As what title said, i still confusing and turn around in deep-hole and get lost about one month in it. So i really need help.
I would like to create client-server online game, and separate Client and Server to different project with each other, and for understanding, i don't using any NetworkManager and script from demo project.
Why i do that ? I want client is always remote client, and server always dedicated server that mean no local client.
All communication until now i using custom message from MessageBase and it ok for me. But the problem come with spawn game object, sync with all remote client, i don't know how to do that.
The server just handle connection, message and send back to client so it just GUI only, then i want to ask that it MUST be share scenes at client ? Does it NEED TO DO IT ?
The client is a remote client, so how to sync movement, spawn, and etc to another client via server ? If i using transfer message base on MessageBase, it look so complicate than using SyncVar or Command. But i don't know how Server handle Command, because it separate different with Client. Can anyone help ?
AM I WRONG WAY ?
Related
I really need your advice on this.
I have many TCP Client Devices. The Web application is going to be accessed by many users after an authentication.
The problem I need to solve is -
Create a TCP Listener for these client machines and that should be accessed by every user -
Solution I think - create a tcp connection on a page. Every user will create a new tcp connection from their device(local host) once the page is load . This is possible because every user pc is diferent so its going to be entirely different connection. But this solution is not going with problem 2.
The Machine broadcasts data every 30 seconds. So my application should be able to catch that data and update on the page.
This is I think is the main problem.
I know live data update on a web page can be done using SignalR. But SignalR does not connect with TCP Client machine directly. So what I was trying to do is -
1st - I tried making a WCF Service for TCP listener. WCF service will get data from machine and save into database from where signalR will do its job. But Whenever I am using wcf service my system is getting hang. So I dont know if its a right way to do that.
2nd - I tried creating Windows service as tcp listener. But I dont think its gonna work with web application.
To be very frank, I am not able to understand what should I do for this functionality.
From my side - I just want a TCP connection on application level that should be persistent, independent of user and should not close on any page reload.
Whenever that connection receives data it should be updated on every user's web browser without any reload.
I cannot use timer. It should be realtime.
According to what I found and understood, TCP connection is with a device so signalR can not be used directly. We need something else(like a service) in between to make it work with signalR.
So at the end, What should I do?
I hope I am clear enough to state my problem.
I just want to discuss so that my doubts can get clear and I may find the desired result at the end.
EDIT 1 :
In websocket, signalR... normally client refers to web browser.
Can a device(Multimedia control device) be a client similar to web browser for signalR?
My job is to write a distributed client/server application with some concurrent tasks. So i decided to use akka.net for the concurrency issues. To implement the ipc between server and client akka remote is used. For some reasons there may run more than one client of the same type on a workstation. So i configured these clients for dynamic assignment of a tcp port. This worked fine for sending messages to the server.
My problem is to push some information to the clients. To accomplish this task an actor on the client exist. Now the server creates a reference for this actor. Therefor it needs the port the client is listening on . My idea is to send the tcp port the client uses to the server in some sort of connection procedure using a actor on the server.
After searching for some hours I didn't find any hint where to find the dynamically assigned tcp port. So how would the client get the assigned tcp port?
Ok, I could use akka.cluster. But using akka.cluster is breaking a fly on the wheel, I think. And if it solves my issue reamins to be seen.
Two suggestions, assuming that it is your client that makes the first contact with the server.
I'd have the server keep track of which clients are connected. I'd probably have a heartbeat message that gets sent once every few seconds from each client system. This way you can store an IActorRef for each alive client and send messages back without the need for finding the port. IActorRefs are preferable wherever possible for location transparency.
If you actually need to explicitly find the port, you may be able to extract it from the Path property of the IActorRef of one of the actors on the client system.
Thanks to patricks suggestions my issue is solved.
The solution is to extract the needed information from the senders path available while executing the hello message. With this information the server is able to maintain a list of all connected clients and theire network address.
Thanks a lot # patrick.
Regards Gregor
I would want to send a message from the server actively, such as using UDP/TCPIP to a client using an arduino. It is known that this is possible if the user has port forward the specific port to the device on local network. However I wouldn't want to have the user to port forward manually, perhaps using another protocol, will this be possible?
1 Arduino Side
I think the closest you can get to this is opening a connection to the server from the arduino, then use available to wait for the server to stream some data to the arduino. Your code will be polling the open connection, but you are avoiding all the back and forth communications to open and close the connection, passing headers back and forth etc.
2 Server Side
This means the bulk of the work will be on the server side, where you will need to manage open connections so you can instantly write to them when a user triggers some event which requires a message to be pushed to the arduino. How to do this varies a bit depending on what type of server application you are running.
2.1 Node.js "walk-through" of main issues
In Node.js for example, you can res.write() on a connection, without closing it - this should give a similar effect as having an open serial connection to the arduino. That leaves you with the issue of managing the connection - should the server periodically check a database for messages for the arduino? That simply removes one link from the arduino -> server -> database polling link, so we should be able to do better.
We can attach a function triggered by the event of a message being added to the database. Node-orm2 is a database Object Relational Model driver for node.js, and it offers hooks such as afterSave and afterCreate which you can utilize for this type of thing. Depending on your application, you may be better off not using a database at all and simply using javascript objects.
The only remaining issue then, is: once the hook is activated, how do we get the correct connection into scope so we can write to it? Well you can save all the relevant data you have on the request to some global data structure, maybe a dictionary with an arduino ID as index, and in the triggered function you fetch all the data, i.e. the request context and you write to it!
See this blog post for a great example, including node.js code which manages open connections, closing them properly and clearing from memory on timeout etc.
3 Conclusion
I haven't tested this myself - but I plan to since I already have an existing application using arduino and node.js which is currently implemented using normal polling. Hopefully I will get around to it soon and return here with results.
Typically in long-polling (from what I've read) the connection is closed once data is sent back to the client (arduino), although I don't see why this would be necessary. I plan to try keeping the same connection open for multiple messages, only closing after a fixed time interval to re-establish the connection - and I hope to set this interval fairly high, 5-15 minutes maybe.
We use Pubnub to send notifications to a client web browser so a user can know immediately when they have received a "message" and stuff like that. It works great.
This seems to have the same constraints that you are looking at: No static IP, no port forwarding. User can theoretically just plug the thing in...
It looks like Pubnub has an Arduino library:
https://github.com/pubnub/arduino
I'm trying to implement a custom live chat program on the web, but I'm not sure how to handle the real-time (or near real-time) updates for users. Would it make more sense to send Ajax requests from the client side every second or so, polling the database for new comments?
Is there a way to somehow broadcast from the database each time a comment is added? If this is possible how would that work? I'm using Sql Server 2008 with Asp.net (c#).
Thanks!
Use long polling/server side push/comet:
http://en.wikipedia.org/wiki/Comet_(programming))
Also see:
http://en.wikipedia.org/wiki/Push_technology
I think when you use long polling you'll also want your web server to provide some support in the form of non-blocking io for requests, so that you aren't holding a thread per connection.
You could have each client poll the server, and at the server side keep the connection open without responding.
As soon there is a message detected at server side, this data is returned through the already open connection. On receipt, your client immediately issues a new request.
There's some complexity as you need to keep track server side which connections is associated with which session, and which should be responded upon to prevent timeouts.
I never actually did this but this should be the most resource efficient way.
Nope. use queuing systems like RabiitMq or ActiveMQ. Check mongoDB too.
A queuing system will give u a publish - subscribe facilities.
Links to articles would also be appreciated--I don't know the terminology to search for.
I'm looking to learn how a web application can allow for server-to-client communications. I know the web was not designed for this and that it has been something of a hurdle, and am just wondering what the state of this is, and what the best practices are.
An alternative is constant or occasional polling via ajax, but is it possible for web servers to maintain stateful connections to a web client?
Edit: Another way to ask this question is how does StackOverflow tell a page that new posts are available for it to display that little bar at the top?
StackOverflow polls the server to check if there is more data.
What you're looking for is Comet.
To get true two way communications from a browser you need to use a plugin technology like Silverlight, Flash, et al. Those plugins can create TCP connections that can establish a two way persistent connection with a server socket. Note that you can't really establish the TCP connection with the HTTP server so you'd have to create an additional server agent to do the communicating back to the browser.
Basically it's a completely differnet deployment model to what AJAX sites like Stackoverflow, Gmail etc. use. They all rely on the browser polling the server at set intervals.
Web browsers really aren't set up to handle this sort of communication. The communication is a one way street where the web server is listening on a port (typically 80 or 443) for for information to be sent to it.
I just read the link on comet, and it's interesting approach, but what has to be remembered is that it is still technically being opened by the client. The server is sending code for it to execute, but the browser is ultimately in control and determines when the server communicates with it.
With today's web browsers the server can never technically execute a message being sent to it without the help of the browser. Technically you might be able to get around that by executing some Active X control on the client machine...but I haven't tried it.
You can't, HTTP is stateless. A long time ago Netscape implemented HTTP Push but it wasn't a sucess.
I'd use polling with a web service or similar; no plugin (that is Flash, Java,Silverlight) will have rights in its sandbox to use raw sockets so it'll be a waste of time trying to implement it that way.