How to use Golang to implement a payment interface for web applications

With the development of e-commerce and the Internet, payment interfaces have become an indispensable part of modern business. In web application development, how to use simple and easy-to-use language to complete the integration of payment interfaces is particularly important. Golang is an efficient, reliable, and highly concurrency programming language. Its syntax is concise and it can efficiently process large amounts of data. Therefore, it is used by more and more developers. This article describes how to use Golang to write a payment interface for web applications.

1. Select a payment interface provider

Before implementing the payment interface, you first need to select a payment interface provider to interact with your web application. There are many well-known payment interface providers on the market, such as Alipay, WeChat Pay, Tenpay, etc. Here we take Alipay as an example to explain.

2. Quote payment interface SDK

Alipay provides a Go language version of the SDK, which includes sdk, util, openapi and other packages. We can introduce the corresponding packages before using them. Bag. For example, if you need to use Alipay's mobile website to pay, you can reference the SDK in the code as follows:

import (
    "fmt"
    "github.com/alipay/alipay-sdk-go"
    "github.com/alipay/alipay-sdk-go/request"
)

3. Configure the merchant's payment information

Before using the Alipay SDK , you need to configure the merchant's payment information first. Specifically, you need to create an application on the Alipay open platform and configure the application's public key, private key, APP_ID and other information. During the payment process, Alipay will use this information to verify the order received to ensure the authenticity of the order.

var (
    client *alipay.Client
)

func init() {
    // 初始化支付宝客户端
    var err error
    client, err = alipay.New(config.APP_ID, config.ALIPAY_PUBLIC_KEY, config.PRIVATE_KEY, false)
    if err != nil {
        panic(err)
    }
}

4. Create order

In the web application, when the user completes filling in the payment information, the order information submitted by the user needs to be sent to Alipay. When creating an order, you need to call the corresponding API provided by Alipay, generate a unique merchant order number, encrypt the order information and submit it to Alipay. If the order is created successfully, Alipay will return a payment link, which can redirect the user to Alipay's payment page. On the payment page, the user can pay using an Alipay account or other payment methods.

// 创建支付宝订单
func createAliPayOrder(c *gin.Context) {
    // 订单号
    outTradeNo := "201910020809"
    // 商品名称
    subject := "Macbook Pro"
    // 订单总金额，单位为元
    totalAmount := 1000.00
    // 商户ID
    sellerID := config.SELLER_ID

    // 构造请求参数
    resp, err := client.TradePagePay(&request.TradePagePay{
        OutTradeNo: outTradeNo,
        ProductCode: "FAST_INSTANT_TRADE_PAY",
        TotalAmount: strconv.FormatFloat(totalAmount, 'f', 2, 64),
        Subject: subject,
        SellerID: sellerID,
        ReturnURL: "http://localhost:8080/return",
        NotifyURL: "http://localhost:8080/notify",
        Body: "Macbook Pro 2019",
    })

    if err != nil {
        fmt.Printf("create ali pay order failed: %v", err)
        return
    }

    // 将支付链接返回给客户端
    c.JSON(http.StatusOK, gin.H{
        "code": 1000,
        "msg": "success",
        "data": gin.H{
            "pay_url": resp,
        },
    })
}

5. Processing payment result callback

When the user completes the payment, Alipay will send the payment result of the order to the web application through an asynchronous callback. Before using Alipay's asynchronous notification function, we need to make relevant configurations in the Alipay open platform. Specifically, we need to provide a fixed URL for the asynchronous callback. When Alipay notifies the result, it will send the notification to this URL and carry the payment information through the Post method.

// 处理支付结果回调
func handleAliPayNotify(c *gin.Context) {
    // 获取支付宝通知结果
    params := make(map[string]string)
    err := c.Request.ParseForm()
    if err != nil {
        c.JSON(http.StatusOK, gin.H{
            "code": 2000,
            "msg": "invalid parameters",
            "data": "",
        })
        return
    }

    for k, v := range c.Request.Form {
        params[k] = strings.Join(v, "")
    }

    // 验证通知结果的真实性
    if err := client.VerifySign(params); err != nil {
        c.JSON(http.StatusOK, gin.H{
            "code": 2000,
            "msg": "invalid signature",
            "data": "",
        })
        return
    }

    // 业务处理
    outTradeNo := params["out_trade_no"]
    tradeNo := params["trade_no"]
    c.JSON(http.StatusOK, gin.H{
        "code": 1000,
        "msg": "success",
        "data": gin.H{
            "out_trade_no": outTradeNo,
            "trade_no": tradeNo,
        },
    })
}

The above is the basic process of using Golang to implement the payment interface of web applications. This article uses the above-mentioned Alipay SDK as an example to explain, but the steps commonly used by other payment interfaces are similar. When implementing the payment interface, you need to pay attention to security, such as ensuring the uniqueness of the merchant's order number and preventing payment information from being tampered with. At the same time, we can optimize the payment interface according to specific needs and add other API calls to improve user experience.

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