How to get Blazor HotReload to work with Startup class - blazor-webassembly

Question

I have a Blazor WebAssembly app which is hosted by a .net Core app. I've been upgrading it from .net 6.0 and was using a Startup class to initialize the server app
public class Program
{
public static void Main(string[] args)
{
CreateHostBuilder(args)
.Build()
.Run();
}
public static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args)
.ConfigureHostConfiguration(conf =>
{
conf.AddJsonFile($"appsettings.{Environment.MachineName}.json", optional: true, reloadOnChange: true);
})
.ConfigureWebHostDefaults(webBuilder =>
{
webBuilder.UseStartup<Startup>();
});
}
public class Startup
{
public Startup(IConfiguration configuration, IWebHostEnvironment environment)
{
Configuration = configuration;
WebHostEnvironment = environment;
}
public IConfiguration Configuration { get; }
public IWebHostEnvironment WebHostEnvironment { get; }
public void ConfigureServices(IServiceCollection services)
{
services.AddControllersWithViews();
services.AddRazorPages();
/*Other services registered here*/
}
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
// Configure the HTTP request pipeline.
if (env.IsDevelopment())
{
app.UseWebAssemblyDebugging();
}
else
{
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.UseBlazorFrameworkFiles();
app.UseStaticFiles();
app.UseRouting();
app.UseEndpoints(endpoints =>
{
endpoints.MapRazorPages();
endpoints.MapControllers();
endpoints.MapFallbackToFile("index.html");
});
}
}
Now when I run this app, I can't get hot reloading of Blazor or CSS at all.
What I've found is that if I use the newer pattern implementing WebApplication.CreateBuilder, hot reloading works.
public static void Main(string[] args)
{
var builder = WebApplication.CreateBuilder(args);
// Add services to the container.
builder.Services.AddControllersWithViews();
builder.Services.AddRazorPages();
ConfigureServices(builder.Services, builder.Configuration);
var app = builder.Build();
// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
app.UseWebAssemblyDebugging();
}
else
{
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.UseBlazorFrameworkFiles();
app.UseStaticFiles();
var imagesPhysicalPath = app.Configuration.GetSection("ImagesDirectoryPath").Get<string>(); ;
app.UseStaticFiles();
app.UseStaticFiles(new StaticFileOptions
{
RequestPath = "/product-images",
FileProvider = new PhysicalFileProvider(imagesPhysicalPath)
});
app.UseRouting();
app.MapRazorPages();
app.MapControllers();
app.MapFallbackToFile("index.html");
app.Run();
}
I marginally prefer the former version as it allows me to customise the Configuration mechanism.
Can anyone tell me what I'm missing in the original setup that might have broken the hot reload process?