Box\Spout\Writer\AbstractWriter::openToBrowser PHP Method

    public function openToBrowser($outputFileName)
    {
        $this->outputFilePath = $this->globalFunctionsHelper->basename($outputFileName);
        $this->filePointer = $this->globalFunctionsHelper->fopen('php://output', 'w');
        $this->throwIfFilePointerIsNotAvailable();
        // Clear any previous output (otherwise the generated file will be corrupted)
        // @see https://github.com/box/spout/issues/241
        $this->globalFunctionsHelper->ob_end_clean();
        // Set headers
        $this->globalFunctionsHelper->header('Content-Type: ' . static::$headerContentType);
        $this->globalFunctionsHelper->header('Content-Disposition: attachment; filename="' . $this->outputFilePath . '"');
        /*
         * When forcing the download of a file over SSL,IE8 and lower browsers fail
         * if the Cache-Control and Pragma headers are not set.
         *
         * @see http://support.microsoft.com/KB/323308
         * @see https://github.com/liuggio/ExcelBundle/issues/45
         */
        $this->globalFunctionsHelper->header('Cache-Control: max-age=0');
        $this->globalFunctionsHelper->header('Pragma: public');
        $this->openWriter();
        $this->isWriterOpened = true;
        return $this;
    }