Autofac Web API 2 和 Owin 在 StartupConfig 中解析

Question

我有一个既是 OWIN 又是 Web 的项目 API 2。我已尽力按照说明进行操作。在 Configration 方法中 StartupConfig class 我有这个：

// Get our configuration
var config = new HttpConfiguration();
var container = ConfigureInversionOfControl(app, config);
var scope = config.DependencyResolver.GetRequestLifetimeScope();
var serverOptions = ConfigureOAuthTokenGeneration(app, scope);

//** removed for brevity **//

// Cors must be first, or it will not work
app.UseCors(CorsOptions.AllowAll);

// Register the Autofac middleware FIRST. This also adds
// Autofac-injected middleware registered with the container.
app.UseAutofacMiddleware(container);
//app.UseAutofacWebApi(config);
app.UseOAuthAuthorizationServer(serverOptions);
app.UseWebApi(config);

我的 ConfigurInversionOfControl 方法如下所示：

private static IContainer ConfigureInversionOfControl(IAppBuilder app, HttpConfiguration config)
{

    // Create our container
    var builder = new ContainerBuilder();

    // You can register controllers all at once using assembly scanning...
    builder.RegisterApiControllers(Assembly.GetExecutingAssembly());

    // Add our dependencies (Can't use life because this is available to all controllers 
    builder.RegisterType<UnitOfWork<DatabaseContext>>().As<IUnitOfWork>().InstancePerRequest();

    // Register our services
    builder.Register(c => new AdvancedEncryptionStandardProvider(ConfigurationManager.AppSettings["rm:key"], ConfigurationManager.AppSettings["rm:secret"])).As<IAdvancedEncryptionStandardProvider>();
    builder.RegisterType<LogService>().As<ILogService>();
    builder.RegisterType<EmailService>().As<IEmailService>();
    builder.RegisterType<RefreshTokenService>().As<IRefreshTokenService>();

    // Register our providers
    builder.Register(c => new SendGridProvider(c.Resolve<IUnitOfWork>(), c.Resolve<IEmailService>(), ConfigurationManager.AppSettings["SendGridApiKey"])).As<ISendGridProvider>();
    builder.RegisterType<LogProvider>().As<ILogProvider>();
    builder.RegisterType<RefreshTokenProvider>().As<IAuthenticationTokenProvider>();
    builder.RegisterType<OAuthProvider>().As<OAuthProvider>();

    // Build
    var container = builder.Build();

    // Lets Web API know it should locate services using the AutofacWebApiDependencyResolver
    config.DependencyResolver = new AutofacWebApiDependencyResolver(container);

    // Return our container
    return container;
}

现在我已经设置好了（我假设是正确的）。如何解决我的 StartupConfig class 中的一项服务？我需要能够创建 OAuthProvider 和 RefreshTokenProvider 的实例。我试过类似的东西：

// Get our providers
var authProvider = scope.Resolve<OAuthProvider>();
var refreshTokenProvider = scope.Resolve<IAuthenticationTokenProvider>();

// Create our OAuth options
return new OAuthAuthorizationServerOptions()
{
    AllowInsecureHttp = true, // TODO: Remove this line
    TokenEndpointPath = new PathString("/oauth/access_token"),
    AccessTokenExpireTimeSpan = TimeSpan.FromDays(1),
    AccessTokenFormat = new Business.Authentication.JwtFormat("http://localhost:62668"),
    Provider = authProvider,
    RefreshTokenProvider = refreshTokenProvider
};

但是当它到达行 var authProvider = scope.Resolve<OAuthProvider>(); 时，我收到一条错误消息：

Parameter cannot be null: Parameter name: context

现在我假设上下文尚未创建，所以我假设我的决心做错了什么。有人可以帮忙吗？

Answer 1

这其实很简单。我需要更改范围：

var scope = config.DependencyResolver.GetRequestLifetimeScope();

到

var scope = config.DependencyResolver.GetRootLifetimeScope();

我假设是因为 "request" 在 StartupConfig class 中不可用。无论如何，改变这个解决了我的问题。

Autofac Web API 2 和 Owin 在 StartupConfig 中解析

Autofac Web API 2 and Owin resolve in StartupConfig

c#

autofac

asp.net-web-api

owin