计划的Windows服务中的一致FTP超时

Question

我在Windows服务中遇到ftp问题。我已经安排了一份工作来通过ftp发送文件。有一段时间我有超时（频率每周一次或可能一个月一次），并继续，直到我重新启动我的Windows服务。

System.Net.WebException：该操作已超时。

我正在处理异常，最后我关闭了所有打开的ftp会话。

try 
     { 
      string uri = String.Format("ftp://{0}/{1}/{2}", server, download, file); 
      Uri serverUri = new Uri(uri); 
      if (serverUri.Scheme != Uri.UriSchemeFtp) 
      { 
       return; 
      } 
      FtpWebRequest reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(uri)); 
      reqFTP.Credentials = new NetworkCredential(username, password); 
      reqFTP.KeepAlive = false; 
      reqFTP.Method = WebRequestMethods.Ftp.DownloadFile; 
      reqFTP.EnableSsl = false; 
      reqFTP.Proxy = null; 
      reqFTP.UsePassive = true; 
      reqFTP.Timeout = Settings.Default.TimeOut; 
      reqFTP.ReadWriteTimeout = Settings.Default.TimeOut; 

      response = (FtpWebResponse)reqFTP.GetResponse(); 
      responseStream = response.GetResponseStream(); 

      using (FileStream writeStream = new FileStream(path + file, FileMode.Create)) 
      { 
       int Length = 10240; 
       Byte[] buffer = new Byte[Length]; 
       int bytesRead = responseStream.Read(buffer, 0, Length); 
       while (bytesRead > 0) 
       { 
        writeStream.Write(buffer, 0, bytesRead); 
        bytesRead = responseStream.Read(buffer, 0, Length); 
       } 
      } 

      response.Close(); 
     } 
     catch (WebException wEx) 
     { 
      LogDatabase.WriteLog("Download File", wEx.ToString(), "Download File"); 
     } 
     finally 
     { 
      if (response != null) 
      { 
       response.Close(); 
      } 
      if (responseStream != null) 
      { 
       responseStream.Close(); 
      } 
     } 

任何想法？

thnx提前。

Answer 1

为什么你不能把这一切放在一个循环？然后，如果你有错误，循环会返回并再次尝试。

另外，您为什么要将KeepAlive选项设置为false？

我玩了一小会儿，并把它放到课堂上，这样我可以更好地看到它，但没有对它做任何测试。我的班级在后台线程中进行FTP调用，如果您希望能够与之进行通信，那么您肯定会这样做。

我当然不能保证这会起作用，但至少有一些故障！

class FtpRequests { 

    private const int BUF_SIZE = 10240; 
    private const string PASSWORD = "password"; 
    private const string USERNAME = "username"; 
    private const string SERVER = "yourserver.com"; 
    private string path; 

    public FtpRequests() { 
    Cancel = false; 
    path = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData); 
    } 

    public bool Cancel { get; set; } 

    public bool Complete { get; set; } 

    public Thread Thread1 { get; set; } 

    public int Timeout { get; set; } 

    public int ReadWriteTimeout { get; set; } 

    public void StartFtpDownload(string download, string file) { 
    string objString = string.Format("{0};{1}", download, file); 
    Thread1 = new Thread(startFtpThread); 
    Thread1.Name = string.Format("{0} download", file); 
    Thread1.IsBackground = true; 
    Thread1.Start(objString); 
    } 

    private void startFtpThread(object obj) { 
    Complete = false; 
    string objString = obj.ToString(); 
    string[] split = objString.Split(';'); 
    string download = split[0]; 
    string file = split[1]; 
    do { 
     try { 
     string uri = String.Format("ftp://{0}/{1}/{2}", SERVER, download, file); 
     Uri serverUri = new Uri(uri); 
     if (serverUri.Scheme != Uri.UriSchemeFtp) { 
      Cancel = true; 
      return; 
     } 
     FtpWebRequest reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(uri)); 
     reqFTP.Credentials = new NetworkCredential(USERNAME, PASSWORD); 
     reqFTP.KeepAlive = true; 
     reqFTP.Method = WebRequestMethods.Ftp.DownloadFile; 
     reqFTP.EnableSsl = false; 
     reqFTP.Proxy = null; 
     reqFTP.UsePassive = true; 
     reqFTP.Timeout = Timeout; 
     reqFTP.ReadWriteTimeout = ReadWriteTimeout; 
     using (FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse()) { 
      using (Stream responseStream = response.GetResponseStream()) { 
      using (FileStream writeStream = new FileStream(path + file, FileMode.Create)) { 
       Byte[] buffer = new Byte[BUF_SIZE]; 
       int bytesRead = responseStream.Read(buffer, 0, BUF_SIZE); 
       while (0 < bytesRead) { 
       writeStream.Write(buffer, 0, bytesRead); 
       bytesRead = responseStream.Read(buffer, 0, BUF_SIZE); 
       } 
      } 
      responseStream.Close(); 
      } 
      response.Close(); 
      Complete = true; 
     } 
     } catch (WebException wEx) { 
     LogDatabase.WriteLog("Download File", wEx.ToString(), "Download File"); 
     } 
    } while (!Cancel && !Complete); 
    } 

}