Blazor TypeClient `AddHttpMessageHandler` 发出 `InvalidOperationException` (ValueFactory 尝试访问此实例的 Value 属性。)

ibo*_*con 5 c# .net-core blazor blazor-webassembly

我尝试应用ASP.NET Core Blazor WebAssemblyHttpClient使用 OIDC 身份验证键入的附加安全方案,如下所示,

// Blazor WebAssembly 'Program.cs'
public static async Task Main(string[] args)
{
    var builder = WebAssemblyHostBuilder.CreateDefault(args);
    builder.RootComponents.Add<App>("#app");

    builder.Services.AddHttpClient<ApplicationHttpClient>(nameof(ApplicationHttpClient), client =>
    {
        client.BaseAddress = new Uri(builder.HostEnvironment.BaseAddress);
    }).AddHttpMessageHandler<BaseAddressAuthorizationMessageHandler>();

    builder.Services.AddScoped(serviceProvider =>
    {
        return serviceProvider.GetRequiredService<IHttpClientFactory>().CreateClient(nameof(ApplicationHttpClient));
    });

    builder.Services.AddOidcAuthentication<RemoteAuthenticationState, RemoteUserAccount>(options =>
    {
        builder.Configuration.Bind("Google", options.ProviderOptions);
        options.ProviderOptions.DefaultScopes.Add("email");
    }).AddAccountClaimsPrincipalFactory<RemoteAuthenticationState, RemoteUserAccount, CustomAccountClaimsPrincipalFactory>();

    await builder.Build().RunAsync();
}
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如果构建并运行,我遇到以下异常,

crit: Microsoft.AspNetCore.Components.WebAssembly.Rendering.WebAssemblyRenderer[100]
      Unhandled exception rendering component: ValueFactory attempted to access the Value property of this instance.
System.InvalidOperationException: ValueFactory attempted to access the Value property of this instance.
   at System.Lazy`1[[Microsoft.Extensions.Http.ActiveHandlerTrackingEntry, Microsoft.Extensions.Http, Version=5.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60]].ViaFactory(LazyThreadSafetyMode mode) in System.Private.CoreLib.dll:token 0x6000fa7+0x43
   at System.Lazy`1[[Microsoft.Extensions.Http.ActiveHandlerTrackingEntry, Microsoft.Extensions.Http, Version=5.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60]].ExecutionAndPublication(LazyHelper executionAndPublication, Boolean useDefaultConstructor) in System.Private.CoreLib.dll:token 0x6000fa8+0x22
   at System.Lazy`1[[Microsoft.Extensions.Http.ActiveHandlerTrackingEntry, Microsoft.Extensions.Http, Version=5.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60]].CreateValue() in System.Private.CoreLib.dll:token 0x6000fad+0x74
   at System.Lazy`1[[Microsoft.Extensions.Http.ActiveHandlerTrackingEntry, Microsoft.Extensions.Http, Version=5.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60]].get_Value() in System.Private.CoreLib.dll:token 0x6000fb3+0xa
   at Microsoft.Extensions.Http.DefaultHttpClientFactory.CreateHandler(String name) in Microsoft.Extensions.Http.dll:token 0x6000065+0xe
   at Microsoft.Extensions.Http.DefaultHttpClientFactory.CreateClient(String name) in Microsoft.Extensions.Http.dll:token 0x6000064+0xe
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如果我注释掉AddHttpMessageHandler<BaseAddressAuthorizationMessageHandler>(),它会像以前一样运行良好。

.NET 6.0.100-预览版.5 21302.13
Visual Studio 2019 16.10.2

重现

吉图布

  1. 运行“TypedHttpClient.Server”
  2. 导航至“获取数据”菜单
  3. 查看控制台错误消息。

异常来自DefaultHttpClientFactory.cs.

// Microsoft.Extensions.Http.DefaultHttpClientFactory.cs
public HttpMessageHandler CreateHandler(string name)
{
    if (name == null)
    {
        throw new ArgumentNullException(nameof(name));
    }

    // Here
    ActiveHandlerTrackingEntry entry = _activeHandlers.GetOrAdd(name, _entryFactory).Value;

    StartHandlerEntryTimer(entry);

    return entry.Handler;
}
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2021.06.24 更新

我用下面的AddHttpMessageHandler方法测试。NoobHandler

public class NoobHandler : DelegatingHandler
{

}
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相反BaseAddressAuthorizationMessageHandler,添加NoobHandler作品。

builder.Services.AddScoped<NoobHandler>();
builder.Services.AddHttpClient<WeatherForecastClient>(nameof(WeatherForecastClient),
    client => client.BaseAddress = new Uri(builder.HostEnvironment.BaseAddress))
.AddHttpMessageHandler<NoobHandler>();
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因此,我怀疑BaseAddressAuthorizationMessageHandler构造函数没有创建实例,而是DefaultHttpClientFactory尝试访问值。