PHP接入微信官方支付（native·APIv3）

一、项目介绍

两个文件实现微信官方支付（native·APIv3）的发起支付和回调应答功能

二、准备资料

1. 商户号：需要使用到营业执照注册商户
2. appid：小程序或者订阅号的appid
3. APIv3秘钥：32位秘钥，APIv2秘钥为16位，不要混淆
4. 证书序号：apiclient_key.pem文件中的秘钥，需要将该文件改为txt后缀，然后获取其中的秘钥

三、支付代码

1.index.php文件

//支付配置
$mchid = '';            //微信支付商户号 PartnerID
$appid = '';            //公众号APPID
$apiKey = '';           //APIv3密钥
$serialNumber = '';     //证书序列号
$privateKey = '';       //apiclient_key.pem的文件内容，可以先将后缀名改为txt，然后获取里面内容

//商品信息，可以由前端获取
$payAmount = '';        //付款金额，单位:元
$orderName = '';        //订单标题

//默认配置
$outTradeNo = date('YmdHis').uniqid();     //订单号，采用时间加微秒计ID
$notifyUrl = 'https://***/notify.php';     //付款成功后的通知地址，需要用https协议

//这里可以填写预下单业务逻辑


//发起支付
$wxPay = new IndexService($mchid, $appid, $apiKey,$privateKey,$serialNumber);
$wxPay->setTotalFee($payAmount);
$wxPay->setOutTradeNo($outTradeNo);
$wxPay->setOrderName($orderName);
$wxPay->setNotifyUrl($notifyUrl);
$result = $wxPay->doPay();

//输出二维码链接，由前端生成二维码
return $result['code_url'];

//IndexService类
class IndexService
{
    protected $mchid;
    protected $appid;
    protected $apiKey;
    protected $privateKey;
    protected $serialNumber;
    protected $totalFee;
    protected $outTradeNo;
    protected $orderName;
    protected $notifyUrl;
    protected $auth;
    protected $gateWay='https://api.mch.weixin.qq.com/v3';

    public function __construct($mchid, $appid, $apikey, $privateKey, $serialNumber)
    {
        $this->mchid = $mchid;
        $this->appid = $appid;
        $this->apiKey = $apikey;
        $this->privateKey = $privateKey;
        $this->serialNumber = $serialNumber;
    }

    public function setTotalFee($totalFee)
    {
        $this->totalFee = floatval($totalFee);
    }

    public function setOutTradeNo($outTradeNo)
    {
        $this->outTradeNo = $outTradeNo;
    }

    public function setOrderName($orderName)
    {
        $this->orderName = $orderName;
    }

    public function setNotifyUrl($notifyUrl)
    {
        $this->notifyUrl = $notifyUrl;
    }

    /**
     * 发起支付
     */
    public function doPay()
    {
        $reqParams = array(
            'appid' => $this->appid,        //公众号或移动应用appid
            'mchid' => $this->mchid,        //商户号
            'description' => $this->orderName,     //商品描述
            'attach' => 'pay',              //附加数据，在查询API和支付通知中原样返回，可作为自定义参数使用
            'notify_url' => $this->notifyUrl,       //通知URL必须为直接可访问的URL，不允许携带查询串。
            'out_trade_no' => $this->outTradeNo,      //商户系统内部订单号，只能是数字、大小写字母_-*且在同一个商户号下唯一，详见【商户订单号】。特殊规则：最小字符长度为6
            'amount'=>array(
                'total'=> floatval($this->totalFee) * 100, //订单总金额，单位为分
                'currency'=> 'CNY', //CNY：人民币，境内商户号仅支持人民币
            ),
            'scene_info'=>array(        //支付场景描述
                'payer_client_ip'=>'127.0.0.1'   //调用微信支付API的机器IP
            )
        );
        $reqUrl = $this->gateWay.'/pay/transactions/native';
        $this->getAuthStr($reqUrl,$reqParams);
        $response = $this->curlPost($reqUrl,$reqParams);
        return json_decode($response,true);

    }

    public function curlPost($url = '', $postData = array(), $options = array())
    {
        if (is_array($postData)) {
            $postData = json_encode($postData);
        }
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_POST, 1);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $postData);
        curl_setopt($ch, CURLOPT_HTTPHEADER, array(
            'Authorization:'.$this->auth,
            'Content-Type:application/json',
            'Accept:application/json',
            'User-Agent:'.$_SERVER['HTTP_USER_AGENT']
        ));
        curl_setopt($ch, CURLOPT_TIMEOUT, 30); //设置cURL允许执行的最长秒数
        if (!empty($options)) {
            curl_setopt_array($ch, $options);
        }
        //https请求 不验证证书和host
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
        $data = curl_exec($ch);
        curl_close($ch);
        return $data;
    }

    private function getSchema(): string
    {
        return 'WECHATPAY2-SHA256-RSA2048';
    }

    public function getAuthStr($requestUrl,$reqParams=array()): string
    {
        $schema = $this->getSchema();
        $token = $this->getToken($requestUrl,$reqParams);
        $this->auth = $schema.' '.$token;
        return $this->auth;
    }

    private function getNonce()
    {
        static $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
        $charactersLength = strlen($characters);
        $randomString = '';
        for ($i = 0; $i < 32; $i++) {
            $randomString .= $characters[rand(0, $charactersLength - 1)];
        }
        return $randomString;
    }

    public function getToken($requestUrl,$reqParams=array()): string
    {
        $body = $reqParams ?  json_encode($reqParams) : '';
        $nonce = $this->getNonce();
        $timestamp = time();
        $message = $this->buildMessage($nonce, $timestamp, $requestUrl,$body);
        $sign = $this->sign($message);
        $serialNo = $this->serialNumber;
        return sprintf('mchid="%s",nonce_str="%s",timestamp="%d",serial_no="%s",signature="%s"',
            $this->mchid, $nonce, $timestamp, $serialNo, $sign
        );
    }

    private function buildMessage($nonce, $timestamp, $requestUrl, $body = ''): string
    {
        $method = 'POST';
        $urlParts = parse_url($requestUrl);
        $canonicalUrl = ($urlParts['path'] . (!empty($urlParts['query']) ? "?{$urlParts['query']}" : ""));
        return strtoupper($method) . "\n" .
            $canonicalUrl . "\n" .
            $timestamp . "\n" .
            $nonce . "\n" .
            $body . "\n";
    }

    private function sign($message): string
    {
        if (!in_array('sha256WithRSAEncryption', openssl_get_md_methods(true))) {
            throw new \RuntimeException("当前PHP环境不支持SHA256withRSA");
        }
        $res = $this->privateKey;
        if (!openssl_sign($message, $sign, $res, 'sha256WithRSAEncryption')) {
            throw new \UnexpectedValueException("签名验证过程发生了错误");
        }
        return base64_encode($sign);
    }
}

说明：

1. 该微信支付属于native的APIv3版本，需要用到商户证书的相关内内容，不要和微信的其他支付方式或者APIv2相混淆
2. index.php中的支付成功通知地址需要用https协议，该文件内容，下面会给出
3. 仅需要填写IndexService类上边的配置即可，IndexService类的内容不需要修改

 2.notify.php

//获取返回json数据
$getCallBackJson = file_get_contents('php://input');

//转化为关联数组
$getCallBackArray = json_decode($getCallBackJson, true);

//获取需要解密字段
$associatedData = $getCallBackArray['resource']['associated_data'];
$nonceStr = $getCallBackArray['resource']['nonce'];
$ciphertext = $getCallBackArray['resource']['ciphertext'];


//执行解密
$apiKey = '';   //这里需要填写APIv3秘钥
$getData = new NotifyService($apiKey);
$resultJson = $getData->decryptToString($associatedData, $nonceStr, $ciphertext);

//解密结果，为关联数组格式
$resultArray = json_decode($resultJson, true);

//交易成功
if ($resultArray['trade_state'] === 'SUCCESS') {

  //这里填写交易成功的相关业务，如更新账单状态，其中可能需要用到的参数如下
  
  //$resultArray['out_trade_no']       商户订单号
  //$resultArray['transaction_id']     订单号
  //$resultArray['amount']['total']    订单金额

}

//NotifyService类
class NotifyService
{
    protected $apiKey;
    const AUTH_TAG_LENGTH_BYTE = 16;
    public function __construct($apiKey)
    {
        $this->apiKey = $apiKey;
    }

    /**
     * Decrypt AEAD_AES_256_GCM ciphertext
     *
     * @param string $associatedData     AES GCM additional authentication data
     * @param string $nonceStr           AES GCM nonce
     * @param string $ciphertext         AES GCM cipher text
     *
     * @return string|bool      Decrypted string on success or FALSE on failure
     */
    public function decryptToString(string $associatedData, string $nonceStr, string $ciphertext)
    {

        $ciphertext = \base64_decode($ciphertext);
        if (strlen($ciphertext) <= self::AUTH_TAG_LENGTH_BYTE) {
            return false;
        }
        $ctext = substr($ciphertext, 0, -self::AUTH_TAG_LENGTH_BYTE);
        $authTag = substr($ciphertext, -self::AUTH_TAG_LENGTH_BYTE);
        return \openssl_decrypt($ctext, 'aes-256-gcm', $this->apiKey, \OPENSSL_RAW_DATA, $nonceStr,
            $authTag, $associatedData);
    }
} 

注意：

1. notify.php中需要再次填写你的APIv3秘钥
2. 在交易成功的if语句中，填写最终支付成功的相关业务逻辑

四、项目总结

1. 如果有相关问题，可以在下面评论区评论