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Having a strange issue with a client side code that should be sending HTTP Put request every 60 seconds to my RoR website/app.

The issues is that The client side app pushes a few request up to the website(anywhere from 2 to 9 request). Then the client side code stops sending the http put request after the few initial successful pushes.

Information: Client side app is a C# windows application. website is running RoR 3.2.

c# code to send http put

    static void HttpPutRequest(string Json)
    {
        Logger("Sending JSON: " + Json);
        try
        {
            var httpWebRequest = (HttpWebRequest)WebRequest.Create("https://miningmonitor.herokuapp.com/workers/update");
            httpWebRequest.ContentType = "application/json";
            httpWebRequest.Method = "PUT";
            using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))
            {
                Logger("To URL: " + httpWebRequest.Address.ToString());
                streamWriter.WriteLine(Json);
                streamWriter.Flush();
                streamWriter.Close();
                try
                {
                    var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();
                    var wRespStatusCode = httpResponse.StatusCode;
                    Logger("Website return code: " + wRespStatusCode.ToString());
                }
                catch (WebException we)
                {
                    var wRespStatusCode = ((HttpWebResponse)we.Response).StatusCode;
                    Logger(" Exception and Website return code: " + wRespStatusCode.ToString());
                }
            }
        }
        catch (WebException we2)
        {
            var GetRequestStreamExp = ((HttpWebResponse)we2.Response).StatusCode;
            Logger(" Exception trying to setup httpWebRequest.GetRequestStream: " + GetRequestStreamExp.ToString());
        }
    }

client side C# logging statements

Sending JSON: {"worker_user_name":"test:worker1","hashrate":"1.91","accepted":"5953","rejected":"152","hw_errors":"0","num_gpu":"3","gpus":["72.00","0.64","73.00","0.64","74.00","0.63"]}
To URL: https://miningmonitor.herokuapp.com/workers/update
Website return code: OK
Sending JSON: {"worker_user_name":"test:worker1","hashrate":"1.91","accepted":"5956","rejected":"152","hw_errors":"0","num_gpu":"3","gpus":["72.00","0.64","73.00","0.64","74.00","0.62"]}
To URL: https://miningmonitor.herokuapp.com/workers/update
Website return code: OK
Sending JSON: {"worker_user_name":"test:worker1","hashrate":"1.91","accepted":"5964","rejected":"152","hw_errors":"0","num_gpu":"3","gpus":["72.00","0.64","73.00","0.64","74.00","0.63"]}
To URL: https://miningmonitor.herokuapp.com/workers/update
Website return code: OK
Sending JSON: {"worker_user_name":"test:worker1","hashrate":"1.91","accepted":"5970","rejected":"152","hw_errors":"0","num_gpu":"3","gpus":["72.00","0.64","73.00","0.64","74.00","0.63"]}
To URL: https://miningmonitor.herokuapp.com/workers/update
Website return code: OK
Sending JSON: {"worker_user_name":"test:worker1","hashrate":"1.91","accepted":"5978","rejected":"152","hw_errors":"0","num_gpu":"3","gpus":["72.00","0.64","73.00","0.64","74.00","0.63"]}
To URL: https://miningmonitor.herokuapp.com/workers/update
Website return code: OK
Sending JSON: {"worker_user_name":"test:worker1","hashrate":"1.91","accepted":"5989","rejected":"153","hw_errors":"0","num_gpu":"3","gpus":["72.00","0.64","73.00","0.64","74.00","0.63"]}
To URL: https://miningmonitor.herokuapp.com/workers/update
Website return code: OK
Sending JSON: {"worker_user_name":"test:worker1","hashrate":"1.91","accepted":"5995","rejected":"153","hw_errors":"0","num_gpu":"3","gpus":["72.00","0.64","73.00","0.64","74.00","0.63"]}
To URL: https://miningmonitor.herokuapp.com/workers/update
Website return code: OK
Sending JSON: {"worker_user_name":"test:worker1","hashrate":"1.91","accepted":"5999","rejected":"153","hw_errors":"0","num_gpu":"3","gpus":["72.00","0.64","73.00","0.63","74.00","0.63"]}
Sending JSON: {"worker_user_name":"test:worker1","hashrate":"1.91","accepted":"6009","rejected":"153","hw_errors":"0","num_gpu":"3","gpus":["72.00","0.64","73.00","0.64","74.00","0.63"]}
Sending JSON: {"worker_user_name":"test:worker1","hashrate":"1.91","accepted":"6015","rejected":"153","hw_errors":"0","num_gpu":"3","gpus":["72.00","0.63","73.00","0.64","74.00","0.63"]}
Sending JSON: {"worker_user_name":"test:worker1","hashrate":"1.91","accepted":"6021","rejected":"153","hw_errors":"0","num_gpu":"3","gpus":["72.00","0.64","73.00","0.64","74.00","0.63"]}
Sending JSON: {"worker_user_name":"test:worker1","hashrate":"1.91","accepted":"6029","rejected":"153","hw_errors":"0","num_gpu":"3","gpus":["72.00","0.64","73.00","0.64","74.00","0.64"]}

from that point on its only creating that json not sending it.

server logs showing put request coming through

 Aug 13 10:31:52 miningmonitor heroku/router: at=info method=PUT path=/workers/update host=miningmonitor.herokuapp.com fwd="198.244.99.204" dyno=web.1 connect=8ms service=101ms status=200 bytes=2005

How I'm running this every 60 seconds is using a timer in c#. But Im just confused why the code stops entering the using statement and therefore stops sending the JSON string. You can tell this by the logging statements in the C# code. Im not really sure how the using statement works I just modified that statement from an example I found online to send http requests. So if someone could also explain the using statement that would be great.

Adding in the timer code.

    public void update(string user_worker)
    {

      System.Timers.Timer timer = new System.Timers.Timer(60000);
      timer.Elapsed += (sender, e) =>
      {
          //query the miner for summary and gpucount information
          String SummaryQuery = QueryMiner("summary");
          String gpuNum = FindKey(QueryMiner("gpucount"), "Count");
          //String PoolQuery = QueryMiner("pools");
          int numgpus = Convert.ToInt32(gpuNum);
          //Array of strings to hold each gpu query
          String[] gpuQueries = new String[numgpus];
          //add the GPU queries into the array
          for (int i = 0; i < numgpus; i++)
              gpuQueries[i] = QueryMiner("gpu|" + i);

          //now add information specific to each gpu to a list
          List<string> gpuList = new List<string>();
          for (int i = 0; i + 1 <= gpuQueries.Length; i++)
          {
              gpuList.Add(FindKey(gpuQueries[i], "Temperature"));
              gpuList.Add(FindKey(gpuQueries[i], "MHS 5s"));
          }
          //set all the values that we have gotten from the queries
          this.worker_user_name = user_worker;
          this.hashrate = FindKey(SummaryQuery, "MHS av");
          this.accepted = FindKey(SummaryQuery, "Accepted");
          this.rejected = FindKey(SummaryQuery, "Rejected");
          this.hw_errors = FindKey(SummaryQuery, "Hardware Errors");
          this.num_gpu = gpuNum;
          this.gpus = gpuList.ToArray();
          //create JSON from the workerUpdate object
          string JSON = JsonConvert.SerializeObject(this);
          //send to website
          HttpPutRequest(JSON);
      };
     timer.Start();
    }

I caught the exception in the logs now. the exception is below. But not sure what it means.

Exception: System.NullReferenceException: Object reference not set to an instance of an object.
 at MiningMonitorClientW.WorkerUpdate.HttpPutRequest(String Json)
 at MiningMonitorClientW.WorkerUpdate.<>c__DisplayClass1.<update>b__0(Object sender, ElapsedEventArgs e)

Update: So I've done more debugging and ive noticed that when I get the error my code runs until this line

using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))

maybe its trying to create a streamwrite and when I am requesting Stream I'm getting a null response? Not sure. But exception is saying something is null.

4

2 回答 2

2

您应该在整个HttpPutRequest方法主体周围放置一个 try/catch 块。httpWebRequest.GetRequestStream()可能失败或超时。

于 2013-08-13T20:36:36.123 回答
1

这不会解决您的问题，但会帮助您找出问题所在。

您必须将 try/catch 添加到事件处理程序。否则，如果发生异常，您将永远不会知道它，因为System.Timers.Timer它将抑制任何逃脱处理程序的异常。在下面的代码中，我只是在您现有的代码中添加了一个 try/catch：

public void update(string user_worker)
{

  System.Timers.Timer timer = new System.Timers.Timer(60000);
  timer.Elapsed += (sender, e) =>
  {
    try
    {
      //query the miner for summary and gpucount information
      String SummaryQuery = QueryMiner("summary");
      String gpuNum = FindKey(QueryMiner("gpucount"), "Count");
      //String PoolQuery = QueryMiner("pools");
      int numgpus = Convert.ToInt32(gpuNum);
      //Array of strings to hold each gpu query
      String[] gpuQueries = new String[numgpus];
      //add the GPU queries into the array
      for (int i = 0; i < numgpus; i++)
          gpuQueries[i] = QueryMiner("gpu|" + i);

      //now add information specific to each gpu to a list
      List<string> gpuList = new List<string>();
      for (int i = 0; i + 1 <= gpuQueries.Length; i++)
      {
          gpuList.Add(FindKey(gpuQueries[i], "Temperature"));
          gpuList.Add(FindKey(gpuQueries[i], "MHS 5s"));
      }
      //set all the values that we have gotten from the queries
      this.worker_user_name = user_worker;
      this.hashrate = FindKey(SummaryQuery, "MHS av");
      this.accepted = FindKey(SummaryQuery, "Accepted");
      this.rejected = FindKey(SummaryQuery, "Rejected");
      this.hw_errors = FindKey(SummaryQuery, "Hardware Errors");
      this.num_gpu = gpuNum;
      this.gpus = gpuList.ToArray();
      //create JSON from the workerUpdate object
      string JSON = JsonConvert.SerializeObject(this);
      //send to website
      HttpPutRequest(JSON);
    }
    catch (Exception ex)
    {
        // handle exception here
    }
  };
 timer.Start();
}

编写通常是不好的做法catch (Exception)，但设计System.Timers.Timer强制它。正如文档所说：

在 .NET Framework 2.0 版及更早版本中，Timer 组件捕获并抑制由 Elapsed 事件的事件处理程序引发的所有异常。此行为可能会在 .NET Framework 的未来版本中发生更改。

从 .NET 4.5 开始，这种行为没有改变。

如果你没有捕捉到异常，那么计时器将抑制它，这意味着你永远不会知道发生了异常。

更新

在大多数情况下，您应该只捕获那些您知道如何处理的特定异常。例如，如果你想捕捉IOExceptionand WebException，你会写：

catch (WebException wex)
{
    // handle WebException
}
catch (IOException ioex)
{
    // handle IOException
}

正如我上面所说的，catch 被认为是不好的做法Exception，因为您可能不知道如何处理它，并且最好让您的程序因未处理的异常而崩溃，而不是在面对未知错误时盲目地继续。但是因为System.Timers.Timer会抑制异常，所以如果没有其他原因，您必须在Elapsed处理程序中捕获所有异常，而不是记录它们，以便您知道到底发生了什么。或者你可能有一些方法让你的处理程序通知主线程事情不正常并且需要关闭。所以在你的Elapsed处理程序中，你必须捏住鼻子，做你通常不应该做的事情。在所有特定例外之后，添加：

catch (Exception ex)
{
    // handle all other exceptions
}
于 2013-08-13T22:12:19.410 回答