I set up session management in my node js/ express js website successfully. I stores session data in mongo db. I want the session to be valid for the users who log in for a couple of weeks. The code is as follows:
var cookieParser = require('cookie-parser');
var session = require('express-session');
var MongoStore = require('connect-mongo')(session);
app.use(cookieParser());
app.use(session({
store: new MongoStore({ mongoose_connection: db }),
secret: 'cookie_secret',
cookie: { maxAge: null }
}));
It works fine for normal users, but my problem is with web crawlers such as google bots and facebook bots. I still want them to crawl my website but I don't want their sessions to be stored in my mongo db. It's taking up lots of space and storage is increasing daily which costs me money.
How to selectively choose which sessions to be stored in the db. I can check for req.headers['user-agent'], but where to use it in my code? How to tell express-session not to store session sometimes?
You can use the session middleware conditionally, based on the User-Agent header. A simple example:
var sessionMiddleware = require('express-session')({
...configuration here...
});
app.use(function(req, res, next) {
var ua = req.get('user-agent');
// If the User-Agent header contains the string "Googlebot",
// skip the session middleware.
if (/Googlebot/.test(ua)) {
req.session = {}; // perhaps a bit too simple?
return next();
}
return sessionMiddleware(req, res, next);
});
It would depend on your actual use of req.session if the code above works, or if you need to mock req.session a bit better (for instance, if you use any of the req.session methods in your code,
you may need to mock those too).
Related
const express = require("express");
const app = express();
var i = new Number;
i=0;
app.get("/", function(req, res){
i++
console.log(i);
});
app.listen(8080);
I created a very small node js project. I have a problem. when I create a variable like above, it doesn't evaluate for each user separately. that is, when a user requests a get, I want it to be 1 each time.
Sample
my problem is that when a jack user enters a site, if he doesn't log out, someone who enters the site's home page from another device enters his account with jack.
how can I do that?
The simplest answer for your question is to simply declare and increment the variable inside the function passed to app.get, but I'm going to assume that you would like a situation where, for a given user's series of requests, the number will increment.
The simplest way to do this is using a server side session, which is provided by the express-session library. Additionally, in order for this to work, you need to call res.end() in order to send the cookie associated with the server session back to the user's browser. More information on sessions generally can be found here.
Below is code to replicate the intent of what you have there, but incrementing for each request from a unique browser instance (identified by the same cookie value associated with the server session):
const express = require('express');
const session = require('express-session');
const app = express();
app.use(session({
resave: false,
saveUninitialized: true,
secret: 'secret',
cookie: {
maxAge: 60000
}
}));
app.get('/', function(req, res){
if (!req.session.value) {
req.session.value = 0;
}
req.session.value++;
console.log(req.session.value);
res.end();
});
app.listen(8080);
I am trying to access my session token from other routes after setting it in a route. I am currently unsuccessful. Following the relevant code of the three files.
server.js: It calls the routes thermostats, login and also sets session token.
var session = require('express-session');
var app = express();
app.use(session({secret: 'keyboard cat',cookie: { secure: true }}))
var router = express.Router();
var thermostats = require('./api/routes/thermostats')(router, app, session);
require('./api/routes/login')(router, app, session, thermostats);
login.js: When the user goes to localhost:3000/login/, the login token needs to be saved in the session
module.exports = function(router,app, session, thermostats){
router.get('/login/', function(req, res) {
list(req, res) //response of this function has session which needs to be saved.
console.log(res.session)
app.use(session(res.session)) //trying to save the res.session as session token
});
}
thermostat.js: Needs to access the session token before can display any information.
module.exports = function(router,app){
router.get('/thermostats/', function(req, res) {
console.log(req.session) //Set to default/null values and not the updated session values
});
}
It might be something small but I cannot figure out the issue. I would appreciate any help.
Thank you
Express-session should automatically save the session, based on the configuration.
Looking at the 'resave' config option in the express-session docs:
resave
Forces the session to be saved back to the session store, even if the session was never modified during the request. Depending
on your store this may be necessary, but it can also create race
conditions where a client makes two parallel requests to your server
and changes made to the session in one request may get overwritten
when the other request ends, even if it made no changes (this behavior
also depends on what store you're using).
This is by default, true, so it should already start working without you needing to add app.use(session(res.session).
Edit: You will be able to save to the session by adding fields to the req.session object:
router.get('/login/', function(req, res) {
getDataFromExternalApi(req, function(err, apiResponse) {
var data = apiResponse.data;
req.session.data = data;
// if resave option is true, this should automatically save to the session store after this request is done.
});
});
Generally, you shouldn't be using app.use in your request handlers. Those are generally reserved for setting up the server, as it defines what middleware express uses.
I'm using cookie-parser, all the tutorial talk about how to set cookie and the time it expiries but no where teach us how to get the value of these cookie
For people that stumble across this question, this is how I did it:
You need to install the express cookie-parser middleware as it's no longer packaged with express.
npm install --save cookie-parser
Then set it up as such:
const cookieParser = require("cookie-parser");
const app = express();
app.use(cookieParser());
Then you can access the cookies from
req.cookies
Hope that help.
First note that Cookies are sent to client with a server request and STORED ON THE CLIENT SIDE. Every time the user loads the website back, this cookie is sent with the request.
So you can access the cookie in client side (Eg. in your client side Java script) by using
document.cookie
you can test this in the client side by opening the console of the browser (F12) and type
console.log(document.cookie);
you can access the cookie from the server (in your case, expressjs) side by using
req.cookies
Best practice is to check in the client side whether it stored correctly. Keep in mind that not all the browsers are allowing to store cookies without user permission.
As per your comment, your code should be something like
var express = require('express');
var app = express();
var username ='username';
app.get('/', function(req, res){
res.cookie('user', username, {maxAge: 10800}).send('cookie set');
});
app.listen(3000);
hope this will help you
const app = require('express')();
app.use('/', (req, res) => {
var cookie = getcookie(req);
console.log(cookie);
});
function getcookie(req) {
var cookie = req.headers.cookie;
// user=someone; session=QyhYzXhkTZawIb5qSl3KKyPVN (this is my cookie i get)
return cookie.split('; ');
}
output
['user=someone', 'session=QyhYzXhkTZawIb5qSl3KKyPVN']
Just want to add that we shouldn't be using modules to do trivial stuff. Modules are very convenient and fast forward development, but keep us from learning by creating infrastructural code.
I'm a professor not a boss so I value more programmers knowledge/skill development than to write code in lesser time without learning anything...
Back to business...
Unless you need signed cookies, or anything more complex, it's perfectly possible to write your own middleware to parse cookies and add the values to the rest of the pipeline as the module does.
app.use((req, res, next) => {
const { headers: { cookie } } = req;
if (cookie) {
const values = cookie.split(';').reduce((res, item) => {
const data = item.trim().split('=');
return { ...res, [data[0]]: data[1] };
}, {});
res.locals.cookie = values;
}
else res.locals.cookie = {};
next();
});
Anywhere you need to read the cookie it's available via res.locals.cookie, conveniently formatted as an object.
You could even add a custom cryptography strategy here to make sure no one is reading your cookie.
Just remember middlewares are ordered, so this one has to be added before any other middleware or route that uses the cookie.
I've been having problems trying to access stored session values! Once I've set the values and try access them from a new route, I get undefined! So basically I've got a login (POST) and in that request I set the session data, and then I have a show user details (POST) where I try and access the session data I've just stored.
Setup
// Setup express and needed modules #############################################
var express = require('express'),
session = require('express-session'),
cookieParser = require('cookie-parser'),
redis = require("redis"),
redisStore = require('connect-redis')(session),
bodyParser = require('body-parser');
var client = redis.createClient(), //CREATE REDIS CLIENT
app = express();
// Setup app
app.use(cookieParser('yoursecretcode'));
app.use(session(
{
secret: 'x',
store: new redisStore({
port: 6379,
client: client
}),
saveUninitialized: true, // don't create session until something stored,
resave: false // don't save session if unmodified
}
));
app.use(bodyParser.urlencoded({ extended: true}));
app.use(bodyParser.json());
app.set('trust proxy', 1) // trust first proxy
So as you've seen my setup, you know I'm using express sessions and Redis. Below is where I'm setting the session values! If I print out the session values here it works, but then If I try and access the session data in another route it returns undefined.
Routes
I send a http post request and set the session data:
router.route('/login/').post(function(req, res) {
req.session.userId = req.body.uId;
req.session.name = req.body.uName;
// THIS PRINTS OUT IF I TRY AND ACCESS THE SESSION DATA HERE
console.log("THIS PRINTS OUT --> " + req.session.name);
});
So now that the session values have been set, I can go access them right, no, I get undefined each time I try and log them out.
router.route('/user/printoutuserdetails').post(function(req, res) {
// THESE RETURN UNDEFINED
console.log(req.session.userId);
console.log(req.session.uName);
console.log("THIS PRINTS OUT --> " + req.session.name);
});
Does anyone have any idea what's happening? I've tried everything and looked everywhere and can't seem to find a way to get it to work!
Solved:
The reason this wasn't was because you're not suppose to use sessions when using a RESTFUL api.
In node.js and express, there are many examples showing how to get session data.
Node.js and Socket.io
Express and Socket.io - Tying it all Together
Socket.io and Session?
As you can see when you visit the 3rd link, it's a link to StackOverflow. There was a good answer, but as pointed out in those comments by #UpTheCreek, connect no longer has the parseCookie method. I have just run into this problem as well. All of the tutorials I have found uses connect's parseCookie method which now doesn't exist. So I asked him how we can get the session data and he said he doesn't know the best approach so I thought I'd post the question here. When using express#3.0.0rc4, socket.io, and redis, how can we get session data and use that to authorize the user? I've been able to use require('connect').utils.parseSignedCookie;, but when I do that, I always get a warning/error when handshaking,
warn - handshake error Error
and from what I've read it sounds like that isn't a permanent solution anyways.
UPDATE
Ok I got session.socket.io working on my server. And as I suspected, I got stuck at the point of authorizing. I think I might be going about this the wrong way, so feel free to correct me. In my Redis database, I will have user's information. The first time that they login, I want to update their cookie so it contains their user information. Then the next time they come back to the site, I want to check if they have a cookie and if the user information is there. If it is not there, I want to send them to the login screen. At the login screen, when a user submits information, it would test that information against the Redis database, and if it matches, it would update the cookie with user information. My questions are these:
1) How can I update/change a cookie through RedisStore?
2) It looks like session data is saved only in cookies. How can I keep track of user information from page to page if someone has cookies turned off?
Here is my applicable code:
//...hiding unapplicable code...
var redis = require('socket.io/node_modules/redis');
var client = redis.createClient();
var RedisStore = require('connect-redis')(express);
var redis_store = new RedisStore();
var cookieParser = express.cookieParser('secret');
app.configure(function(){
//...hiding unapplicable code...
app.use(cookieParser);
app.use(express.session({secret: 'secret', store: redis_store}));
});
//...hiding code that starts the server and socket.io
var SessionSockets = require('session.socket.io');
var ssockets = new SessionSockets(io, redis_store, cookieParser);
io.configure(function(){
io.set('authorization', function(handshake, callback){
if(handshake.headers.cookie){
//var cookie = parseCookie(handshake.headers.cookie);
//if(cookie.user){
// handshake.user = cookie.user;
//}
}
callback(null, true);
});
});
ssockets.on('connection', function(err, socket, session){ ... });
Have a look at socket.io's wiki. Especially the parts Configuring Socket.IO and Authorization and handshaking.
It shows how to use socket.io with a RedisStore and gives two different authorization methods.
More information about connecting express v3, redis and socket.io
connect issue#588
socket.io and express 3
session.socket.io module
socket.io-express library
After switching to session.socket.io for a while I ran into a few problems due to the asynchronous nature of the module when loading the session information. So I ended up creating my own module called session.io. It is used like this:
var express = require('express');
var app = express();
var server = require('http').createServer(app);
//Setup cookie and session handlers
//Note: for sessionStore you can use any sessionStore module that has the .load() function
//but I personally use the module 'sessionstore' to handle my sessionStores.
var cookieParser = express.cookieParser('secret');
var sessionStore = require('sessionstore').createSessionStore();
app.configure(function(){
app.set('port', process.env.PORT || 3000);
//...truncate...//
app.use(cookieParser);
//make sure to use the same secret as you specified in your cookieParser
app.use(express.session({secret: 'secret', store: sessionStore}));
app.use(app.router);
});
app.get('/', function(req, res){
res.send('<script src="/socket.io/socket.io.js"></script><script>io.connect();</script>Connected');
});
server.listen(app.get('port'), function(){
console.log('Listening on port ' + app.get('port'));
});
var io = require('socket.io').listen(server);
io.configure(function(){
//use session.io to get our session data
io.set('authorization', require('session.io')(cookieParser, sessionStore));
});
io.on('connection', function(socket){
//we now have access to our session data like so
var session = socket.handshake.session;
console.log(session);
});
Your questions:
How can I update/change a cookie through RedisStore?
It looks like session data is saved only in cookies. How can I keep track of user information from page to page if someone has cookies turned off?
Cookies / Sessions / RedisStore Thoughts:
Typically, you have exactly one cookie, which is the session id
All user-state is stored on the server in a "session" which can be found via the session id
You can use Redis as your back-end storage for your session data.
Redis will allow you to keep session state, even when your server is restarted (good thing)
You can store a mountain of data in your session (req.session.key = value)
All data stored in the session will be persistant until the user logs out, or their session expires
Example node.js Code:
var app = express.createServer(
express.static(__dirname + '/public', { maxAge: 31557600000 }),
express.cookieParser(),
express.session({ secret: 'secret', store: new RedisStore({
host: 'myredishost',
port: 'port',
pass: 'myredispass',
db: 'dbname',
}, cookie: { maxAge: 600000 })})
);
Session and Cookie Thoughts:
Your second issue us about sessions without cookies. This is possible.
You, basically, put the session id on the url of every request you send to the server.
I strongly believe that most people allow cookies.
If this is a requirement, google: "session without cookies"
Session data is available with:
req.session