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?
Related
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 ?
We have a gaming application in which clients, all running IE make calls to web services using the API generated by the ASP.NET ScriptManager.
After a certain period of time, we start getting failures, with Fiddler showing the following error coming back from the server:
Connection to xxx.yyy.net failed.Exception Text: Only one usage of each socket address (protocol/network address/port) is normally permitted
We are not in control of the server's hardware, so altering the TCP/IP settings is not an easy option. Anyone have thoughts on how to deal with this?
This blog post seems relevant.
"Here is the scoop 1. When you make authenticated calls, the client is closing connections. And when you are making authenticated calls repeatedly to the same server, you are making and closing connections repeatedly 2. The same might happen when you are making regular http [un authenticated] calls but setting keep-alive = false."
http://blogs.msdn.com/b/dgorti/archive/2005/09/18/470766.aspx
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.
I have created a simple chat server that is driven by client polling. Clients send requests for data every few seconds, and get handed any new messages as well as information about whether their peer is still connected.
Since the client is running on a mobile platform (iPhone), I've been looking for ways of getting rid of the polling, which quickly drains the battery. I've read that it's possible to keep an http connection open indefinitely, but haven't understood how to utilize this technique in practice. I'm also wondering whether such connections are stable enough to use in a mobile setting.
The ideal scenario would be that the server only sends data to clients when an event that affects them has occurred (such as a peer posting a message or going off line).
Is it advisable to try to accomplish this over http, or would I have to write my own protocol over tcp? How hard would it be to customize xmpp to my need (my chat server has some specialized features that I would have to easily implement).
How about push technology? see http://en.wikipedia.org/wiki/Comet_(programming)
I think you're describing XMPP over BOSH.
http://xmpp.org/extensions/xep-0206.html
I've used this http-binding method between a chat server and javascript client on non-mobile devices. It worked well for me.
You might like to check out this project which uses a variety of techniques including Comet. Release details are here, here's a snippet from that page
It’s my distinct pleasure to be able
to announce the first public showing
of a project that I’ve been working on
in my spare time in the last month or
two, a new Web Based IRC chat
application.
This project brings together a lot of
new technologies which had to be
developed to make this a feasible,
scalable and efficient.
Some of the underlying tools build to
make this posible that i consider
’stable enough’ are already released,
such as the php Socket Daemon library
i wrote to be able to deal with
hundreds up to many thousands of
“Comet” http connections, and an equal
amount of IRC client connections.
I just found this article myself, which describes the following technique (which I referred to in the question):
... have the client make an HTTP request
and have the server hold the request
on the queue until there is a message
to push. if the TCP/IP connection is
lost or times-out, the client will
make a new HTTP request, and the delay
will only be the round trip time for a
request/response pair . . . this model
effectively requires two TCP/IP
connections for HTTP, client to
server, though none permanent and
hence mobile friendly
I think this is nearly impossible and dangerous. The internet works stateless and connectionless meaning that the connection between client and server is always handled as unreliable. And this is not for fun.
By trying to get a stateful connection you are introducing new issues. Especially from a 3g application. What if the connection breaks? You have no control over the server and cannot push.
I think it would even be easier to send sms/text messages and have an application that handles that.
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.