Nodejs Frame Express Unable to get the session value solution

We first look at the official sample code of the session in Express

First
$ NPM Install Redis
$ redis-server

var express = require ('.. /..');

var app = Express ();

App.use (Express.logger (' dev '));

Required by session () middleware
Pass the secret for signed cookies
(required by session ())
App.use (Express.cookieparser (' Keyboard Cat '));

Populates req.session
App.use (Express.session ());

App.get ('/', function (req, res) {
var body = ';
if (req.session.views) {
++req.session.views;
Res.send (body + ' <p>viewed <strong> ' + req.session.views + ' </strong> times.</p> ');
} else {
Req.session.views = 1;
Body + = ' <p>first time visiting? View this page in several browsers:) </p> ';
Res.send (body + ' <p>viewed <strong> ' + req.session.views + ' </strong> times.</p> ');
}
});

App.listen (3000);
Console.log (' Express app started on Port 3000 ');

Before you run, you need to know a few things:

Two lines of code for green grass are required, keyboard cat ' is the key used to encrypt cookies.

Session requires media storage storage, express.session () is stored in memory by default. There is also a commonly used method is stored in the database, Redis is a non-sql database, there are Nodejs Plug-ins can access him, Redis is commonly used. But given the weight, I didn't use it. Instead, it is stored in memory.

The session provides a regenerate method for emptying the entire session and then assigning the value again.

The problem I encountered was to create a new session in the login request using the Regenerate method of the session:

function login (request, response) {
...
Request.session.regenerate (function () {
Request.session.username = Userinfo.username;
Console.log ("set Session username =" + request.session.username);
Console.log (Request);
Response.Write (Json.stringify (Loginresult));
Response.End ();
} );
}

Then, in other requests after the login, determine if request.session.username exists, but not get it, request.session.username is undefined.

This question bothered me for 3 mornings, and I've been troubleshooting various possibilities:

I do not know if there is a problem in memory session, I did not run the express session of the official sample, later in the official sample code, I learned that this is not a problem. Before that, I tried using Redis to store the session, and later I thought that using the database was too heavy to accept the answer, so I gave up.

I wonder if query's Ajax request method did not pass the cookie in session to the background, through Google (thanks to google) I found the cookie property path, if set to/, then all requests will send this cookie, By grasping the bag also saw a cookie.

Because the client has sent, but the server did not receive, my logic has a request to jump, whether it is a jump after the session was reset? I began to observe each request session, by printing out each request session information, finally observed that each login, is an empty session will be generated before the session covered:

Sessionstore:
{sessions:
{' C+bfzyy2z23b8b3wa+fv6nco ': ' {' cookies ': {' originalmaxage ': null, ' expires ': null, ' HttpOnly ': true, ' path ': '/'} ',
Fk8djoqgwoyrq4jiffwu4hry: ' {"cookie": {"originalmaxage": null, "Expires": null, "HttpOnly": True, "path": "/"}, " Username ":" Lucy "} ',
' sjjychwsy+janarqvuw4jhl0 ': ' {cookie ': {' originalmaxage ': null, ' expires ': null, ' HttpOnly ': true, ' path ': '/'} ',

So it is certain that there is something wrong with the request, the session is covered. By searching, it is found that a claim is caused by the request Favicon function in the Express framework, which needs to be solved by adding app.use (Express.favicon ()); I tried, but I still couldn't.

I request.session.regenerate (function () {method has no bottom, so do not reconstruct the session, directly assign value, find the problem solved.

Later I will App.use (Express.favicon ()), after deletion, still no problem, this is more strange, because I have tried in the beginning do not use the request.session.regenerate (function () {, but not effective. But I think it's a cache problem, because the favicon on the browser has not changed since I used App.use (Express.favicon ());

But I added the request.session.regenerate (function () {method) to the sample code, and did not use App.use (Express.favicon ()); method, but there is no problem. I suspect that it is a multithreaded problem, and if you ask for more, there may be a problem.

This question, my final suggestion is: Use App.use (Express.favicon ()), methods, to assign values to the session, do not use Request.session.regenerate (function () { method to rebuild the session.