WP File System Helper

wp-file-system-helper.php

<?php
private static function wp_filesystem_init($form_url, $context, $fields) {

    if (!function_exists('request_filesystem_credentials')) {
        load_template(ABSPATH.'wp-admin/includes/file.php');
    }

    if ((!is_admin() && 'direct' !== get_filesystem_method(null, $context)) || 
        false === ($creds = request_filesystem_credentials($form_url, null, false, false, $fields))) {
        return false;
    }

    if (!WP_Filesystem($creds)) {
        request_filesystem_credentials($form_url, null, false, $context, $fields);
        return false;
    }

    return true;
}

static function file_handler($form_url, $path, $action = 'read', $data = null) {

    global $wp_filesystem;

    if (!in_array($action, array('write', 'read', 'delete')) || ('write' === $action && empty($data))) {
        return false;
    }

    $form_fields = null;

    if (!empty($data)) {
        $form_fields = array('data');
    }

    $pathinfo = pathinfo($path);
    $context = $pathinfo['dirname'];
    $filename = $pathinfo['basename'];

    $form_url = wp_nonce_url($form_url, 'prefix-'.$action);
    if (!self::wp_filesystem_init($form_url, $context, $form_fields)) {
        return false;
    }

    if (!$wp_filesystem->exists($context)) {
        $wp_filesystem->mkdir($context, 0775);
    }

    $target_dir = $wp_filesystem->find_folder($context);
    $target_file = trailingslashit($target_dir).'/'.$filename;

    switch ($action) {
        case 'read':
            if ($wp_filesystem->exists($target_file)) {
                if (!$output = $wp_filesystem->get_contents($target_file)) {
                    return false;
                }
                return $output;
            }
            break;

        case 'delete':
            if ($wp_filesystem->exists($target_file)) {
                return $wp_filesystem->delete($target_file);
            }
            break;

        case 'write':
            if (!$wp_filesystem->put_contents($target_file, $data)) {
                return false;
            }
            break;
    }

    return true;
}