i'm developing using Spring stomp chatting application.
I created a chat room, and user A and user B had /queue/chat/{roomId} subscribe.
What I'm curious about is if a reuses the session if it loses connection during communication and then communicates again.
If not, I will create a new session and subscribe to /roomId. If that happens, it seems to create a session whenever the connection is disconnected and reconnected.
Or, I wonder if it will be automatically released from management when the session is over.
I hope my opinion is wrong, and if it is wrong, I want someone to teach me the correct answer.
Related
NestJS 8， socket.io 4
Client user has a socket being able to receive data from the server. Not sending.
Refresh browser, the socket ID changed. Socket on the client receive 'connect' event! Yet. On server side, no logging at all. Which kind of explained point 1.
After reboot nest, problem is gone. But it comes back eventually.
My current troubleshooting direction is
Was the connection on the client dead already and it's still trying somehow to update the socket?
Browser does some caching, service worker?
I hope someone can enlighten. This happens after upgrade to socket.io 4 from 2.
It's my own stupidity.
My tenant who own the namespace. In order to reach him, I create his namespace and send message to it no matter he's online or offline.
This works fine in socket.io 2. I don't know why.
What I should do, is to check whether or not, the namespace exists or not first.
That's why the issue that I have is that the server somehow seems able to pipe message to the namespace, yet the tenant cannot send the message to the server because the tenant was not initialized properly in the nest gateway.
I'm new to software development in general, and I'm writing a backend for a simple ride-sharing iOS application (which I'll develop later). I'm using Vapor to create the backend.
When a user makes a trip request to the API, I want to create a new trip and establish a websocket session between the user and a driver. The problem I'm having is how can I notify a driver that a request is in and add him to the session?
Here's what I've come up with so far, although I'm not sure if it's going to work:
When a trip request comes in, I would create a session and a trip object with the session id. When a driver visits the "Trip requests" tab in the app he would make a get request to retrieve active trip requests. When he then clicks on one of the trip requests, he would make a request with the session id of that particular trip to be added to that session.
The problems I'm seeing with the above solution is that that would make the User the Poster, and the Driver the Observer, which I'm not sure is the way to go since I want the driver to act as a poster (to send location updates so that the user can track the driver on the map in real time).
Another problem is that users would have to wait indefinitely before a driver accepts their request.
Is there a better way to notify the driver of a trip request? How can I go about achieving this?
First, you will get trouble when trying to establish a direct connection between user and driver, because it's quite difficult to directly connect to an app on a smartphone (changing IPs, NAT, firewalls and opening ports are some of the problems).
I'd suggest, you implement some kind of REST API for the trips/trip requests. To notify the driver or send updates back to the user, you can either use push notifications (for iOS it's APNS) or websockets. In the best case both for different situations.
Here are some hints for further research on those topics:
WebSockets: In Vapor, an example chat app using websockets , WebSocket wrapper for Vapor
Push notifications: Gorush, push notification server, Apple Notifications, (WIP: APNS on NIO)
I hope that helps for your next steps. Your question is quite broad to be more specific.
I am new to Spring framework, now I chose it for a new project.
The project is actually an online consulting application. when a customer chooses to query by open page window, A consulting engineer will be assigned to him(many to one). to sum up, this app requires the following considerations.
1- anonymity connections for customer and authentication for consulting engineers.
2- one engineer can serve several customers at a time.
3- the way to assign customer could be configured.
4- WebSocket session should remain open while HTTP session expired.
so I have two questions:
for 1-3 items, I am not sure if I should choose STOMP or plain WebSocket in Spring. it seems STOMP is more advanced but more likely to fit a general messaging requirement (topics, subscriptions ... etc). WebSocket in another hand is simpler and more flexible. I wonder which one is better in this consulting application?
for point 4, session expired. google result suggests spring-session. but I can only found its tutorial about integration spring-session with STOMP. if WebSocket is the better choice, how can I integrate spring-session with Plain WebSocket?
Thanks
When you talk about websocket you have to have in mind that it is a simple and "raw" communication protocol without many defined message controls. If you choose to use plain websocket you should be able to authenticate using basic authentication [1]. In this case, your websocket connection, once opened, will stay open and working indefinitely.
But it's also up to you to control the message flow, deciding how to specify the target for each message. That's where STOMP should help you.
Using STOMP you could define "channels" to which customers and consulting enginners would "subscribe" to and begin communication. And you could also send private messages using the "Principal" from an authenticated Spring Security session.
So, answering your points:
1- anonymity connections for customer and authentication for
consulting engineers.
It is possible to define multiple endpoints within Spring Websocket configuration [2]. You could try to request authentication with only one of the endpoints using a implementation of ChannelInterceptorAdapter.
2- one engineer can serve several customers at a time.
Using the definition of channels, with the help of STOMP, you could subscribe the enginner in multiple channels, each for one customer... Or use private messages between them.
3- the way to assign customer could be configured.
I'm not sure what you meant... But it should be easy to assign a customer to a "channel".
4- WebSocket session should remain open while HTTP session expired.
The HTTP session is only used in the initial process, to connect to the websocket. After that the websocket will remain open or, if you use SockJS for fallback, the HTTP session will be constantly renewed.
I have coded an example of websocket server and client using Spring API. It's not exactly what you need, but I think it'll give a good idea.
Can you help me to make clear one thing about WebSockets and Spring Security auth? I have an js client with websocket connection. When I load it for first time the user is unautharized and my spring server returns undefined in frame.headers['user-name'] after websocket connect. Is it correct to make websocket reconnect on client side when user performs login/logout operations in sence to make websocket messaging authorized? The one thing is that after every connect client make some subscriptions and it sounds not good to make connect/disconnect and make new subcriptions every time. I hope you will help me and my question is clear. Sorry for my English. Thank you in advance.
Is it enough to cleanup on disconnect? What happens if a browser disappears before sending an explicit disconnect?
What is the recommended pattern for server side cleanup, so that the resources bound to the connection are not leaked (e.g. Namespace)?
(using gevent-socketio, if it matters)
If you use WebSockets as transport, it would automaticaly disconnect the socket on browser close.
If you use xhr-polling for example it would not automaticaly disconnect (speaking about gevent-socketio).
My approach when xhr-polling is used was:
Saving the socket session id among with logged in user id in database
On next user login detect if such a record exists
Use the stored session id in the record to disconect the unused socket since the fresh user login would generate new socket
This is not rapid solution since you may have unused sockets connected until new login is performed by the user, but it performs a kind of cleanup when the user log in.
This article may be a hint to something more creative than mine solution: http://flask.pocoo.org/snippets/71/