ConnectionId Required when navigating to SignalR page

[alexanderjwoods]

Startup from Server:
[code]
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.ResponseCompression;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Newtonsoft.Json.Serialization;
using System.Linq;

namespace BlazorAndSignalR.Server
{
public class Startup
{
// This method gets called by the runtime. Use this method to add services to the container.
// For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
public void ConfigureServices(IServiceCollection services)
{
services.AddMvc().AddNewtonsoftJson();
services.AddResponseCompression(opts =>
{
opts.MimeTypes = ResponseCompressionDefaults.MimeTypes.Concat(
new[] { "application/octet-stream" });
});

        services.AddCors(options => options.AddPolicy("CorsPolicy", builder =>
        {
            builder.AllowAnyMethod()
                .AllowAnyHeader()
                .AllowCredentials()
                .WithOrigins("http://localhost:51742");
        }));
        services.AddSignalR();
    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        app.UseResponseCompression();

        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
            app.UseBlazorDebugging();
        }

        app.UseRouting();

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapDefaultControllerRoute();
        });

        app.UseCors("CorsPolicy");
        app.UseSignalR(routes => routes.MapHub<ChatHub>("/chathub"));
        app.UseHttpsRedirection();
        app.UseBlazor<Client.Startup>();
    }
}

}

[/code]

Hub:
[code]
using Microsoft.AspNetCore.SignalR;
using System.Threading.Tasks;

namespace BlazorAndSignalR.Server
{
public class ChatHub : Hub
{
public override Task OnConnectedAsync()
{
if(string.IsNullOrEmpty(Context.ConnectionId))
{
throw new System.Exception(nameof(Context.ConnectionId)); //This code is never hit
}
Clients.All.SendAsync("broadcastMessage", "system", $"{Context.ConnectionId} joined the conversation");
return base.OnConnectedAsync();
}
public void Send(string name, string message)
{
Clients.All.SendAsync("broadcastMessage", name, message);
}

    public override Task OnDisconnectedAsync(System.Exception exception)
    {
        Clients.All.SendAsync("broadcastMessage", "system", $"{Context.ConnectionId} left the conversation");
        return base.OnDisconnectedAsync(exception);
    }
}

}
[/code]

Page:
[code]
@page "/chathub"

@foreach (var message in messages) {
• @message
}

@functions { [Inject] IJSRuntime jsRuntime { get; set; }

HubConnection connection;
string Message = "";
IList<string> messages = new List<string>();

protected override async Task OnInitAsync()
{
    connection = new HubConnectionBuilder(jsRuntime).WithUrl("https://localhost:51742/chathub").Build();
    connection.On<string, string>("broadcastMessage", this.OnBroadcastMessage);
    await connection.StartAsync();
}

Task OnBroadcastMessage(string name, string message)
{
    messages.Add(name + " : " + message);
    StateHasChanged();
    return Task.CompletedTask;
}

async Task SendMessage()
{
    await connection.InvokeAsync("Send", "Blazor Client", Message);
    Message = "";
}

}
[/code]

[galvesribeiro]

The preview7 package was published. Please try it out.