Question

我有一个asp.net webform，它写了大约25-30个项目（当用户从表单提出后续请求时需要信息）到自定义缓存中。目前所有这些都在主线程上同步发生。但是在更高的负载下，addcache正成为瓶颈。

如何在后台运行此任务而不使用asp.net工作进程线程池中的线程。

Answer 1

备选方案：

完全异步：

从客户端使用AJAX调用服务器代码，并添加代码以监控调用过程

我刚刚添加了与此过程相关的答案：

https://stackoverflow.com/a/11524718/1268570

部分异步：

从客户端到服务器的调用将是同步的，这意味着响应将不会返回到客户端，直到整个过程结束，但真正的代码将执行async释放ASP.Net使用的线程增加可伸缩性

执行页面异步。您需要在后面的ASPX代码中实现IHttpAsyncHandler接口。这是一个例子：

    public partial class _Default : System.Web.UI.Page, IHttpAsyncHandler
    {
        public void EndProcessRequest(IAsyncResult result)
        {
            var context = (result as AsyncOperation).Context;

            context.Response.Write(string.Format("<p>End Process Request on {0}</p>", Thread.CurrentThread.ManagedThreadId.ToString()));
        }

        public IAsyncResult BeginProcessRequest(HttpContext context, AsyncCallback cb, object extraData)
        {
            var operation = new AsyncOperation(cb, this.Context, extraData);
            operation.StartAsync();

            this.Context.Response.Write(string.Format("<p>Begin Process Request on: {0}...</p>", Thread.CurrentThread.ManagedThreadId.ToString()));

            return operation;
        }
    }

    public class AsyncOperation : IAsyncResult
    {
        private AsyncCallback asyncCallback;

        public AsyncOperation(AsyncCallback asyncCallback, HttpContext context, object state)
        {
            this.AsyncState = state;
            this.asyncCallback = asyncCallback;
            this.Context = context;

            this.IsCompleted = false;
            this.AsyncWaitHandle = null;
            this.CompletedSynchronously = false;
        }

        public HttpContext Context { get; private set; }
        public object AsyncState { get; private set; }
        public WaitHandle AsyncWaitHandle { get; private set; }
        public bool CompletedSynchronously { get; private set; }
        public bool IsCompleted { get; private set; }

        public void StartAsync()
        {
            ThreadPool.QueueUserWorkItem(new WaitCallback(StartAsyncOperation), this.AsyncState);
        }

        public void StartAsyncOperation(object workItemState)
        {
            // place here the async logic

            this.Context.Response.Write(string.Format("<p>Long Async operation started on: {0}</p>", Thread.CurrentThread.ManagedThreadId.ToString()));
            Thread.Sleep(2000);
            this.Context.Response.Write(string.Format("<p>Long Async operation ended on: {0}</p>", Thread.CurrentThread.ManagedThreadId.ToString()));
            this.IsCompleted = true;
            this.asyncCallback(this);
        }
    }

<强>输出

enter image description here

创建一个HttpAsyncHandler。您需要创建实现HttpHandler接口的自定义IHttpAsyncHandler。例如：

public class AsyncHandler : IHttpAsyncHandler
{
    public IAsyncResult BeginProcessRequest(HttpContext context, AsyncCallback cb, object extraData)
    {
        var operation = new AsyncOperation(cb, context, extraData);
        operation.StartAsync();

        context.Response.Write(string.Format("<p>Begin Process Request on: {0}...</p>", Thread.CurrentThread.ManagedThreadId.ToString()));

        return operation;
    }

    public void EndProcessRequest(IAsyncResult result)
    {
        var context = (result as AsyncOperation).Context;

        context.Response.Write(string.Format("<p>End Process Request on {0}</p>", Thread.CurrentThread.ManagedThreadId.ToString()));
    }

    public bool IsReusable
    {
        get { return false; }
    }

    public void ProcessRequest(HttpContext context)
    {
        throw new NotImplementedException();
    }
}

asp.net中的后台工作者（threadpool）

1 个答案:

完全异步：

部分异步：