How do I receive a file sent from WebClient.UploadFile()?

Question

Since this simplistic test worked (passing a string in the body):

Server code:

public string PostArgsAndFile([FromBody] string value, string serialNum, string siteNum)
{
    string s = string.Format("{0}-{1}-{2}", value, serialNum, siteNum);
    return s;
}

Client code:

private void ProcessRESTPostFileData(string uri)
{
    using (var client = new WebClient())
    {
        client.Headers[HttpRequestHeader.ContentType] = "application/x-www-form-urlencoded";
        var data = "=Short test...";
        var result = client.UploadString(uri, "POST", data);
        MessageBox.Show(result);
    }
}

...I then tried to take it a step further (toward what I really need to do - send a file, not a string); I changed the server code to this:

public string PostArgsAndFile([FromBody] byte[] value, string serialNum, string siteNum)
{
    byte[] bite = value;
    string s = string.Format("{0}{1}{2}", value.ToString(), serialNum, siteNum);
    return s;
}

...and the client code to this:

using (var client = new WebClient())
{
    client.Headers[HttpRequestHeader.ContentType] = "application/x-www-form-urlencoded";
    var result = client.UploadFile(uri, @"C:\MiscInWindows7\SampleXLS.csv");
}

...but that dies at runtime with:

System.Net.WebException was unhandled HResult=-2146233079 Message=The remote server returned an error: (415) Unsupported Media Type.

So how can I receive a file uploaded this way? What media type do I need, and how do I specify it?

UPDATE

As I need to ultimately send a file, or at least the contents of a file, I found this SO Question/Answer and changed my code to be:

using (var client = new WebClient())
{
    client.Headers[HttpRequestHeader.ContentType] = "application/x-www-form-urlencoded";
    StringBuilder sb = new StringBuilder();
    using (StreamReader sr = new StreamReader(@"C:\MiscInWindows7\SampleXLS.csv"))
    {
        String line;
        while ((line = sr.ReadLine()) != null)
        {
            sb.AppendLine(line);
        }
    }
    string allLines = sb.ToString();
    byte[] byteData = UTF8Encoding.UTF8.GetBytes(allLines);
    byte[] responseArray = client.UploadData(uri, byteData);

    // Decode and display the response.
    MessageBox.Show("\nResponse Received.The contents of the file uploaded are:\n{0}",
        System.Text.Encoding.ASCII.GetString(responseArray));
}

...and although that shows me that byteData is correctly assigned to, nothing seems to be going to the server - the server's "value" property:

public void PostArgsAndFile([FromBody] byte[] value, string serialNum, string siteNum)

...is just an empty byte array when the method is called.

I tried removing the [FromBody], to no avail (no change), and changing it to [FromUri] (which I didn't think would work, but tried it on a lark) caused it to crash with a WebException.

So how do I get the server to accept/recognize/receive the byte array?

score 0 · Accepted Answer · answered Feb 26 '14 at 19:34

This works:

It's not passing a file per se, or literally, but it is passing the file's contents, and that's good enough for me. If the client has to create an xml file, it will just have to serialize that file into a string before sending it, like so:

CLIENT

private void button1_Click(object sender, EventArgs e)
{
    ProcessRESTPostXMLFileAsStr("http://Platypus:28642/api/Platypi/PostArgsAndXMLFileAsStr?serialNum=192837465&siteNum=42");
}

private void ProcessRESTPostXMLFileAsStr(string uri)
{
    using (var client = new WebClient())
    {
        client.Headers[HttpRequestHeader.ContentType] = "application/x-www-form-urlencoded";
        StringBuilder sb = new StringBuilder();
        using (StreamReader sr = new StreamReader(@"C:\Platypus\eXtraneousMothLepidoptera.XML"))
        {
            String line;
            while ((line = sr.ReadLine()) != null)
            {
                sb.AppendLine(line);
            }
        }
        // I don't know why the prepended equals sign is necessary, but it is
        string allLines = "=" + sb.ToString();
        var result = client.UploadString(uri, "POST", allLines);
        MessageBox.Show(result);
    }            
}

SERVER (Web API app)

[Route("api/Platypi/PostArgsAndXMLFileAsStr")]
public void PostArgsAndXMLFileAsStr([FromBody] string stringifiedXML, string serialNum, string siteNum)
{
    string s = string.Format("{0}{1}{2}", stringifiedXML, serialNum, siteNum);
    // Parsing the contents of the stringified XML left as an exercise to the exorcist
}

How do I receive a file sent from WebClient.UploadFile()?

UPDATE

1 Answers1