Azure SignalR Service 403 after publishing to Azure

Question

I've recently started experimenting with the .Net Core 6 Blazor server chat app using signalR. I was able to get the sample app to work locally. However, migrating the app to Azure SignalR service with a published Azure app service has been a struggle.

I'm consistently getting 403 forbidden results.

I have not found much in the way of tutorials for using .net core 6 AND SignalR service. I'd welcome a link to a step-by-step!

Program.cs

using Microsoft.AspNetCore.ResponseCompression;
using RunOn.Hubs;
using Microsoft.AspNetCore.Components;
using Microsoft.AspNetCore.Components.Web;
using RunOn.Data;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddRazorPages();
builder.Services.AddServerSideBlazor();
builder.Services.AddSingleton<WeatherForecastService>();

builder.Services.AddSignalR().AddAzureSignalR();

builder.Services.AddResponseCompression(opts =>
{
    opts.MimeTypes = ResponseCompressionDefaults.MimeTypes.Concat(
        new[] { "application/octet-stream" });
});

var app = builder.Build();


app.UseResponseCompression();


// Configure the HTTP request pipeline.
if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Error");
    // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
    app.UseHsts();
}

app.UseHttpsRedirection();

app.UseStaticFiles();

app.UseRouting();

app.MapBlazorHub();
app.MapHub<ChatHub>("/chathub");
app.MapFallbackToPage("/_Host");

app.Run();

Index.razr

@page "/"
@using Microsoft.AspNetCore.SignalR.Client
@inject NavigationManager NavigationManager
@inject IJSRuntime JsRuntime
@implements IAsyncDisposable

<PageTitle>Index</PageTitle>

<div class="form-group">
    <label>
        User:
        <input @bind="userInput" />
    </label>
</div>
<div class="form-group">
    <label>
        Message:
        <input @bind="messageInput" size="50" />
    </label>
</div>
<button @onclick="Send" disabled="@(!IsConnected)">Send</button>

<hr>

<ul id="messagesList">
    @foreach (var message in messages)
    {
        <li>@message</li>
    }
</ul>

@code {
    private HubConnection? hubConnection;
    private List<string> messages = new List<string>();
    private string? userInput;
    private string? messageInput;

    protected override async Task OnInitializedAsync()
    {
        hubConnection = new HubConnectionBuilder()
            .WithUrl(NavigationManager.ToAbsoluteUri("/chathub"))
            .Build();

             

        hubConnection.On<string, string>("ReceiveMessage", (user, message) =>
        {
            var encodedMsg = $"{user}: {message}";
            messages.Add(encodedMsg);
            StateHasChanged();
        });

        await hubConnection.StartAsync();
    }

    private async Task Send()
    {
        if (hubConnection is not null)
        {
            await hubConnection.SendAsync("SendMessage", userInput, messageInput);
        }
    }

    public bool IsConnected =>
        hubConnection?.State == HubConnectionState.Connected;

    public async ValueTask DisposeAsync()
    {
        if (hubConnection is not null)
        {
            await hubConnection.DisposeAsync();
        }
    }
}

Here is the error: Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware[1] An unhandled exception has occurred while executing the request. System.Net.Http.HttpRequestException: Response status code does not indicate success: 403 (Forbidden).

I'm not sure what other information I could provide that would be helpful to troubleshoot this.

Answer 1

Turns out the issue was related to Authentication. My App Service had Authentication enabled but my Published app is not using authentication at the moment. I turned off Authentication (for now) in the App Service settings and re-published. It is working now.