Question

我有一个API，它接受XML并最终根据XML中的信息上传文件。上传按时间表（也来自XML），我测试了它周围的一切，并知道它的工作原理。

我在每个时间周期尝试上传的第一个文件上有大约40％的时间出现错误（某些文件的时间周期= 45分钟，其他文件的时间周期为30分钟）。

以下是我上传的代码：

try {
    LoggerFTP.Log("Uploading file: " + filename, false);

    // Create the request.
    FtpWebRequest request = (FtpWebRequest)WebRequest.Create(appSettingsFTP.ftpUrl + @"/" + filename);
    request.Method = WebRequestMethods.Ftp.UploadFile;
    request.Timeout = 6000000; //set to 100 minutes
    //request.Timeout = -1; //set to infinite

    // Add the login credentials.
    request.Credentials = new NetworkCredential(appSettingsFTP.ftpLogin, appSettingsFTP.ftpPassword);

    // Grab the file contents.
    StreamReader sourceStream = new StreamReader(appSettingsFTP.uploadFileDirectory + filename);
    byte[] fileContents = Encoding.UTF8.GetBytes(sourceStream.ReadToEnd());
    sourceStream.Close();
    request.ContentLength = fileContents.Length;

    // Copy the file contents to the outgoing stream.
    Stream requestStream = request.GetRequestStream();
    requestStream.Write(fileContents, 0, fileContents.Length);
    requestStream.Close();

    FtpWebResponse response = (FtpWebResponse)request.GetResponse();
    //Logger.Log(filename.ToString() + " " + "Upload Complete, Status: " + response.StatusCode + " " + response.StatusDescription, false);
    //Took response.StatusDescription out because it appears to be creating extra line feeds.
    LoggerFTP.Log(filename.ToString() + " " + "Upload Complete, Status: " + response.StatusCode, false);
}
catch (Exception ex) {
    LoggerFTP.Log(ex.ToString(), false);
}

我已经研究过这个问题，并在网上看到一些关于它可能是速度的事情。就像，有一个超时。但我的FtpWebRequest的超时设置为100分钟，所以它可能不是这样吗？我不知道。这也是作为服务运行的，因此很难测试代码的这个方面。

以下是记录在我的记录器中的异常（e.ToString）：

System.Net.WebException: System error. ---> System.Net.InternalException: System error.
   at System.Net.PooledStream.PrePush(Object expectedOwner)
   at System.Net.ConnectionPool.PutConnection(PooledStream pooledStream, Object owningObject, Int32 creationTimeout, Boolean canReuse)
   at System.Net.FtpWebRequest.FinishRequestStage(RequestStage stage)
   at System.Net.FtpWebRequest.SyncRequestCallback(Object obj)
   at System.Net.FtpWebRequest.RequestCallback(Object obj)
   at System.Net.CommandStream.Dispose(Boolean disposing)
   at System.IO.Stream.Close()
   at System.IO.Stream.Dispose()
   at System.Net.ConnectionPool.Destroy(PooledStream pooledStream)
   at System.Net.ConnectionPool.PutConnection(PooledStream pooledStream, Object owningObject, Int32 creationTimeout, Boolean canReuse)
   at System.Net.FtpWebRequest.AttemptedRecovery(Exception e)
   at System.Net.FtpWebRequest.SubmitRequest(Boolean async)
   --- End of inner exception stack trace ---
   at System.Net.FtpWebRequest.GetRequestStream()
   at CPMainSpringAPIExportsSC.UploadFTP.FTPUploadMethod(String viewname, String filename)

Answer 1

我在尝试通过SSL进行FTP的SSIS包中获得完全相同的堆栈跟踪。没有SSL它可以很好地工作，但是一旦启用SSL，它就会爆炸。

    System.Net.WebException: System error. --->
    System.Net.InternalException: System error.    at
    System.Net.PooledStream.PrePush(Object expectedOwner)    at
    System.Net.ConnectionPool.PutConnection(PooledStream pooledStream, Object owningObject, Int32 creationTimeout, Boolean canReuse)    at
    System.Net.FtpWebRequest.FinishRequestStage(RequestStage stage)    at
    System.Net.FtpWebRequest.SyncRequestCallback(Object obj)    at
    System.IO.Stream.Close()    at
    System.Net.ConnectionPool.Destroy(PooledStream pooledStream)    at
    System.Net.ConnectionPool.PutConnection(PooledStream pooledStream, Object owningObject, Int32 creationTimeout, Boolean canReuse)    at
    System.Net.FtpWebRequest.AttemptedRecovery(Exception e)    at
    System.Net.FtpWebRequest.SubmitRequest(Boolean async)
    --- End of inner exception stack trace ---    at
    System.Net.FtpWebRequest.CheckError()    at
    System.Net.FtpWebRequest.GetRequestStream()    at
    ST_0ff7348de65a468bb358ab0206e3721f.ScriptMain.Main() in c:\Users\Stephens\AppData\Local\Temp\Vsta\e664c8a71bb647ff9e9dc6ac32d7b615\ScriptMain.cs:line 155 at 
    System.Net.FtpWebRequest.CheckError()    at
    System.Net.FtpWebRequest.GetRequestStream()    at
    ST_0ff7348de65a468bb358ab0206e3721f.ScriptMain.Main() in c:\Users\Stephens\AppData\Local\Temp\Vsta\e664c8a71bb647ff9e9dc6ac32d7b615\ScriptMain.cs:line 155

因为错误是如此通用，我决定查看.NET源代码，看看我是否可以找到有关什么是破坏的线索。如果你去这里：

http://labs.developerfusion.co.uk/SourceViewer/browse.aspx?assembly=SSCLI&namespace=System.Net#{%22pageClientState%22%3A%22type-2844%2Ccsharp%22}

并跳到第281行，您将看到内部void PrePush（对象expectedOwner）的定义，它是异常发生时执行的内容。这是它的样子：

    internal void PrePush(object expectedOwner)
    {
        lock (this) {
            //3 // The following tests are retail assertions of things we can't allow to happen.
            if (null == expectedOwner) {
                if (null != m_Owner && null != m_Owner.Target)
                    throw new InternalException();
                // new unpooled object has an owner
            }
            else {
                if (null == m_Owner || m_Owner.Target != expectedOwner)
                    throw new InternalException();
                // unpooled object has incorrect owner
            }

            m_PooledCount++;

            if (1 != m_PooledCount)
                throw new InternalException();
            // pushing object onto stack a second time
            if (null != m_Owner)
                m_Owner.Target = null;
        }
    }

最终我发现FtpWebRequest仅支持显式FTP（端口21）而不支持隐式FTP（端口990）。这在这里明确说明：

Does .NET FtpWebRequest Support both Implicit (FTPS) and explicit (FTPES)?

无论如何，就我而言，这是一个防火墙问题。最初我们配置了隐式FTP，即端口989,990,49152-65535（根据供应商的技术人员）。我检查了我的网络人员，我们打开了端口20,21,989,990和40000-655535的显式内容，之后的事情像冠军一样。

但是，在您的情况下，您似乎有一些连接池兴奋。这里有一篇关于这个主题的好文章：

How to improve the Performance of FtpWebRequest?

您可能希望看一下设置连接池的情况，看看是否可以取得一些进展。希望这有帮助！

此致

斯图尔特

Answer 2

我知道这是一个老话题，但对于遇到同样问题的人来说，缺少的代码是：

            request.EnableSsl = false;

试图上传到FTP：System.Net.WebException：系统错误

2 个答案: