编辑：
该错误似乎与location在 web.config 中使用有关。
我能够在一个全新的项目中获得解决方法，但是，一旦我为 API 指定了特定位置，我又开始看到错误。
我有一个要添加服务堆栈的现有 ASP.NET Web 应用程序。该应用程序严重依赖 ASP.NET 会话。不幸的是，我无法访问我的服务堆栈类中的会话，因为 HttpContext.Current.Session 始终为空。
所以我已经从这个 Stack Overflow answer实现了一个 VB.NET 版本的解决方法，但是当我导航到配置了 URL 服务堆栈时，我收到以下错误：
Handler for Request not found:
Request.ApplicationPath: /
Request.CurrentExecutionFilePath: /api/
Request.FilePath: /api/
Request.HttpMethod: GET
Request.MapPath('~'): D:\Hg\MyApp.Web\
Request.Path: /api/
Request.PathInfo:
Request.ResolvedPathInfo: /api
Request.PhysicalPath: D:\Hg\MyApp.Web\api\
Request.PhysicalApplicationPath: D:\Hg\MyApp.Web\
Request.QueryString:
Request.RawUrl: /api/
Request.Url.AbsoluteUri: http://localhost:28858/api/
Request.Url.AbsolutePath: /api/
Request.Url.Fragment:
Request.Url.Host: localhost
Request.Url.LocalPath: /api/
Request.Url.Port: 28858
Request.Url.Query:
Request.Url.Scheme: http
Request.Url.Segments: System.String[]
App.IsIntegratedPipeline: True
App.WebHostPhysicalPath: D:\Hg\MyApp.Web
App.WebHostRootFileNames: [aspnetemail.xml.lic,componentart.uiframework.lic,debug.aspx,debug.aspx.designer.vb,debug.aspx.vb,default.aspx,default.aspx.designer.vb,default.aspx.vb,favicon.ico,global.asax,global.asax.vb,licenses.licx,login.aspx,login.aspx.designer.vb,login.aspx.vb,logout.aspx,logout.aspx.designer.vb,logout.aspx.vb,packages.config,MyApp.web.vbproj,MyApp.web.vbproj.user,readme.txt,robots.txt,switch.aspx,switch.aspx.designer.vb,switch.aspx.vb,web.config,web.debug.config,web.release.config,_app_offline.htm,api,apps,app_code,app_data,app_start,bin,content,error,frameset,homepages,my project,obj,_clientdata,_system]
App.DefaultHandler: DefaultHttpHandler
App.DebugLastHandlerArgs: GET|/api/|D:\Hg\MyApp.Web\api\
当我使用默认的服务堆栈 HTTP 处理程序时，一切正常（会话除外）。当我换入时SessionHttpHandlerFactory，出现上述错误。
根据解决方法的说明，您必须将 type 属性从更改ServiceStack.WebHost.Endpoints.ServiceStackHttpHandlerFactory, ServiceStack为SomeNamespace.SessionHttpHandlerFactory：
网络配置：
<location path="api">
<system.web>
<authorization>
<allow users="*" />
</authorization>
<httpHandlers>
<add path="*" type="MyApp.Web.SessionHttpHandlerFactory" verb="*" />
<!--<add path="*" type="ServiceStack.WebHost.Endpoints.ServiceStackHttpHandlerFactory, ServiceStack" verb="*" />-->
</httpHandlers>
</system.web>
<!-- Required for IIS7 -->
<system.webServer>
<modules runAllManagedModulesForAllRequests="true"/>
<validation validateIntegratedModeConfiguration="false" />
<handlers>
<add path="*" name="ServiceStack.Factory" type="MyApp.Web.SessionHttpHandlerFactory" verb="*" preCondition="integratedMode" resourceType="Unspecified" allowPathInfo="true" />
<!--<add path="*" name="ServiceStack.Factory" type="ServiceStack.WebHost.Endpoints.ServiceStackHttpHandlerFactory, ServiceStack" verb="*" preCondition="integratedMode" resourceType="Unspecified" allowPathInfo="true" />-->
</handlers>
</system.webServer>
</location>
以下是解决方法使用的两个类，从 C# 转换为 VB.NET：
SessionHandlerDecorator.vb：
Public Class SessionHandlerDecorator
Implements IHttpHandler
Implements IRequiresSessionState
Private Property Handler() As IHttpHandler
Get
Return m_Handler
End Get
Set(value As IHttpHandler)
m_Handler = value
End Set
End Property
Private m_Handler As IHttpHandler
Friend Sub New(handler As IHttpHandler)
Me.Handler = handler
End Sub
Public ReadOnly Property IsReusable() As Boolean Implements IHttpHandler.IsReusable
Get
Return Handler.IsReusable
End Get
End Property
Public Sub ProcessRequest(context As HttpContext) Implements IHttpHandler.ProcessRequest
Handler.ProcessRequest(context)
End Sub
End Class
会话HttpHandlerFactory：
Imports ServiceStack.WebHost.Endpoints
Public Class SessionHttpHandlerFactory
Implements IHttpHandlerFactory
Private Shared ReadOnly factory As New ServiceStackHttpHandlerFactory()
Public Function GetHandler(context As HttpContext, requestType As String, url As String, pathTranslated As String) As IHttpHandler Implements IHttpHandlerFactory.GetHandler
Dim handler = factory.GetHandler(context, requestType, url, pathTranslated)
Return If(handler Is Nothing, Nothing, New SessionHandlerDecorator(handler))
End Function
Public Sub ReleaseHandler(handler As IHttpHandler) Implements IHttpHandlerFactory.ReleaseHandler
factory.ReleaseHandler(handler)
End Sub
End Class
这是我的服务堆栈实现。就像我说的，它使用默认的服务堆栈 HTTP 处理程序可以完美地工作。
应用主机.vb：
Imports ServiceStack.WebHost.Endpoints
<Assembly: WebActivator.PreApplicationStartMethod(GetType(LoginAppHost), "Start")>
Public Class LoginAppHost
Inherits AppHostBase
Public Sub New()
'Tell ServiceStack the name and where to find your web services
MyBase.New("My Happy Login API", GetType(LoginService).Assembly)
End Sub
Public Overrides Sub Configure(container As Funq.Container)
'Set JSON web services to return idiomatic JSON camelCase properties
ServiceStack.Text.JsConfig.EmitCamelCaseNames = True
End Sub
Public Shared Sub Start()
Dim app As New LoginAppHost
app.Init()
End Sub
End Class
登录.vb：
Imports ServiceStack.ServiceInterface
Imports ServiceStack.ServiceHost
Public Class LoginService
Inherits Service
Public Function Any(request As SSOLogin) As Object
Return New SSOLoginResponse With {.Valid = True, .RedirectUri = "http://localhost:28858/Iloveturtles.aspx"}
End Function
End Class
<Route("/login")> _
Public Class SSOLogin
Public Property UserName As String
Public Property Key As String
Public Property Redirect As String
End Class
Public Class SSOLoginResponse
Public Property Valid As Boolean
Public Property RedirectUri As String
End Class
我对如何进行完全不知所措。有什么想法吗？