在单独的线程上重用连接

Question

I need to listen to an open API, upon correct data I need to download some file and process it. I am using timer to automatically issue a download request every x seconds which keeps the connection alive, hence available for reuse.

There is a total of 3 components:

1. Parent Class
2. Listener Class
3. Timer

The parent class spawns the listener on a separate thread, and also initiates the timer. Both, timer and listener invoke a delegate on the parent.

The problem is that on every download from timer the connection is reused (evident from download time) but when listener invokes the same, it is not.

Bare-bone code:

using Timer = System.Timers.Timer;

namespace Hallelujah
{
    public delegate void downloadData(bool process, string url);
    public delegate void downloadDataInvoker(bool process, string url);

class Listener2
{
    downloadData _downloadData;
    public void start(string storeID, string shoes)
    {
        ServicePointManager.DefaultConnectionLimit = 500;
        ServicePointManager.Expect100Continue = false;
        ServicePointManager.MaxServicePoints = 0;

        _downloadData += new downloadData(downloadDataCb);

        Timer timer = new Timer(10000);
        timer.Elapsed += timer_Elapsed;
        timer.Enabled = true;

        Listen listenTool = new Listen();
        listenTool._downloadData += new downloadDataInvoker(invoker);

        Thread thread = new Thread(new ParameterizedThreadStart(listenTool.init));
        string[] str = { params };
        thread.Start(str);

        F1.updateStatus(System.Threading.Thread.CurrentThread.ManagedThreadId.ToString());
    }

    void timer_Elapsed(object sender, ElapsedEventArgs e)
    {
        _downloadData.Invoke(false, "example.com");
    }

    public void invoker(bool process, string url)
    {
        _downloadData.Invoke(process, url);
    }
    public void downloadDataCb(bool process, string url)
    {
        F1.updateStatus(System.Threading.Thread.CurrentThread.ManagedThreadId.ToString());
        HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
        req.KeepAlive = true;
        req.ProtocolVersion = HttpVersion.Version10;
        req.UnsafeAuthenticatedConnectionSharing = true;
        req.Pipelined = true;
        WebResponse res = req.GetResponse();
        Stream sr = res.GetResponseStream();
        //Reading response
        if (process)
        {
            F1.updateStatus("Downloaded  in " + t1.Seconds + " s " + t1.Milliseconds + "ms ");
        }
        else
            F1.updateStatus("Downloaded NULL(from timer) in " + t1.Seconds + " s " + t1.Milliseconds + "ms ");
    }

    public void updateStatusCB(string status)
    {
        F1.updateStatus(status);
    }

}
internal class Listen
{
    public downloadDataInvoker _downloadDataInvoker;
    public updateStatus _updateStatus;
    public bool ToListen = true;

    public void init(object objpass)
    {
        _updateStatus.Invoke(System.Threading.Thread.CurrentThread.ManagedThreadId.ToString());

         while(ToListen){
            //When a match is found
            _downloadDataInvoker.Invoke(true, media_url);
        }


    }
}

Any idea why is this happening this way?

Answer 1

You create a new keep-alive request when timer event invoked.

According to your needs, there are many download task(via user_id?), you can create a keep-alive request per task, and begin the request async, call the update delegate in the callback event.