微信小程序之 PHP 小程序支付

前言

微信小程序开发文档：

https://pay.weixin.qq.com/wiki/doc/api/wxa/wxa_api.php?chapter=7_3&index=1

需要注意的是：

• appid必须为最后拉起收银台的小程序appid；
• mch_id为和appid成对绑定的支付商户号，收款资金会进入该商户号；
• trade_type请填写JSAPI；
• openid为appid对应的用户标识，即使用wx.login接口获得的openid

代码

<?php
/*
 * 小程序微信支付
 * time 2018-1-11 13:11
 * author-email wanghongbin@ngoos.org 
*/
class WeixinPay {
    protected $appid;
    protected $mch_id;
    protected $key;
    protected $openid;
    protected $out_trade_no;
    protected $body;
    protected $total_fee;
    protected $notify_url;
    function __construct($appid, $openid, $mch_id, $key, $out_trade_no, $body, $total_fee, $notify_url) {
        $this->appid = $appid;
        $this->openid = $openid;
        $this->mch_id = $mch_id;
        $this->key = $key;
        $this->out_trade_no = $out_trade_no;
        $this->body = $body;
        $this->total_fee = $total_fee;
        $this->notify_url = $notify_url;
    }
    public function pay() {
        //统一下单接口
        $return = $this->weixinapp();
        return $return;
    }
    //统一下单接口
    private function unifiedorder() {
        $url = ''https://api.mch.weixin.qq.com/pay/unifiedorder'';
        $parameters = array(
            ''appid'' => $this->appid, //小程序ID
            ''mch_id'' => $this->mch_id, //商户号
            ''nonce_str'' => $this->createNoncestr(), //随机字符串
            ''body'' => $this->body,//商品描述
            ''out_trade_no'' => $this->out_trade_no,//商户订单号
            ''total_fee'' => $this->total_fee,//总金额 单位 分
            ''spbill_create_ip'' => $_SERVER[''REMOTE_ADDR''], //终端IP
            ''notify_url'' => $this->notify_url, //通知地址  确保外网能正常访问
            ''openid'' => $this->openid, //用户id
            ''trade_type'' => ''JSAPI'' //交易类型
        );
        //统一下单签名
        $parameters[''sign''] = $this->getSign($parameters);
        $xmlData = $this->arrayToXml($parameters);
        $return = $this->xmlToArray($this->postXmlCurl($xmlData, $url, 60));
        return $return;
    }
    private static function postXmlCurl($xml, $url, $second = 30) {
        $ch = curl_init();
        //设置超时
        curl_setopt($ch, CURLOPT_TIMEOUT, $second);
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE); //严格校验
        //设置header
        curl_setopt($ch, CURLOPT_HEADER, FALSE);
        //要求结果为字符串且输出到屏幕上
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
        //post提交方式
        curl_setopt($ch, CURLOPT_POST, TRUE);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $xml);
        curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 20);
        curl_setopt($ch, CURLOPT_TIMEOUT, 40);
        set_time_limit(0);
        //运行curl
        $data = curl_exec($ch);
        //返回结果
        if ($data) {
            curl_close($ch);
            return $data;
        } else {
            $error = curl_errno($ch);
            curl_close($ch);
            throw new WxPayException("curl出错，错误码:$error");
        }
    }
    //数组转换成xml
    private function arrayToXml($arr) {
        $xml = "<root>";
        foreach ($arr as $key => $val) {
            if (is_array($val)) {
                $xml.= "<" . $key . ">" . arrayToXml($val) . "</" . $key . ">";
            } else {
                $xml.= "<" . $key . ">" . $val . "</" . $key . ">";
            }
        }
        $xml.= "</root>";
        return $xml;
    }
    //xml转换成数组
    private function xmlToArray($xml) {
        //禁止引用外部xml实体
        libxml_disable_entity_loader(true);
        $xmlstring = simplexml_load_string($xml, ''SimpleXMLElement'', LIBXML_NOCDATA);
        $val = json_decode(json_encode($xmlstring), true);
        return $val;
    }
    //微信小程序接口
    private function weixinapp() {
        //统一下单接口
        $unifiedorder = $this->unifiedorder();
        // print_r($unifiedorder);
        $parameters = array(
            ''appId'' => $this->appid, //小程序ID
            ''timeStamp'' => '''' . time() . '''', //时间戳
            ''nonceStr'' => $this->createNoncestr(), //随机串
            ''package'' => ''prepay_id='' . $unifiedorder[''prepay_id''], //数据包
            ''signType'' => ''MD5'' //签名方式
        );
        //签名
        $parameters[''paySign''] = $this->getSign($parameters);
        return $parameters;
    }
    //作用：产生随机字符串，不长于32位
    private function createNoncestr($length = 32) {
        $chars = "abcdefghijklmnopqrstuvwxyz0123456789";
        $str = "";
        for ($i = 0;$i < $length;$i++) {
            $str.= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
        }
        return $str;
    }
    //作用：生成签名
    private function getSign($Obj) {
        foreach ($Obj as $k => $v) {
            $Parameters[$k] = $v;
        }
        //签名步骤一：按字典序排序参数
        ksort($Parameters);
        $String = $this->formatBizQueryParaMap($Parameters, false);
        //签名步骤二：在string后加入KEY
        $String = $String . "&key=" . $this->key;
        //签名步骤三：MD5加密
        $String = md5($String);
        //签名步骤四：所有字符转为大写
        $result_ = strtoupper($String);
        return $result_;
    }
    ///作用：格式化参数，签名过程需要使用
    private function formatBizQueryParaMap($paraMap, $urlencode) {
        $buff = "";
        ksort($paraMap);
        foreach ($paraMap as $k => $v) {
            if ($urlencode) {
                $v = urlencode($v);
            }
            $buff.= $k . "=" . $v . "&";
        }
        $reqPar;
        if (strlen($buff) > 0) {
            $reqPar = substr($buff, 0, strlen($buff) - 1);
        }
        return $reqPar;
    }
}

// 使用
$weixinpay = new \\WeixinPay($appid, $openid, $mch_id, $key, $trade_no, $body, $total_fee, $notify_url);
$return=$weixinpay->pay();