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Signalr Client results

docs/en/Community-Articles/2022-11-23-Signalr-client-results/POST.md

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Signalr Client results

ASP.NET Core 7 supports requesting a result from a client, in this article, we will show you how to use client results with the ABP framework.

Create a SignalR hub

csharp
public class ChatHub : AbpHub
{
    public async Task<string> WaitForMessage(string connectionId)
    {
        var message = await Clients.Client(connectionId).InvokeAsync<string>("GetMessage");
        return message;
    }
}
  • ChatHub inherits from AbpHub that has useful base properties like CurrentUser.
  • Define the WaitForMessage method to call the client's GetMessage method and get the return value.

Using InvokeAsync from a Hub method requires setting the MaximumParallelInvocationsPerClient option to a value greater than 1.

Client

Clients should return results in their .On(...) handlers.

.NET Client

csharp
hubConnection.On("GetMessage", async () =>
{
    Console.WriteLine("Enter message:");
    var message = await Console.In.ReadLineAsync();
    return message;
});

JavaScript client

js
connection.on("GetMessage", function () {

    const message = prompt("Enter message:");
    return message;
});

Strongly-typed hubs

We can use strongly-typed instead of InvokeAsync by inheriting from AbpHub<T> or Hub<T>:

csharp
public interface IClient
{
    Task<string> GetMessage();
}

public class ChatHub : AbpHub<IClient>
{
    public async Task<string> WaitForMessage(string connectionId)
    {
        string message = await Clients.Client(connectionId).GetMessage();
        return message;
    }
}

See also: