Saving uploaded files with file_save()for Drupal 8 , 9 , 10 , and 11

Continuing our journey through the Drupal Form API, in the previous lesson, we explored creating or updating entities during form submission. In this lesson, we focus on a frequently required yet intricate task: managing and saving uploaded files using file_save(). Mastering this will enhance your ability to handle file inputs efficiently and securely.

Understanding file_save() in Drupal

The file_save() function is part of the Drupal's file management system. It is a mechanism that enables developers to save uploaded files to the server and associate them with the Drupal system through entities. This handling ensures files are correctly managed and accessible within the Drupal ecosystem.

Why Use file_save()?

• Security: Handles files in a secure manner, preventing unauthorized access or data leaks.
• Accessibility: Ensures files are appropriately indexed and available for retrieval and display.
• Integration: Seamlessly integrates uploaded files into Drupal's content management, enhancing data utility and organization.

Adding a File Upload Field to a Form

To start with, let's add a file upload field to a form:

function mymodule_form(array &$form, \Drupal\Core\Form\FormStateInterface $form_state) {
    $form['file_upload'] = [
        '#type' => 'managed_file',
        '#title' => t('Upload File'),
        '#upload_location' => 'public://uploads/',
        '#required' => TRUE,
    ];

    $form['submit'] = [
        '#type' => 'submit',
        '#value' => t('Submit'),
    ];

    return $form;
}
    

In this form definition:

• The managed_file element type handles file uploads with a built-in widget for user interaction.
• The #upload_location denotes where the uploaded files will be stored in the file directory.

Processing and Saving the Uploaded File

Upon form submission, it's crucial to manage the uploaded file correctly using file_save_data() and file_save():

use Drupal\file\Entity\File;

function mymodule_form_submit(array &$form, \Drupal\Core\Form\FormStateInterface $form_state) {
    $file_id = $form_state->getValue('file_upload')[0];
    $file = File::load($file_id);
    
    if ($file) {
        $file->setPermanent();
        $file->save();
        
        \Drupal::messenger()->addMessage(t('File uploaded successfully.'));
    } else {
        \Drupal::messenger()->addMessage(t('File upload failed, please try again.'), 'error');
    }
}
    

This code performs the following:

• File::load($file_id) loads the temporary file entity using its ID.
• setPermanent() marks the file as permanent, ensuring it isn't deleted by the cron job cleaning up temporary files.
• file->save() commits changes, fully registering the file with Drupal.

Best Practices

• File Validation: Implement file validation before saving, ensuring file types and sizes are as expected.
• Error Handling: Provide clear user feedback and handle errors gracefully to enhance the user experience.
• Security Protocols: Regularly review your file handling practices to mitigate security risks like directory traversal attacks and ensure data privacy.

Conclusion

Handling file uploads effectively using file_save() expands your ability to deliver robust, feature-rich applications in Drupal. By mastering file management, you can confidently build applications that manage media and documents effectively.

Next Step: Executing Custom Logic in Submit Handlers

In our upcoming lesson, we will focus on executing custom logic within submit handlers. This capability provides the flexibility to execute specialized processes tailored to form submissions, advancing your Drupal form handling skills. Stay tuned!