NodeJS+Postman POST请求报错Cannot POST /bookstore求助

我在使用Postman发送POST请求到/bookstore时收到错误，错误页面显示如下：

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="utf-8">
    <title>Error</title>
</head>

<body>
    <pre>Cannot POST /bookstore</pre>
</body>

</html>

但GET请求访问/bookstore和/bookstore/:id都能正常工作。我原本编写的POST请求代码如下：

app.post("/bookstore", (req, res) => {
  const books = req.body;
  db.collection("bookstore")
    .insertOne(books)
    .then((result) => res.json(result))
    .catch((err) => res.send(err));
});

完整项目代码如下：

db.js #

const { MongoClient } = require("mongodb");

let dbConnection;

module.exports = {
  connectToDb: (cb) => {
    MongoClient.connect("mongodb://localhost:27017/bookstore")
      .then((res) => {
        dbConnection = res.db();
        return cb();
      })
      .catch((error) => {
        console.log(error);
        return cb(error);
      });
  },
  getDb: () => dbConnection,
};

index.js #

const express = require("express");
const { connectToDb, getDb } = require("./db");
const { ObjectId } = require("mongodb");
const e = require("express");

// init app and middleware
const app = express();
app.use(express.json());

//db connection
let db;

connectToDb((xato) => {
  if (!xato) {
    app.listen(3000, () => {
      console.log("The 3000 port is installed");
    });
    db = getDb();
    return db;
  }
});

//routes
app.get("/bookstore", (req, res) => {
  let mybook = [];
  // the collection name from mongoDB
  db.collection("bookstore")
    .find()
    .sort({ author: 1 })
    .forEach((book) => mybook.push(book))
    .then(() => {
      return res.json(mybook);
    })
    .catch(() => {
      return res.send("there were an error");
    });
  // res.json({ MyWords: "I am coming from json res" });
});

app.get("/bookstore/:id", (req, res) => {
  if (ObjectId.isValid(req.params.id)) {
    db.collection("bookstore")
      .findOne({ _id: new ObjectId(req.params.id) })
      .then((doc) => res.json(doc))
      .catch((err) => res.send(err));
  } else {
    res.send(" wrong id request");
  }
});
app.post("/", (req, res) => {
  const books = req.body;
  db.collection("bookstore")
    .insertOne(books)
    .then((result) => res.json(result))
    .catch((err) => res.send(err));
});

我已经重启过Express服务器，但问题依旧，请求找出错误并修复！

问题根源 #

你在index.js中实际注册的POST路由是根路径/，而非你预期的/bookstore。当你向/bookstore发送POST请求时，Express找不到对应的处理路由，因此返回Cannot POST /bookstore错误。

修复步骤 #

将index.js中的POST路由路径从/修改为/bookstore，与你最初编写的代码一致：

// 替换原有的app.post("/", ...)代码
app.post("/bookstore", (req, res) => {
  const books = req.body;
  db.collection("bookstore")
    .insertOne(books)
    .then((result) => res.json(result))
    .catch((err) => res.send(err));
});

额外验证项 #

1. 重启Express服务器，确保代码修改生效
2. 在Postman中确认请求地址为http://localhost:3000/bookstore，请求方法为POST
3. 在Postman的Body选项卡中选择raw -> JSON格式，传入合法的书籍数据示例：

   {
     "title": "Node.js实战",
     "author": "张三",
     "price": 59.9
   }
   

4. 确认MongoDB服务处于运行状态，且bookstore数据库已存在

内容的提问来源于stack exchange，提问作者Sardor Sirojov