Question

On my site I allow users to authenticate via creating an account with my site or using their Facebook account. In the case they choose to log in with my site account rather than FB, on one page within my site I allow them to search for friends using the friend list from their FB account. So at the point they choose to search for friends that also have accounts with my site, I have to authenticate them at that point so I make the call to present the FB login page. I am using the Facebook SDK to do this. No problems to this point…

string[] extendedPermissions = FacebookApp.ExtendedPermissions.Split(',');

        FacebookOAuthClient oauth = new FacebookOAuthClient { ClientId = FacebookApp.AppId };

        var parameters = new Dictionary<string, object>
                {
                    { "response_type", responseType },
                    { "display", display },
                    { "state",  state},
                    { "redirect_uri", FacebookApp.RedirectUri + redirectUriPage}
                };

        if (extendedPermissions != null && extendedPermissions.Length > 0)
        {
            var scope = new StringBuilder();
            scope.Append(string.Join(",", extendedPermissions));
            parameters["scope"] = scope.ToString();
        }

        Uri loginUrl = oauth.GetLoginUrl(parameters);

        return loginUrl;

In my app settings on Facebook I have specified the Site URL as: [http://www.]suchandsuch.com/Subdir/. Facebook states that they will only redirect to this URL. When I make the call to authenticate the person, I pass in a redirect_uri parameter as seen above because instead of [http://www.]suchandsuch.com/Subdir/ I want to redirect to http://www.suchandsuch.com/Subdir/subpage.aspx. The redirect works but when I check Response.QueryString it is empty however when I look at the address bar on the browser, all the parameters are there on the querystring. I assume that FB will redirect to any page underneath the url specified on the Apps page. Am I missing something or is it true that FB will only redirect to the exact url specified?

PS ignore the [] around the urls, SO wouldn’t let me post that many links in my question. 🙂

Answer 1

Apparently, FB will only redirect to that exact URL with the parmeters.