在 C#/.NET 中将文件上载和下载到/从 FTP 服务器下载文件

Question

我正在使用.NET 4 C#。我正在尝试上传然后将ZIP文件下载到(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();
}

这似乎有效，因为我在服务器上获得了一个大小合适的文件。

1) 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)一切似乎都正常...除非当我尝试解压缩下载的 ZIP 文件时，我得到一个无效的 ZIP 文件。

Answer 1

上传

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

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

如果您需要更好的控制，WebClient不提供(如 TLS/SSL 加密、ASCII/文本传输模式、传输恢复等)，请使用FtpWebRequest。简单的方法是使用以下Stream.CopyTo将FileStream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:localpathfile.zip"))
using (Stream ftpStream = request.GetRequestStream())
{
fileStream.CopyTo(ftpStream);
}

如果您需要监控上传进度，则必须自己按块复制内容：

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:localpathfile.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(WinFormsProgressBar)，请参阅：
我们如何显示使用FtpWebRequest上传的进度条

如果要上载文件夹中的所有文件，请参阅 C# 中的
递归上载到 FTP 服务器。

<小时 />

下载

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

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

如果您需要更好的控制，WebClient不提供(如 TLS/SSL 加密、ascii/文本传输模式、恢复传输等)，请使用FtpWebRequest。简单的方法是使用Stream.CopyTo将 FTP 响应流复制到FileStream：

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:localpathfile.zip"))
{
ftpStream.CopyTo(fileStream);
}

如果您需要监控下载进度，则必须自己按块复制内容：

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:localpathfile.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 (WinFormsProgressBar)，请参阅：
FtpWebRequest FTP 下载与进度栏

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