在C＃/。NET中向FTP服务器上载二进制文件或从FTP服务器下载二进制文件

小编典典

在C＃/。NET中向FTP服务器上载二进制文件或从FTP服务器下载二进制文件

我正在使用.NET 4 C＃。我正在尝试上传ZIP文件，然后将其下载到（我的）服务器。

对于上传我有

using (WebClient client = new WebClient())
{
    FtpWebRequest request = (FtpWebRequest)WebRequest.Create(MyUrl);
    request.Method = WebRequestMethods.Ftp.UploadFile;
    request.EnableSsl = false;
    request.Credentials = new NetworkCredential(MyLogin, MyPassword);
    byte[] fileContents = null;
    using (StreamReader sourceStream = new StreamReader(LocalFilePath))
    {
        fileContents = Encoding.UTF8.GetBytes(sourceStream.ReadToEnd());
    }
    request.ContentLength = fileContents.Length;
    using (Stream requestStream = request.GetRequestStream())
    {
        requestStream.Write(fileContents, 0, fileContents.Length);
    }
    FtpWebResponse response = null;
    response = (FtpWebResponse)request.GetResponse();
    response.Close();
}

这似乎可行，因为我在服务器上获得了正确大小的文件。

1）我如何流式传输它，而不是先将其加载到内存中？我将上传非常大的文件。

对于下载，我有

using (WebClient client = new WebClient())
{
    string HtmlResult = String.Empty;
    FtpWebRequest request = (FtpWebRequest)WebRequest.Create(remoteFile);
    request.Method = WebRequestMethods.Ftp.DownloadFile;
    request.EnableSsl = false;
    request.Credentials = new NetworkCredential(MyLogin, MyPassword);
    using (FtpWebResponse response = (FtpWebResponse)request.GetResponse())
    using (Stream responseStream = response.GetResponseStream())
    using (StreamReader reader = new StreamReader(responseStream))
    using (FileStream writer = new FileStream(localFilename, FileMode.Create))
    {
        long length = response.ContentLength;
        int bufferSize = 2048;
        int readCount;
        byte[] buffer = new byte[2048];
        readCount = responseStream.Read(buffer, 0, bufferSize);
        while (readCount > 0)
        {
            writer.Write(buffer, 0, readCount);
            readCount = responseStream.Read(buffer, 0, bufferSize);
        }
    }
}

2）一切似乎都可以正常工作……除了当我尝试解压缩下载的ZIP文件时，我得到的是无效的ZIP文件。

阅读 216

2020-05-19

共1个答案

小编典典

上载

使用.NET框架将二进制文件上传到FTP服务器的最简单的方法是使用WebClient.UploadFile：

WebClient client = new WebClient();
client.Credentials = new NetworkCredential("username", "password");
client.UploadFile("ftp://ftp.example.com/remote/path/file.zip", @"C:\local\path\file.zip");

如果您需要更大的控制权WebClient（例如TLS /
SSL加密等），则无法使用，请使用FtpWebRequest。简单的方法是FileStream使用Stream.CopyTo以下命令将a复制到FTP流：

FtpWebRequest request =
    (FtpWebRequest)WebRequest.Create("ftp://ftp.example.com/remote/path/file.zip");
request.Credentials = new NetworkCredential("username", "password");
request.Method = WebRequestMethods.Ftp.UploadFile;

using (Stream fileStream = File.OpenRead(@"C:\local\path\file.zip"))
using (Stream ftpStream = request.GetRequestStream())
{
    fileStream.CopyTo(ftpStream);
}

如果需要监视上传进度，则必须自己逐块复制内容：

FtpWebRequest request =
    (FtpWebRequest)WebRequest.Create("ftp://ftp.example.com/remote/path/file.zip");
request.Credentials = new NetworkCredential("username", "password");
request.Method = WebRequestMethods.Ftp.UploadFile;

using (Stream fileStream = File.OpenRead(@"C:\local\path\file.zip"))
using (Stream ftpStream = request.GetRequestStream())
{
    byte[] buffer = new byte[10240];
    int read;
    while ((read = fileStream.Read(buffer, 0, buffer.Length)) > 0)
    {
        ftpStream.Write(buffer, 0, read);
        Console.WriteLine("Uploaded {0} bytes", fileStream.Position);
    } 
}

有关GUI进度（WinForms ProgressBar），请参见：
我们如何显示进度栏，以便使用FtpWebRequest上传

如果要从文件夹上传所有文件，请参阅
C＃中的“递归上传到FTP服务器”。

下载

使用.NET框架从FTP服务器下载二进制文件的最简单的方法是使用WebClient.DownloadFile：

WebClient client = new WebClient();
client.Credentials = new NetworkCredential("username", "password");
client.DownloadFile(
    "ftp://ftp.example.com/remote/path/file.zip", @"C:\local\path\file.zip");

如果您需要更大的控制权WebClient（例如TLS /
SSL加密等），则无法使用，请使用FtpWebRequest。简单的方法是将FTP响应流复制到FileStream使用Stream.CopyTo：

FtpWebRequest request =
    (FtpWebRequest)WebRequest.Create("ftp://ftp.example.com/remote/path/file.zip");
request.Credentials = new NetworkCredential("username", "password");
request.Method = WebRequestMethods.Ftp.DownloadFile;

using (Stream ftpStream = request.GetResponse().GetResponseStream())
using (Stream fileStream = File.Create(@"C:\local\path\file.zip"))
{
    ftpStream.CopyTo(fileStream);
}

如果需要监视下载进度，则必须自己逐块复制内容：

FtpWebRequest request =
    (FtpWebRequest)WebRequest.Create("ftp://ftp.example.com/remote/path/file.zip");
request.Credentials = new NetworkCredential("username", "password");
request.Method = WebRequestMethods.Ftp.DownloadFile;

using (Stream ftpStream = request.GetResponse().GetResponseStream())
using (Stream fileStream = File.Create(@"C:\local\path\file.zip"))
{
    byte[] buffer = new byte[10240];
    int read;
    while ((read = ftpStream.Read(buffer, 0, buffer.Length)) > 0)
    {
        fileStream.Write(buffer, 0, read);
        Console.WriteLine("Downloaded {0} bytes", fileStream.Position);
    }
}

有关GUI进度（WinForms ProgressBar），请参见：
FtpWebRequest使用ProgressBar下载FTP

如果要从远程文件夹
下载所有文件，请参见C＃通过FTP下载所有文件和子目录。

2020-05-19