访问Azure KeyVault时出现“找不到方法”错误

Question

我正在尝试从我的.Net Web应用程序的application_start事件中获取Azure Keyvault的连接字符串。

    protected void Application_Start(Object sender, EventArgs e)
    {
        var azureServiceTokenProvider = new AzureServiceTokenProvider();
                var kvClient = new KeyVaultClient(new KeyVaultClient.AuthenticationCallback(GetToken));

      RegisterRoutes(RouteTable.Routes);
   }

 public static async Task<string> GetToken(string authority, string resource, string scope)
    {
        var authContext = new AuthenticationContext(authority);
        ClientCredential clientCred = new ClientCredential(ConfigurationManager.AppSettings["clientId"],
                                                  ConfigurationManager.AppSettings["clientSecret"]);
                AuthenticationResult result = await authContext.AcquireTokenAsync(resource, clientCred);

                if (result == null)
                    throw new InvalidOperationException("Failed to obtain the JWT token");

      return result.AccessToken;
  }

但我在下面收到此错误。 这是一个带有.Net 4.6的新MVC Web应用程序。 完全相同的代码在Console应用程序上正常工作。 我比较了包版本，它们是相同的。 我也尝试将该代码放在控制器的构造函数中但是同样的错误。 有什么想法吗？

  

未找到方法：'无效   Microsoft.Azure.KeyVault.KeyVaultClient..ctor（AuthenticationCallback，   System.Net.Http.DelegatingHandler []）”

     

[MissingMethodException：找不到方法：'无效   Microsoft.Azure.KeyVault.KeyVaultClient..ctor（AuthenticationCallback，   System.Net.Http.DelegatingHandler []）”。]
  WebApplication1.MvcApplication.Application_Start（）in   C：\ Users \ test \ Documents \ Visual Studio   2017 \项目\ ConsoleApp1 \ WebApplication1 \ Global.asax.cs中：27

     

[HttpException（0x80004005）：找不到方法：'无效   Microsoft.Azure.KeyVault.KeyVaultClient..ctor（AuthenticationCallback，   System.Net.Http.DelegatingHandler []）”。]
  System.Web.HttpApplicationFactory.EnsureAppStartCalledForIntegratedMode（HttpContext的   上下文，HttpApplication app）+10062145
  System.Web.HttpApplication.RegisterEventSubscriptionsWithIIS（IntPtr的   appContext，HttpContext上下文，MethodInfo []处理程序）+118
  System.Web.HttpApplication.InitSpecial（HttpApplicationState状态，   MethodInfo []处理程序，IntPtr appContext，HttpContext context）+173
  System.Web.HttpApplicationFactory.GetSpecialApplicationInstance（IntPtr的   appContext，HttpContext context）+336
  System.Web.Hosting.PipelineRuntime.InitializeApplication（IntPtr的   appContext）+296

     

[HttpException（0x80004005）：找不到方法：'无效   Microsoft.Azure.KeyVault.KeyVaultClient..ctor（AuthenticationCallback，   System.Net.Http.DelegatingHandler []）”。]
  System.Web.HttpRuntime.FirstRequestInit（HttpContext context）+10043436   System.Web.HttpRuntime.EnsureFirstRequestInit（HttpContext context）+95   System.Web.HttpRuntime.ProcessRequestNotificationPrivate（IIS7WorkerRequest   wr，HttpContext context）+254

<packages>
  <package id="Antlr" version="3.4.1.9004" targetFramework="net461" />
  <package id="bootstrap" version="3.0.0" targetFramework="net461" />
  <package id="jQuery" version="1.10.2" targetFramework="net461" />
  <package id="jQuery.Validation" version="1.11.1" targetFramework="net461" />
  <package id="Microsoft.ApplicationInsights" version="2.2.0" targetFramework="net461" />
  <package id="Microsoft.ApplicationInsights.Agent.Intercept" version="2.0.6" targetFramework="net461" />
  <package id="Microsoft.ApplicationInsights.DependencyCollector" version="2.2.0" targetFramework="net461" />
  <package id="Microsoft.ApplicationInsights.PerfCounterCollector" version="2.2.0" targetFramework="net461" />
  <package id="Microsoft.ApplicationInsights.Web" version="2.2.0" targetFramework="net461" />
  <package id="Microsoft.ApplicationInsights.WindowsServer" version="2.2.0" targetFramework="net461" />
  <package id="Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel" version="2.2.0" targetFramework="net461" />
  <package id="Microsoft.AspNet.Mvc" version="5.2.3" targetFramework="net461" />
  <package id="Microsoft.AspNet.Razor" version="3.2.3" targetFramework="net461" />
  <package id="Microsoft.AspNet.Web.Optimization" version="1.1.3" targetFramework="net461" />
  <package id="Microsoft.AspNet.WebPages" version="3.2.3" targetFramework="net461" />
  <package id="Microsoft.Azure.KeyVault" version="2.3.2" targetFramework="net461" />
  <package id="Microsoft.Azure.KeyVault.WebKey" version="2.0.7" targetFramework="net461" />
  <package id="Microsoft.Azure.Services.AppAuthentication" version="1.1.0-preview" targetFramework="net461" />
  <package id="Microsoft.CodeDom.Providers.DotNetCompilerPlatform" version="1.0.7" targetFramework="net461" />
  <package id="Microsoft.Extensions.Configuration" version="2.0.0" targetFramework="net461" />
  <package id="Microsoft.Extensions.Configuration.Abstractions" version="2.0.0" targetFramework="net461" />
  <package id="Microsoft.Extensions.Configuration.AzureKeyVault" version="2.0.0" targetFramework="net461" />
  <package id="Microsoft.Extensions.Configuration.FileExtensions" version="2.0.0" targetFramework="net461" />
  <package id="Microsoft.Extensions.FileProviders.Abstractions" version="2.0.0" targetFramework="net461" />
  <package id="Microsoft.Extensions.FileProviders.Physical" version="2.0.0" targetFramework="net461" />
  <package id="Microsoft.Extensions.FileSystemGlobbing" version="2.0.0" targetFramework="net461" />
  <package id="Microsoft.Extensions.Primitives" version="2.0.0" targetFramework="net461" />
  <package id="Microsoft.IdentityModel.Clients.ActiveDirectory" version="3.14.2" targetFramework="net461" />
  <package id="Microsoft.jQuery.Unobtrusive.Validation" version="3.2.3" targetFramework="net461" />
  <package id="Microsoft.Net.Compilers" version="2.1.0" targetFramework="net461" developmentDependency="true" />
  <package id="Microsoft.Rest.ClientRuntime" version="2.3.8" targetFramework="net461" />
  <package id="Microsoft.Rest.ClientRuntime.Azure" version="3.3.7" targetFramework="net461" />
  <package id="Microsoft.Web.Infrastructure" version="1.0.0.0" targetFramework="net461" />
  <package id="Modernizr" version="2.6.2" targetFramework="net461" />
  <package id="Newtonsoft.Json" version="6.0.8" targetFramework="net461" />
  <package id="Respond" version="1.2.0" targetFramework="net461" />
  <package id="System.Runtime.CompilerServices.Unsafe" version="4.4.0" targetFramework="net461" />
  <package id="WebGrease" version="1.5.2" targetFramework="net461" />
</packages>

Answer 1

我不得不从引用中删除System.Net.Http并重新添加它，因为应用程序因某种未知原因加载了该库的2个不同版本。

Answer 2

在我们的案例中，我们根据KeyVault nuget软件包在项目中使用以下属性来解决该问题：

<ImplicitlyExpandNETStandardFacades>false</ImplicitlyExpandNETStandardFacades>

结果，这会强制引用GAC中的System.Net.Http。

Answer 3

面临类似问题。我的解决方案是：

我在.NET Framework 4.6.2中具有解决方案，当我从块中添加KeyVault SDK时，它也采用了System.Net.Http 4.3.4。但是，根据密钥库SDK的描述，仅.NET标准1.4和2.0才需要，而.NET Framework则没有。当我的整个应用程序使用GAC的System.Net.Http 4.0.0时，我手动删除了通过块添加的System.Net.Http（将其从packages.config中删除），并将引用从GAC添加到了4.0.0版。

在那之后，我摆脱了错误。