express.js 中 req.body 的目的是什么？

Question

why req.body is called in the code

post(function(req, res, next) {
  res.end('Will add the promotion: ' + req.body.name + ' with details: ' + req.body.description);
})

Answer 1

req

The req object contains the request , that is, the thing the client sends to your server.

Let's look at a common HTTP request scenario:

POST /gimme-json HTTP/1.1
User-Agent: some cool user agent
Content-Type: application/json

{ "hello": "world" }

HTTP/1.1 200 OK
Content-Type: application/json

{"ok":true}

Now, let's see how we would implement this in Express:

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

// this will take the JSON bodies and put it into 'req.body'
app.use(express.json());

app.post('/gimme-json', (req, res) => {
    console.log('req.body =', req.body); // logs "req.body = { "hello": "world" }"
    res.json({ ok: true });
});

app.listen(80, () => {});

See? req.body contains the body of the request as parsed by whatever middleware you have.

In this case, the middleware stack is simple:

           HTTP GET
      | express internals |
      |JSON parser to body|
      |  handler for GET  |