Express：使用 post 方法未定义的主体

Question

I'm trying to get data from a post request using express. But when I use Postman to create the resquest, the req.body is empty (console.log shows 'req {}') I tried a couple of things and read similar questions in StackOverflow but I couldn't solve my issue.

Here are two screens of my Postman request using form-data and raw: postman request postman form For the second, I also tried with the default content-type before adding application/json

Thanks for your help !

// File : router.js

import express from 'express'

const router = express.Router()

// I tried some router.get routes here and it works with no problem...

router.post('/myurl', (req, res) => {
    console.log('req', req.body)
})

export default router



// File : app.js


import express from 'express';

import router from './router.js';

const app = express();
const port = 3000;

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

app.use('/', router)

app.listen(port, () => {
    console.log(`App listening at http://localhost:${port}`);
}
);

Answer 1

You need three elements of the request and server side code to match.

• The Content-Type request header must specific the format you are sending the data in
• The request body must be encoded to match that header (and be valid)
• The server needs body parsing middleware that supports that format.

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Your first screenshot shows you are POSTing raw data which is invalid JSON. It does not show what Content-Type request header you are including.

You need to make the JSON valid and ensure that you have Content-Type: application/json in the request headers.

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Your second screenshot shows that you are posting multipart/form-data , but you only have middleware that parses application/json and application/x-www-form-urlencoded data.

Either change the format you are POSTing in, or add suitable middleware.

Note also that the Content-Type of the individual parts is wrong. example is not valid JSON ( 100 is valid JSON but you probably don't want it to be treated as such).

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