Blazor Default constructor not found for type Microsoft.AspNetCore.Components.Authorization.AuthorizeRouteView

Question

I cannot understand why do i keep getting this exception. I try to secure a Blazor WebAssembly

blazor.webassembly.js:1 WASM: System.MissingMethodException: Default constructor not found for type Microsoft.AspNetCore.Components.Authorization.AuthorizeRouteView

app.razor

<Router AppAssembly="@typeof(Program).Assembly">
    <Found Context="routeData">
        <AuthorizeRouteView RouteData="@routeData" DefaultLayout="@typeof(MainLayout)" />
    </Found>
    <NotFound>
        <CascadingAuthenticationState>
            <LayoutView Layout="@typeof(MainLayout)">
                <p>Sorry, there's nothing at this address.</p>
            </LayoutView>
        </CascadingAuthenticationState>
    </NotFound>
</Router>

this is the client program.cs

    public class Program
    {
        public static async Task Main(string[] args)
        {
            var builder = WebAssemblyHostBuilder.CreateDefault(args);
            builder.RootComponents.Add<App>("app");
            builder.Services.AddScoped<AuthenticationStateProvider, ApiAuthenticationStateProvider>();
            builder.Services.AddAuthorizationCore(options => { });            
            await builder.Build().RunAsync();
        }
    }

the custom auth state provider

public class ApiAuthenticationStateProvider : AuthenticationStateProvider
{
    private readonly HttpClient _httpClient;
    private readonly ILocalStorageService _localStorage;

    public ApiAuthenticationStateProvider(HttpClient httpClient, ILocalStorageService localStorage)
    {
        _httpClient = httpClient;
        _localStorage = localStorage;
    }
    public override async Task<AuthenticationState> GetAuthenticationStateAsync()
    {
        var savedToken = await _localStorage.GetItemAsync<string>("authToken");

        if (string.IsNullOrWhiteSpace(savedToken))
        {
            return new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity()));
        }

        _httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("bearer", savedToken);

        return new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity(ParseClaimsFromJwt(savedToken), "jwt")));
    }

    public void MarkUserAsAuthenticated(string email)
    {
        ClaimsPrincipal authenticatedUser = new ClaimsPrincipal(new ClaimsIdentity(new[] { new Claim(ClaimTypes.Name, email) }, "apiauth"));
        var authState = Task.FromResult(new AuthenticationState(authenticatedUser));
        NotifyAuthenticationStateChanged(authState);
    }

    public void MarkUserAsLoggedOut()
    {
        var anonymousUser = new ClaimsPrincipal(new ClaimsIdentity());
        var authState = Task.FromResult(new AuthenticationState(anonymousUser));
        NotifyAuthenticationStateChanged(authState);
    }

    private IEnumerable<Claim> ParseClaimsFromJwt(string jwt)
    {
        var claims = new List<Claim>();
        var payload = jwt.Split('.')[1];
        var jsonBytes = ParseBase64WithoutPadding(payload);
        var keyValuePairs = JsonSerializer.Deserialize<Dictionary<string, object>>(jsonBytes);

        keyValuePairs.TryGetValue(ClaimTypes.Role, out object roles);

        if (roles != null)
        {
            if (roles.ToString().Trim().StartsWith("["))
            {
                var parsedRoles = JsonSerializer.Deserialize<string[]>(roles.ToString());

                foreach (var parsedRole in parsedRoles)
                {
                    claims.Add(new Claim(ClaimTypes.Role, parsedRole));
                }
            }
            else
            {
                claims.Add(new Claim(ClaimTypes.Role, roles.ToString()));
            }

            keyValuePairs.Remove(ClaimTypes.Role);
        }

        claims.AddRange(keyValuePairs.Select(kvp => new Claim(kvp.Key, kvp.Value.ToString())));

        return claims;
    }

    private byte[] ParseBase64WithoutPadding(string base64)
    {
        switch (base64.Length % 4)
        {
            case 2: base64 += "=="; break;
            case 3: base64 += "="; break;
        }
        return Convert.FromBase64String(base64);
    }
}

}

the server startup.cs

  public class Startup
    {
        public IConfiguration Configuration { get; }

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

        public void ConfigureServices(IServiceCollection services)
        {

            services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
                .AddJwtBearer(options =>
                {
                    options.TokenValidationParameters = new TokenValidationParameters
                    {
                        ValidateIssuer = true,
                        ValidateAudience = true,
                        ValidateLifetime = true,
                        ValidateIssuerSigningKey = true,
                        ValidIssuer = Configuration["JwtIssuer"],
                        ValidAudience = Configuration["JwtAudience"],
                        IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(Configuration["JwtSecurityKey"]))
                    };
                });

            services.AddBlazoredLocalStorage();
            services.AddAuthorizationCore();
            services.AddScoped<AuthenticationStateProvider, ApiAuthenticationStateProvider>();
            services.AddScoped<IAuthService, AuthService>();

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


            services.AddDbContext<ApplicationDbContext>(options =>
                options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

            services.AddDefaultIdentity<IdentityUser>()
                .AddEntityFrameworkStores<ApplicationDbContext>();
        }

        // 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.UseStaticFiles();
            app.UseClientSideBlazorFiles<Client.Program>();

            app.UseRouting();

            app.UseAuthentication();
            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapDefaultControllerRoute();
                endpoints.MapFallbackToClientSideBlazor<Client.Program>("index.html");
            });
        }
    }

Answer 1

Add @using Microsoft.AspNetCore.Components.Authorization at the top of the App.razor file.

Add services for options and authorization to Program.Main (Client-side):

builder.Services.AddOptions();
builder.Services.AddAuthorizationCore();

Note: The following (Client-side):

 services.AddBlazoredLocalStorage();
 services.AddAuthorizationCore();
 services.AddScoped<AuthenticationStateProvider, 
                          ApiAuthenticationStateProvider>();
        services.AddScoped<IAuthService, AuthService>();

Belongs in the client, not in the server, though at the end of the day its the same configuration...

Note: The following (Client-side):

services.AddScoped<AuthenticationStateProvider, 
                          ApiAuthenticationStateProvider>();

Should be (Client-side):

services.AddScoped<ApiAuthenticationStateProvider>();
services.AddScoped<AuthenticationStateProvider>(provider => provider.GetRequiredService<ApiAuthenticationStateProvider>());

You should pay attention to order in the Startup class

Update:

Disabling the linker, as I've suggested in a comment below seems to be working. However, this should be a temporary solution. This is how you disable the linker: <BlazorLinkOnBuild>false</BlazorLinkOnBuild>

By disabling the linker, you prevent the removal of unused or un-referenced code, which may be the cause of the error... And by enabling the linker, you allow this. However, this code:

builder.Services.AddOptions();
builder.Services.AddAuthorizationCore();

should have prevented the linker from stripping off un-referenced logic. Still better, adding a custom AuthenticationStateProvider implementation in the Program class:

 builder.Services.AddScoped<AuthenticationStateProvider, 
                          ApiAuthenticationStateProvider>(); 

should have fixed this issue. Did you do that like that ?

Once again, disabling the linker is a temporary solution.

Answer 2

I had this problem. It went away when I installed Microsoft.AspNetCore.Components.Authorization from NuGet. The @using Microsoft.AspNetCore.Components.Authorization directive does not give any visual clues in Visual Studio that the package is missing