企业用户使用备案资源包进行网站备案ICP并开通微信H5支付（附API V3版本支付nodejs代码）

//APIV3支付
const { Wechatpay } = require('wechatpay-axios-plugin');
const { readFileSync } = require('fs');
// 商户号，支持「普通商户/特约商户」或「服务商商户」
const merchantId = ''; //商户号
const appid = '' // APPID
// 「商户API证书」的「证书序列号」， 通过网页查看
const merchantCertificateSerial = '';
// 从本地文件中加载「商户API私钥」
const merchantPrivateKeyFilePath = '/key/apiclient_key.pem';
const merchantPrivateKeyInstance = readFileSync(merchantPrivateKeyFilePath);
// 「微信支付平台证书」的「证书序列号」，下载器下载后有提示`serial`序列号字段
const platformCertificateSerial = '';

// 从本地文件中加载「微信支付平台证书」，用来验证微信支付请求响应体的签名
const platformCertificateFilePath = '/key/wechatpay_573AB99XXXXXXXXXXXXXX.pem';
const platformCertificateInstance = readFileSync(platformCertificateFilePath);

// 创建支付实例
const wxpay = new Wechatpay({
  mchid: merchantId,
  serial: merchantCertificateSerial,
  privateKey: merchantPrivateKeyInstance,
  certs: { [platformCertificateSerial]: platformCertificateInstance, },
});

// 云函数入口函数
exports.main = async (event, context) => {
  wxpay.v3.pay.transactions.h5
  .post({
    appid:appid,
    mchid:merchantId,
    description:"此处为唤起支付后的页面抬头，商户自拟",
    out_trade_no:"AABBCC"+Date.now().toString(),//此处为商户端的订单号，自拟
    notify_url:"XXXXX",// 此处为支付通知回调，非常重要，不要填错
    amount:{
      total:1,// 此处为消费金额，应由前端传入
      currency:'CNY'
    },
    scene_info:{
      payer_client_ip:"127.0.0.1",
      h5_info:{
        type:'Wap'
      }
    }
  })
  .then(({data: {h5_url}}) => console.info(h5_url))
  .catch(console.error)
}

//nodejs解密
const crypto = require('crypto');
//APIV3 nodejs模块
const { Wechatpay } = require('wechatpay-axios-plugin');
const { readFileSync } = require('fs');
//npm install wechatpay-axios-plugin
// 商户号
const merchantId = '';
// 商户证书序列号
const merchantCertificateSerial = '';
// 商户私钥路径
const merchantPrivateKeyFilePath = './merchant/apiclient_key.pem';
// 商户API私钥 PEM格式的文本字符串或者文件buffer
const merchantPrivateKeyInstance = readFileSync(merchantPrivateKeyFilePath);
// 平台证书
const platformCertificateFilePath = './merchant/wechatpay_XXXXX.pem';
const platformCertificateInstance = readFileSync(platformCertificateFilePath);
//平台证书公钥
const platformPubKeyFilePath = './merchant/wechatpay_XXXXXXXX.pem';
const platformPubKeyInstance = readFileSync(platformPubKeyFilePath);
// 平台证书序列号，下载器下载后有提示序列号字段，也可由命令行
const platformCertificateSerial = '';
//初始化
const wxpay = new Wechatpay({
  mchid: merchantId,
  serial: merchantCertificateSerial,
  privateKey: merchantPrivateKeyInstance,
  certs: { [platformCertificateSerial]: platformCertificateInstance, },
});

exports.main = async (event, context) => {
    //接收支付通知结果
    var body = JSON.parse(event.body);
    // 解密 ciphertext字符  AEAD_AES_256_GCM算法，验证消息来源
    let ciphertext = body.resource.ciphertext;
    let nonce = body.resource.nonce;
    let associated_data = body.resource.associated_data;
    let apiv3key = "";//商户端的APIV3密钥，在网页中设置
    ciphertext = Buffer.from(ciphertext, 'base64');
    let authTag = ciphertext.slice(ciphertext.length - 16);
    let data = ciphertext.slice(0, ciphertext.length - 16);
    let decipher = crypto.createDecipheriv('aes-256-gcm', apiv3key, nonce);
    decipher.setAuthTag(authTag);
    decipher.setAAD(Buffer.from(associated_data));
    let decoded = decipher.update(data, null, 'utf8');
    decipher.final();
    let payData = JSON.parse(decoded); //解密后的数据
    console.log(payData)
    var sub_mchid =payData.sub_mchid;
    var transaction_id = payData.transaction_id;
    var out_trade_no = payData.out_trade_no;
    
    // 商户自行拟定后续逻辑
    // TODO
    
    // 收到回调后必须返回如下字段，否则通知会持续进行
    return {   
        "code": "SUCCESS",
        "message": "成功"
    }
};