Paypal与Flask应用程序的集成

我在阅读https://developer.paypal.com/docs/api/后稍微误解了Paypal流程事件.我想将快速结账和信用卡付款整合到我的网站.我正在使用Flask并且paypalrestsdk没有任何Flask扩展.

以下是我的应用摘录:

@app.route('/', methods=['GET'])
def index():
    # Page with but form, price/quantity/name values
    # are stored in hidden fields, "Buy now" acts as submit
    return render_template('index.html')

@app.route('/payment/paypal', methods=['POST'])
def payment_paypal():
    # Here I am creating dict with required params
    payment_template = {
        'intent': 'sale',
        'payer': {'payment_method': 'paypal'},
        'redirect_urls': {
          'return_url': url_for('payment_paypal_execute'),
          'cancel_url': url_for('payment_paypal_error')
        },
        ......
    }

    payment = paypalrestsdk.Payment(payment)

    if payment.create():
        print('Payment "{}" created successfully'.format(payment.id))

        for link in payment.links:
            if link.method == "REDIRECT":
                redirect_url = str(link.href)
                print('Redirect for approval: {}'.format(redirect_url))
                return redirect(redirect_urls)

@app.route('/payment/paypal/execute', methods=['GET'])
def payment_paypal_execute():
    payer_id = request.args.get('payerId')
    payment_id = request.args.get('paymentId')
    token = request.args.get('token')

    pending_payment = PayPalPayment.query.filter_by(token=token).filter_by(state='created').first_or_404()

    try:
        payment = paypalrestsdk.Payment.find(pending_payment.payment_id)
    except paypalrestsdk.exceptions.ResourceNotFound as ex:
        print('Paypal resource not found: {}'.format(ex))
        abort(404)

    if payment.execute({"payer_id": payer_id}):
        pending_payment.state = payment.state
        pending_payment.updated_at = datetime.strptime(payment.update_time, "%Y-%m-%dT%H:%M:%SZ")
        db.session.commit()
        return render_template('payment/success.html', payment_id=payment.id, state=payment.state)

    return render_template('payment/error.html', payment_error=payment.error, step='Finallizing payment')

单击payment 成功创建的按钮(使用状态created)用户重定向到批准页面后,它工作正常.在那里,他点击"确认"......当我指定return_url时,我从未返回到我的应用程序,事件!即,应用程序永远不会被告知买方批准付款,并且应该在我自己的数据库中进行更新,并且应该向该人发送新的许可证.

问题:

我无法找到定义一些回调的方法pyhtonrestsdk.怎么做？

即使我添加回调(我尝试使用纯Javascript按钮代码嵌入Express Checkout),data-callback我的应用程序也没有被调用.我怀疑因为远程服务器无法调用http://127.0.0.1/payment/paypal/success

用户可以在点击"确认"后立即关闭带有PayPal确认的窗口,这样我就无法信任它稍后以某种方式执行的浏览器重定向.

最后,我怀疑我不明白PayPal工作流程,但我无法在开发人员门户网站上找到有关它的更多信息.