Swagger No API definition provided

Question

I was implementing Swagger into my Blazor WebAssembly project and swagger does not seem to recognise any of my APIs? Can't seem to figure out the issue and was wondering if anyone knew why this might be occurring. Thanks in advance.

Installed Swashbuckle.AspNetCore in the Server project

My controllers do not use the traditional Route(["api/controller"]) but instead uses Route(["controller"]) which I do not think would cause this issue.

Furthermore all controller functions have been labelled with get/post/put e.g. HttpGet[(...)] ... etc

Startup.cs

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

    public IConfiguration Configuration { get; }

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddDbContext<ApplicationDbContext>(options =>
            options.UseSqlServer(
                Configuration.GetConnectionString("DefaultConnection")));

        services.AddDatabaseDeveloperPageExceptionFilter();

        services.AddDefaultIdentity<ApplicationUser>(options => options.SignIn.RequireConfirmedAccount = false)
            .AddRoles<IdentityRole>()
            .AddEntityFrameworkStores<ApplicationDbContext>();

        services.AddIdentityServer()
            .AddApiAuthorization<ApplicationUser, ApplicationDbContext>(options => {
                options.IdentityResources["openid"].UserClaims.Add("role");
                options.ApiResources.Single().UserClaims.Add("role");
            });

        JwtSecurityTokenHandler.DefaultInboundClaimTypeMap.Remove("role");

        services.AddAuthentication()
            .AddIdentityServerJwt();

        services.AddControllersWithViews();

        services.AddRazorPages();

        services.Configure<IdentityOptions>(options =>
        options.ClaimsIdentity.UserIdClaimType = ClaimTypes.NameIdentifier);

       services.AddControllers().AddNewtonsoftJson(x => x.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Serialize);

        services.AddSwaggerGen();
    
    }

    // This method gets called by the runtime. Use th   is method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
            app.UseMigrationsEndPoint();
            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();

        app.UseRouting();
        app.UseIdentityServer();
        app.UseAuthentication();
        app.UseAuthorization();

        app.UseSwagger();
        app.UseSwaggerUI();

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapRazorPages();
            endpoints.MapControllers();
            endpoints.MapFallbackToFile("index.html");
        });
    }
}

Answer 1

The docs are a bit fragmented by the various options and versions. But the relevant line is:

• Add endpoints if you're using endpoint-based routing.

app.UseEndpoints(endpoints =>
{
    endpoints.MapRazorPages();
    endpoints.MapControllers();
    endpoints.MapSwagger();     // add this line
    endpoints.MapFallbackToFile("index.html");
});