Streaming Large CSV Files with chunk()

gistfile1.txt

// See: https://medium.com/@barryvdh/streaming-large-csv-files-with-laravel-chunked-queries-4158e484a5a2

/*
 * Response
 */
$response = new StreamedResponse(function() {

    // Set the file name
    $filename = 'claims.csv';

    /*
     * Prepare CSV
     */
    $handle = fopen('php://output', 'w');

    /*
     * Add headers
     */
    $headers = [];
    $columns = $this->makeList('export')->getVisibleColumns();
    foreach ($columns as $column) {
        $headers[] = Lang::get($column->label);
    }
    fputcsv($handle, $headers);

    /*
     * Add records
     */
    $query = $list->prepareQuery();

    // Scope to user company
    if (!$this->user->hasAccess('bg.company.manage_all_claims')) {
        $query->forCompany($this->user->company->name);
    }

    $results = $query->chunk(1000, function ($result) use ($list, $handle, $columns) {
        foreach ($result as $claim) {
            $record = [];
            foreach ($columns as $column) {
                $value = $list->getColumnValueRaw($user, $column);
                if (is_array($value)) {
                    $value = implode('|', $value);
                }
                $record[] = $value;
            }
            fputcsv($handle, $record);
        }
    });

fclose($handle);
}, 200, [
    'Content-Type' => 'text/csv',
    'Content-Disposition' => 'attachment; filename="claims.csv"',
]);

return $response;