How to create file download link in drupal 8

Question

I have created a custom field formatter for mp3 files and added a settings form field named "Provide Download Link" which is a checkbox. I want to provide a file download link if the "Provide Download Link" is checked. Can anyone please tell me how can I create this download link in drupal 8? I have to pass the dynamic download link to the formatter template file(twig) so that user can download the mp3 file by clicking the link.

Bon Kim Bon Kim · Accepted Answer · 2015-09-10T13:08:20

I am assuming the field you are adding the formatter is a field that allows uploading of files e.g mp3 files

Mp3Formatter.php assuming that’s the formatter’s class name. Make sure your formatter class extends from FileFormatterBase

    use Drupal\file\Plugin\Field\FieldFormatter\FileFormatterBase;

        // Get "Provide Download Link”  settings value.
        // Assuming the machine name you gave  to your setting is : download_link_setting.
        // Add the code below to your formatter class under the method body: viewElements
        // Get the referenced entities in this case files.

        $files = $this->getEntitiesToView($items);

        // initialise $url variable.

        $url = NULL;

        $download_link_setting = $this->getSetting(‘download_link_setting’);

        // Loop through the file entities.

        foreach ($files as $delta => $file) {

          // For each file add code below.
          // Check if the setting isn’t empty and then create the file url.

          if (!empty($download_link_setting)) {
            $mp3_uri = $file->getFileUri();
            $url = Url::fromUri(file_create_url($mp3_uri));
          }

          // Add the $url parameter to your render array e.g

          $elements[$delta] = [
            '#theme' => ‘mp3_formatter',
            '#item' => $item,
            '#url' => $url,
            '#filename' => $item->getFilename(),
          ];
        }

      return $elements;

In the .module file of your module.

        // Register your theme under hook_theme.

        'mp3_formatter' => [
          'variables' => [
            'item' => NULL, 
            'url' => NULL, 
            'filename' => NULL,
          ],
        ],

In the corresponding TWIG template

        // Now add your download link into the twig element.
        // check if the url variable is set
        {% if url %}
          <a href="{{ url }}" download>{{ filename }}</a>
        {% else %}
          <p> {{ filename }} </p>
        {% endif %}

How to create file download link in drupal 8

1 Answers