带有OWIN的Web API会为HttpMessageInvoker抛出ObjectDisposedException

Question

我在ASP.NET WebApi2设置中遇到了一些OWIN的困难.重启后的第一个请求导致异常:

    [ObjectDisposedException: Cannot access a disposed object.
    Object name: 'System.Net.Http.HttpMessageInvoker'.]
       System.Net.Http.HttpMessageInvoker.CheckDisposed() +327456
       System.Net.Http.HttpMessageInvoker.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken) +24
       System.Web.Http.Owin.<InvokeCore>d__0.MoveNext() +501
       System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
       System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58
       Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.<RunApp>d__5.MoveNext() +187
       System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
       System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58
       Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.<DoFinalWork>d__2.MoveNext() +185
       Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.StageAsyncResult.End(IAsyncResult ar) +69
       Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.IntegratedPipelineContext.EndFinalWork(IAsyncResult ar) +64
       System.Web.AsyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +483
       System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +157
    

我认为这个问题是由于第一次点击EF DbContext时长时间运行的任务造成的.总而言之,第一个请求大约是4-6000毫秒.在第一次请求之后,没有更多例外.

我已经使用webapi项目和以下OWIN启动(并且没有global.asax)以简化形式重现了该问题:

public class Startup
{
    public void Configuration(IAppBuilder app) {
        var config = new HttpConfiguration();
        config.MapHttpAttributeRoutes();

        // ---- simulate long running initialization code -------
        Thread.Sleep(3000);
        // ------------------------------------------------------

        app.UseWebApi(config);
    }
}

我添加一个控制器:

[Route("api/test/number")]
public class TestController : ApiController
{
    public object Get() {
        return 42;
    }
}

当我请求时,第一个请求导致异常.

Answer 1

这是一个老问题,但是花了好几个小时试图击败ObjectDisposedException并且刚刚找到了一个解决方案,这个解决方案在Codeplex上的这个AspNetWebStack问题帮助我:

当你的owin web api应该在自托管环境中运行时,你可以在owin启动类中绑定web api配置

public void Configuration(IAppBuilder app)
{
    ConfigureOAuth(app);

    HttpConfiguration config = new HttpConfiguration();
    WebApiConfig.Register(config);
    app.UseWebApi(config);
}

如果您打算使用IIS作为您的owin web api的主机,那么将web api配置绑定到全局asax类中

protected void Application_Start(object sender, EventArgs e)
{
    GlobalConfiguration.Configure(WebApiConfig.Register);
}

这消除了ObjectDisposedException,我的web api像魅力一样运行