Facebook Photo Upload in C#? - silverlight

Question

I am trying to upload an photo to Facebook from a Windows Phone Silverlight application using the Facebook Graph API but I am getting an error: (#324) Requires upload file. Can anyone see anything wrong in my code?
internal void PublishPhoto(System.IO.MemoryStream stream, string message, string accessToken)
{
var requestUriString = string.Format(
CultureInfo.InvariantCulture,
"https://graph.facebook.com/{0}/photos?access_token={1}&message={2}",
"me",
accessToken,
message);
var webRequest = WebRequest.CreateHttp(requestUriString);
webRequest.Method = "POST";
var boundary = "7db3d9202a1";
webRequest.ContentType = string.Format("multipart/form-data; boundary={0}", boundary);
webRequest.BeginGetRequestStream(new AsyncCallback(delegate (IAsyncResult result)
{
GetRequestStream(stream, boundary, result);
BeginGetResponse(webRequest);
}), webRequest);
}
private static void GetRequestStream(System.IO.MemoryStream imageStream, string boundary, IAsyncResult result)
{
var webRequest2 = result.AsyncState as HttpWebRequest;
using (var requestStream = webRequest2.EndGetRequestStream(result))
{
using (StreamWriter writer = new StreamWriter(requestStream))
{
writer.WriteLine("--{0}\r", boundary);
writer.WriteLine("Content-Disposition: form-data; filename=\"sketch.jpg\"\r");
writer.WriteLine("Content-Type: image/jpg\r");
byte[] buffer = imageStream.GetBuffer();
requestStream.Write(buffer, 0, buffer.Length);
writer.WriteLine("\r");
writer.WriteLine("--{0}--\r", boundary);
}
imageStream.Close();
}
}
private static void BeginGetResponse(HttpWebRequest webRequest)
{
webRequest.BeginGetResponse(new AsyncCallback(delegate(IAsyncResult result2)
{
var webRequest2 = result2.AsyncState as HttpWebRequest;
try
{
using (var response = webRequest2.EndGetResponse(result2))
{
using (var responseStream = response.GetResponseStream())
{
using (StreamReader reader = new StreamReader(responseStream))
{
System.Diagnostics.Debug.WriteLine(reader.ReadToEnd());
}
}
}
}
catch (WebException we)
{
System.Diagnostics.Debug.WriteLine(we.Message);
using (var responseStream = we.Response.GetResponseStream())
{
using (StreamReader reader = new StreamReader(responseStream))
{
var errorJson = reader.ReadToEnd();
var response = Newtonsoft.Json.JsonConvert.DeserializeObject<FacebookErrorResponse>(errorJson);
System.Diagnostics.Debug.WriteLine("Could not upload image to Facebook: {0}", response.Error.Message);
}
}
}
}), webRequest);
}
}

Answer 1

Try specifying a name of "source" as well as a filename in the Content-Disposition header, i.e.
writer.WriteLine("Content-Disposition: form-data; name=\"source\"; filename=\"sketch.jpg\"\r");

Answer 2

Ok, I was wrong the first time around, but now I have it.
The first problem, which we already took care of above, was that you were missing the "--" before each boundary and the "--" after the last boundary in the POST body.
The second problem is that you're not leaving a blank line after the MIME headers before writing the image content.
The third problem is that you're not flushing the writer before writing the image data to its underlying stream (unless silverlight on a phone is different from normal .NET in auto-flushing StreamWriters).
To sum up, this should work:
writer.WriteLine("--{0}\r", boundary);
writer.WriteLine("Content-Disposition: form-data; filename=\"sketch.jpg\"\r");
writer.WriteLine("Content-Type: image/jpg\r");
writer.WriteLine("\r");
writer.Flush();
byte[] buffer = imageStream.GetBuffer();
requestStream.Write(buffer, 0, buffer.Length);
writer.WriteLine("\r");
writer.WriteLine("--{0}--\r", boundary);