回答

在proxyReq中修改header：

const http = require('http');
const httpProxy = require('http-proxy');

// 创建一个代理服务器实例
const proxy = httpProxy.createProxyServer({
    ws: true
});
// 修改请求头中的 Host 字段
proxy.on('proxyReq', (proxyReq, req, res, options) => {
    proxyReq.setHeader('Host', 'generativelanguage.googleapis.com');

});
// 创建一个HTTP服务器
const server = http.createServer((req, res) => {
  // 设置目标服务器地址
  const target = 'https://generativelanguage.googleapis.com';

  // 代理请求到目标服务器
  proxy.web(req, res, { target });

  // 处理代理服务器错误
  proxy.on('error', (err, req, res) => {
    res.writeHead(500, {
      'Content-Type': 'text/plain'
    });
    res.end('Something went wrong. And we are reporting a custom error message.');
  });
});

// 启动服务器，监听端口8000
server.listen(8000,"0.0.0.0", () => {
  console.log('Proxy server is running on http://localhost:8000');
});