Problem/Motivation

I'm using views_data_export module to export a view result as csv file. Everything works well untill the view we want to export is empty. If there is no result, the csv header row is not generated and the file is empty.

The extractHeaders method seems to priorities results keys over view fields in case of view context. It doesn't seems to be a bug.

Steps to reproduce

  • Install views_data_export which will install csv_serialization 2.0.
  • Create a view page on a content type with exposed filter (pay attention to check the remembering filter option)
  • Add an export data view display and configure it to be csv export and to be shown on the preceding view page
  • Navigate to the view page and add filter which result in an empty table
  • Clic on the export button and open the file

The file is empty with no header row.

Proposed resolution

In case we have a views_style_plugin context, assume that view fields are our header (at least when there is no data).

I'm not sure why this filtering code has been written so I don't know if we can just remove it.

Remaining tasks

Choose either if we keep that filtering feature or not.

Comments

colin.eininger created an issue. See original summary.

colin.eininger’s picture

colin.eininger commented
Issue summary: View changes
markdorison’s picture

markdorison
he/him
commented
Version: 8.x-2.0 » 4.x-dev
s3b0un3t’s picture

s3b0un3t
Primary language French
Location Nantes
commented

Hello,

I also needed to generate a CSV with headers even when there were no results.
I'm providing my code as an example for others who may have this issue.

In a *.module file, i declare a hook:

/**
 * Implements hook_views_post_render().
 */
function mymodule_views_post_render(ViewExecutable $view, array &$output, CachePluginBase $cache): void {
  if ($view->id() !== 'my_view_id') {
    return;
  }

  $options = $view->getStyle()->options;

  // The CSV output is empty when there is no result,
  // even if a header row is requested.
  if (
    empty($view->result) &&
    isset($options['csv_settings']['output_header']) &&
    $options['csv_settings']['output_header']
  ) {
    $header_row = [];
    foreach ($view->field as $name => $field) {
      // Check that the field is not excluded from the display.
      if ($field->options['exclude']) {
        continue;
      }

      $header_row[$name] = $field->label();
    }

    // Override output markup with the header row.
    $output['#markup'] = ViewsRenderPipelineMarkup::create(
      \Drupal::service('serializer')->serialize([$header_row],
        reset($options['formats']),
        ['csv_settings' => ['output_header' => FALSE] + $options['csv_settings']]
      )
    );
  }
}

Don't forget to rename the mymodule hook function name prefix with your module name and the my_view_id with your view ID.

Regards,