calling SignalR hub from WebAPI controller issues

问题:

I cannot figure out how I can call into a SignalR hub from a WebAPI ApiController. I have put together a sample you can download here that simplifies the problem and demonstrates the issue.

1. I created a new project from the ASP.NET MVC WebAPI template.
2. I added a new SignalR Hub to the project called ChatHub.
3. Added a HTML page that on load, connects to ChatHub, joins to a group and sends a message to that group. This works great.
4. HTML page also has a button that when clicked will fire an ajax call to the ValuesController's post method. In the ValuesController's post method, I want to broadcast a message to all the connected clients of the group. I cannot get this to work.

I have a simple SignalR hub with just 2 methods.

[HubName("chat")] public class ChatHub : Hub {     public void Join(string room)     {         // NOTE: this is not persisted - ....         Groups.Add(Context.ConnectionId, room);     }      public void Send(string room, string message)     {         var msg = String.Format(             "{0}: {1}", Context.ConnectionId, message);         Clients.Group(room).newMessage(msg);     } } 

I created a very simple HTML page that connects to the Chat hub when the DOM is ready as shown here.

      
         
Chat
         
             
Message(s) Received
             
     
   

Nothing fancy. Whenever the connected hub receives a new message, a new item is added to the unordered list. There is a button that makes an Ajax call into the ValuesController post method.

public class ValuesController : ApiController {     // POST api/values     public void Post([FromBody]string value)     {         var hubContext = GlobalHost.ConnectionManager.GetHubContext();         hubContext.Clients.Group("TestGroup").send("TestGroup", "Called from Controller");     } 

The Hub call does not work. An error is not thrown, but, the message is never received. Putting a breakpoint in the "Send" method of the Hub does not work either. I feel like I am doing it right. Anyone help? Again, source code can be found here

回答1:

You are calling different methods on the client:

API controller

hubContext.Clients.Group("TestGroup").send("TestGroup", "Called from Controller"); 

Hub

Clients.Group(room).newMessage(msg); 

The method you want to call is newMessage not send

chat.client.newMessage = onNewMessage; 

文章来源: calling SignalR hub from WebAPI controller issues