How to use PHP to develop the recharge function of WeChat applet?

How to use PHP to develop the recharge function of WeChat applet?

With the rapid development of WeChat mini programs, more and more companies choose to conduct business on WeChat mini programs. For some applications that require users to purchase virtual goods or recharge balances, the recharge function becomes particularly important. In this article, I will introduce how to use PHP to develop the recharge function of the WeChat applet and provide specific code examples.

First of all, we need to use the WeChat payment interface to implement the recharge function. WeChat Pay provides a variety of payment methods, and we can choose the payment method suitable for mini program recharge. Specifically, we can use WeChat payment (JSAPI) or scan code payment (Native) of the mini program to achieve this. The following are the steps to use PHP to develop the WeChat mini program recharge function:

1. Create an application and obtain payment parameters
   First, we need to register on the WeChat payment platform and create a mini program application. After creating the application, we can obtain some important payment parameters, such as App ID, merchant number and payment key. These parameters will be used in subsequent code.
2. Generate prepayment order
   In the mini program, after the user selects the amount to be recharged and clicks the payment button, we need to generate a prepayment order in the backend. In order to generate a prepaid order, we need to call the WeChat payment interface and pass the recharge amount, product description, merchant number, payment key and some other parameters to the interface.

In PHP, we can use the cURL library to send HTTP requests. The following is a code example for generating a prepaid order:

<?php
$url = "https://api.mch.weixin.qq.com/pay/unifiedorder";
$data = array(
    'appid' => 'YOUR_APPID',
    'mch_id' => 'YOUR_MCH_ID',
    'nonce_str' => uniqid(),
    'body' => '充值余额',
    'out_trade_no' => uniqid(),
    'total_fee' => 100, // 充值金额，单位为分
    'spbill_create_ip' => $_SERVER['REMOTE_ADDR'],
    'notify_url' => 'http://yourdomain.com/notify.php', // 接收支付结果的回调地址
    'trade_type' => 'JSAPI', // 小程序支付方式
    'openid' => $_SESSION['openid'], // 通过小程序登录获取的用户openid
);

// 将参数转换为XML格式
$xml = "<xml>";
foreach ($data as $key => $value) {
    $xml .= "<{$key}>{$value}</{$key}>";
}
$xml .= "</xml>";

// 发送HTTP请求
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $xml);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
$result = curl_exec($ch);
curl_close($ch);

// 解析XML结果
$xml = simplexml_load_string($result);
if ($xml->return_code == 'SUCCESS' && $xml->result_code == 'SUCCESS') {
    $prepay_id = $xml->prepay_id; // 获取预支付订单号
    // 将prepay_id和其他必要参数返回给小程序
} else {
    // 支付失败，返回错误信息给小程序
}
?>

In the above code, we use 'YOUR_' to represent the parameters that need to be replaced, including App ID, merchant number, payment key, etc. Also note that when generating a prepayment order, we need to obtain the user's openid, which can usually be obtained through the mini program login interface.

3. Call up mini program payment
   On the mini program side, we can use the wx.requestPayment interface provided by WeChat to call up mini program payment. The following is a code example for calling up payment:

wx.requestPayment({
    'timeStamp': 'YOUR_TIMESTAMP',
    'nonceStr': 'YOUR_NONCESTR',
    'package': 'prepay_id=YOUR_PREPAYID',
    'signType': 'MD5',
    'paySign': 'YOUR_PAYSIGN',
    'success': function(res) {
        // 支付成功，更新用户余额等操作
    },
    'fail': function(res) {
        // 支付失败，显示错误信息
    }
});

In the above code, we also need to replace some parameters, such as timestamp, random string, prepayment order number, signature, etc. These parameters can be returned to the applet after generating a prepayment order.

4. Processing payment results
   In the callback address (notify_url) that receives the payment results, we need to process the payment results. Usually, we can update the user's balance or write the recharge record to the database, etc. The following is a code example for processing payment results:

<?php
$data = file_get_contents("php://input");
$xml = simplexml_load_string($data);

if ($xml->return_code == 'SUCCESS' && $xml->result_code == 'SUCCESS') {
    // 支付成功，更新用户余额或者记录充值记录等操作
    // 回应微信支付平台，告知支付已成功
    $response = array(
        'return_code' => 'SUCCESS',
        'return_msg' => 'OK'
    );
    echo arrayToXml($response);
} else {
    // 支付失败，记录错误日志等操作
}
?>

In the above code, we directly obtain the XML data of the payment result through the file_get_contents() function, and then parse the XML data. If the payment result is successful, corresponding processing will be performed and a response will be sent to the WeChat payment platform. Otherwise, we can record payment failure information for subsequent analysis.

Through the above steps, we can use PHP to develop the recharge function of the WeChat applet. Of course, the above is just a simple sample code, and more scenarios and security issues may need to be considered in actual development. I hope this article can be helpful to you, and I wish you smooth development!

The above is the detailed content of How to use PHP to develop the recharge function of WeChat applet?. For more information, please follow other related articles on the PHP Chinese website!