Post file from one MVC3 action to another site

Question

This might sound crazy, but I have an MVC3 action (server-side code) that needs to post a file to another web site. I have control over both sites, but the second site never receives the posted file data. I use WebRequest to successfully request a file from the remote site, so I figured I could post the file data using this approach:

private WebRequest _SetupCopyToRequest(string source, string expectedDestination)
{
    var request = HttpWebRequest.Create(_Settings.CopyToServerUrl);
    var info = new FileInfo(source);
    request.Method = "POST";
    request.ContentLength = info.Length;
    request.ContentType = "multipart/form-data";
    var dispositionValue = String.Format("form-data; name=\"file\"; filename=\"{0}\"", expectedDestination);
    request.Headers.Set("Content-Disposition", dispositionValue);
    using (var destStream = request.GetRequestStream())
    {
        using (var sourceStream = info.OpenRead())
        {
            var length = (int) info.Length;
            var buffer = new byte[info.Length];
            sourceStream.Read(buffer, 0, length);
            destStream.Write(buffer, 0, length);
        }
    }
    return request;
}

My problem is that the action on the receiving site receives the request as soon I call request.GetRequestStream() on the first site, and Request.Files is empty on the second site. Here is the code for the receiving action on the second site:

[HttpPost]                                                           
public ActionResult CopyToServer()
{
    if (Request.Files.Count == 0 || Request.Files[0].ContentLength == 0)
        return new ContentResult();

    var file = Request.Files[0];
    var fileName = Path.GetFileName(file.FileName);
    var directory = Path.GetDirectoryName(file.FileName);
    var uniqueFileName = CeoPath.GetUniqueFileName(directory, fileName);
    var path = Path.Combine(directory, uniqueFileName);
    file.SaveAs(path);
    return new ContentResult {Content = path};
}

So how do I get my file data from the first site's server posted to the second site's server?

score 2 · Answer 1 · answered Aug 24 '11 at 16:49

2

You need to use multipart/form-data encoding for uploading files. For a single file upload you could use the UploadFile method or I have blogged about a technique allowing you to upload multiple files.

answered Aug 24 '11 at 16:49

Darin Dimitrov

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score 1 · Answer 2 · answered Aug 24 '11 at 16:41

1

My guess is that your content-type is messing things up - you're declaring that you're sending multipart form-data, but I don't see where you do proper multipart encoding:

http://www.w3.org/TR/html4/interact/forms.html#h-17.13.4.2

answered Aug 24 '11 at 16:41

Antoine Latter

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score 0 · Accepted Answer · edited May 23 '17 at 11:47

Found my answer by searching SO for HttpWebRequest and came across this one on Upload files with HttpWebRequest (multipart/form-data). Especially the link to Upload files using an RFC 1867 POST request with HttpWebRequest/WebClient. So I just replaced my first method with the following working code:

public string CopyToServer(string source, string expectedDestination)
{
    var file = new UploadFile(source, "file", null);
    var form = new NameValueCollection();
    form["expectedFileName"] = expectedDestination;
    var request = (HttpWebRequest) WebRequest.Create(_Settings.CopyToServerUrl);
    var response = HttpUploadHelper.Upload(request, new[] {file}, form);
    using (var s = response.GetResponseStream())
    {
        using (var sr = new StreamReader(s))
        {
            return sr.ReadToEnd();
        }
    }
}

Hurrah!

Post file from one MVC3 action to another site

3 Answers3