Facebook OAuth + AppHarbor workaround on random port

Question

I a have a sample app, hosted on AppHarbor and now want to integrate authorization through facebook. So i downloaded nugget Facebook.Web.Mvc package to implement it.

After reading tutorial, in controller i have method:

 public ActionResult Login(string returnUrl)
    {
        var oauthClient = new FacebookOAuthClient(FacebookApplication.Current) { RedirectUri = GetFacebookRedirectUri() };


        if (!string.IsNullOrWhiteSpace(returnUrl))
        {
            returnUrl = Url.Action("Index", "Facebook");
        }

        dynamic parameters = new ExpandoObject();
        parameters.scope = ExtendedPermissions;

        var state = new { csrf_token = CalculateMD5Hash(Guid.NewGuid().ToString()), return_url = returnUrl };
        parameters.state = Base64UrlEncode(Encoding.UTF8.GetBytes(JsonSerializer.Current.SerializeObject(state)));
        SetFacebookCsrfToken(state.csrf_token);

        string s = oauthClient.GetLoginUrl(parameters).AbsoluteUri;

        ViewBag.FacebookLoginUrl = s;
        //new LogEvent(s).Raise();

        return View(new AccountModel());
    }

View:

<a href="@ViewBag.FacebookLoginUrl" id="lUrl">
<div class="fblogin"></div>

In localhost this works for me. But when i upload it to appharbor, i see, that generated link indicates to address + port 16013 (as support told always random port). So clicking it shows me facebook login window, than blank page.

I manually configured my app settings in facebook to this port but it did not helped.

Also i tried to access my site through this port - nothing.

Then i changed port number through jquery to 80, its also did not help.

you have had such problems?

Answer 1

I'm not familiar with the Facebook api, but I've had a similar problem. I suspect that the returnUrl value being passed in is incorrect. It probably contains a port number that AppHarbor uses internally for load balancing.

See this article on how to create a public url for AppHarbor: http://support.appharbor.com/kb/getting-started/workaround-for-generating-absolute-urls-without-port-number

Then make sure that the value in your returnUrl is publicly available.

Answer 2

You can now set the aspnet:UseHostHeaderForRequestUrl appSetting to true which effectively solves this problem. This can be done by adding a Configuration Variable to your application with the corresponding key and value.

Source on AppHarbor