multithreading - Parallel For Each with a Thread.Sleep

Question

基本上，我想从同一个 URl 访问很多页面，但我不想在同一秒内发送垃圾邮件。而且我不想在 30 分钟内结束。
并行内部的 Thread.Sleep() 工作正常吗？
因为只有在大约 90 分钟后我才完成。

        var pages = new List<string>( urls );
        var sources = new BlockingCollection<string>();

        string htmlCode = "";

        Random randomN = new Random();

        Parallel.ForEach(pages, x =>
        {
            x = x.Replace("//", "http://");
            int sleep = randomN.Next(0, 1800000);
            Thread.Sleep(sleep);

            HttpWebResponse response = null;
            CookieContainer cookie = new CookieContainer();

            HttpWebRequest newRequest = (HttpWebRequest)WebRequest.Create(x);
            newRequest.Timeout = 15000;
            newRequest.Proxy = null;
            newRequest.CookieContainer = cookie;
            newRequest.UserAgent = "Mozilla / 5.0(Windows NT 5.1) AppleWebKit / 537.11(KHTML, like Gecko) Chrome / 23.0.1300.0 Iron / 23.0.1300.0 Safari / 537.11";
            newRequest.ContentLength = 0;
            response = (HttpWebResponse)newRequest.GetResponse();
            htmlCode = new StreamReader(response.GetResponseStream(), Encoding.GetEncoding(1252)).ReadToEnd();
            sources.Add(htmlCode);

        });

        return sources;

Answer 1

但是，对于您要实现的目标，要求不是很清楚。但是 Thread.Sleep in parallel.foreach 可能不是正确的选择。尝试通过以下线程，它们可能会有所帮助并解决您的问题。

[1]。 Parallel.ForEach using Thread.Sleep equivalent

[2]。 Thread.Sleep blocking parallel execution of tasks

[3]。 Parallel ForEach wait 500 ms before spawning