使用FluentFTP从FTP同时下载多个文件 [英] Download multiple files simultaneously from FTP using FluentFTP

问题描述

我正在使用FluentFTP从FTP连接，下载等
https://github.com/robinrodricks/FluentFTP/wiki

I'm using FluentFTP for connecting, downloading, etc. from FTP
https://github.com/robinrodricks/FluentFTP/wiki

我想同时从列表下载文件.毫无疑问，一个一个地下载它们.

I would like to download files simultaneously from List. There is no problem downloading them one by one.

这是我的代码的样子:

下载功能:

public async Task<bool> DownloadFileAsync(string RemoteUrl, string AppName, Progress<FtpProgress> progress = null)
    {
        return await Task.Run(async() =>
        {

            using (FileStream read = new FileStream("settings.xml", FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite))
            {
                if (ftpClient.IsConnected)
                {
                    if (File.Exists("settings.xml"))
                    {
                        Information info = (Information)xs.Deserialize(read);
                    
                        if (Directory.Exists(info.Downloads))
                        {
                            bool DownloadFinished = await ftpClient.DownloadFileAsync(info.Downloads + "\\" + AppName, RemoteUrl, FtpLocalExists.Overwrite, FtpVerify.Retry, progress);
                            if (DownloadFinished == true)
                            {
                                loger.LogWrite("File " + RemoteUrl + " downloaded succesfully.");
                                //read.Dispose();
                                return true;
                            }
                            else
                            {
                                loger.LogWrite("File" + RemoteUrl + " download failed.");
                                //read.Dispose();
                                return false;
                            }
                        }
                        else
                        {
                            loger.LogWrite("Could not locate folder " + info.Downloads + " downloading terminated.");
                            return false;
                        }
                    }
                    else
                    {
                        MessageBox.Show("settings.xml file is missing.");
                        loger.LogWrite("settings.xml file is missing.");
                        read.Dispose();
                        return false;
                    }
                }
                else
                {
                    loger.LogWrite("FTP Client is not connected could not download: " + RemoteUrl);
                    read.Dispose();
                    return false;
                }
            }
        });

    }

我如何填写列表:

Arta_Variables.ArtaSoftware.Add(new Software() { RemoteUrl = "Ultra_Script/Basic_SW/Adobe_Reader.exe", SoftwareName = "Adobe_Reader.exe", FileExistsOnRemoteUrl = null, Downloaded = null });

这是一个一个地下载它们的方法:

This is how downloading them one by one:

if(Arta_Variables.DAAOChecked == false)
{
    if (CheckFinished == true)
    {
        using (FileStream read = new FileStream("settings.xml", FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite))
        {

            XmlSerializer xs = new XmlSerializer(typeof(Information));
            Information info = (Information)xs.Deserialize(read);

            AddBlackLine("");
            AddBlackLine("Downloading all available files.");
            AddBlackLine("");

            foreach (Software software1 in ArtaChosenSW)
            {

                string item = software1.SoftwareName;
                int index = ArtaChosenSW.FindIndex(p => p.SoftwareName == item);

                if (software1.FileExistsOnRemoteUrl == true)
                {
                    AddBlackLine("Downloading " + software1.SoftwareName);

                    Dispatcher.Invoke(() =>
                    {
                        DWGProgressLab.Visibility = Visibility.Visible;
                        DP_ProgressPercentage.Visibility = Visibility.Visible;
                    });

                    Progress<FtpProgress> prog = new Progress<FtpProgress>(x =>
                    {
                        int ConvertedInt = (int)x.Progress;
                        DP_ProgressPercentage.Dispatcher.BeginInvoke((Action)(() => DP_ProgressPercentage.Content = ConvertedInt + "%"));
                    });

                    bool DWFinished = await ftp.DownloadFileAsync(software1.RemoteUrl, software1.SoftwareName, prog);

                    if (DWFinished == true)
                    {
                        AddGreenLine("Download of " + software1.SoftwareName + " succesfull.");
                        ArtaChosenSW[index].Downloaded = true;
                        ArtaChosenSW[index].LocalUrl = info.Downloads;

                        Dispatcher.Invoke(() =>
                        {
                            DWGProgressLab.Visibility = Visibility.Hidden;
                            DP_ProgressPercentage.Visibility = Visibility.Hidden;
                        });

                    }
                    else
                    {
                        AddRedLine("Download of " + software1.SoftwareName + " failed");
                        ArtaChosenSW[index].FileExistsOnRemoteUrl = false;
                    }
                }
                else
                {
                    ArtaChosenSW[index].FileExistsOnRemoteUrl = true;
                    AddBlackLine("File " + software1.SoftwareName + " did not found on ftp. Could not download.");
                    loger.LogWrite("File " + software1.SoftwareName + " did not found on ftp. Could not download.");
                }
            }
        }
    }
}

我尝试同时下载:

foreach(Software software in ArtaChosenSW)
{
    var tasks = ArtaChosenSW.Select(c => Task.Factory.StartNew(() => ftp.DownloadFileAsync(c.RemoteUrl, c.SoftwareName))).ToArray();
    Task.WaitAll(tasks);
}

可悲的是，它正在使用0kb的本地url创建空白文件，但没有下载.

Sadly what it does it's creating blank files in local url with 0kb but no downloading is happening.

我在异步编程方面经验不足，所以我很高兴能得到所有答案或更好的方法.

I'm not much experienced in async programming so I'll be glad for all answers or some better approaches.

推荐答案

似乎您正在使用一个FtpClient实例进行所有传输.

It seems that you are using one FtpClient instance for all your transfers.

FtpClient表示与FTP服务器的一个连接. FTP协议不允许通过一个连接进行多次并行传输.您必须为每次并行传输打开一个新连接.

The FtpClient represents one connection to an FTP server. FTP protocol does not allow multiple parallel transfers over one connection. You have to open a new connection for every parallel transfer.

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