c# - 每 60 秒向 RoR 应用程序发送一次 http put 请求的问题

Question

客户端代码出现奇怪问题，应该每 60 秒向我的 RoR 网站/应用发送 HTTP Put 请求。

问题是客户端应用程序将一些请求推送到网站(从 2 到 9 个请求的任何地方)。然后客户端代码在几次初始成功推送后停止发送 http put 请求。

信息:客户端应用程序是一个 C# Windows 应用程序。网站正在运行 RoR 3.2。

发送http put的c#代码

    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());
        }
    }

客户端 C# 日志记录语句

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"]}

从那时起，它只创建 json 而不是发送它。

服务器日志显示通过的放置请求

 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 

我每 60 秒运行一次的方法是在 C# 中使用计时器。但我只是困惑为什么代码停止输入 using 语句并因此停止发送 JSON 字符串。您可以通过 C# 代码中的日志记录语句来判断这一点。我不太确定 using 语句是如何工作的 我只是根据我在网上找到的发送 http 请求的示例修改了该语句。因此，如果有人也可以解释 using 语句，那就太好了。

添加定时器代码。

    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();
    }

我现在在日志中捕获了异常。异常(exception)情况如下。但是不知道是什么意思。

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)

更新:所以我做了更多的调试，我注意到当我收到错误时，我的代码一直运行到这一行

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

也许它试图创建一个流写入，当我请求流时我得到一个空响应？没有把握。但异常(exception)情况是说某些内容为空。

Answer 1

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