我尝试在express.js中学习REST API和基于会话的身份验证。但在尝试重新定位端点时，我遇到了非常有趣的错误。
在重新定位端点之后，我向/me端点发送了一个请求，但是收到了一个错误。

// This code works fine
router.get("/me", sessionChecker, async (req, res, next) => {
  const { userId } = req.session.payload;

  const user = await UserService.findUserById(userId);

  return res.json(user);
});

router.get("/:userId", sessionChecker, async (req, res, next) => {
  const { userId } = req.params;

  const user = await UserService.findUserById(userId);
  return res.json(user);
});

到这;

// This code gives error
router.get("/:userId", sessionChecker, async (req, res, next) => {
  const { userId } = req.params;

  const user = await UserService.findUserById(userId);
  return res.json(user);
});

router.get("/me", sessionChecker, async (req, res, next) => {
  const { userId } = req.session.payload;

  const user = await UserService.findUserById(userId);

  return res.json(user);
});

我得到这个错误;

/Users/Desktop/projects/Curioso/backend/node_modules/mongoose/lib/query.js:4913
  const castError = new CastError();
                    ^

CastError: Cast to ObjectId failed for value "me" (type string) at path "_id" for model "User"
    at model.Query.exec (/Users/Desktop/projects/Curioso/backend/node_modules/mongoose/lib/query.js:4913:21)
    at model.Query.Query.then (/Users/Desktop/projects/Curioso/backend/node_modules/mongoose/lib/query.js:5012:15)
    at processTicksAndRejections (node:internal/process/task_queues:96:5) {
  messageFormat: undefined,
  stringValue: '"me"',
  kind: 'ObjectId',
  value: 'me',
  path: '_id',
  reason: BSONTypeError: Argument passed in must be a string of 12 bytes or a string of 24 hex characters or an integer

我不明白这个错误的逻辑和问题是什么。

• • 索引. js**

const express = require("express");
const session = require("express-session");
const MongoStore = require("connect-mongo");
const mongoose = require("mongoose");
const authRouter = require("./routes/auth");
const roomsRouter = require("./routes/rooms");
const usersRouter = require("./routes/users");
var cors = require("cors");
require("dot-env");

const app = express();

mongoose
.connect(process.env.MONGODB_URL)
.then(() => {
 console.log("Connected to DB");
})
.catch((error) => {
 console.log(error);
});

var whitelist = ["http://localhost:3000"];
var corsOptions = {
origin: whitelist,
methods: ["POST", "PUT", "GET", "OPTIONS", "HEAD"],
credentials: true,
};

app.use(cors(corsOptions));
app.use(express.json());
app.use(express.urlencoded({ extended: true }));

app.use(
session({
 secret: process.env.SESSION_SECRET_KEY,
 resave: false,
 saveUninitialized: true,
 cookie: {
   maxAge: 1000 * 60 * 60 * 24,
   secure: process.env.NODE_ENV === "production",
   httpOnly: true,
 },
 store: MongoStore.create({
   mongoUrl: process.env.MONGODB_URL,
 }),
})
);
app.use("/auth", authRouter);
app.use("/rooms", roomsRouter);
app.use("/users", usersRouter);

app.listen(8000, () => {
console.log(`Example app listening on port 8000`);
});

• • 路由/用户. js**

const express = require("express");
const { sessionChecker } = require("../middlewares/auth");
const router = express.Router();
const UserService = require("../services/user");

router.get("/", sessionChecker, async (req, res, next) => {
  const allUsers = await UserService.getAllUsers();

  return res.json(allUsers);
});

router.get("/:userId", sessionChecker, async (req, res, next) => {
  const { userId } = req.params;

  const user = await UserService.findUserById(userId);
  return res.json(user);
});
router.get("/me", sessionChecker, async (req, res, next) => {
  const { userId } = req.session.payload;

  const user = await UserService.findUserById(userId);

  return res.json(user);
});

module.exports = router;

• • 中间件/auth. js**

const { HTTP_ERRORS } = require("../utils/constants");

const sessionChecker = (req, res, next) => {
  const userSession = req.session.payload.userId;

  if (!userSession) {
    return res
      .status(HTTP_ERRORS.UNAUTHORIZED.CODE)
      .send(HTTP_ERRORS.UNAUTHORIZED.MESSAGE);
  }

  next();
};

module.exports = { sessionChecker };