如何将POST正文数据传递到另一条路径而不丢失数据？

Question

Let us assume that i have this route

 app.post('/category',function(req,res){
    res.redirect('/category/item');
 })

The user is going to post some data in this route and then is going to be redirected automatically to another route for an example /category/item to post another data

So at the end i want to collect those two post's data the one in route /category and the other one in route /category/item to query my database.

Answer 1

Using express session is the best choice to save the first posted data and then get those data in the second request, here is an example:

add session middleware

const express = require('express'),
    app = express(),
    session = require('express-session');

// use session middleware
app.use(session({
    secret: 'secret',
    resave: false,
    saveUninitialized: true,
    cookie: { maxAge: 60000 }
}));

Store data in session

app.post('/category', function (req, res) {
    // store posted data in the session
    req.session.category = req.body;

    res.redirect('/category/item');
});

app.post('/category/item', function (req, res) {

    // force users to deal with /category first
    if ( !req.session.category ) {
        return res.redirect('/category');
    }

    // get data from the session
    var category = req.session.category;

    // req.body contains the second submited data
});

Answer 2

You can do this using http status code 307 which indicates that the request should be repeated using the same method and post data.

app.post('/', function(req, res) {
  res.redirect(307, '/category/item');
});

Which will preserve the send data.

For reference, the 307 http code spec is:

307 Temporary Redirect (since HTTP/1.1) In this occasion, the request should be repeated with another URI, but future requests can still use the original URI.2 In contrast to 303, the request method should not be changed when reissuing the original request. For instance, a POST request must be repeated using another POST request.

Answer 3

You'll need to store the data from the first call either in memory (a variable) or in your database. HTTP is a completely stateless protocol, so there will be no way to communicate across that boundary (one request to another). I'd recommend storing the data in your DB, perhaps in a temporary hold table, then syncing it up after the second request is made.

app.post('/category',function(req, res){
  // store data from req.body in a temporary table in your DB
  // be sure to key it with something that will tie it to future requests
  // such as a userId, sessionId, etc

  res.redirect('/category/item');
});

app.post('/category/item',function(req, res){
  // find existing data from the temporary DB table using some key
  // like the userId, sessionId, etc

  // then add take the new data from req.body, merge it with the data 
  // from the temporary table above, and store it in the final 
  // location in the DB
});