DownloadFileAsync (WebClient)的奇怪行为

Question

我有一个简单的脚本下载/上传文件到FTP。它在Unity 2018.1.9f1上运行良好，但最近我将Unity更新到2018.4.5f1，DownloadFileAsyn崩溃了。它会写入一个空文件，并显示错误"Server returned an error: 550没有这样的文件或目录“。文件在那里，权限是正确的(我确信这一点，因为我的UploadFile方法仍然工作得很好)。我用FtpWebRequest写了一个新的方法(相同的凭证，文件路径等)，猜猜是什么--它也运行得很好！但是WebClient下载坏了。

我的DownloadFileAsync方法：

    public void DownloadFile(string FilePath)
    {
        Debug.Log("Download Path: " + FilePath);

        WebClient client = new System.Net.WebClient();
        Uri uri = new Uri(FTPHost + new FileInfo(FilePath).Name);

        client.DownloadProgressChanged += new DownloadProgressChangedEventHandler(OnFileDownloadProgressChanged);
        client.DownloadFileCompleted += new System.ComponentModel.AsyncCompletedEventHandler(OnFileDownloadCompleted);

        client.QueryString.Add("filename", FilePath);
        client.Credentials = new System.Net.NetworkCredential(FTPUserName, FTPPassword);
        client.DownloadFileAsync(uri, Application.persistentDataPath + "/" + FilePath);
    }

我使用FtpWebRequest的新下载方法(它可以工作，但我更喜欢WebClient)：

public void DownloadFileNew(string FilePath)
{
    Uri uri = new Uri(FTPHost + new FileInfo(FilePath).Name);

    FtpWebRequest request = (FtpWebRequest)WebRequest.Create(uri);
    request.Method = WebRequestMethods.Ftp.DownloadFile;
    request.Credentials = new NetworkCredential(FTPUserName, FTPPassword);

    FtpWebResponse response = (FtpWebResponse)request.GetResponse();

    Stream responseStream = response.GetResponseStream();
    StreamReader reader = new StreamReader(responseStream);

    using (Stream ftpStream = request.GetResponse().GetResponseStream())
    using (Stream fileStream = File.Create(god.persPath + "/" + FilePath))
    {
        ftpStream.CopyTo(fileStream);
    }

    reader.Close();
    response.Close();
}

最后是使用WebClient的UploadFile方法，它仍然工作得很好：

public void UploadFile(string FilePath)
{
    FilePath = Application.persistentDataPath + "/" + FilePath;
    Debug.Log("Upload Path: " + FilePath);

    WebClient client = new System.Net.WebClient();
    Uri uri = new Uri(FTPHost + new FileInfo(FilePath).Name);

    client.UploadProgressChanged += new UploadProgressChangedEventHandler(OnFileUploadProgressChanged);
    client.UploadFileCompleted += new UploadFileCompletedEventHandler(OnFileUploadCompleted);
    client.Credentials = new System.Net.NetworkCredential(FTPUserName, FTPPassword);

    client.UploadFileAsync(uri, "STOR", FilePath);
}

Answer 1

我找到了答案。

client.QueryString.Add("filename", FilePath);

不知何故，问题就出在这条线上。我用它来识别我在OnFileDownloadCompleted中下载的文件。

对于这一点，userToken似乎是一个更好的选择。