Question

please provide me a simple piece of code in c# to post photo on facebook without using the very famous facebook sdk for c#, as per my knowledge there are two methods of posting photos,

METHOD 1:

The fb documentation below shows a method to post image with the url provided,

https://developers.facebook.com/blog/post/526/?ref=nf

of course I tried, it does not seem to accept my image url, when I tried debugging here on facebook API explorer using the post method and entered the parameters as below,

SomeAlbumID/photos?=access_token=MyTOKEN&url=http%3a%2f%2fcutree.com%2fcutreefbapp%2fimg1.bmp&message=Family+Tree

It returns an exception saying

{
  "error": {
    "message": "http\u00253a\u00252f\u00252fcutree.com\u00252fcutreefbapp\u00252fimg1.bmp is an internal url, but this is an external request.", 
    "type": "CurlUrlInvalidException"
  }
}

“internal url, but this is an external request.” I am not sure what this means as I am using the same domain as registered on my fbapp, and also giving the request from the server itself.

I have read some where that fb accepts images from only a few servers, can anyone help me out.

METHOD 2:

This is a method where image data in bytes are atttached with the Post body as fb says “To publish a photo, issue a POST request with the photo file attachment as multipart/form-data.”

However everyone does that using the fb sdk for c#, can anyone provide simple http post method for this issue.

I have tried streaming image data using a method below

public MyFacebookClass FBPost(string URI, string Parameters)
{
    System.Net.WebRequest req = System.Net.WebRequest.Create("https://graph.facebook.com/" + URI);
    req.ContentType = "application/x-www-form-urlencoded";
    req.Method = "POST";
    byte[] bytes = BmpToBytes_Serialization(new Bitmap("C:\\Users\\atul\\cutreefbapp\\DefaultThumb.bmp"));
    req.ContentLength = bytes.Length;
    System.IO.Stream os = req.GetRequestStream();
    os.Write(bytes, 0, bytes.Length); 
    os.Close();
    System.Net.WebResponse resp = req.GetResponse();
    if (resp == null) return null;
    System.IO.StreamReader sr = new System.IO.StreamReader(resp.GetResponseStream());
    return new System.Web.Script.Serialization.JavaScriptSerializer().Deserialize<MyFacebookClass>(sr.ReadToEnd().Trim());

}

Answer 1

The problem you have is your code isn’t correct. In order to post a photo to Facebook you’ll need to use a multi-part form data post. I haven’t used the C# SDK, but I’m sure it builds a multi-part form post internally before submitting the image.

You will have to do something similar to what is posted here. I was about to post my code that does this exactly for Facebook from my app, but it is a bit long.