Solution: Send Metadata with notification email

Just because I was searching here and only found some questions on that topic, here’s my solution to send all metadata with the notification email – find and replace the function in frontend-uploader.php

In fact, I just snatched some piece of code from another function and added a little bit of white-belt php kung fu to generate the contents of the email:

/**
	 * Notify site administrator by email
	 */
	function _notify_admin( $result = array() ) {

		// Notify site admins of new upload
		if ( ! ( 'on' == $this->settings['notify_admin'] && $result['success'] ) )
			return;
		// @todo It'd be nice to add the list of upload files
		$to = !empty( $this->settings['notification_email'] ) && filter_var( $this->settings['notification_email'], FILTER_VALIDATE_EMAIL ) ? $this->settings['notification_email'] : get_option( 'admin_email' );
		$subj = __( 'New content was uploaded on your site', 'frontend-uploader' );

		$cont = "A new THING arrived!\n\n";

		foreach ( $this->form_fields['meta'] as $meta_field ) {
			if ( !isset( $_POST[$meta_field] ) )
				continue;

			$value = $_POST[$meta_field];

			// Sanitize array
			if ( is_array( $value ) ) {
				$value = array_map( array( $this, '_sanitize_array_element_callback' ), $value );
				// Sanitize everything else
			} else {
				$value = sanitize_text_field( $value );
			}
			$cont .= $meta_field;
			$cont .= " : ";
			$cont .= $value;
			$cont .= "\n";
		}
		wp_mail( $to,  $subj,  $cont );
	}

https://wordpress.org/plugins/frontend-uploader/