当然,当一个过程正在运行时,其他人应该等到它完成.如果进程可用,则执行.如果没有,则发送BUSY应答.

这是实施：

1. usingSystem;
2. usingSystem.Net;
3. usingSystem.Reflection;
4. usingSystem.Runtime.InteropServices;
5. usingSystem.Threading;
6. usingSystem.Threading.Tasks;
7.  
8. namespace simplehttp
9. {
10. classProgram
11. {
12. privatestaticSystem.AsyncCallback task;
13. privatestaticSystem.Threading.ManualResetEvent mre =newSystem.Threading.ManualResetEvent(false);// Notifies one or more waiting threads that an event has occurred.
14. privatestaticHttpListenerContext workingContext =null;
15.  
16. publicstaticbool isBackgroundWorking()
17. {
18. return mre.WaitOne(0);
19. }
20. staticvoidMain(string[] args)
21. {
22. newThread(()=>
23. {
24. Thread.CurrentThread.IsBackground=true;
25. while(true)
26. {
27. Console.WriteLine(" waitOne "+ isBackgroundWorking());
28. mre.WaitOne();// Blocks the current thread until the current WaitHandle receives a signal.
29. Console.WriteLine(" do job"+" ["+Thread.CurrentThread.Name+":"+Thread.CurrentThread.ManagedThreadId+" ]\n");
30. HttpListenerRequest request = workingContext.Request;
31. HttpListenerResponse response = workingContext.Response;
32. string responseString ="WORK "+DateTime.Now;
33. byte[] buffer =System.Text.Encoding.UTF8.GetBytes(responseString);
34. response.ContentLength64= buffer.Length;
35. System.IO.Stream output = response.OutputStream;
36. Thread.Sleep(10000);
37. output.Write(buffer,buffer.Length);
38. output.Close();
39. Console.WriteLine(" "+ responseString +"\t"+DateTime.Now);
40. workingContext =null;
41. mre.Reset();// Sets the state of the event to nonsignaled,causing threads to block.
42. }
43. }).Start();
44.  
45. // Create a listener.
46. HttpListener listener =newHttpListener();
47.  
48. listener.Prefixes.Add("http://localhost:6789/index/");
49. listener.Start();
50. Console.WriteLine("Listening..."+" ["+Thread.CurrentThread.Name+":"+Thread.CurrentThread.ManagedThreadId+" ]\n");
51.  
52. task =newAsyncCallback(ListenerCallback);
53.  
54. IAsyncResult resultM = listener.BeginGetContext(task,listener);
55. Console.WriteLine("Waiting for request to be processed asyncronously.");
56.  
57. Console.ReadKey();
58. Console.WriteLine("Request processed asyncronously.");
59. listener.Close();
60. }
61.  
62. privatestaticvoidListenerCallback(IAsyncResult result)
63. {
64. HttpListener listener =(HttpListener) result.AsyncState;
65.  
66. //If not listening return immediately as this method is called one last time after Close()
67. if(!listener.IsListening)
68. return;
69.  
70. HttpListenerContext context = listener.EndGetContext(result);
71. listener.BeginGetContext(task,listener);
72.  
73. if(workingContext ==null&&!isBackgroundWorking())
74. {
75. // Background work
76. workingContext = context;
77. mre.Set();//Sets the state of the event to signaled,allowing one or more waiting threads to proceed.
78. }
79. else
80. {
81. HttpListenerRequest request = context.Request;
82. HttpListenerResponse response = context.Response;
83. string responseString ="BUSY "+DateTime.Now+" ["+Thread.CurrentThread.Name+":"+Thread.CurrentThread.ManagedThreadId;
84. byte[] buffer =System.Text.Encoding.UTF8.GetBytes(responseString);
85. response.ContentLength64= buffer.Length;
86. System.IO.Stream output = response.OutputStream;
87. output.Write(buffer,buffer.Length);
88. output.Close();
89. Console.WriteLine(responseString +"\t"+DateTime.Now);
90. }
91. }
92. }
93. }

为了测试我做2个http调用.我希望有2个不同的答案WORK和BUSY.
但是我看到第二个请求先等待完成然后执行.

1. waitOne False
2. Listening...[:10]
3.  
4. Waitingfor request to be processed asyncronously.
5. do job [:11]
6.  
7. WORK 1/24/201610:34:01 AM 1/24/201610:34:11 AM
8. waitOne False
9. do job [:11]
10.  
11. WORK 1/24/201610:34:11 AM 1/24/201610:34:21 AM
12. waitOne False

我理解它应该如何运作有什么问题？

我的代码看起来很尴尬,因为它是真实进程的复制.在“我的”应用程序中,工作过程是主要过程,在某些特定时刻运行嵌入式C#代码具有“礼貌”.因此,我无法运行新任务来处理请求,并且它必须是异步的,因为工作流程完成自己的工作,并且只调用从属代码片段以在数据可用时通知客户端.它是异步的,因为代码被调用并且应该尽快完成,否则它将阻止主应用程序.
我将尝试添加其他线程与同步调用,并看到它影响情况.

此示例中未使用调试器来干扰打印到控制台的实时进程和时间戳.调试很棒且必要但在这种情况下我尝试用输出替换以避免同步/等待场景中的额外actor.

应用程序本身并不是繁重的对话. 1-3个客户很少向主要申请人询问答案. http协议用于方便而不是繁重或经常对话.看起来像IE这样的浏览器工作正常(Windows到Windows会话？),有些像Chrome(更多系统不可知)复制我的应用程序行为.看看时间戳,Chrome,IE,Chrome和最后一个Chrome仍然进入了WORK流程.顺便说一句,每个会话建议更改代码,现在在检索前一个请求后立即发出新请求.

1. HttpListenerContext context = listener.EndGetContext(result);
2. listener.BeginGetContext(task,listener);

另外,根据建议,我改变了对syncroniuos的异步调用,结果仍然相同

1. privatestaticvoidListenerCallback(IAsyncResult result)
2. {
3. HttpListener listener =(HttpListener) result.AsyncState;
4.  
5. //If not listening return immediately as this method is called one last time after Close()
6. if(!listener.IsListening)
7. return;
8.  
9. HttpListenerContext context = listener.EndGetContext(result);
10.  
11. while(true)
12. {
13. if(workingContext ==null&&!isBackgroundWorking())
14. {
15. // Background work
16. workingContext = context;
17. mre.Set();//Sets the state of the event to signaled,allowing one or more waiting threads to proceed.
18. }
19. else
20. {
21. HttpListenerRequest request = context.Request;
22. HttpListenerResponse response = context.Response;
23. string responseString ="BUSY "+DateTime.Now+" ["+Thread.CurrentThread.Name+":"+
24. Thread.CurrentThread.ManagedThreadId;
25. byte[] buffer =System.Text.Encoding.UTF8.GetBytes(responseString);
26. response.ContentLength64= buffer.Length;
27. System.IO.Stream output = response.OutputStream;
28. output.Write(buffer,buffer.Length);
29. output.Close();
30. Console.WriteLine(responseString +"\t"+DateTime.Now);
31. }
32. context=listener.GetContext();
33. }
34. }

无法重现.我想这回答了这个问题,因为显然你错误地推动了测试工作量.我通过反复点击fiddler composer发送按钮开车.

谢谢你发布可执行代码.我应该早点尝试过！

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