Connection ID required SignalR Asp.net core Web api

Question

Good Day Everyone

i have created a Asp.net Core web api for the purpose of SignalR

my hub is defined like this

 public class ChatHub : Hub  
{  
    public ChatHub()  
    {  
    }  
    public void SendMessage(string AUTHOR, string CHAT_MESSAGE, string model)  
    {  
        try  
        {   
  
            CHAT_MESSAGES_Model chanmessagemodel = Newtonsoft.Json.JsonConvert.DeserializeObject<CHAT_MESSAGES_Model>(model);   
               
            Clients.All.SendAsync("ReceiveMessage",AUTHOR, chanmessagemodel.CHAT_MESSAGE, model);   
        }  
        catch (Exception ex)  
        {  
             //  
        }  
    }  
   
    public async Task SendMessageAsync( string AUTHOR, string CHAT_MESSAGE, string model)  
    {  
        try  
        {  
            CHAT_MESSAGES_Model chanmessagemodel = Newtonsoft.Json.JsonConvert.DeserializeObject<CHAT_MESSAGES_Model>(model);  
  
            await Clients.All.SendAsync("ReceiveMessage",AUTHOR, chanmessagemodel.CHAT_MESSAGE, model);  
  
        }  
        catch (Exception ex)  
        {  
           //  
        }  
    }  
}  

 

and Program.cs looks like this

 var builder = WebApplication.CreateBuilder(args);  
  
// Add services to the container.  
  
builder.Services.AddControllers();  
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle  
builder.Services.AddEndpointsApiExplorer();  
builder.Services.AddSwaggerGen();  
  
//services cors  
builder.Services.AddCors(p => p.AddPolicy("corsapp", builder =>  
{  
    builder.WithOrigins("*").AllowAnyMethod().AllowAnyHeader();  
}));  
  
  
builder.Services.AddSignalR();  
  
  
builder.Services.AddResponseCompression(opts =>  
{  
    opts.MimeTypes = ResponseCompressionDefaults.MimeTypes.Concat(new[] { "application/octet-stream" });  
});  
   
var app = builder.Build();  
  
app.UseRouting();  
  
//app cors  
app.UseCors("corsapp");  
  
  
  
// Configure the HTTP request pipeline.  
if (app.Environment.IsDevelopment())  
{  
    app.UseSwagger();  
    app.UseSwaggerUI();  
}  
     
app.UseHttpsRedirection();  
  
app.UseAuthorization();  
  
app.MapControllers();  
  
app.MapHub<ChatHub>("/chat");  
    
app.Run();  

when i access the local host or the hosted URL (https://localhost:7054/chat
) for testing purposes , i get this error

Connection ID required

In using this in Xamarin like this

 string serverurl = "https://myserver.com/SignalRChat";  
  
       hubConnection = new HubConnectionBuilder()  
                 .WithUrl($"{serverurl}/chatHub")  
                 .Build();  
  
   await hubConnection.StartAsync();  

 Receiving the message  

   hubConnection.On<string, string,string>("ReceiveMessage", (AUTHOR, MESSAGE, Model) =>  
        {  
            //Do work   
        });  

and i get an error

Response status code does not indicate success: 404 (Not Found).  

The error happens on this line

 await hubConnection.StartAsync();  

What could be the issue ?

Answer 1

Hi @Vuyiswa Maseko ,

when i access the local host or the hosted URL (https://localhost:7054/chat
) for testing purposes , i get this error

Connection ID required

What could be the issue ?

As we all known, in asp.net core SignalR, to send messages between clients and server, we need to build the connection first and then calling the hub method or client method to send messages. But, if you directly access the chat hub, the SignalR connection isn't connected, so it doesn't have the connection ID and will show this error.

To solve this issue, you can create a web page(html/cshtml page) and refer to the following JavaScript to builder the SignalR Connection and create a JavaScript client:

Then, access the web page (html/cshtml) page to send or receive the messages. More detail information, see Get started with ASP.NET Core SignalR.

---

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Best regards,
Dillion

Answer 2

Can the following stackoverflow thread help?

Connection ID required
https://stackoverflow.com/questions/47919678/connection-id-required

"The problem was that I have configured the hub at route /chat while my ChatController was also responsible for it."

Answer 3

hi @Zhi Lv - MSFT

sorry i did not add the part on how i consume this service. after that i use Xamarin to access it like this

In using this in Xamarin like this

string serverurl = "https://myserver.com/SignalRChat";

   hubConnection = new HubConnectionBuilder()  
             .WithUrl($"{serverurl}/chatHub")  
             .Build();  

await hubConnection.StartAsync();

Receiving the message

   hubConnection.On<string, string,string>("ReceiveMessage", (AUTHOR, MESSAGE, Model) =>  
        {  
            //Do work   
        });  

and i get an error

Response status code does not indicate success: 404 (Not Found).

Answer 4

Good Day @Zhilz-MSFT

you have steered me to the right direction, all is working now . this is what i did

initialization looks like this

  hubConnection  = new HubConnectionBuilder()  
                          .WithUrl($"{serverurl}/chat")  
                          .Build();  
  
                await hubConnection.StartAsync();  

and when i send the message its like this

        string json = JsonConvert.SerializeObject(model);    
        await hubConnection.InvokeAsync("SendMessage", GenericMethods.USER_DATA.USER_HANDLE, model.CHAT_MESSAGE, json);  
      

And it works nicely.