I've got SignalR hubs in one .NetCore project and SignalR clients in another .NetCore project (to comply with internal infrastructure guidelines). I'm struggling with how to implement the client code that will provide the connection to the hubs. All my projects build fine, I'm just missing the connectivity part.
Client Project:
public class MyClientController
{
private readonly IHubContext<MyHub, IMyHubClient> _hub;
public MyClientController(IHubContext<MyHub, IMyHubClient> hub)
{
_hub = hub;
// THIS NEVER GETS CALLED/HIT BECAUSE I DON'T KNOW HOW TO REGISTER IT
_hub.Clients.All.BroadcastMessage("Notify", $"Hello everyone. This has been constructed");
}
}
I'm guessing I need to do some configuration in the Startup.Configure() method? I've installed the client package already,
EDIT: I added the following code, but it's complaining about the format (remember, this is not a relative path, it's in another service).
app.UseEndpoints(endpoints =>
{
endpoints.MapHub<MyHub>("http://localhost:60913/myHub");
}
Am I on the right path here?
The connection is made by mapping a route to your hub class. The docs have a good example. This includes:
// Add to services collection
services.AddSignalR();
// Map the route "/chathub" to a ChatHub class
app.UseRouting();
app.UseEndpoints(endpoints =>
{
endpoints.MapHub<ChatHub>("/chathub");
});
By the way, a hub can be a standalone class not associated to a controller.
Related
I am building the most basic of an ASP.NET Core Web API, and after a lot of experimenting on my own, I found that running any middleware (custom, app.run, app.use) after the .MapControllers() method doesn't work at all.
internal class Startup
{
public void ConfigureServices(IServiceCollection services)
{
services.AddControllers();
}
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
app.UseRouting();
app.UseEndpoints(endpoint =>
{
endpoint.MapControllers();
});
}
}
I'm asking here because the documentation didn't clarify: how does the MapControllers() method affect other middleware in the pipeline?
I found that running any middleware (custom, app.run, app.use) after
the .MapControllers() method doesn't work at all.
The issue might relate the middleware order, using the MapController method, it already find the endpoint and return the response, so it will not invoke the next middleware.
You can refer the following code: in this sample, by using the MapControllser method, it can't match the /map1, so we can access it using https://localhost:44379/map1 (change the port to yours).
The result like this:
More detail information, see ASP.NET Core Middleware.
I have a .net framework 4.7 project which is essentially an HTTPmodule to be used independantly in IIS server to detect incoming requests and responses, to 3rd party applications installed in IIS,which then need to be modified.
We were adding the module using the webconfig for the respective applications.However now i am migrating it to .net core 6.we use a sample web api to test the httpmodule project.However it seems the addition has to be in startup.cs of the sample web app.
Issue:-
1.I add a middlware to the 1st project like below
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using System.Threading.Tasks;
namespace Myspace.HttpModule.Example
{
// You may need to install the Microsoft.AspNetCore.Http.Abstractions package into your project
public class MyMiddleware
{
private readonly RequestDelegate _next;
public MyMiddleware(RequestDelegate next)
{
_next = next;
}
public Task Invoke(HttpContext httpContext)
{
return _next(httpContext);
}
}
// Extension method used to add the middleware to the HTTP request pipeline.
public static class MyMiddlewareExtensions
{
public static IApplicationBuilder UseMyMiddleware(this IApplicationBuilder builder)
{
return builder.UseMiddleware<MyMiddleware>();
}
}
}
2.Now i need to add this to the 2nd project which is the sample web app to test the HTTPModule.However when i try to add it to the startup.cs file that i created in the sample web app project
using Myspace.HttpModule.Example;
using System.Globalization;
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();
var app = builder.Build();
// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
app.UseSwagger();
app.UseSwaggerUI();
}
app.UseAuthorization();
app.UseMiddleware<MyMiddleware>();
app.UseMyMiddleware();
app.MapControllers();
app.Run();
I get compilation errors at
app.UseMiddleware<MyMiddleware>();
app.UseMyMiddleware();
So is it that i cant add like this.Wouldnt "using" work in this case?
Also is this the only way to add a middleware to be able to get requests globally or from the specific sample or 3rd party app?
I googled a lot but couldn't find piece together a definite answer. I am a newbie to .Net
The error is like below
Update:-
The error image is
your screenshot is pointing to a spelling mistake. its UseMiddleware not Middelware as it can be seen in your screenshot.
please check if you are using correct name.
and also you only need to use either
app.UseMiddleware<MyMiddleware>();
or
app.UseMyMiddleware();
not both.
the method should be included in
namespace Microsoft.AspNetCore.Builder
assembly:Microsoft.AspNetCore.Http.Abstractions.dll
which was included in Microsoft.AspNetCore.app in your project when you created the project :
please check the framewok if there's something wrong with it
I want to send messages from the server (from a class, not a controller) via the SignalR Hub.
The hub works for messages originating from the client but not for messages from the server.
I've tried multiple methods of which non seem to work. For example, I tried retrieving the hub context using:
GlobalHost.ConnectionManager.GetHubContext<MyHub>()
with no success.
What is the best and up-to-date method of doing this in .NET Core?
Temporary Solution:
Having a websocket client inside the host api. Then making it connect to itself. This is not an ideal solution but works as a temporary fix.
You can inject the context in your class as service. Your class must be initialized via DI and added as a service. There is no difference between class or controller.
public class SomeClass
{
public IHubContext<ChatHub, IChatClient> _strongChatHubContext { get; }
public SomeClass(IHubContext<ChatHub, IChatClient> chatHubContext)
{
_strongChatHubContext = chatHubContext;
}
public async Task SendMessage(string message)
{
await _strongChatHubContext.Clients.All.ReceiveMessage(message);
}
}
You can also get service like following by injecting IHttpContextAccessor
var _strongChatHubContext = httpContextAccessor.HttpContext.RequestServices.GetRequiredService<IHubContext<ChatHub, IChatClient>>()
reference:
https://learn.microsoft.com/en-us/aspnet/core/signalr/hubcontext?view=aspnetcore-2.1
First you need to somewhere instantiate your hub (normally when your app is bootstrapping).
MyHub myHub = new MyHub();
Then on your class inject the context:
private readonly IHubContext<NotifyHub, ITypedHubClient> hubContext;
And in your class method just call the hub:
hubContext.Clients.All.yourHubMethod(yourPayload);
SignalR ChatHub is defined as a controller.
[Route("{tenantName}/chatHub")]
public class ChatHub: Hub
In startup configure method,
app.UseSignalR(routes =>
{
routes.MapHub<MessageHub>("/dev/chatHub");
});
This works fine in development environment.
My question is, how can useSignalR method be defined so that mapHub path is independent of the tenant or there is a different way to define so as to work on all the tenants like $"/{tenant}/chatHub"?
I've handled the issue in the following way;
Created chatHub controller without a tenant like
[Route("/chatHub")]
public class ChatHub: Hub
and in the startup.cs defined as
app.UseSignalR(routes =>
{
routes.MapHub<ChatHub>("/chatHub");
});
So this way common instance is handling all the tenants call and identifying tenants by method arguments like
public async Task SendMessage(string tenant, string message)
{
...
}
I have been looking at this and if you are using Finbuckle as your Multitenant library you can use the following to specify your Route
app.UseSignalR(routes =>
{
routes.MapHub<ChatHub>("/{__tenant__}/chatHub");
});
(Regarding Web apps, asp.net 5)
I'm new to this stuff, i want to push data from the server to the client. Displaying 'real-time' data on a website. (something like a chat window).
How should i realize this? I've read about SingalR, but most information seems to be outdated? Is this still a good choice?
For example, one of the problems i run into is when i try to add this:
app.MapSignalR();
to my startup.cs
Error CS1061 'IApplicationBuilder' does not contain a definition for 'MapSignalR' and no extension method 'MapSignalR' accepting a first argument of type 'IApplicationBuilder' could be found
Can someone point me in the right direction?
I believe you can do this with a bridge between IAppBuilder and IApplicationBuilder as shown here:
public static IApplicationBuilder UseAppBuilder(this IApplicationBuilder app, Action<IAppBuilder> configure)
{
app.UseOwin(addToPipeline =>
{
addToPipeline(next =>
{
var appBuilder = new AppBuilder();
appBuilder.Properties["builder.DefaultApp"] = next;
configure(appBuilder);
return appBuilder.Build<AppFunc>();
});
});
return app;
}
Which you would then call from startup to start SignalR:
public void Configure(IApplicationBuilder app)
{
app.UseAppBuilder(appBuilder =>
{
appBuilder.MapSignalR();
appBuilder.Run(context =>
{
});
});
}
Some context, excerpted from the link above:
[In ASP.NET 5, now ASP.NET Core 1.0] the Startup class conventions
have been refined. Katana [the previous version] would search for an
assembly that specified the OwinStartup attribute and then fallback
to searching all assemblies for a class named Startup or
AssemblyName.Startup. ASP.NET does not define an attribute and it only
searches the primary application assembly for a type named Startup (in
any namespace). The Configuration(IAppBuilder app) method is now
Configure(IApplicationBuilder app)...
Middleware that can’t remove their IAppBuilder or OwinMiddleware
dependencies can use a modified approach to run in ASP.NET 5. See this
linked sample for an IApplicationBuilder extension that provides an
IAppBuilder for use with Katana v3 based middleware. This extension
creates a new AppBuilder instance and then wraps the OWIN pipeline
builder pattern around it to integrate into ASP.NET 5.