发布请求完成后如何重定向用户

Question

I'm using Node.js and express and I want to send a POST Request to a webserver, wait for the result and then redirect the user to a different page.

My problem is that the res.redirect('xxx'); gets executed before the post request is complete. And in the function res1.on('end', function () { I can't do a res.redirect() .

So how do i do a redirect in the on end function?

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

  console.log(req.body.user);
  console.log(req.body.pw);
  console.log("-------- POST -------------");

  // form data
  var postData = querystring.stringify({
    grant_type: "password",
    client_id: "xxx",
    client_secret:"xxx",
    username:req.body.user,
    password:req.body.pw
  });

  var options = {
    host: 'xxx',
    port: 443,
    method: 'POST',
    path: '/oauth_token.do',
    headers: {
      'Content-Type': 'application/x-www-form-urlencoded',
      'Content-Length': postData.length
    }
  };

  var req = https.request(options, function (res1) {
    result = '';
    res1.on('data', function (chunk) {
      result += chunk;
    });
    res1.on('end', function () {
     var obj = JSON.parse(result);
     console.log(obj.access_token);
     access_token = obj.access_token;
     });
    res1.on('error', function (err) {
      console.log("Error 1");
    })
  });

  req.write(postData);
  req.end();

 // res.redirect('xxx');

});

Answer 1

You wanna do it in the callback so that you know it's done:

res1.on('end', function() {
    var obj = JSON.parse(result);
    console.log(obj.access_token);
    access_token = obj.access_token;
    // res.redirect('xxx');
});
res1.on('error', function(err) {
    console.log("Error 1");
})

Answer 2

whenever response was returned from the server, it goes to callback function so write your redirect logic in the callback so that you know it's done.

res1.on('end', function () {
     var obj = JSON.parse(result);
     console.log(obj.access_token);
     access_token = obj.access_token;

     //call your redirect function after success response 
    // res.redirect('xxx');

});