1. 背景 

请求三方服务，因为服务器在海外， 网络延迟高， 实际部署上线后， 各种接口全都超时，严重影响实用效率.

2. 技术设计

  通过加一层 proxy server 做转发

        user --> client. --> proxy server --> business server .    

3. 代码实现

    3.1 代码结构

    3.2 

        proxy.js

const express = require("express");
const { createProxyMiddleware } = require("http-proxy-middleware");
const target = require("./.TARGET");

const app = express();
app.get("/", (req, res) => {
  res.send("express 20010 home");
});

app.use(
  "/api",
  createProxyMiddleware({
    target,
    changeOrigin: true,
    pathRewrite: {
      "^/api": "", // rewrite path
    },
  })
);
app.listen(20010);

    shell.js

const fs = require("fs");
const shell = require("shelljs");
const { resolve } = require("path");
const order = process.argv.slice(2);
if (!order || order.length === 0) {
  shell.echo("pls add target host!");
  shell.exit(1);
}

const target = order[0].split("=")[1];
if (!target.startsWith("http")) {
  return console.error("target error!");
}
fs.writeFile(
  resolve(__dirname, ".TARGET"),
  `module.exports = "${target}";`,
  (err) => {
    if (err) {
      return console.error("Err: ", err);
    }
    const image = "sira-http-proxy";
    shell.exec(`docker image rm ${image} -f`)
    shell.exec(`docker container stop sira-proxy`);
    shell.exec(`docker container rm sira-proxy`);
    shell.exec(`docker image build -t ${image} .`);
    shell.exec(
      `docker container run --name="sira-proxy" -p 10000:20010 -itd ${image} `,
      {
        async: true,
      }
    );
  }
);

    Dockerfile

FROM node:12.18.4
COPY . /app
WORKDIR /app
RUN npm install
EXPOSE 20010
CMD ["npx", "pm2-runtime", "proxy.js"]

3.3 执行命令

    node shell -t=https://www.tiankele.cn