CODEWITHSUNDEEP
reactjsasp.net-core-2.1asp.net-core-signalr
Mapple
Mapple

Reputation: 15

.Net Core 2.1 React and Signalr 1.0.4 throwing a /negotiate 404 error

I am currently working with React and SignalR. I am using .Net Core 2.1 and the Microsoft.AspNetCore.App package to get the recent SignalR. I have installed @aspnet/signalr as well and I keep getting a 404 error because it is still attempting to go to the /negotiate endpoint which I know it doesn't use anymore. I have confirmed I am up to date on on all packages. Any pointers on where I should be going? 

    const hubConnection = new HubConnectionBuilder().withUrl('http://localhost:3000/ChatHub').build();

public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            //services.AddCors(o => o.AddPolicy("CorsPolicy", builder =>
            //{
            //    builder
            //        .AllowAnyMethod()
            //        .AllowAnyHeader()
            //        .WithOrigins("http://localhost:3000");
            //}));

            services.AddSignalR();
            //services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);

            // In production, the React files will be served from this directory
            services.AddSpaStaticFiles(configuration =>
            {
                configuration.RootPath = "ClientApp/build";
            });
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Error");
                app.UseHsts();
            }

            //app.UseCors("CorsPolicy");

            app.UseFileServer();

            app.UseSignalR(routes =>
            {
                routes.MapHub<ChatHub>("/ChatHub");
            });

            app.UseHttpsRedirection();
            app.UseStaticFiles();
            app.UseSpaStaticFiles();

            //app.UseMvc(routes =>
            //{
            //    routes.MapRoute(
            //        name: "default",
            //        template: "{controller}/{action=Index}/{id?}");
            //});

            app.UseSpa(spa =>
            {
                spa.Options.SourcePath = "ClientApp";

                if (env.IsDevelopment())
                {
                    spa.UseReactDevelopmentServer(npmScript: "start");
                }
            });
        }

Upvotes: 0

Views: 2015

Answers (1)

Andrew Stanton-Nurse
Andrew Stanton-Nurse

Reputation: 6294

I keep getting a 404 error because it is still attempting to go to the /negotiate endpoint which I know it doesn't use anymore

ASP.NET Core SignalR definitely still uses the /negotiate endpoint. In the previews, we used an OPTIONS request instead but that caused a lot of problems so we went back to the /negotiate endpoint.

It looks like you're using a "development server" (spa.UseReactDevelopmentServer in your Startup). That usually means that the development server is serving up your HTML/JS content from a different server than your ASP.NET Core app is running on (rather than just being static files served by the ASP.NET Core app). If that's the case, you need to reference the ASP.NET Core server using a full URL when you connect.

This is because your HTML/JS content is being served by the development server at http://localhost:X but your ASP.NET Core server is running at http://localhost:Y. So when you use /ChatHub as a URL, the browser interprets that as http://localhost:X/ChatHub, so you aren't hitting your ASP.NET Core app (with the SignalR server) but rather then dev server, which has no content at that URL and produces a 404.

Upvotes: 4

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