How to Override Behavior Functionality

When exporting, the behavior makes use of the dosamigos\exportable\services\ExportableService to create the contents and force download the file. If you look at the class's code, you see that it implements the dosamigos\exportable\contracts\ExportableServiceInterface interface. That means, that you can create your very own exportable service class as long as it implements that interface and set it to the exportableService attribute of the behavior.

For the sake of the example, we will image we create a PdfWriter (no code will be included)

Create your PdfWriter

Writers extend from Box\Spout\Writer\AbstractWriter and require to override three methods:

namespace app\components\writers;

use Box\Spout\Writer\AbstractWriter;

class PdfWriter extends AbstractWriter
{

    protected function openWriter()
    {
        // ... init code for pdf writer
    }

    protected function addRowToWriter(array $dataRow, $style)
    {
        // ... write code to stream handler ($this->filePointer)
    }

    protected function closeWriter()
    {
        // .. end code for pdf writer
    }

Create your ExportableService

namespace app\components\services;

use app\components\writers\PdfWriter;
use dosamigos\exportable\contracts\ExportableServiceInterface;
use dosamigos\exportable\factory\WriterFactory;
use dosamigos\exportable\helpers\TypeHelper;
use dosamigos\exportable\iterators\DataProviderIterator;
use dosamigos\exportable\iterators\SourceIterator;
use dosamigos\exportable\mappers\ColumnValueMapper;
use Yii;
use yii\data\BaseDataProvider;
use yii\grid\GridView;

class MyCustomExportableService implements ExportableServiceInterface 
{
    /**
     * @inheritdoc
     */
    public function run(GridView $grid, $type, array $columns, $filename)
    {
        /** @var BaseDataProvider $dataProvider */
        $dataProvider = $grid->dataProvider;
        // Ff using mpdf we could actually state that is HTML as it converts from HTML to PDF.
        $isHtml = $type === TypeHelper::HTML || $type === 'pdf';
        $mapper = new ColumnValueMapper($grid->columns, $columns, $isHtml);
        $source = new SourceIterator(new DataProviderIterator($dataProvider, $mapper));
        $model = $dataProvider->getTotalCount() > 0 ? $dataProvider->models[0] : null;

        if('pdf' === $type) {
            $writer = new PdfWriter(); // your writer!!!
        } else {
            $writer = WriterFactory::create($type); // rollback to defaults
        }

        $this->clearBuffers();
        $writer->openToBrowser($filename);
        if ($model !== null && !in_array($type, [TypeHelper::JSON, TypeHelper::XML])) {
            $writer->addRow($mapper->getHeaders($model));
        }
        foreach ($source as $data) {
            $writer->addRow($data);
        }
        $writer->close();

        Yii::$app->end();
    }
}

Add Custom Type & Service

use app\components\services\MyCustomExportableService;
use dosamigos\exportable\ExportableButton; 
use dosamigos\exportable\behaviors\ExportableBehavior; 
use dosamigos\grid\GridView;
use dosamigos\grid\behaviors\LoadingBehavior;
use dosamigos\grid\behaviors\ResizableColumnsBehavior;
use dosamigos\grid\behaviors\ToolbarBehavior;
use dosamigos\grid\buttons\ReloadButton;
use yii\helpers\Url;

echo GridView::widget(
    [
        'behaviors' => [
            [
                'class' => 'ExportableBehavior',
                'exportableService' => new MyCustomExportableService() // Your service! Yay!
            ],
            'ResizableColumnsBehavior',
            [
                'class' => 'LoadingBehavior',
                'type' => 'bars'
            ],
            [
                'class' => 'ToolbarBehavior',
                'options' => ['style' => 'margin-bottom: 5px'],
                'encodeLabels' => false, // like this we will be able to display HTML on our buttons
                'buttons' => [
                    ReloadButton::widget(['options' => ['class' => 'btn-success']]),
                    '-',
                    ExportableButton::widget(
                        [
                            'label' => '<i class="glyphicon glyphicon-export"></i>',
                            'options' => ['class' => 'btn-default'],
                            'dropdown' => [
                                'options' => ['class' => 'dropdown-menu-right']
                            ],
                            'types' => [
                                'pdf' => 'PDF <span class="label label-default">.pdf</span>',
                                TypeHelper::CSV => 'CSV <span class="label label-default">.csv</span>',
                                TypeHelper::XLSX => 'Excel 2007+ <span class="label label-default">.xlsx</span>',
                                TypeHelper::ODS => 'Open Document Spreadsheet <span class="label label-default">.ods</span>',
                            ] 
                        ]
                    )
                ]
            ]

        ],
        'layout' => "{toolbar}\n{items}\n{pager}",

        // ...  more grid view configuration stuff here