asp.net – 保持负载均衡器在长时间运行期间超时

在asp.net mvc 4中,您可以将控制器更改为从AsyncController继承.这允许您分离异步任务,然后等待它们完成.此解决方案创建一个“保持活动”任务,每10秒通过asp.net响应发回数据,以便负载均衡器检测到活动并且不会超时.此任务一直运行,直到它看到uploadFinished变量设置为true.

另一个任务执行长时间运行的上载,或者在asp.net mvc控制器结束它正在处理的Web请求之前需要完成的任何任务.在长时间运行操作完成后,它将uploadFinished变量设置为true.

最后,我在实际的json响应周围手动构建一个容器json对象,这样我就可以将“keep alive”数据作为有效json的一部分发送回浏览器.一个稍微丑陋的黑客,但它的作品！

using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using System.Web;
using System.Web.Mvc;
using System.Web.Script.Serialization;

namespace MvcApplication4.Controllers
{
    public class ExampleController : AsyncController
    {

        [HttpPost]
        public string Upload(UploadModel model,HttpPostedFileBase videoFile)
        {
            // when using jquery ajax form for upload
            // IE requires text/plain content type
            // otherwise it will try to open the response as a file
            // instead of pass the response back to your javascript
            if (Request.AcceptTypes.Contains("application/json"))
            {
                Response.ContentType = "application/json";
            }
            else
            {
                Response.ContentType = "text/plain";
            }

            // start json object
            Response.Write("{"keepalive":"");
            Response.Flush();

            Task[] tasks = new Task[2];
            tasks[0] = Task.Factory.StartNew(() => DoKeepAlive());
            tasks[1] = Task.Factory.StartNew(() => DoUpload(model,videoFile));
            Task.WaitAll(tasks);

            // end keepalive json property
            Response.Write("","data":");

            // insert actual response data
            JavaScriptSerializer json = new JavaScriptSerializer();
            Response.Write(json.Serialize(uploadResponse));

            // end json object
            Response.Write("}");

            return "";
        }

        public bool uploadFinished = false;
        public UploadResponseModel uploadResponse = null;

        public void DoUpload(UploadModel model,HttpPostedFileBase videoFile)
        {
            // do upload to 3rd party
            MyServiceClient c = new MyServiceClient();
            uploadResponse = c.UploadVideo(model,videoFile);
            uploadFinished = true;
        }

        public void DoKeepAlive()
        {
            // send . every 10 seconds
            while (!uploadFinished)
            {
                Response.Write(".");
                Response.Flush();
                Thread.Sleep(10000);
            }
        }
    }
}

这个解决方案依赖.Net 4来做异步的东西.如果您有.Net 4.5,则有更新的方法可以在mvc控制器中执行异步,而不依赖于AsyncController类.

这个站点很有用,并解释了如何在各种版本的.Net框架中在asp.net mvc中进行异步操作：

http://dotnet.dzone.com/news/net-zone-evolution