找不到课程

Question

我想用php打印我的oauth访问令牌我得到了我的代码和库 我用php得到了这个错误：

Fatal error: Class 'OAuth2' not found in /home/u490548713/public_html/auth.php on line 13

我的文件如下：

public_html
  - GrantType
      - AuthorizationCode.php
      - ClientCredentials.php
      - IGrantType.php
      - Password.php
      - RefreshToken.php
  - Client.php
  - auth.php

我的代码看起来像这样：

<?php
require('Client.php');
require('GrantType/IGrantType.php');
require('GrantType/AuthorizationCode.php');

const CLIENT_ID     = '**';
const CLIENT_SECRET =     '***';

const REDIRECT_URI           = 'http://*****/****?';
const AUTHORIZATION_ENDPOINT = 'https://beam.pro/oauth/authorize';
const TOKEN_ENDPOINT         = 'https://beam.pro/api/v1/oauth/token';

$client = new OAuth2/Client(CLIENT_ID, CLIENT_SECRET);
if (!isset($_GET['code']))
{
$auth_url = $client->getAuthenticationUrl(AUTHORIZATION_ENDPOINT, REDIRECT_URI);
    header('Location: ' . $auth_url);
    die('Redirect');
}
else
{
    $params = array('code' => $_GET['code'], 'redirect_uri' => REDIRECT_URI);
    $response = $client->getAccessToken(TOKEN_ENDPOINT, 'authorization_code',     $params);
    parse_str($response['result'], $info);
    echo($info['access_token']);

}

?>

我该如何解决？