手写一个仿微信登录的nodejs程序

let http = require("http");
let express = require("express");
let qrcode = require("qr-image");
let app = express();
let path = require("path");
let server = http.createServer(app);
let url = require("url");
let fs = require("fs");
let UUID = require("uuid-js");
let generateHTML = null;
app.use(express.static("./public"));
/*
 * Description: 读取网页文件，用于替换关键字，相当于简易模板
 * Params:
 * sessionID - 生成的uid
 * req - 网页请求
 * res - 网页应答
 * fileName - 网页文件所在路径
 */
generateHTML = function (sessionID, req, res, fileName) {
  fs.readFile(fileName, "UTF-8", function (err, data) {
    if (!err) {
      data = data.replace(/SESSION_UID/g, sessionID);
      res.writeHead(200, {
        "Content-Type": "text/html; charset=UTF-8",
      });
      res.end(data);
    } else {
      console.log(err);
      res.writeHead(404, {
        "Content-Type": "text/html; charset=UTF-8",
      });
      res.end();
    }
  });
};
/*
 * Description: 写入JSON文件
 * Params:
 * fileName - JSON文件所在路径
 * uid - 生成的uid
 * writeData - 需要写入的JSON格式数据
 *
 */
let setJSONValue = function (fileName, uid, writeData) {
  let data = fs.readFileSync(fileName);
  let users = JSON.parse(data.toString());
  let addFlag = true;
  let delFlag = writeData === null;
  for (let i = 0; i < users.data.length; i++) {
    if (users.data[i].uid === uid) {
      addFlag = false;
      if (delFlag) {
        users.data.splice(i, 1);
      } else {
        users.data[i].status = writeData.status;
        console.log(
          "writeJSON: " + JSON.stringify(users.data[i]) + " modified."
        );
      }
    }
  }
  if (addFlag) {
    users.data.push(writeData);
    console.log("writeJSON: " + JSON.stringify(writeData) + " inserted.");
  }
  // 同步写入文件
  let writeJSON = JSON.stringify(users);
  fs.writeFileSync(fileName, writeJSON);
};
/*
 * Description: 读取JSON文件（要返回数据，选择同步读取）
 * Params:
 * fileName - JSON文件所在路径
 * uid - 生成的uid
 *
 */
getJSONValue = function (fileName, uid) {
  let readData = null;
  // 同步读取文件
  let data = fs.readFileSync(fileName);
  let users = JSON.parse(data.toString());
  for (let i = 0; i < users.data.length; i++) {
    if (users.data[i].uid === uid) {
      readData = JSON.stringify(users.data[i]);
      break;
    }
  }
  return readData;
};
// 显示网站首页
app.get("/", function (req, res) {
  // 生成唯一的ID
  let uid = UUID.create();
  console.log("uid: '" + uid + "' generated.");
  // 替换网页模板内的UID关键字
  generateHTML(uid, req, res, path.join(__dirname, "/views/main.html"));
});
// 生成二维码图片并显示
app.get("/qrcode", function (req, res, next) {
  let uid = url.parse(req.url, true).query.uid;
  try {
    if (typeof uid !== "undefined") {
      // 写入二维码内的网址，微信扫描后自动跳转。下面的网址是我的网址，https://www.maomin.club/qrcodelogin ，你可以换成自己的线上网址或者本地服务器。加上后面的"/scanned?uid="
      let jumpURL = "https://www.maomin.club/qrcodelogin/scanned?uid=" + uid;
      // 生成二维码(size：图片大小， margin: 边框留白)
      let img = qrcode.image(jumpURL, { size: 6, margin: 2 });
      res.writeHead(200, { "Content-Type": "image/png" });
      img.pipe(res);
    } else {
      res.writeHead(414, { "Content-Type": "text/html" });
      res.end("<h1>414 Request-URI Too Large</h1>");
    }
  } catch (e) {
    res.writeHead(414, { "Content-Type": "text/html" });
    res.end("<h1>414 Request-URI Too Large</h1>");
  }
});
// 显示手机扫描后的确认界面
app.get("/scanned", function (req, res) {
  let uid = url.parse(req.url, true).query.uid;
  if (typeof uid !== "undefined") {
    generateHTML(uid, req, res, path.join(__dirname, "/views/confirm.html"));
    console.log("uid: '" + uid + "' scanned.");
    // 获取JSON文件内对应uid的数据，更改其数据状态
    let jsonData = getJSONValue(path.join(__dirname, "/bin/data.json"), uid);
    if (jsonData === null) {
      jsonData = {
        uid: uid,
        status: "scanned",
        name: "USER",
      };
    } else {
      jsonData = JSON.parse(jsonData);
      jsonData.status = "scanned";
    }
    // 写入JSON文件
    setJSONValue(path.join(__dirname, "/bin/data.json"), uid, jsonData);
  } else {
    res.writeHead(414, { "Content-Type": "text/html" });
    res.end("<h1>414 Request-URI Too Large</h1>");
  }
});
// 在确认界面操作的响应
app.get("/confirmed", function (req, res) {
  let uid = url.parse(req.url, true).query.uid;
  let operate = url.parse(req.url, true).query.operate;
  if (typeof uid !== "undefined") {
    console.log("uid: '" + uid + "' " + operate);
    let jsonData = getJSONValue(path.join(__dirname, "/bin/data.json"), uid);
    let status = operate === "confirm" ? "verified" : "canceled";
    if (jsonData === null) {
      jsonData = {
        uid: uid,
        status: status,
        name: "USER",
      };
    } else {
      jsonData = JSON.parse(jsonData);
      jsonData.status = status;
    }
    setJSONValue(path.join(__dirname, "/bin/data.json"), uid, jsonData);
    if (status === "verified") {
      res.writeHead(200, { "Content-Type": "text/html" });
      res.end("<h1 style='textAlign:center;'>登录成功!</h1>");
    } else {
      res.writeHead(200, { "Content-Type": "text/html" });
      res.end("<h1 style='textAlign:center;'>Canceled!</h1>");
    }
  } else {
    res.writeHead(414, { "Content-Type": "text/html" });
    res.end("<h1 style='textAlign:center;'>414 Request-URI Too Large</h1>");
  }
});
// 响应主页不断的AJAX请求
app.get("/verified", function (req, res) {
  let uid = url.parse(req.url, true).query.uid;
  // normal   - 没有任何触发
  // scanned  - 已扫描
  // canceled - 已取消
  // verified - 已验证
  let dataStatus = {
    cmd: "normal",
    user: "",
  };
  console.log("uid: '" + uid + "' query ...");
  if (typeof uid !== "undefined") {
    let userData = getJSONValue(path.join(__dirname, "/bin/data.json"), uid);
    // 返回JSON数据用于首页AJAX操作
    if (userData !== null) {
      userData = JSON.parse(userData);
      dataStatus.cmd = userData.status;
      dataStatus.user = userData.name;
    }
  }
  res.end(JSON.stringify(dataStatus));
});
server.listen(4000);
console.log(
  "Express server listening on port %d in %s mode",
  server.address().port,
  app.settings.env
);

https://github.com/maomincoding/qrcodelogin.git