Express 4.17 req.body 为空

Question

我希望你能在这里帮助我，因为在尝试了十几个 s/o 解决方案并阅读了几次快速文档之后，我很难过。我正在构建一个 Node 应用程序，它将（最终）接受来自前端应用程序的 POST，将其保存到 Mongo，然后允许后端用户操作数据。我刚刚开始，试图让 POST 路线工作并到目前为止：

app.js：

const express = require("express");
const cors = require("cors");

const mongoose = require('mongoose');
const AppData = require("./model/AppData");
const uri = "mongodb://localhost:27017/lunch"
mongoose.connect(uri, { useNewUrlParser: true, useCreateIndex: true, useUnifiedTopology: true });
const connection = mongoose.connection;

const router = require("./routes/index");
const PORT = 3005;
const app = express();

app.use(cors());
app.use("/", router);
app.use(express.raw({type: "application/json"}));
app.use(express.json({strict: false}));

connection.once('open', () => {
    console.log('????Successfully connected to MongoDB????');
});

app.listen(PORT, function () {
    console.log(`????The Backend Server is up and running on port ${PORT}????`);
});

index.js（路由...计划更改名称）

const express = require('express');
const router = express.Router();
const appDataController = require('../controllers/appDataController');

router.post('/submit', appDataController.createAppData);

module.exports = router;

和 appDataController.js：

const mongoose = require('mongoose');
const AppData = mongoose.model('AppData');

exports.createAppData = (req, res) => {
    let reqData = req.body;
    console.log(reqData);
    res.send(reqData);
}

真的很简单，但是当我抓住 Postman 并使用 body/raw/json 设置请求并发送时

{
    "name": "John",
    "age": "21"
}

我总是看到 body 是未定义的。从我所看到的一切来看，我没有做错任何事，但结果清楚地表明不是……我错过了什么？

Answer 1

您还应该包含urlencoded 选项，以便在x-www-form-urlencoded 正文上获取POST 请求的正文。

const app = express();

app.use(cors()); 
app.use(express.raw({type: "application/json"}));
app.use(express.json({strict: false}));
app.use(express.urlencoded({extended: false})); // include this line
app.use("/", router);

Answer 2

因为你在路由之后使用你的 express.json 中间件，所以改变这个：

const express = require("express");
const cors = require("cors");

const mongoose = require('mongoose');
const AppData = require("./model/AppData");
const uri = "mongodb://localhost:27017/lunch"
mongoose.connect(uri, { useNewUrlParser: true, useCreateIndex: true, useUnifiedTopology: true });
const connection = mongoose.connection;

const router = require("./routes/index");
const PORT = 3005;
const app = express();

app.use(cors()); 
app.use(express.raw({type: "application/json"}));
app.use(express.json({strict: false}));
app.use("/", router); // this need to be here

connection.once('open', () => {
    console.log('?Successfully connected to MongoDB?');
});

app.listen(PORT, function () {
    console.log(`?The Backend Server is up and running on port ${PORT}?`);
});

首先是中间件，然后是路由（取决于您使用的中间件）。