Question

I’m developping a Facebook Application (using ASP.NET C# and Nathan Totten’s Facebook C# SDK) and trying to access to extended permissions.
I tried on localhost (with an existing app in facebook), and everybody works. But when I try to use it directly in facebook, I obtain a blank page (i’m still connected on facebook).

Here is my code :

Page/aspx :

protected void btn_ask_question_Click(object sender, EventArgs e)
    {
        if (ControllerAccess.testUserConnected())
        {
            if (txt_ask_question.InnerText != "")
            {
                Dictionary<string, object> action = new Dictionary<string,object>();
                action.Add("action", "askQuestion");
                action.Add("message", txt_ask_question.InnerText);
                action.Add("idTheme", ddl_choose_question_category.SelectedValue);
                HttpContext.Current.Session["ActionToDo"] = action;
                String s = Controller.GetExtendedPermission2(this, ControllerAccess.getScopeByAction("askQuestion"));
                try{
                    Response.Redirect(s, false);
                } catch(Exception ex)
                {
                }
            }
        }
    }

In my Page_Load() :

if (HttpContext.Current.Session["ActionToDo"] != null)
            {
                Dictionary<string, object> action = HttpContext.Current.Session["ActionToDo"] as Dictionary<string, object>;
                String s = action["action"].ToString();
                switch (s)
                {
                    case "askQuestion":
                        Guid idTheme;
                        Boolean themeExists =  Guid.TryParse(action["idTheme"].ToString(), out idTheme);
                        if(themeExists)
                        {
                            askQuestion(action["message"].ToString(), idTheme);
                            lbl_errors.Text = "Votre question a bien été posée";
                        }
                        break;
                    default:
                        break;
                }
                HttpContext.Current.Session["ActionToDo"] = null;
            }

In Control.cs :

    public static string GetCustomOAuthDialogParameters(string AppID, string RedirectURI, string Scope, string State)
    {
        string CustomParameters = "?client_id=" + AppID + "&redirect_uri=" + RedirectURI + "&scope=" + Scope + "&state=" + State;
        return CustomParameters;
    }

    public static void GetExtendedPermission(Page page, String scope)
    {

        ecritureFichier("GetExtendedPermission");
        Label lbl_errors = page.Form.FindControl("lbl_errors") as Label;
        string OAuthDialogAbsoluteURL = "";
        try
        {
            string OAuthDialogURL = "https://www.facebook.com/dialog/oauth";
            string PageLocation = GetCurrentPageFacebookPublishedPath(page.Request); //The redirect page (eg: https://apps.facebook.com/democsharpsdk/TestsExtendedPermission.aspx)
            string UniqueReferenceCode = Guid.NewGuid().ToString();

            OAuthDialogAbsoluteURL = OAuthDialogURL + GetCustomOAuthDialogParameters(AppID, PageLocation, scope, UniqueReferenceCode);
            page.Response.Redirect(OAuthDialogAbsoluteURL, false);
        }
        catch (Exception exp)
        {
            lbl_errors.Text += "Erreur Catchée via ASP.NET : " + exp.Message;
        }
    }

The blank page appears when I use this line : page.Response.Redirect(OAuthDialogAbsoluteURL, false);

But I log all my steps and my OAuthDialogAbsoluteURL is correct :

https://www.facebook.com/dialog/oauth?client_id=XXXXXXXXXXXXXXXXX&redirect_uri=https://apps.facebook.com/name_of_my_app&scope=email&state=0443030f-dddd-4fe6-9d6c-9454409d01b3

When I type it into the adress bar manually, everything works correctly.

Do you have any idea about the difference between local version and published version or why the redirect doesn’t work? Maybe facebook block some requests?

Thanks.

Answer 1

I finally resolved my problem usingChrome Debugger. The error was :

Refused to display document because display forbidden by X-Frame-Options

I used Javascript to fix it, and did my redirection like this :

Response.Write("<script>");
Response.Write("window.open('"+redirect+"','_top')");
Response.Write("</script>");

Hope it’ll help some people.