ASP.NET Core Web服务不会将appsettings.json加载到配置中

Question

我有一个带有Razor Pages的ASP.NET Core 2.1 Web应用程序,它具有在appsettings.json文件中定义的AAD身份验证信息(由默认应用程序模板提供 - 请参阅下面我如何到达那里).但是,当尝试在配置中配置身份验证时Startup.cs,我没有任何配置值appsettings.json.如果我IConfiguration在调试器中检查对象,那么它似乎只有环境变量配置:

这是Startup.ConfigureServices问题所在的方法:

public void ConfigureServices(IServiceCollection services)
{
    services.Configure<CookiePolicyOptions>(options =>
    {
        // This lambda determines whether user consent for non-essential cookies is needed for a given request.
        options.CheckConsentNeeded = context => true;
        options.MinimumSameSitePolicy = SameSiteMode.None;
    });

    services.AddAuthentication(AzureADDefaults.AuthenticationScheme)
        .AddAzureAD(options =>
        {
            // This is from the default template. It should work, but the relevant settings aren't there so options isn't populated.
            this.Configuration.Bind("AzureAd", options);

            // This of course works fine
            options.Instance = "MyInstance";
            options.Domain = "MyDomain";
            options.TenantId = "MyTenantId";
            options.ClientId = "MyClientId";
            options.CallbackPath = "MyCallbackPath";
        });

    services.AddMvc(options =>
    {
        var policy = new AuthorizationPolicyBuilder()
            .RequireAuthenticatedUser()
            .Build();
        options.Filters.Add(new AuthorizeFilter(policy));
    })
    .SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
}

并且服务配置在重要的情况下(请注意,这是在服务结构无状态服务之上构建的):

protected override IEnumerable<ServiceInstanceListener> CreateServiceInstanceListeners()
{
    return new ServiceInstanceListener[]
    {
        new ServiceInstanceListener(serviceContext =>
            new KestrelCommunicationListener(serviceContext, "ServiceEndpoint", (url, listener) =>
            {
                ServiceEventSource.Current.ServiceMessage(serviceContext, $"Starting Kestrel on {url}");

                return new WebHostBuilder()
                            .UseKestrel(opt =>
                            {
                                int port = serviceContext.CodePackageActivationContext.GetEndpoint("ServiceEndpoint").Port;
                                opt.Listen(IPAddress.IPv6Any, port, listenOptions =>
                                {
                                    listenOptions.UseHttps(GetCertificateFromStore());
                                    listenOptions.NoDelay = true;
                                });
                            })
                            .ConfigureServices(
                                services => services
                                    .AddSingleton<StatelessServiceContext>(serviceContext))
                            .UseContentRoot(Directory.GetCurrentDirectory())
                            .UseStartup<Startup>()
                            .UseServiceFabricIntegration(listener, ServiceFabricIntegrationOptions.None)
                            .UseUrls(url)
                            .Build();
            }))
    };
}

为了创建这个服务,我使用了VS2017中的向导.我选择了一个现有的服务结构项目(.sfproj)并选择Services > Add > New Service Fabric Service并选择Stateless ASP.NET Core [for .NET Framework],然后在我选择的下一页Web Application(使用Razor Pages,而不是MVC)并点击Change Authentication我选择的位置Work or School Accounts并输入我的AAD信息.只是我对这个模板所做的更改都将里面调用的代码AddAzureAD中Startup.ConfigureServices,并设置appsettings.json文件总是被复制到输出目录.

为什么appsettings.json文件没有加载到配置中？据我了解,这应该是默认发生的,但似乎缺少某些东西......

Answer 1

WebHostBuilderappsettings.json默认情况下不加载,您需要手动调用AddJsonFile.例如:

return new WebHostBuilder()
            .UseKestrel(opt =>
            {
                //snip
            })
            .ConfigureAppConfiguration((builderContext, config) =>
            {
                config.AddJsonFile("appsettings.json", optional: false);
            })
            .ConfigureServices(
                services => services
                    .AddSingleton<StatelessServiceContext>(serviceContext))
            .UseContentRoot(Directory.GetCurrentDirectory())
            .UseStartup<Startup>()
            .UseServiceFabricIntegration(listener, ServiceFabricIntegrationOptions.None)
            .UseUrls(url)
            .Build();

或者,您可以使用WebHost.CreateDefaultBuilder哪个将加载更多默认值.

Answer 2

另一种方法是通过ConfigurationBuilder然后使用该UseConfiguration方法手动创建配置。

var configuration = new ConfigurationBuilder()
     .SetBasePath(Directory.GetCurrentDirectory())
     .AddJsonFile("appsettings.json", false, true)
     .Build();

var host = new WebHostBuilder()
     .UseConfiguration(configuration)
     .UseKestrel()
     .UseStartup<Startup>();

主要目的是在实施时提供一点灵活性，但他们经常犯“少即是多”的错误。你必须明确地说出你想要什么，这样管道就保持相对较小。