使用Node+Redis做数据访问缓存

在 上张贴 由 孔 祥博使用Node+Redis做数据访问缓存已关闭评论

关于Redis的安装搭建见下面链接：

https://blog.csdn.net/kong1287988804/article/details/75645617

这里设置了redis的密码root，下面连接的时候会用到

注意在node中package.json中redis的版本要在3.+不能超过4，否则会连不上；

如果不设置密码那么createClient第三个参数传空对象即可

const express = require("express");
const fetch = require("node-fetch");
const redis = require("redis");

const PORT = process.env.PORT || 5000;
const REDIS_PORT = process.env.REDiS_PORT || 6379;
const REDIS_HOST = '127.0.0.1';
const REDIS_OPTS = {auth_pass: 'root'};

const app = express();
const client = redis.createClient(REDIS_PORT, REDIS_HOST, REDIS_OPTS);


let whiteList = ['http://192.168.80.128:3000']
app.use(function(req,res,next){
        let origin = req.headers.origin;
        if(whiteList.includes(origin)){
                res.setHeader('Access-Control-Allow-Origin', origin);
                res.setHeader('Access-Control-Allow-Headers', 'Origin,Accept,Content-Type,X-Requested-With,Authorization,Referer,Access-Control-Allow-Origin,User-Agent');
                res.setHeader('Access-Control-Allow-Methods', 'GET,POST,OPTION,DELETE,PUT');
                res.setHeader('Access-Control-Expose-Headers', '*');
        }
        next();
});

client.on('ready', function(){
   console.log('ready');
})

client.on('error', function(err){
   console.log('error', err);
})

client.on('connect', function(){
    client.set('author', 'kong', redis.print);
    client.get('author', redis.print);
    console.log('connect');
})

// Cache middleware
function cache(req, res, next) {
  const { username } = req.params;
  client.get(username, (err, data) => {
    if (err) throw err;
    if (data !== null) {
      console.log('走缓存');
      // 缓存中有数据，返回缓存中的数据
      res.send(setResponse(username, data));
    } else {
      // 否则继续之前的请求
      next();
    }
  });
}

// 设置响应
function setResponse(username, repos) {
  return `<h2>${username} has ${repos} Github repositories</h2>`;
}
// 获取github仓库数量
async function getRepos(req, res, next) {
  try {
    console.log("Fetching Data...");
    const { username } = req.params;
    const response = await fetch(`https://api.github.com/users/${username}`);
    const data = await response.json();
    const repos = data.public_repos;
    // 存到redis
    // 三个参数分别是键、有效期、值
    client.setex(username, 3600, repos);

    res.send(setResponse(username, repos));
  } catch (error) {
    console.error(error);
    res.status = 500;
  }
}
// 使用中间件，加上第二个参数cache
app.get("/repos/:username", cache, getRepos);

app.listen(5000, () => {
  console.log(`App listening on port ${PORT}`);
});

还是用之前zookeeper的index.html测试，加个按钮

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Demo</title>
</head>
<body>
<div id="console1"></div>
<div id="console2"></div>
<div id="container">
    <h1>
        hello world
    </h1>
</div>
<button id="btn1" >点我一下调用zookeeper</button>
<button id="btn2" >点我一下调用redis</button>

</body>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.6.0/jquery.min.js"></script>
<script>
    $(function () {
        $("#btn1").click(function () {
            //alert("hello world");
            $.ajax({
                method: 'GET',
                url: 'http://192.168.80.128:8084/hello',
                headers: {
                    'Service-Name': 'HelloService/Google',
                    'key': 'url'
                },
                success: function (data) {
                    $("#console1").text(data);
                    //window.open(data)
                }
            })
        });
	$("#btn2").click(function () {
            $.ajax({
                method: 'GET',
                url: 'http://192.168.80.128:5000/repos/k1287988804',
                success: function (data) {
                    $("#console2").html(data);
                }
            })
        });
    })
</script>
</html>