Publish an image from .NET to Facebook using the Graph API

Question

I am using the Facebooks Javascript API to develop an application that should be able to post an image to a user's wall. This part of the application should be server-side, as far as I can tell, since it should place image data as "multipart / form-data".

Note. This is not a simple version using "post", but the real "photos" method.

http://graph.facebook.com/me/photos

I think I have two problems: .NET and Facebook problem:

Problem with Facebook: I'm not quite sure that all parameters should be sent as multipart / form-data (including access_token and message). The only code sample uses the cUrl util / application utility.

.NET Problem: I have never produced multidisciplinary / form data requests from .NET, and I'm not sure if .NET automatically creates mime parts, or if I need to encode parameters in some special way.

It's a little tricky to debug, as the only error response I get from the Graph API is "400 is a bad request." Below is the code that looked when I decided to write this question (yes, this is a bit detailed :-)

The final answer, of course, would be a sample fragment sending an image from .NET, but I can count on less.

string username = null;
string password = null;
int timeout = 5000;
string requestCharset = "UTF-8";
string responseCharset = "UTF-8";
string parameters = "";
string responseContent = "";

string finishedUrl = "https://graph.facebook.com/me/photos";

parameters = "access_token=" + facebookAccessToken + "&message=This+is+an+image";
HttpWebRequest request = null;
request = (HttpWebRequest)WebRequest.Create(finishedUrl);
request.Method = "POST";
request.KeepAlive = false;
//application/x-www-form-urlencoded | multipart/form-data
request.ContentType = "multipart/form-data";
request.Timeout = timeout;
request.AllowAutoRedirect = false;
if (username != null && username != "" && password != null && password != "")
{
    request.PreAuthenticate = true;
    request.Credentials = new NetworkCredential(username, password).GetCredential(new Uri(finishedUrl), "Basic");
}
//write parameters to request body
Stream requestBodyStream = request.GetRequestStream();
Encoding requestParameterEncoding = Encoding.GetEncoding(requestCharset);
byte[] parametersForBody = requestParameterEncoding.GetBytes(parameters);
requestBodyStream.Write(parametersForBody, 0, parametersForBody.Length);
/*
This wont work
byte[] startParm = requestParameterEncoding.GetBytes("&source=");
requestBodyStream.Write(startParm, 0, startParm.Length);
byte[] fileBytes = File.ReadAllBytes(Server.MapPath("images/sample.jpg"));
requestBodyStream.Write( fileBytes, 0, fileBytes.Length );
*/
requestBodyStream.Close();

HttpWebResponse response = null;
Stream receiveStream = null;
StreamReader readStream = null;
Encoding responseEncoding = System.Text.Encoding.GetEncoding(responseCharset);
try 
{
    response = (HttpWebResponse) request.GetResponse();
    receiveStream = response.GetResponseStream();
    readStream = new StreamReader( receiveStream, responseEncoding );
    responseContent = readStream.ReadToEnd();
}
finally 
{
    if (receiveStream != null)
    {
        receiveStream.Close();
    }
    if (readStream != null)
    {
        readStream.Close();
    }
    if (response != null)
    {
        response.Close();
    }
}

Answer 1

. /me/photos :( . , . - "Wall ", URL == " graph.facebook.com/%wall-album-id%/photos", ( ).

{
    string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");
    uploadRequest = (HttpWebRequest)WebRequest.Create(@"https://graph.facebook.com/me/photos");
    uploadRequest.ServicePoint.Expect100Continue = false;
    uploadRequest.Method = "POST";
    uploadRequest.UserAgent = "Mozilla/4.0 (compatible; Windows NT)";
    uploadRequest.ContentType = "multipart/form-data; boundary=" + boundary;
    uploadRequest.KeepAlive = false;

    StringBuilder sb = new StringBuilder();

    string formdataTemplate = "--{0}\r\nContent-Disposition: form-data; name=\"{1}\"\r\n\r\n{2}\r\n";
    sb.AppendFormat(formdataTemplate, boundary, "access_token", PercentEncode(facebookAccessToken));
    sb.AppendFormat(formdataTemplate, boundary, "message", PercentEncode("This is an image"));

    string headerTemplate = "--{0}\r\nContent-Disposition: form-data; name=\"{1}\"; filename=\"{2}\"\r\nContent-Type: {3}\r\n\r\n";
    sb.AppendFormat(headerTemplate, boundary, "source", "file.png", @"application/octet-stream");

    string formString = sb.ToString();
    byte[] formBytes = Encoding.UTF8.GetBytes(formString);
    byte[] trailingBytes = Encoding.UTF8.GetBytes("\r\n--" + boundary + "--\r\n");

    long imageLength = imageMemoryStream.Length;
    long contentLength = formBytes.Length + imageLength + trailingBytes.Length;
    uploadRequest.ContentLength = contentLength;

    uploadRequest.AllowWriteStreamBuffering = false;
    Stream strm_out = uploadRequest.GetRequestStream();

    strm_out.Write(formBytes, 0, formBytes.Length);

    byte[] buffer = new Byte[checked((uint)Math.Min(4096, (int)imageLength))];
    int bytesRead = 0;
    int bytesTotal = 0;
    imageMemoryStream.Seek(0, SeekOrigin.Begin);
    while ((bytesRead = imageMemoryStream.Read(buffer, 0, buffer.Length)) != 0)
    {
        strm_out.Write(buffer, 0, bytesRead); bytesTotal += bytesRead;
        gui.OnUploadProgress(this, (int)(bytesTotal * 100 / imageLength));
    }

    strm_out.Write(trailingBytes, 0, trailingBytes.Length);

    strm_out.Close();

    HttpWebResponse wresp = uploadRequest.GetResponse() as HttpWebResponse;
}

Answer 2

@fitz. . , .

public string UploadPhoto(string album_id, string message, string filename, Byte[] bytes, string Token)
{
    // Create Boundary
    string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");

    // Create Path
    string Path = @"https://graph.facebook.com/";
    if (!String.IsNullOrEmpty(album_id))
    {
        Path += album_id + "/";
    }
    Path += "photos";

    // Create HttpWebRequest
    HttpWebRequest uploadRequest;
    uploadRequest = (HttpWebRequest)HttpWebRequest.Create(Path);
    uploadRequest.ServicePoint.Expect100Continue = false;
    uploadRequest.Method = "POST";
    uploadRequest.UserAgent = "Mozilla/4.0 (compatible; Windows NT)";
    uploadRequest.ContentType = "multipart/form-data; boundary=" + boundary;
    uploadRequest.KeepAlive = false;

    // New String Builder
    StringBuilder sb = new StringBuilder();

    // Add Form Data
    string formdataTemplate = "--{0}\r\nContent-Disposition: form-data; name=\"{1}\"\r\n\r\n{2}\r\n";

    // Access Token
    sb.AppendFormat(formdataTemplate, boundary, "access_token", HttpContext.Current.Server.UrlEncode(Token));

    // Message
    sb.AppendFormat(formdataTemplate, boundary, "message", message);

    // Header
    string headerTemplate = "--{0}\r\nContent-Disposition: form-data; name=\"{1}\"; filename=\"{2}\"\r\nContent-Type: {3}\r\n\r\n";
    sb.AppendFormat(headerTemplate, boundary, "source", filename, @"application/octet-stream");

    // File
    string formString = sb.ToString();
    byte[] formBytes = Encoding.UTF8.GetBytes(formString);
    byte[] trailingBytes = Encoding.UTF8.GetBytes("\r\n--" + boundary + "--\r\n");
    byte[] image;
    if (bytes == null)
    {
        image = File.ReadAllBytes(HttpContext.Current.Server.MapPath(filename));
    }
    else
    {
        image = bytes; 
    }

    // Memory Stream
    MemoryStream imageMemoryStream = new MemoryStream();
    imageMemoryStream.Write(image, 0, image.Length);

    // Set Content Length
    long imageLength = imageMemoryStream.Length;
    long contentLength = formBytes.Length + imageLength + trailingBytes.Length;
    uploadRequest.ContentLength = contentLength;

    // Get Request Stream
    uploadRequest.AllowWriteStreamBuffering = false;
    Stream strm_out = uploadRequest.GetRequestStream();

    // Write to Stream
    strm_out.Write(formBytes, 0, formBytes.Length);
    byte[] buffer = new Byte[checked((uint)Math.Min(4096, (int)imageLength))];
    int bytesRead = 0;
    int bytesTotal = 0;
    imageMemoryStream.Seek(0, SeekOrigin.Begin);
    while ((bytesRead = imageMemoryStream.Read(buffer, 0, buffer.Length)) != 0)
    {
        strm_out.Write(buffer, 0, bytesRead); bytesTotal += bytesRead;
    }
    strm_out.Write(trailingBytes, 0, trailingBytes.Length);

    // Close Stream
    strm_out.Close();

    // Get Web Response
    HttpWebResponse response = uploadRequest.GetResponse() as HttpWebResponse;

    // Create Stream Reader
    StreamReader reader = new StreamReader(response.GetResponseStream());

    // Return
    return reader.ReadToEnd();
}

Answer 3

multipart/form-data, . , . Facebook Graph Toolkit http://computerbeacon.net/. 0.8 , "- facebook wall", .

Answer 4

, RestSharp:

// url example: https://graph.facebook.com/you/photos?access_token=YOUR_TOKEN
request.AddFile("source", imageAsByteArray, openFileDialog1.SafeFileName, getMimeType(Path.GetExtension(openFileDialog1.FileName)));
request.addParameter("message", "your photos text here");

API API

-

Note. I was missing an empty line since the mime and facebook types were smart enough to figure this out.

Answer 5

Perhaps useful

        [TestMethod]
        [DeploymentItem(@".\resources\velas_navidad.gif", @".\")]
        public void Post_to_photos()
        {
            var ImagePath = "velas_navidad.gif";
            Assert.IsTrue(File.Exists(ImagePath));

            var client = new FacebookClient(AccessToken);
            dynamic parameters = new ExpandoObject();

            parameters.message = "Picture_Caption";
            parameters.subject = "test 7979";
            parameters.source = new FacebookMediaObject
{
    ContentType = "image/gif",
    FileName = Path.GetFileName(ImagePath)
}.SetValue(File.ReadAllBytes(ImagePath));

            //// Post the image/picture to User wall
            dynamic result = client.Post("me/photos", parameters);
            //// Post the image/picture to the Page Wall Photo album
            //fb.Post("/368396933231381/", parameters); //368396933231381 is Album id for that page.

            Thread.Sleep(15000);
            client.Delete(result.id);
        }

Link: Query Execution