Question

I’m trying to make a server-side login process with facebook in my C# MVC application.

At the moment of submiting an status update in my app it has to publish it on facebook, I make a redirect to:

https://www.facebook.com/dialog/oauth?client_id={0}&scope={1}&redirect_uri={2}

Using this Method:

Response.Redirect(...);

where my redirect uri is encoded like this:

HttpUtility.UrlEnconde("http://local.mydomain.com/getAuthToken?message=the original message");

And back into my MVC app (after accepting the fb permissions) the getAuthToken action makes a request to the URI:

 https://graph.facebook.com/oauth/access_token?client_id={0}&client_secret={1}&code={2}&redirect_uri={3}

Using this Method:

 using (var wc = new WebClient()){
      wc.DownloadString(...)
 }

where my redirect uri again is encoded like this:

 HttpUtility.UrlEnconde("http://local.mydomain.com/getAuthToken?message=the original message");

if “the original message” contains no spaces it works but when I start adding spaces and other special characters I get an OAuth Exception:

Error validating verification code

So my question is, what kind of URL Enconding should I have to use to make it work

I Found something here but I’m getting the same error, I dont know if I need a special method to make the redirects or if I need diferent Encodings for this two request.

Answer 1

To solve this I used this to encode:

static public string EncodeTo64(string toEncode)
  {
     byte[] toEncodeAsBytes
           = Encoding.ASCII.GetBytes(toEncode);
     string returnValue
           = Convert.ToBase64String(toEncodeAsBytes);
     return returnValue;
  }

and this to decode

  static public string DecodeFrom64(string encodedData)
  {
     byte[] encodedDataAsBytes
         = Convert.FromBase64String(encodedData);
     string returnValue =
        Encoding.ASCII.GetString(encodedDataAsBytes);
     return returnValue;
  }

In case someone needs it
Thaks