我正在尝试为客户Wordpress网站创建一个简单的“添加每月订阅（每月付款）按钮”自定义插件。我当前的问题是如何在插件中包含Stripe的PHP库？我在本地通过Composer（autoload.php）运行它。但将其添加到Wordpress。。。。

我在Stripe的网站上添加了以下基本代码：https://stripe.com/docs/recipes/subscription-signup

 <form action="/create_subscription.php" method="POST">
  <script
    src="https://checkout.stripe.com/checkout.js" class="stripe-button"
    data-key="pk_test_mlHAlLZMWfb2URJZIvb6Qntd"
    data-image="/images/marketplace.png"
    data-name="Emma\'s Farm CSA"
    data-description="Subscription for 1 weekly box"
    data-amount="2000"
    data-label="Sign Me Up!">
  </script>
</form>

<?php // Create a customer using a Stripe token

// If you\'re using Composer, use Composer\'s autoload:
require_once(\'vendor/autoload.php\');

// Be sure to replace this with your actual test API key
// (switch to the live key later)
\\Stripe\\Stripe::setApiKey("sk_test_000000000000");

try
{
  $customer = \\Stripe\\Customer::create(array(
    \'email\' => $_POST[\'stripeEmail\'],
    \'source\'  => $_POST[\'stripeToken\'],
    \'plan\' => \'weekly_box\'
  ));

  header(\'Location: thankyou.html\');
  exit;
}
catch(Exception $e)
{
  header(\'Location:oops.html\');
  error_log("unable to sign up customer:" . $_POST[\'stripeEmail\'].
    ", error:" . $e->getMessage());
}