The server will be a web API in .Net and client is UWP app.There are some messages stored in the database along with the expiry time and deviceId.Each message should be broadcasted to the device on the expiration of time.How can we keep a persistent connection from web API to UWP and how can we broadcast the message to a particular device.Thanks in advance for all suggestion!
In the case you will you signalR (which will be a good solution) I suggest you to read:
https://learn.microsoft.com/en-us/aspnet/signalr/overview/guide-to-the-api/hubs-api-guide-server
Simple create a hub on server. Each client then should connect to this hub. After the connection is established you can send messages in both directions.
Here are some possibilities for sending messages from server to client:
Send message to all connected clients:
Clients.All.addNewMessageToPage(name, message);
To specific client:
Clients.Client(Context.ConnectionId).addContosoChatMessageToPage(name,
message);
There are a lot other possibilities like groups.
The best solution for your scenario would be WebSockets. These allow you to implement a lightweight two way connection between your app and the API and send data between them. Info on UWP implementation of WebSockets is here in documentation and for server side you can use ASP.NET SignalR for example.
Related
I have an ASP.NET MVC application that runs on server A and some web services that run on server B. I have implemented real-time notifications for which I have used SignalR on server A. But now I need server B to also be able to send messages to a View served from server A (the main web application). Hence, I am trying the tutorial here to involve Redis backplane.
In my startup in server A, I have added the following:
GlobalHost.DependencyResolver.UseRedis("localhost", 6379, string.Empty, "abc");
app.MapHubs();
Here, I assume that "myApp" indicates the channel and when I run publish abc "hello world" on the Redis console, I can see the subscriber count returned as 1, but I am not able to figure out how a SignalR hub interacts with the channel. Where do I receive the message on the server/view? Can we subscribe to only one redis channel? Can't we dynamically configure to subscribe to a particular channel?
EDIT: I can see messages sent from chat Application implemented using SignalR on redis console if I subscribe to abc.
Also for now I have implemented my own redis listener on server A which in receiving a message from redis channel, calls the signalR hub function. I am sure there must be a different way to do this and I am hoping redis backplane can help me but unsure how it works.
Backplane distributes messages between servers.
GlobalHost.DependencyResolver.UseRedis("localhost", 6379, string.Empty, "abc");
Here, abc is the redis channel, that means whichever server is connected to redis server with this channel, they will share messages. SignalR channel (group) is different than Redis channel. You can share also SignalR channel (group) messages.
Then just install the Microsoft.AspNet.SignalR.Redis NuGet to your servers.
Connect your servers to Redis like this:
GlobalHost.DependencyResolver.UseRedis("server", port, "password", "AppName");
app.MapSignalR();
Then, use your signalr as before. You don't have to do anything else.
When Server A sends a message to the clients, it will send the message first to Redis. Then Redis will share the message with all subscribers (servers A and B). Then, A and B will send the message to their clients. (Also viceversa is true, it will be same for if B sends a message).
Let's say A sends a message to the clients. _context.Clients.All.TestMessage("Hello");
This will go first to redis and redis will share this with A and B.
Then both A an B will send this message to their clients.
_context.Clients.All.TestMessage("Hello");
But you don't have to worry about these kind of things. I said before. Install package, conntect your servers to redis and use signalr as before.
If we come in your question. The answer is Yes. Server B can send messages to server A clients by Signalr Backplane.
This image summarizes what I told:
I have a websocket connection where I want to constantly listen and receive events on that websocket's URL. It's a status watcher, and I will be returned a json on a regular basis. I have a signalR client that is listening to a server/hub on one point. There is also a third device, not the signalR server or the battery, that has a websocket connection.
Is it possible to setup a SignalR client, point it to a websocket server that is not signalR, and just listen to all the traffic that way? I have a listener already in the SignalR client built in, could I make a "second hub" and have it listen also to the other websocket on the other device? It's not one I have control over, and is not a SignalR server, but since it's a websocket connection, shouldn't I be able to read off of it?
Here is a high tech diagram to help.
SignalR client cannot connect to any websocket. First, websocket is just one transport that SignalR uses but not the only one. If the client cannot connect to the server it will by default automatically switch to a different transport (e.g. server sent events or long polling). Second, SignalR uses a protocol to talk to the server (if you are interested you can find the protocol description here) - if the protocol is not followed the client won't be able to connect to the server. Hence the SignalR client can only work with a SignalR server.
My client sends messages to the my server using tcp protocol (my server has a listener).
I'm trying to send messages back from the server to the client, but I'm not sure what do I need to add to the client in order to get those messages.
I tried looking it up, but I didn't understand how to implement it.
Could you please assist?
It's the exact same process, but in reverse.
If you intend to receive messages independently (i.e. not in response to a request by the client), you need to make the client a TCP server, too. The client needs to implement exactly the same thing as the server you have now and the server needs to connect to the client.
Can't you use WCF, which supports callback contracts?
If you want a console example of a client server application using a network library see here http://www.networkcomms.net/how-to-create-a-client-server-application-in-minutes/.
If you want a WPF application example then see here http://www.networkcomms.net/creating-a-wpf-chat-client-server-application/
I want to build a web-based irc client with JQuery. I know I need to open a socket to the irc server. What I'm wondering is, is it possible to open a socket purely from server-side C# code? Or would the nature of a web application prevent this and I would have to write a service to run on the host machine?
Thanks for any help :)
Yes, you should be able to make a socket connection from server-side ASP.NET code. On the other hand, given that you'd presumably want a persistent connection to the IRC server (rather than a new one on every request), you may want to write a separate service anyway - you don't want ASP.NET recycling to kick in and wipe all your context, for example.
Your ASP.NET code could then talk to your service to find out what had happened since the last request for that user, etc.
One simple approach would be to setup a singleton WCF service which acts as the bridge to IRC. jQuery AJAX calls against that service could then post messages that were input by the user, as well as retrieve messages sent by other users.
I have implement the chat with ASP.Net by using the SingnalR for duplex communication.
What I really done consist on the following steps.
1) ChatHub.cs
I have write down all the logic to connect with the IRC server and connect to the channels, receive different messages and notification from the IRC server. I then send these notifications to my ChatHub client by calling the javascript call backs from the ChatHub.cs
2) Client.aspx
Simple HTML page and it is using jquery to register the callbacks from the ChatHub.cs
3) IRCDotNet.dll
I have used this library to communicate with the IRC Server.
Hope, It will help somebody. Here is the link to download the IRCDotNet.dll
http://ircdotnet.codeplex.com/releases/view/50639
I need to re-write an existing client-server application.
The existing application communicate using socket, I have to convert it into WCF.
At server side I need to
Monitor connected clients
Validate client request
Broadcast live data (comming from diff source).
Listen to client and respond to it
At client end I need to
Receive server broadcast and display it on UI.
Display UI and take input from user
Submit user data to server and display response
I have chosen tcp protocol on self hosting environment.
I need some immediate level references (link, tutorial, book)...
Have a look at this MSDN article, covers pretty much everything you need to know to build a duplex service in WCF:
http://msdn.microsoft.com/en-us/magazine/cc163537.aspx
You can try this : WCF on MSDN
I don't know if you can get it, but Microsoft book on WCF (course 6461A) is not bad.