I am building a notification application in which every time an event is triggered the associated user gets a notification. I am using localstorage of NodeJs to store the information of the logged in user. The problem is that when two users are logged in,the localstorage values are overridden by the new users value.
I need to create multiple instances of NodeJS server so that every user has its own localStorage.
For example
If two users log in with credentials
{
userName:name1
}
and
{
userName:name2
}
then two separate localStorage should be created one having userName:name1 and one having userName:name2.
I have tried all the solutions available online but I am unable to create multiple states of NodeJS server.
Thanks in advance
You do not have to create a new server for each user. Take the IP address and port instead. This means that each user can be uniquely identified. You can simply name the files of the users after the variable client.
Here an example code
net.createServer((netSocket : net.Socket) => {
netSocket.on('data', (data) => {
var client = netSocket.remoteAddress + ':' + netSocket.remotePort;
})
})
I wasn't able to create multiple nodejs instances hence I stored the user data in session storage and passed it to nodejs server every time I triggered a request.
Related
I'm wondering if it's possible to pass any data to socket client?
What I want to archieve?
I have nodejs + Angular app where I need socket.io functionality. I configured connection and it's working. I'm able to retrieve clientId but I want to pass also username and maybe avatar of logged user so when user is connecting it will show his name nad photo. And behavior should be reversed when user is disconnected.
Does anybody know the way to do it or it's not possible?
Thanks.
You can pass the required data as an object on emit and use it in frontend. Create an object with required key values.
var obj= { username:'xyz',avatar:imageUrl };
Socket.on('userConnected',(data)=>{
//do something with data
Socket.emit('userDetails',obj);
}
My backend is written in NodeJS. I would like to push some real time data for my firestore database. My question how can i run a function once when a user is connected to my server. Also, this function will extract info from a cookie stored in the browser. I tried the singleton design pattern, but it is totally wrong because it runs for one user only.
This will involve storing some state per user (presumably you could do this in Firestore). As each user request comes in, you just need to check for said state and if it's not been set yet, invoke the function and set the state.
For example, here's how it might look if you were using Express:
app.use((req, res, next) => {
// assume user is deserialized with state from store
if (!req.user.hasRunFunc) {
// run some function
// update store setting 'hasRunFunc' state
}
})
As long as the state is set, then subsequent requests from the same user would be skipped.
I want to send a json object to another server, independent of my website.
The API I am using requires a user (user x in this case) to log into their service to be authorized so user x can manipulate user x's list. However, other users can't write to x's list. So, users need to request an item to be added to x's list, then a server who is logged into x's account can add it to x's list. Refer to the image below.
http://imgur.com/a/wT53t
I am using node/express.js for the servers on the user's side. However, I don't know what I should use for a server who's only job is to receive requests and write to x's list. Can you provide some guidance as to how I can achieve something like this?
Thanks!
There are two options here:
You have to refresh the list in the realtime for connected users.
To achieve this you should use either: WebSockets(e.g. socket.io) or LongPolling.
In second option you dont have to refresh the list in the realtime. You simply use express. Accept data and refresh the list server-side.
Auth with web sockets:
Once understanding the nature of web sockets, you're free to build any logic around them, including authentication/authorization. The great library doing lots of auth things is passport.js.
Very quick and abstract example of server-side:
socket.on('auth', function(data) {
const vendor = data.vendor,
token = data.id
switch(vendor) {
/*
Here you grab through some social API user social id
and save it to database
*/
}
/* set socket as logged in */
socket.logged = true
/* or even save user object */
socket.user = { vendor, token }
})
Next time you need authorized user, you check:
socket.on('mustBeAuthorized', function() {
if(socket.logged || socket.user) {
/* Continue your logic*/
}
})
I'm trying to implement NodeJS and Socket.io for real time communication between two devices (PC & Smartphones) in my company product.
Basically what I want to achieve is sending a notification to all online users when somebody change something on a file.
All the basic functionality for saving the updates are already there and so, when everything is stored and calculated, I send a POST request to my Node server saying that something changed and he need to notify the users.
The problem now is that when I want to change some code in the NodeJS scripts, as long as I work alone, I can just upload the new files via FTP and just restart the pm2 service, but when my colleagues will start working with me on this story we will have problems merging our changes without overlapping each other.
Launching a local server is also not possible because we need the connection between our current server and the node machine and since our server is online it cannot access our localhosts.
It's there a way for a team to work together in the same Node server but without overlapping each other ?
Implement changes using some other option rather than FTP. For example:
You can use webdav-fs in authenticated or non-authenticated mode:
// Using authentication:
var wfs = require("webdav-fs")(
"http://example.com/webdav/",
"username",
"password"
);
wfs.readdir("/Work", function(err, contents) {
if (!err) {
console.log("Dir contents:", contents);
} else {
console.log("Error:", err.message);
}
});
putFileContents(remotePath, format, data [, options])
Put some data in a remote file at remotePath from a Buffer or String. data is a Buffer or a String. options has a property called format which can be "binary" (default) or "text".
var fs = require("fs");
var imageData = fs.readFileSync("someImage.jpg");
client
.putFileContents("/folder/myImage.jpg", imageData, { format: "binary" })
.catch(function(err) {
console.error(err);
});
And use callbacks to notify your team, or lock the files via the callback.
References
webdav-fs
webdav
lockfile
Choosing Secure Passwords
I'm building a nodejs app I would like to make available under various settings by my customers. I want my customers to build their websites on top of my app, so: - the app can be configured in a way that domains "A.com" and "B.com" use the configuration "X" of the app, while "C.com" uses "Y", etc. - I'm thinking about using kubernetes and dockers containers to isolate version "X", "Y" etc. of my app - I'm also thinking about using nginx for reverse-proxy
Each domain will have its distinct documents in a mongodb collection. Because I need a way to retrieve the right data, I'm giving each domain a unique token matching their documents. All the tokens are also saved in mongodb and will be retrieved on my (nodejs) server's start or updated on the fly. The tokens will be saved on a "app.locals" variable: - I'm thinking about having a middleware that will grap the domain from every request (req.hostname) and get the corresponding token
// set locals
app.locals.domainTokens = {};
after retrieving and assigning the tokens, "domainTokens" will look like:
app.locals.domainToken = {
"Acom" : "token_1",
"Bcom" " "token_2" // and so on
}
// the middleware
function grabToken(req, res, next) {
var tokens = app.locals.domainToken,
host = req.hostname;
req.params.token = host ? tokens[host] : undefined;
next();
}
When new customers register, tokens will be assigned on the fly for their domain (containers talk to each other, right?).
So basically, when a request is made for "A.com", my middleware sets the "token" so that the mongodb documents related to "A.com" can be found and sent back to client running version "X" of my app (nginx).
What do you think about this approach ? is it unsafe? a bad practice? do you have a better suggestion to implement it? Am I better off using one container per domain ? (I would have to monitor hundreds of nodejs instances instead of 3 or 4)
Also, is it possible to dynamically configure a Nginx server?