Gist for https://github.com/yajra/laravel-datatables/pull/1852

DataProcessor.php

<?php

namespace Yajra\DataTables\Processors;

use Illuminate\Support\Arr;
use Yajra\DataTables\Utilities\Helper;

class DataProcessor
{
    /**
     * @var int
     */
    protected $start;

    /**
     * Columns to escape value.
     *
     * @var array
     */
    protected $escapeColumns = [];

    /**
     * Processed data output.
     *
     * @var array
     */
    protected $output = [];

    /**
     * @var array
     */
    protected $appendColumns = [];

    /**
     * @var array
     */
    protected $editColumns = [];

    /**
     * @var array
     */
    protected $excessColumns = [];

    /**
     * @var mixed
     */
    protected $results;

    /**
     * @var array
     */
    protected $templates;

    /**
     * @var bool
     */
    protected $includeIndex;

    /**
     * @var string
     */
    protected $indexColumn;

    /**
     * @var array
     */
    protected $rawColumns;

    /**
     * @var array
     */
    protected $exceptions = ['DT_RowId', 'DT_RowClass', 'DT_RowData', 'DT_RowAttr'];

    /**
     * @param mixed $results
     * @param array $columnDef
     * @param array $templates
     * @param int   $start
     */
    public function __construct($results, array $columnDef, array $templates, $start)
    {
        $this->results       = $results;
        $this->appendColumns = $columnDef['append'];
        $this->editColumns   = $columnDef['edit'];
        $this->excessColumns = $columnDef['excess'];
        $this->onlyColumns   = $columnDef['only'];
        $this->escapeColumns = $columnDef['escape'];
        $this->includeIndex  = $columnDef['index'];
        $this->rawColumns    = $columnDef['raw'];
        $this->templates     = $templates;
        $this->start         = $start;
    }

    /**
     * Process data to output on browser.
     *
     * @param bool $object
     * @return array
     */
    public function process($object = false)
    {
        $this->output      = [];
        $this->indexColumn = config('datatables.index_column', 'DT_Row_Index');

        foreach ($this->results as $row) {
            $data  = Helper::convertToArray($row);
            $value = $this->addColumns($data, $row);
            $value = $this->editColumns($value, $row);
            $value = $this->setupRowVariables($value, $row);
            $value = $this->selectOnlyNeededColumns($value);
            $value = $this->removeExcessColumns($value);
            $value = $this->addIndexColumn($value);
            $value = $this->escapeRow($value);

            $this->output[] = $object ? $value : $this->flatten($value);
        }

        return $this->output;
    }

    /**
     * Process add columns.
     *
     * @param mixed $data
     * @param mixed $row
     * @return array
     */
    protected function addColumns($data, $row)
    {
        foreach ($this->appendColumns as $key => $value) {
            $value['content'] = Helper::compileContent($value['content'], $data, $row, $this->shouldEscapeColumn($key));
            $data             = Helper::includeInArray($value, $data);
        }

        return $data;
    }

    /**
     * Process add index column.
     *
     * @param mixed $data
     * @return array
     */
    protected function addIndexColumn($data)
    {
        if ($this->includeIndex) {
            $data[$this->indexColumn] = ++$this->start;
        }

        return $data;
    }

    /**
     * Process edit columns.
     *
     * @param mixed $data
     * @param mixed $row
     * @return array
     */
    protected function editColumns($data, $row)
    {
        foreach ($this->editColumns as $key => $value) {
            $value['content'] = Helper::compileContent($value['content'], $data, $row, $this->shouldEscapeColumn($key));
            Arr::set($data, $value['name'], $value['content']);
        }

        return $data;
    }

    /**
     * Setup additional DT row variables.
     *
     * @param mixed $data
     * @param mixed $row
     * @return array
     */
    protected function setupRowVariables($data, $row)
    {
        $processor = new RowProcessor($data, $row);

        return $processor
            ->rowValue('DT_RowId', $this->templates['DT_RowId'])
            ->rowValue('DT_RowClass', $this->templates['DT_RowClass'])
            ->rowData('DT_RowData', $this->templates['DT_RowData'])
            ->rowData('DT_RowAttr', $this->templates['DT_RowAttr'])
            ->getData();
    }

    /**
     * Get only needed columns.
     *
     * @param array $data
     * @return array
     */
    protected function selectOnlyNeededColumns(array $data)
    {
        if (is_null($this->onlyColumns)) {
            return $data;
        } else {
            return array_intersect_key($data, array_flip(array_merge($this->onlyColumns, $this->exceptions)));
        }
    }

    /**
     * Remove declared hidden columns.
     *
     * @param array $data
     * @return array
     */
    protected function removeExcessColumns(array $data)
    {
        foreach ($this->excessColumns as $value) {
            unset($data[$value]);
        }

        return $data;
    }

    /**
     * Flatten array with exceptions.
     *
     * @param array $array
     * @return array
     */
    public function flatten(array $array)
    {
        $return = [];

        foreach ($array as $key => $value) {
            if (in_array($key, $this->exceptions)) {
                $return[$key] = $value;
            } else {
                $return[] = $value;
            }
        }

        return $return;
    }

    /**
     * Escape all values of row.
     *
     * @param array $row
     * @return array
     */
    protected function escapeRow(array $row)
    {
        $arrayDot = array_filter(array_dot($row));

        foreach ($arrayDot as $key => $value) {
            if ($this->shouldEscapeColumn($key)) {
                $arrayDot[$key] = e($value);
            }
        }

        foreach ($arrayDot as $key => $value) {
            array_set($row, $key, $value);
        }

        return $row;
    }

    /**
     * Whether to escape column or no.
     *
     * @param string $key
     * @return bool
     */
    protected function shouldEscapeColumn($key)
    {
        foreach ($this->appendColumns as $column) {
            if ($column['name'] == $key && is_string($column['content'])) {
                return false;
            }
        }

        foreach ($this->editColumns as $column) {
            if ($column['name'] == $key && is_string($column['content'])) {
                return false;
            }
        }

        if ($this->escapeColumns === '*') {
            return ! in_array($key, $this->rawColumns); // escape if is not a raw column
        } elseif (is_array($this->escapeColumns)) {
            return in_array($key, array_diff($this->escapeColumns, $this->rawColumns));
        } else {
            return true;
        }
    }
}

RawFaxDataTable.php

<?php

namespace App\DataTables;

use App\Fax;
use App\Queries\RawFaxQuery;
use Carbon\Carbon;
use Illuminate\Database\Eloquent\Builder;
use Yajra\DataTables\Services\DataTable;

class RawFaxDataTable extends DataTable
{
    /**
     * Build DataTable class.
     *
     * @param mixed $query Results from query() method.
     * @return \Yajra\DataTables\DataTableAbstract
     */
    public function dataTable($query)
    {
        return datatables()->eloquent($query)
                           ->addColumn('deleted_html', function (Fax $fax) {
                               return view('raw.partials.deleted', compact('fax'));
                           })
                           ->addColumn('processed_html', function (Fax $fax) {
                               return view('raw.partials.processed', compact('fax'));
                           })
                           ->addColumn('to', function (Fax $fax) {
                               return $fax->toCaller();
                           })
                           ->addColumn('agent', function (Fax $fax) {
                               return $fax->lastname ? $fax->lastname . ', ' . $fax->firstname : "";
                           })
                           ->addColumn('filename_html', function (Fax $fax) {
                               return view('raw.partials.filename', compact('fax'));
                           })
                           ->filter(function (Builder $builder) {
                               if (request()->has('deleted')) {
                                   $builder->where('fax.deleted', 'N');
                               }

                               if (request()->has('processed')) {
                                   $builder->where('fax.processed', 'N');
                               }

                               if ($filename = request()->get('filename')) {
                                   $builder->where('fax.filename', 'like', "%$filename%");
                               }

                               if ($filename = request()->get('from_fax')) {
                                   $builder->where('fax.filename', 'like', "%$filename%");
                               }

                               if ($filename = request()->get('to_fax')) {
                                   $builder->where('fax.filename', 'like', "%$filename%");
                               }

                               if ($agent = request()->get('agent')) {
                                   $builder->whereRaw(
                                       "(upper(agent.firstname) LIKE upper(?) or upper(agent.lastname) LIKE upper(?))",
                                       ["%$agent%", "%$agent%"]
                                   );
                               }

                               if ($received_at = request()->get('received_at')) {
                                   $builder->whereDate(
                                       'fax.daterecieved',
                                       Carbon::parse($received_at)->format('Y-m-d')
                                   );
                               }

                               if ($recent_date = request()->get('recent_date')) {
                                   $builder->whereRaw(
                                       "fax.daterecieved >= trunc(sysdate) - ? AND daterecieved <= trunc(sysdate)+1",
                                       [$recent_date]
                                   );
                               }
                           })
                           ->rawColumns(['filename_html', 'deleted_html', 'processed_html']);
    }

    /**
     * @param \App\Queries\RawFaxQuery $rawFaxQuery
     * @return \Illuminate\Database\Eloquent\Builder
     */
    public function query(RawFaxQuery $rawFaxQuery)
    {
        $builder = $rawFaxQuery->handle();

        return $builder;
    }

    /**
     * Optional method if you want to use html builder.
     *
     * @return \Yajra\DataTables\Html\Builder
     */
    public function html()
    {
        $script = <<<CDATA
var formData = $("#search-fax").find("input, select").serializeArray();
$.each(formData, function(i, obj){
    data[obj.name] = obj.value;
});
CDATA;

        return $this->builder()
                    ->columns($this->getColumns())
                    ->minifiedAjax('', $script)
                    ->parameters([
                        'order'      => [[2, 'desc']],
                        'searching'  => false,
                        'lengthMenu' => [10, 20, 50, 100],
                        'pageLength' => 20,
                        'buttons'    => [],
                    ]);
    }

    /**
     * Get columns.
     *
     * @return array
     */
    protected function getColumns()
    {
        return [
            'deleted'      => [
                'class' => 'text-center',
                'data' => 'deleted_html',
                'width' => '10px',
            ],
            'processed'    => [
                'title' => 'Cooked',
                'data' => 'processed_html',
                'class' => 'text-center',
                'width' => '10px',
            ],
            'faxid'        => [
                'title' => 'Fax ID',
            ],
            'filename'     => [
                'data'  => 'filename_html',
                'title' => 'File Name',
            ],
            'callername'         => [
                'title'      => 'Faxed From',
                'orderable'  => false,
                'searchable' => false,
            ],
            'to'           => [
                'title'      => 'Faxed To',
                'orderable'  => false,
                'searchable' => false,
            ],
            'daterecieved' => [
                'title' => 'Date Received',
            ],
            'agent'        => [
                'name'  => 'agent.lastname',
                'title' => 'Agent',
            ],
        ];
    }

    /**
     * Get filename for export.
     *
     * @return string
     */
    protected function filename()
    {
        return 'raw-fax_' . time();
    }
}