SignalR Console app example

Question

Is there a small example of a console or winform app using signalR to send a message to a .net hub?. I have tried the .net examples and have looked at the wiki but it is not making sense to me the relationship between the hub(.net) and client(console app) (could not find an example of this). Does the app just need the address and name of hub to connect?.

If someone could provide a small tidbit of code showing the app connecting to a hub and sending "Hello World" or something that the .net hub receives?.

PS. I have a standard hub chat example which works well , if I try to assign a hub name in Cs to it , it stops working i.e [HubName("test")] , do you know the reason for this?.

Thanks.

Current Console app Code.

static void Main(string[] args)
{
    //Set connection
    var connection = new HubConnection("http://localhost:41627/");
    //Make proxy to hub based on hub name on server
    var myHub = connection.CreateProxy("chat");
    //Start connection
    connection.Start().ContinueWith(task =>
    {
        if (task.IsFaulted)
        {
            Console.WriteLine("There was an error opening the connection:{0}", task.Exception.GetBaseException());
        }
        else
        {
            Console.WriteLine("Connected");
        }
    }).Wait();

    //connection.StateChanged += connection_StateChanged;

    myHub.Invoke("Send", "HELLO World ").ContinueWith(task => {
        if(task.IsFaulted)
        {
            Console.WriteLine("There was an error calling send: {0}",task.Exception.GetBaseException());
        }
        else
        {
            Console.WriteLine("Send Complete.");
        }
    });
 }

Hub Server. (different project workspace)

public class Chat : Hub
{
    public void Send(string message)
    {
        // Call the addMessage method on all clients
        Clients.addMessage(message);
    }
}

Info Wiki for this is http://www.asp.net/signalr/overview/signalr-20/hubs-api/hubs-api-guide-net-client

Answer 1

First of all, you should install SignalR.Host.Self on the server application and SignalR.Client on your client application by nuget :

PM> Install-Package SignalR.Hosting.Self -Version 0.5.2

PM> Install-Package Microsoft.AspNet.SignalR.Client

Then add the following code to your projects ;)

(run the projects as administrator)

Server console app:

using System;
using SignalR.Hubs;

namespace SignalR.Hosting.Self.Samples {
    class Program {
        static void Main(string[] args) {
            string url = "http://127.0.0.1:8088/";
            var server = new Server(url);

            // Map the default hub url (/signalr)
            server.MapHubs();

            // Start the server
            server.Start();

            Console.WriteLine("Server running on {0}", url);

            // Keep going until somebody hits 'x'
            while (true) {
                ConsoleKeyInfo ki = Console.ReadKey(true);
                if (ki.Key == ConsoleKey.X) {
                    break;
                }
            }
        }

        [HubName("CustomHub")]
        public class MyHub : Hub {
            public string Send(string message) {
                return message;
            }

            public void DoSomething(string param) {
                Clients.addMessage(param);
            }
        }
    }
}

Client console app:

using System;
using SignalR.Client.Hubs;

namespace SignalRConsoleApp {
    internal class Program {
        private static void Main(string[] args) {
            //Set connection
            var connection = new HubConnection("http://127.0.0.1:8088/");
            //Make proxy to hub based on hub name on server
            var myHub = connection.CreateHubProxy("CustomHub");
            //Start connection

            connection.Start().ContinueWith(task => {
                if (task.IsFaulted) {
                    Console.WriteLine("There was an error opening the connection:{0}",
                                      task.Exception.GetBaseException());
                } else {
                    Console.WriteLine("Connected");
                }

            }).Wait();

            myHub.Invoke<string>("Send", "HELLO World ").ContinueWith(task => {
                if (task.IsFaulted) {
                    Console.WriteLine("There was an error calling send: {0}",
                                      task.Exception.GetBaseException());
                } else {
                    Console.WriteLine(task.Result);
                }
            });

            myHub.On<string>("addMessage", param => {
                Console.WriteLine(param);
            });

            myHub.Invoke<string>("DoSomething", "I'm doing something!!!").Wait();


            Console.Read();
            connection.Stop();
        }
    }
}

Answer 2

Example for SignalR 2.2.1 (May 2017)

Server

Install-Package Microsoft.AspNet.SignalR.SelfHost -Version 2.2.1

[assembly: OwinStartup(typeof(Program.Startup))]
namespace ConsoleApplication116_SignalRServer
{
    class Program
    {
        static IDisposable SignalR;

        static void Main(string[] args)
        {
            string url = "http://127.0.0.1:8088";
            SignalR = WebApp.Start(url);

            Console.ReadKey();
        }

        public class Startup
        {
            public void Configuration(IAppBuilder app)
            {
                app.UseCors(CorsOptions.AllowAll);

                /*  CAMEL CASE & JSON DATE FORMATTING
                 use SignalRContractResolver from
                https://stackguides.com/questions/30005575/signalr-use-camel-case

                var settings = new JsonSerializerSettings()
                {
                    DateFormatHandling = DateFormatHandling.IsoDateFormat,
                    DateTimeZoneHandling = DateTimeZoneHandling.Utc
                };

                settings.ContractResolver = new SignalRContractResolver();
                var serializer = JsonSerializer.Create(settings);
                  
               GlobalHost.DependencyResolver.Register(typeof(JsonSerializer),  () => serializer);                
            
                 */

                app.MapSignalR();
            }
        }

        [HubName("MyHub")]
        public class MyHub : Hub
        {
            public void Send(string name, string message)
            {
                Clients.All.addMessage(name, message);
            }
        }
    }
}

Client

(almost the same as Mehrdad Bahrainy reply)

Install-Package Microsoft.AspNet.SignalR.Client -Version 2.2.1

namespace ConsoleApplication116_SignalRClient
{
    class Program
    {
        private static void Main(string[] args)
        {
            var connection = new HubConnection("http://127.0.0.1:8088/");
            var myHub = connection.CreateHubProxy("MyHub");

            Console.WriteLine("Enter your name");    
            string name = Console.ReadLine();

            connection.Start().ContinueWith(task => {
                if (task.IsFaulted)
                {
                    Console.WriteLine("There was an error opening the connection:{0}", task.Exception.GetBaseException());
                }
                else
                {
                    Console.WriteLine("Connected");

                    myHub.On<string, string>("addMessage", (s1, s2) => {
                        Console.WriteLine(s1 + ": " + s2);
                    });

                    while (true)
                    {
                        Console.WriteLine("Please Enter Message");
                        string message = Console.ReadLine();

                        if (string.IsNullOrEmpty(message))
                        {
                            break;
                        }

                        myHub.Invoke<string>("Send", name, message).ContinueWith(task1 => {
                            if (task1.IsFaulted)
                            {
                                Console.WriteLine("There was an error calling send: {0}", task1.Exception.GetBaseException());
                            }
                            else
                            {
                                Console.WriteLine(task1.Result);
                            }
                        });
                    }
                }

            }).Wait();

            Console.Read();
            connection.Stop();
        }
    }
}

Answer 3

The Self-Host now uses Owin. Checkout http://www.asp.net/signalr/overview/signalr-20/getting-started-with-signalr-20/tutorial-signalr-20-self-host to setup the server. It's compatible with the client code above.

Answer 4

To build on @dyslexicanaboko's answer for dotnet core, here is a client console application:

Create a helper class:

using System;
using Microsoft.AspNetCore.SignalR.Client;

namespace com.stackoverflow.SignalRClientConsoleApp
{
    public class SignalRConnection
    {
        public async void Start()
        {
            var url = "http://signalr-server-url/hubname";

            var connection = new HubConnectionBuilder()
                .WithUrl(url)
                .WithAutomaticReconnect()
                .Build();

            // receive a message from the hub
            connection.On<string, string>("ReceiveMessage", (user, message) => OnReceiveMessage(user, message));

            var t = connection.StartAsync();

            t.Wait();

            // send a message to the hub
            await connection.InvokeAsync("SendMessage", "ConsoleApp", "Message from the console app");
        }

        private void OnReceiveMessage(string user, string message)
        {
            Console.WriteLine($"{user}: {message}");
        }

    }
}

Then implement in your console app's entry point:

using System;

namespace com.stackoverflow.SignalRClientConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            var signalRConnection = new SignalRConnection();
            signalRConnection.Start();

            Console.Read();
        }
    }
}

Answer 5

This is for dot net core 2.1 - after a lot of trial and error I finally got this to work flawlessly:

var url = "Hub URL goes here";

var connection = new HubConnectionBuilder()
    .WithUrl($"{url}")
    .WithAutomaticReconnect() //I don't think this is totally required, but can't hurt either
    .Build();

//Start the connection
var t = connection.StartAsync();

//Wait for the connection to complete
t.Wait();

//Make your call - but in this case don't wait for a response 
//if your goal is to set it and forget it
await connection.InvokeAsync("SendMessage", "User-Server", "Message from the server");

This code is from your typical SignalR poor man's chat client. The problem that I and what seems like a lot of other people have run into is establishing a connection before attempting to send a message to the hub. This is critical, so it is important to wait for the asynchronous task to complete - which means we are making it synchronous by waiting for the task to complete.