Since today, form submissions always returning 400.

Hello there, Lapzor!

We have requested the account details from our client and are waiting for them to get back to us.

Do you have any further troubleshooting tips or advice we can follow whilst we wait for that information, please?

Hello there, Lapzor!

Thank you very much for the suggestion regarding swapping the theme out – it let us isolate the problem. We have some custom code to handle file uploads through a MC4WP form, that had stopped correctly working.

Summary – the file upload success check was incorrectly being applied to all forms.

Code Reference – For reference (and any other users that might find this in future), here is the full code:

class File_Uploads_Mailchimp extends Child_Theme {

  /**
   * Add file upload support to MC4WP forms
   *
   * @param  array        $data
   * @param  \MC4WP_Form  $form
   *
   * @return array
   */

  public function process_form_data($data, MC4WP_Form $form) {
    $file_successfully_processed = false;
    $field_name                  = "RECEIPT";

    if (
      isset($_FILES[$field_name]) &&
      $_FILES[$field_name]['error'] === UPLOAD_ERR_OK // uploaded okay
    ) {
      // Allowed mime-types and extensions
      $allowed = [
        "jpg" => "image/jpeg",
        "png" => "image/png",
      ];

      // Ensure needed functions exist before attempting to call:
      $wp_admin_includes = ABSPATH . 'wp-admin/includes';
      if ( !function_exists('wp_handle_upload') ) {
        require_once( "{$wp_admin_includes}/file.php" );
      }
      if ( !function_exists('media_handle_upload') ) {
        require_once( "{$wp_admin_includes}/media.php" );
      }
      if ( !function_exists('wp_read_image_metadata') ) {
        require_once( "{$wp_admin_includes}/image.php" );
      }

      $file_type = $_FILES[$field_name]['type']; //returns the mimetype

      if (
        in_array($file_type, $allowed) && // Doubly ensure only images are uploaded
        (int) $_FILES[$field_name]['size'] < 2621440 // 2.5MB in bytes
      ) {
        // Handle file upload:
        add_filter('upload_dir', [ $this, 'alter_upload_directory' ]); // Change the upload directory for this upload only
        $upload = wp_handle_upload($_FILES[$field_name], [
          'test_form' => false,
          'test_file' => false,
          'mimes'     => $allowed,
        ]);
        remove_filter('upload_dir', [ $this, 'alter_upload_directory' ]); // Remove the directory change.

        if (
          $upload &&
          !isset($upload['error'])
        ) {
          // Store the file URL in subscriber data:
          $data[$field_name]           = $upload['url'];
          $file_successfully_processed = true;
        }
      }
    }

    if (
      /* THIS ISSET() CHECK WAS MISSING, ADDING THIS ISSET() FIXED THE PROBLEM IN THIS THREAD */
      isset($_FILES[$field_name]) &&
      $file_successfully_processed !== true
    ) {
      // empty data to prevent signup, but provide a receipt URL to ensure any later hooks can delete the file
      //  uploaded if necessary, such as on a submission error.
      $data = [
        'EMAIL'   => '', // prevents a fatal error
        'RECEIPT' => ( isset($data[$field_name]) && $data[$field_name] ) ? $data[$field_name] : '',
      ];
      if (
        isset($upload['file']) &&
        $upload['file'] &&
        file_exists($upload['file']) &&
        is_writeable($upload['file'])
      ) {
        unlink($upload['file']);
      }
    }

    return $data;
  }

  /**
   * Add the required enctype to the form.
   *
   * @param  array  $attributes
   * @param         $form
   */
  function add_form_attributes($attributes, $form) {
    $attributes['enctype'] = "multipart/form-data";
    $attributes['accept']  = "image/png, image/jpeg, image/jpg";
    return $attributes;
  }

  /**
   * Changes the upload directory
   *
   * @param $upload
   *
   * @return mixed
   */
  function alter_upload_directory($upload) {
    $upload['subdir'] = "/_receipt-images{$upload['subdir']}";
    $upload['path']   = "{$upload['basedir']}{$upload['subdir']}";
    $upload['url']    = "{$upload['baseurl']}{$upload['subdir']}";
    return $upload;
  }

  function _var_export_form($form) {
    self::var_export($form);
  }

  public function __construct() {
    parent::__construct();
    $this->add_filters_from_array([
      [ 'mc4wp_form_data', [ $this, 'process_form_data' ], 10, 2 ],
      [ 'mc4wp_form_element_attributes', [ $this, 'add_form_attributes' ], 10, 2 ],
    ]); 
  }
}

File_Uploads_Mailchimp::get_instance();

• This reply was modified 7 months, 3 weeks ago by richardlampitt.