What is the correct way to check if WP_Filesystem can write to a directory without aking for username / password?

Question

I'm trying to implement caching using the filesystem so i need to check if i can write in a directory. I've read Otto's article, but i've failed to understand how should i implement a check where the user doesn't input any kind of password. So basically i need to use the direct method, what's the correct way to do it?

Answer 1

This is what i ended up using

/**
 * check if the path is writable. To make the check .
 *
 * @param string $path
 * @return boolean
 */
public static function is_writable( $path ) {
    global $wp_filesystem;
    include_once ABSPATH . 'wp-admin/includes/file.php';
    // If for some reason the include doesn't work as expected just return false.
    if( ! function_exists( 'WP_Filesystem' ) ) {
        return false;
    }
    $writable = WP_Filesystem( false, $path );
    // We consider the directory as writable if it uses the direct transport,
    // otherwise credentials would be needed
    return $writable && $wp_filesystem->method === 'direct';
}