$data = [];
foreach ($user_request as $ur)
{
    $data[] = [
        $ur->username,
        $ur->type,
        $ur->request
    ];
}

$arrCompiledData = [
    'data' => $data,
    'draw' => $this->input->get('draw'),
    'recordsTotal' => $this->model->getRecordsTotal(),
    'recordsFiltered' => $this->model->getRecordsTotal(),
];

$this->output
    ->set_content_type('application/json')
    ->set_output(json_encode($arrCompiledData));

Please keep in mind i just wrote this down - maybe there are some typos, but you should be able to understand how the serverside processing of a datatables request should work.

回答2:

As long as you chose the server mode, you have to manage everything via the requests. So, you have to dynamically create the values of the output array :

$output = array(
    "draw" => $_POST['draw'],
    "recordsTotal" => $this->my_model->get_total_records(),
    "recordsFiltered" => $this->my_model->get_total_filtered(),
    "data" => $this->my_model->all_user_request($id)
);

and the model functions

public function all_user_request($task_id) {
    $query = "SELECT * FROM user_request WHERE task_id = ?"; // add limit $_POST['length'], $_POST['start'] to your request

    return $this->db->query($query, $task_id)->result();
}

回答3:

If you're using serverSide = true, you should provide your own filter count and total count. Also provide your own search function, ordering and etc. Use controller & model below for your reference.

Controller

$task = $this->input->post('task', TRUE);
$user_request = $this->model->all_user_request($task);

$output = array(
     'draw' => $this->input->post('draw', TRUE),
     'recordsTotal' => $user_request['recordsTotal'],
     'recordsFiltered => $user_request['recordsFiltered'],
     'data'           => empty($user_request['data'])? array() : $user_request['data']
);

echo json_encode($output);

Model

public function all_user_request($task_id) {

   $params = $this->input->post(null, TRUE);

   $search_fields = array('username','type','request'); //change this into your table fields

   $data = array();
   $this->db->start_cache();
   $this->db->select("username, type, request");
   $this->db->from("user_request");
   $this->db->where("task_id", $task_id);

    if(!empty($params['search']['value'])){
        $str = $params['search']['value'];
        $this->db->group_start();
        foreach($search_fields as $row){
            $this->db->or_like($row, $str, 'BOTH');
        }
        $this->db->group_end();
    }

   $data['recordsTotal'] = $this->db->count_all_results();

   $this->db->stop_cache();
   $this->db->limit($params['length'], $params['start']);
   $data['recordsFiltered'] = $this->db->count_all_results();
   $query = $this->db->get();
   $this->db->flush_cache();
    foreach($query->result_array() as $row){
        $data['data'][] = array_values($row);
    }
   return $data;
}