Upload file uploaded via HTTP to ASP.NET further to FTP server in C#

问题

Upload form:

<form asp-action="Upload" asp-controller="Uploads" enctype="multipart/form-data">
<input type="file" name="file" maxlength="64" />
<button type="submit">Upload</button>

Controller/File upload:

public void Upload(IFormFile file){
    using (WebClient client = new WebClient())
    {
        client.Credentials = new NetworkCredential("xxxx", "xxxx");
        client.UploadFile("ftp://xxxx.xxxx.net.uk/web/wwwroot/images/", "STOR", file.FileName);
    }
}

Problem:

Getting error "Could not find file xxxx". I understand the issue is that it's trying to find the file as it is "C:\path-to-vs-files\examplePhoto.jpg" on the FTP server, which obviously doesn't exist. I've been looking at many questions/answers on here and I think I need some kind of FileStream read/write cod. But I'm not fully understanding the process at the moment.

回答1:

Use IFormFile.CopyTo or IFormFile.OpenReadStream to access the contents of the uploaded file.

Though WebClient cannot work with Stream interface. So you better use FtpWebRequest:

public void Upload(IFormFile file)
{
    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 ftpStream = request.GetRequestStream())
    {
        file.CopyTo(ftpStream);
    }
}

来源：https://stackoverflow.com/questions/55499008/upload-file-uploaded-via-http-to-asp-net-further-to-ftp-server-in-c-sharp