BP_Attachment::__construct( array|string $args = '' )

	public function __construct( $args = '' ) {
		// Upload action and the file input name are required parameters.
		if ( empty( $args['action'] ) || empty( $args['file_input'] ) ) {
			return false;
		}

		// Sanitize the action ID and the file input name.
		$this->action     = sanitize_key( $args['action'] );
		$this->file_input = sanitize_key( $args['file_input'] );

		/**
		 * Max file size defaults to php ini settings or, in the case of
		 * a multisite config, the root site fileupload_maxk option
		 */
		$this->default_args['original_max_filesize'] = (int) wp_max_upload_size();

		$params = bp_parse_args( $args, $this->default_args, $this->action . '_upload_params' );

		foreach ( $params as $key => $param ) {
			if ( 'upload_error_strings' === $key ) {
				$this->{$key} = $this->set_upload_error_strings( $param );

			// Sanitize the base dir.
			} elseif ( 'base_dir' === $key ) {
				$this->{$key} = sanitize_title( $param );

			// Sanitize the upload dir filter arg to pass.
			} elseif ( 'upload_dir_filter_args' === $key ) {
				$this->{$key} = (int) $param;

			// Action & File input are already set and sanitized.
			} elseif ( 'action' !== $key && 'file_input' !== $key ) {
				$this->{$key} = $param;
			}
		}

		// Set the path/url and base dir for uploads.
		$this->set_upload_dir();
	}