Analysis of process issues of WeChat mini program payment (code analysis)

The content of this article is about the analysis of process issues (code analysis) of WeChat applet payment. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

I have been doing payment for small programs these days without using the official SDK. Here I will just use the official documents.

* Note: PHP is used, but the payment process is like this

Must read before development

Main process

• The front-end of the mini program sends a parameter request

• Accepts the request package "Unified Order" and obtainspackage

• The applet accepts the "Unified Order" and brings the package value obtained into wx.requestPaymentInitiate a payment request

##Preparation Tool

• Apply for Mini Program WeChat Payment

• Get the merchant number and setting key for Mini Program WeChat Payment

Note: The mini program only requires these two steps. If it is a web application, you also need to set the payment directory authorization domain name. It is also written in the document: https://pay.weixin.qq.com/wik..

Unified ordering

Official document: https://pay.weixin.qq.com/wik...

/**
 * 统一订单
 */
public function unifiedorder(){
    // 以下配置是必填项，如有其它需求请自行配置
    $config = array(
        'appid'         =>    'xxxxxxx',//这里是小程序appid
        'mch_id'        =>    'xxxxxxx',//商户ID
        'nonce_str'     =>    $this->getNonceStr(),//随机字符串
        'body'          =>    '这里是测试 - 测试',//请按照文档要求填写合格名称
        'out_trade_no'  =>    time().$this->getNonceStr(2),//流水单号
        'total_fee'     =>    '20',//金额，分为单位，这里是0.2元
        'spbill_create_ip' => '123.123.123.123',//当前IP
        'notify_url'    =>    'http://xxxx.com',//请恕我愚昧，我没搞懂他有什么用
        'trade_type'    =>    'JSAPI',//必须填写JSAPI
        'openid'        =>    'xxxxxxxx'//当前用户的openid，在trade_type=JSAPI的时候，此项就变成必填项了
    );
    $config['sign'] = $this->getSignPay($config);
    $xmlData = $this->ToXml($config);//转成xml数据
    $postData = $this->http_post($xmlData);
    $arrayData = $this->FromXml($postData);
    if($arrayData['return_code'] == 'SUCCESS' || $arrayData['result_code'] == 'SUCCESS'){
        return $arrayData['prepay_id'];//重点来了：走了这么多路，就为了这个值。到这一步就证明成功一多半了。
    }else{
        return $arrayData;//返回错误
    }
}

/**
 * 获取签名
 */
public function getSignPay($config){
    $key = 'xxxxxxx';//商户秘钥，就是自己生成的32位密码
    $strA = 'appid='.$config['appid'].'&body='.$config['body'].'&mch_id='.$config['mch_id'].'&nonce_str='.$config['nonce_str'].'&notify_url='.$config['notify_url'].'&spbill_create_ip'.$config['spbill_create_ip'].'&total_fee='.$config['total_fee'].'&trade_type='.$config['trade_type'];//ASCII 字典序
    $strB = $strA.'&key='.$key;
    $sign = strtoupper(md5($strB));//大写MD5
    return $sign;
}

/**
 * 随机字符串 32位
 */
public function getNonceStr($length = 32){
    $chars = "abcdefghijklmnopqrstuvwxyz0123456789";  
    $str ="";
    for ( $i = 0; $i < $length; $i++ )  {  
        $str .= substr($chars, mt_rand(0, strlen($chars)-1), 1);  
    } 
    return $str;
}

/**
 * array转XML
 */
public function ToXml($data){
    if(!is_array($data) || count($data) <= 0){
        throw new WxPayException("数组数据异常！");
    }
    $xml = "<xml>";
    foreach ($data as $key=>$val){
        $xml.="<".$key.">".$val."</".$key.">";
    }
    $xml.="</xml>";
    return $xml; 
}

/**
 * xml转array
 */
public function FromXml($xml){    
    if(!$xml){
        throw new WxPayException("xml数据异常！");
    }
    libxml_disable_entity_loader(true);
    $this->values = json_decode(json_encode(simplexml_load_string($xml, 'SimpleXMLElement', LIBXML_NOCDATA)), true);
    return $this->values;
}


/**
 * post 请求
 */
public function http_post($url,$param,$post_file=false){
    $oCurl = curl_init();
    if(stripos($url,"https://")!==FALSE){
        curl_setopt($oCurl, CURLOPT_SSL_VERIFYPEER, FALSE);
        curl_setopt($oCurl, CURLOPT_SSL_VERIFYHOST, false);
        curl_setopt($oCurl, CURLOPT_SSLVERSION, 1); //CURL_SSLVERSION_TLSv1
    }
    if (PHP_VERSION_ID >= 50500 && class_exists('\CURLFile')) {
        $is_curlFile = true;
    } else {
        $is_curlFile = false;
        if (defined('CURLOPT_SAFE_UPLOAD')) {
            curl_setopt($oCurl, CURLOPT_SAFE_UPLOAD, false);
        }
    }
    if (is_string($param)) {
        $strPOST = $param;
    }elseif($post_file) {
        if($is_curlFile) {
            foreach ($param as $key => $val) {
                if (substr($val, 0, 1) == '@') {

                }
            }
        }
        $strPOST = $param;
    } else {
        $aPOST = array();
        foreach($param as $key=>$val){
            $aPOST[] = $key."=".urlencode($val);
        }
        $strPOST =  join("&", $aPOST);
    }
    curl_setopt($oCurl, CURLOPT_URL, $url);
    curl_setopt($oCurl, CURLOPT_RETURNTRANSFER, 1 );
    curl_setopt($oCurl, CURLOPT_POST,true);
    curl_setopt($oCurl, CURLOPT_POSTFIELDS,$strPOST);
    $sContent = curl_exec($oCurl);
    $aStatus = curl_getinfo($oCurl);
    curl_close($oCurl);
    if(intval($aStatus["http_code"])==200){
        return $sContent;
    }else{
        return false;
    }
}

Okay, now I have obtained it# The value of ##prepay_id

, our unified order is completed. In fact, I would rather call him data seal小programWeChat payment

Official document: https://developers .weixin.qq....

Let’s start with an episode. First, the front end of our mini program needs to trigger pay. The function must be to click on a trigger of the mini program before payment can be made, right?

pay:function(e){
    //这里面使用post去请求。然后通过我接下来要写的API支付代码获取小程序支付参数
    success:function(res){
         wx.requestPayment({
             'timeStamp':toString(res.timeStamp),//这里转字符串，这里被坑过，不转的话可能会出现total_fee为空
             'nonceStr':toString(res.nonceStr),
             'package':toString(res.package),
             'signType':'MD5',
             'paySign':toString(res.paySign),
             success:function(res){
                 console.log(res);//这里可以跳转到带参地址
             },
             fail:function(res){
                 console.info('支付失败',res);
             },
             complete:function(){
                 console.info('支付触发回调',res);
             }
         })  
    }
       
}

api payment

That is, the backend request address of the above mini program code

/**
 * api组装数据
 */
public function payApiBlack(){
    $appid = 'xxxxxx';//小程序appid，上面有重复，不过这样比较直观
    $timeStamp = time();
    $nonceStr = $this->getNonceStr();//这是调用统一下单里面的方法，为了直观，我把这些代码都写在了一个类里
    $package = 'prepay_id='.$this->unifiedorder();
    $signType = 'MD5';
    $key = 'xxxxxx';//这里是商户秘钥，32位，同上面也有
    $strA = 'appId='.$appid.'&nonceStr='.$nonceStr.'package='.$package.'&= signType='.$signType.'&timeStamp='.$timeStamp.'&key='.$key;
    $paySign = strtoupper(md5($strA));
    $data = array(
        'appid'=>$appid,
        'timeStamp'=>$timeStamp,
        'nonceStr'=>$nonceStr,
        'package'=>$package,
        'signType'=>$signType
    );
    return $data;//返回给小程序
}

The above is all the code, and the payment callback of the mini program has no information, so, My idea is to jump to the parameter after judging success

//此代码为wx.requestPayment success,部分代码省略
//res 回调参数包括用户uid及其他重要传递
success:function(res){
    wx.redirect({
        url:'pages/pay/done?uid='+res.uid
    })
}

Of course, the notify_url for unified ordering seems to be related to the callback. As for how to use it, I tried the callback CURD several times but no response, so I will study it when I have time. La.

The above code is only used to explain the payment process, so if you really want to use it in the project, you should use the official SDK. After all, money is involved.

Related recommendations:

Comparison and difference between WeChat mini program and Alipay mini program

How to enter payment from 0 in WeChat mini program

WeChat Mini Program WeChat Payment Access Development

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