Node.js 在execute\u payment\u json中获取可变金额

我想在我使用Paypal rest sdk的站点中集成Paypal。 我希望execute_payment_json中的金额等于用户输入的金额

paypal社区有一个帖子，但没有得到回复。

从用户处获取值后运行的代码

app.post("/paypal-pay",(req,res) => {
    console.log(req.body.amount);
    const create_payment_json = {
        "intent": "sale",
        "payer": {
            "payment_method": "paypal"
        },
        "redirect_urls": {
            "return_url": "http://localhost:3000/success",
            "cancel_url": "http://localhost:3000/cancel"
        },
        "transactions": [{
            "item_list": {
                "items": [{
                    "name": "Donation",
                "sku": "item",
                "price": req.body.amount,
                "currency": "USD",
                "quantity": 1
                }]
            },
            "amount": {
                "currency": "USD",
                "total": req.body.amount
            },
            "description": "The Donation that you are doing"
        }]
    };
    paypal.payment.create(create_payment_json, function (error, payment) {
        if (error) {
            throw error;
        } else {
            console.log(payment);
            payment.links.forEach(url => {
                if(url.rel === "approval_url"){
                    res.redirect(url.href);
                }
            });
        }
    });
    })

成功后，上面的代码将我重定向到/success，我希望总数等于提供的值

    app.get("/success",(req,res)=>{
        console.log(req.body);
        const payerId = req.query.PayerID;
        const paymentId = req.query.paymentId;

        const execute_payment_json = {
            "payer_id" : payerId,
            "transactions": [{
                    "amount": {
                        "currency": "USD",

// I want this total to be equal to the payment provided by user.

                        "total": "1.00"
                    }
                }]
            }