DataTables warning: table id=DataTables_Table_0 - Ajax error. For more information about this error, please see http://datatables.net/tn/7

Question

I tried server processing for jQuery data table but getting error:

DataTables warning: table id=DataTables_Table_0 - Ajax error

and when I remove below code from server.php

require( '/machines/jquery/ssp.class.php' );

echo json_encode(
    SSP::simple( $_POST, $sql_details, $table, $primaryKey, $columns )
);

then getting error:

DataTables warning: table id=DataTables_Table_0 - Invalid JSON response

Also note that, previously require was: require( 'ssp.class.php' ); as per https://datatables.net/examples/server_side/post.html but I tried to find ssp.class.php in entire / directory in my ubuntu OS but there was no such php file so searched google and copied that file and kept under /machines/jquery/ssp.class.php but still no luck.

I have already checked all the php, pdp .. settings and it is correct so something is wrong in the code or my server doesn't understand the way jQuery given the server processing example.

There is no problem for client side data processing but server side data processing gives above error.

 root@m100:~# php -i|grep PDO
 PDO
 PDO support => enabled
 PDO drivers => mysql
 PDO Driver for MySQL => enabled

client.php:

<div>

<h3>Machines Data</h3>
<div class="container">
    <div id="machines-data" style="padding-left: 15px; padding-right:  15px;"></div>

    <table class="table machines-data" border="1">

    </table>

</div>

</div>


<script>

$(document).ready(function () {

});

<script>
 $(function(){
    $("#progress").show();

        $(".machines-data").dataTable({
            "processing": true,
            "serverSide": true,
            "ajax": { "url": "/machines/server.php", "type": "POST" },
            "columns": [
        { "data": "id" },
        { "data": "ip" },
        { "data": "machine" },
        { "data": "action" },
    ]

        });
  })
 </script>

server.php:

<?php

ignore_user_abort(true);

if($_POST) {

$table = '1_machine_data';

$primaryKey = 'id';

 $columns = array(
     array( 'db' => 'id', 'dt' => 'id' ),
     array( 'db' => 'ip',  'dt' => 'ip' ),
     array( 'db' => 'machine',   'dt' => 'machine' ),
     array( 'db' => 'action',     'dt' => 'action' ),
 );

$sql_details = array(
    'user' => 'root',
    'pass' => 'pass',
    'db'   => 'machine',
    'host' => 'localhost'
);

require( '/machines/jquery/ssp.class.php' );

echo json_encode(
     SSP::simple( $_POST, $sql_details, $table, $primaryKey, $columns )
);

exit (0);

}

?>

Answer 1

For whatever it may be worth. I had the same problem. It happened because I deployed two shiny applications in Windows 10. I needed to completely force-close RStudio from task manager before executing the second app. After this, the DT table load well.

Answer 2

Here is the answer:

<?php

ignore_user_abort(true);

if($_POST) {

    $aColumns = array( 'id', 'ip', 'machine', 'status' );
    
    $sIndexColumn = "id";
    
    $sTable = "1_machines";
    
    $gaSql['user']       = "root";
    $gaSql['password']   = "pwd";
    $gaSql['db']         = "machines";
    $gaSql['server']     = "localhost";
    
    function fatal_error ( $sErrorMessage = '' )
    {
        header( $_SERVER['SERVER_PROTOCOL'] .' 500 Internal Server Error' );
        die( $sErrorMessage );
    }

    if ( ! $gaSql['link'] = mysql_pconnect( $gaSql['server'], $gaSql['user'], $gaSql['password']  ) )
    {
        fatal_error( 'Could not open connection to server' );
    }

    if ( ! mysql_select_db( $gaSql['db'], $gaSql['link'] ) )
    {
        fatal_error( 'Could not select database ' );
    }
    
    $sLimit = "";
    if ( isset( $_GET['iDisplayStart'] ) && $_GET['iDisplayLength'] != '-1' )
    {
        $sLimit = "LIMIT ".intval( $_GET['iDisplayStart'] ).", ".
            intval( $_GET['iDisplayLength'] );
    }
    
    $sOrder = "";
    if ( isset( $_GET['iSortCol_0'] ) )
    {
        $sOrder = "ORDER BY  ";
        for ( $i=0 ; $i<intval( $_GET['iSortingCols'] ) ; $i++ )
        {
            if ( $_GET[ 'bSortable_'.intval($_GET['iSortCol_'.$i]) ] == "true" )
            {
                $sOrder .= "`".$aColumns[ intval( $_GET['iSortCol_'.$i] ) ]."` ".
                    ($_GET['sSortDir_'.$i]==='asc' ? 'asc' : 'desc') .", ";
            }
        }
        
        $sOrder = substr_replace( $sOrder, "", -2 );
        if ( $sOrder == "ORDER BY" )
        {
            $sOrder = "";
        }
    }
    
    $sWhere = "";
    if ( isset($_GET['sSearch']) && $_GET['sSearch'] != "" )
    {
        $sWhere = "WHERE (";
        for ( $i=0 ; $i<count($aColumns) ; $i++ )
        {
            $sWhere .= "`".$aColumns[$i]."` LIKE '%".mysql_real_escape_string( $_GET['sSearch'] )."%' OR ";
        }
        $sWhere = substr_replace( $sWhere, "", -3 );
        $sWhere .= ')';
    }
    
    for ( $i=0 ; $i<count($aColumns) ; $i++ )
    {
        if ( isset($_GET['bSearchable_'.$i]) && $_GET['bSearchable_'.$i] == "true" && $_GET['sSearch_'.$i] != '' )
        {
            if ( $sWhere == "" )
            {
                $sWhere = "WHERE ";
            }
            else
            {
                $sWhere .= " AND ";
            }
            $sWhere .= "`".$aColumns[$i]."` LIKE '%".mysql_real_escape_string($_GET['sSearch_'.$i])."%' ";
        }
    }
    
    
    $sQuery = "
        SELECT SQL_CALC_FOUND_ROWS `".str_replace(" , ", " ", implode("`, `", $aColumns))."`
        FROM   $sTable
        $sWhere
        $sOrder
        $sLimit
        ";
    $rResult = mysql_query( $sQuery, $gaSql['link'] ) or fatal_error( 'MySQL Error: ' . mysql_errno() );
    
    $sQuery = "
        SELECT FOUND_ROWS()
    ";
    $rResultFilterTotal = mysql_query( $sQuery, $gaSql['link'] ) or fatal_error( 'MySQL Error: ' . mysql_errno() );
    $aResultFilterTotal = mysql_fetch_array($rResultFilterTotal);
    $iFilteredTotal = $aResultFilterTotal[0];
    
    $sQuery = "
        SELECT COUNT(`".$sIndexColumn."`)
        FROM   $sTable
    ";
    $rResultTotal = mysql_query( $sQuery, $gaSql['link'] ) or fatal_error( 'MySQL Error: ' . mysql_errno() );
    $aResultTotal = mysql_fetch_array($rResultTotal);
    $iTotal = $aResultTotal[0];
    
    $output = array(
        "sEcho" => intval($_GET['sEcho']),
        "iTotalRecords" => $iTotal,
        "iTotalDisplayRecords" => $iFilteredTotal,
        "aaData" => array()
    );
    
    while ( $aRow = mysql_fetch_array( $rResult ) )
    {
        $row = array();
        for ( $i=0 ; $i<count($aColumns) ; $i++ )
        {
            if ( $aColumns[$i] == "started_on" )
            {
                $row[] = ($aRow[ $aColumns[$i] ]=="0") ? ' - ' : $aRow[ $aColumns[$i] ];
            }
            else if ( $aColumns[$i] != ' ' )
            {
                /* General output */
                $row[] = $aRow[ $aColumns[$i] ];
            }
        }
        $output['aaData'][] = $row;
    }
    
    echo json_encode( $output );
    
    exit (0);

}

?>

Answer 3

DataTables warning: table id=DataTables_Table_0 - Ajax error

mostly this error coming because you call POST method to GET data or there is no any GET function/method..

if i explain with ASP.NET Core .. You want to load DataTable with data getting from Back-end and the method is like this public IActionResult GetAll() then this work, But if you put [HttpPost] and set it like this

[HttpPost]
public IActionResult GetAll()

then this is a POST method. so now you do not have a GET Method , so then it search for a GET method but there is no any GET method. Now in this case you will get

DataTables warning: table id=DataTables_Table_0 - Ajax error

if you expecting some response from POST, it is OK to have 0 data or what you expecting is empty but if you get Undefined , null or something other than what DataTable expected, this is the case that this error triggered

Answer 4

Here is the answer! I used php+datatable server processing code, instead of SSP stuff..

<?php

ignore_user_abort(true);

if($_POST) {

    $aColumns = array( 'id', 'ip', 'machine', 'status' );

    $sIndexColumn = "id";

    $sTable = "1_machines";

    $gaSql['user']       = "root";
    $gaSql['password']   = "pwd";
    $gaSql['db']         = "machines";
    $gaSql['server']     = "localhost";

    function fatal_error ( $sErrorMessage = '' )
    {
        header( $_SERVER['SERVER_PROTOCOL'] .' 500 Internal Server Error' );
        die( $sErrorMessage );
    }

    if ( ! $gaSql['link'] = mysql_pconnect( $gaSql['server'], $gaSql['user'], $gaSql['password']  ) )
    {
        fatal_error( 'Could not open connection to server' );
    }

    if ( ! mysql_select_db( $gaSql['db'], $gaSql['link'] ) )
    {
        fatal_error( 'Could not select database ' );
    }

    $sLimit = "";
    if ( isset( $_GET['iDisplayStart'] ) && $_GET['iDisplayLength'] != '-1' )
    {
        $sLimit = "LIMIT ".intval( $_GET['iDisplayStart'] ).", ".
            intval( $_GET['iDisplayLength'] );
    }

    $sOrder = "";
    if ( isset( $_GET['iSortCol_0'] ) )
    {
        $sOrder = "ORDER BY  ";
        for ( $i=0 ; $i<intval( $_GET['iSortingCols'] ) ; $i++ )
        {
            if ( $_GET[ 'bSortable_'.intval($_GET['iSortCol_'.$i]) ] == "true" )
            {
                $sOrder .= "`".$aColumns[ intval( $_GET['iSortCol_'.$i] ) ]."` ".
                    ($_GET['sSortDir_'.$i]==='asc' ? 'asc' : 'desc') .", ";
            }
        }

        $sOrder = substr_replace( $sOrder, "", -2 );
        if ( $sOrder == "ORDER BY" )
        {
            $sOrder = "";
        }
    }

    $sWhere = "";
    if ( isset($_GET['sSearch']) && $_GET['sSearch'] != "" )
    {
        $sWhere = "WHERE (";
        for ( $i=0 ; $i<count($aColumns) ; $i++ )
        {
            $sWhere .= "`".$aColumns[$i]."` LIKE '%".mysql_real_escape_string( $_GET['sSearch'] )."%' OR ";
        }
        $sWhere = substr_replace( $sWhere, "", -3 );
        $sWhere .= ')';
    }

    for ( $i=0 ; $i<count($aColumns) ; $i++ )
    {
        if ( isset($_GET['bSearchable_'.$i]) && $_GET['bSearchable_'.$i] == "true" && $_GET['sSearch_'.$i] != '' )
        {
            if ( $sWhere == "" )
            {
                $sWhere = "WHERE ";
            }
            else
            {
                $sWhere .= " AND ";
            }
            $sWhere .= "`".$aColumns[$i]."` LIKE '%".mysql_real_escape_string($_GET['sSearch_'.$i])."%' ";
        }
    }


    $sQuery = "
        SELECT SQL_CALC_FOUND_ROWS `".str_replace(" , ", " ", implode("`, `", $aColumns))."`
        FROM   $sTable
        $sWhere
        $sOrder
        $sLimit
        ";
    $rResult = mysql_query( $sQuery, $gaSql['link'] ) or fatal_error( 'MySQL Error: ' . mysql_errno() );

    $sQuery = "
        SELECT FOUND_ROWS()
    ";
    $rResultFilterTotal = mysql_query( $sQuery, $gaSql['link'] ) or fatal_error( 'MySQL Error: ' . mysql_errno() );
    $aResultFilterTotal = mysql_fetch_array($rResultFilterTotal);
    $iFilteredTotal = $aResultFilterTotal[0];

    $sQuery = "
        SELECT COUNT(`".$sIndexColumn."`)
        FROM   $sTable
    ";
    $rResultTotal = mysql_query( $sQuery, $gaSql['link'] ) or fatal_error( 'MySQL Error: ' . mysql_errno() );
    $aResultTotal = mysql_fetch_array($rResultTotal);
    $iTotal = $aResultTotal[0];

    $output = array(
        "sEcho" => intval($_GET['sEcho']),
        "iTotalRecords" => $iTotal,
        "iTotalDisplayRecords" => $iFilteredTotal,
        "aaData" => array()
    );

    while ( $aRow = mysql_fetch_array( $rResult ) )
    {
        $row = array();
        for ( $i=0 ; $i<count($aColumns) ; $i++ )
        {
            if ( $aColumns[$i] == "started_on" )
            {
                $row[] = ($aRow[ $aColumns[$i] ]=="0") ? ' - ' : $aRow[ $aColumns[$i] ];
            }
            else if ( $aColumns[$i] != ' ' )
            {
                /* General output */
                $row[] = $aRow[ $aColumns[$i] ];
            }
        }
        $output['aaData'][] = $row;
    }

    echo json_encode( $output );

    exit (0);

}

?>

Answer 5

Open the server side file ssp.class.php and comment line 20-23.

    //REMOVE THIS BLOCK - used for DataTables test environment only!
    //$file = $_SERVER['DOCUMENT_ROOT'].'/datatables/mysql.php';
    //if ( is_file( $file ) ) {
        //include( $file );
    //}