通过 User-Agent 请求头区分扫码端应用，可实现一码适配多平台支付

payment-adapter.js

const http = require("http");

const hostname = "0.0.0.0"; // 允许局域网内访问
const port = 3000;

const server = http.createServer((req, res) => {
  let clientDisplayName = undefined;
  const userAgent = req.headers["user-agent"];
  if (userAgent.includes("MicroMessenger")) {
    // wechat
    // user-agent: Mozilla/5.0 (iPhone; CPU iPhone OS 17_6_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/15E148 MicroMessenger/8.0.52(0x18003426) NetType/WIFI Language/zh_CN
    clientDisplayName = "微信扫码";
  } else if (userAgent.includes("AliApp")) {
    // alipay
    // user-agent: Mozilla/5.0 (iPhone; CPU iPhone OS 17_6_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/21G93 Ariver/1.1.0 AliApp(AP/10.6.36.6000) Nebula WK RVKType(1) AlipayDefined(nt:WIFI,ws:414|832|2.0) AlipayClient/10.6.36.6000 Alipay Language/zh-Hans Region/CN NebulaX/1.0.0 DTN/2.0
    clientDisplayName = "支付宝扫码";
  } else {
    clientDisplayName = "未知客户端扫码\r\n" + userAgent;
  }

  // 返回响应
  res.statusCode = 200;
  res.setHeader("Content-Type", "text/plain; charset=utf-8;");
  res.end(clientDisplayName);
});

server.listen(port, hostname, () => {
  console.log(`服务器运行在 http://${hostname}:${port}/`);
});