c# - 通过 ftp 上传文本文件，但文件为空白/空

Question

以下是将 txt 文件从某个位置复制到 ftp 路径的代码片段：

WebRequest WRequest = WebRequest.Create(FtpPath + OriginalfileName);
WRequest.Method = WebRequestMethods.Ftp.UploadFile;
WRequest.Credentials = new NetworkCredential("myusername", "FtpPassword");
FileStream stream = File.OpenRead(OriginalFilePath);
byte[] buffer = new byte[stream.Length];
Stream RStream = WRequest.GetRequestStream();
RStream.Write(buffer, 0, buffer.Length);
RStream.Close();

但是在 ftp 目的地复制的文件总是空的。为什么？

Answer 1

您没有使用文件的内容填充缓冲区。您只是在以下代码行中设置长度：

byte[] buffer = new byte[stream.Length];

而且您也没有在其他任何地方填充文件的内容，因此您只是将空数据发送到 FTP 服务器。字节可能有一定的长度，但都是空字节。

Answer 2

作为一个简单的解决方案，您可以使用WebClient类

WebClient client = new WebClient();
client.Credentials = new NetworkCredential("username", "password");
client.UploadFile(uriString,fileName);

Answer 3

您可以在写入字节时应用相同类型的逻辑，但在我的情况下，我传入了初始大小

public static void CopyStream(Stream input, Stream output)
{

    byte[] buffer = new byte[1024];

    int bytesRead;
    while ((bytesRead = input.Read(buffer, 0, buffer.Length)) > 0)
    {
        output.Write(buffer, 0, bytesRead);
    }
}

Answer 4

这应该有效：

WebRequest WRequest = WebRequest.Create(FtpPath + OriginalfileName);
WRequest.Method = WebRequestMethods.Ftp.UploadFile;
WRequest.Credentials = new NetworkCredential("myusername", "FtpPassword");
using (FileStream stream = File.OpenRead(OriginalFilePath)) {
  using (Stream RStream = WRequest.GetRequestStream()) {
    stream.CopyTo(RStream);
  }
}

Answer 5

这是asp.net core 2.1中使用IFormFile上传文件的解决方案

// Get the object used to communicate with the server.
                FtpWebRequest request = (FtpWebRequest)WebRequest.Create("*******/site/wwwroot/wwwroot/images/" + TempFileName);
                request.Method = WebRequestMethods.Ftp.UploadFile;
                request.UseBinary = true;
                request.KeepAlive = false;
                request.Method = "STOR";
                request.Credentials = new NetworkCredential("***", "****");

                // Copy the contents of the file to the request stream.
                byte[] fileContents = null;

                if (vehicle.FileUpload.Length > 0)
                {
                    using (var ms = new MemoryStream())
                    {
                        await vehicle.FileUpload.CopyToAsync(ms);
                        var fileBytes = ms.ToArray();
                        fileContents = fileBytes;
                    }
                }
                request.ContentLength = fileContents.Length;

                using (Stream requestStream = request.GetRequestStream())
                {
                    requestStream.Write(fileContents, 0, fileContents.Length);
                }

这是文件的视图模型

public class VehicleSeriesViewModel
    {
        public Guid VehicleBadgeId { get; set; }
        public Guid VehicleSeriesId { get; set; }
        public string Name { get; set; }
        public DateTime CreatedAt { get; set; }
        public DateTime? UpdatedAt { get; set; }
        public IFormFile FileUpload { get; set; }
        public string PictureUrl { get; set; }
    }